The 50

[cotswold]

Just got back from a practice day at the track, the 50 performed faultlessly and I'm pretty pleased with the way it went. The new pit bike shock worked beautifully but my front brake still feels a little wooden,
( can't get the RS125 front end in fast enough )
The gearing is a bit out but not too bad.
I had one huge front end slide that should have seen me picking bits of bike off the track but the bike is so low it just seemed to sort itself out, made me feel like Valentino :lol:
Looking forward to tomorrow and race day.

[cotswold]

I had one huge front end slide that should have seen me picking bits of bike off the track but the bike is so low it just seemed to sort itself out, made me feel like Valentino :lol:
Looking forward to tomorrow and race day.[/QUOTE]

Well Vale crashed in the 2nd points race re-mounted and finished behind his Nemesis (fast Fred) :facepalm:

We need more entrants in Auckland F5 as the turn out was rubbish yesterday, if it were not for team ESE bringing a spare it would have been pitiful.

Pro's for building an F5 bike

You can chuck an XL/XR/CB100 in a discarded FXR chassis and you have a very reliable bike that will not get you into trouble on the corners
You will be racing against riders who have been at it for years and wont take you out fighting over 17th position
The pace of a good F5 bike with a very good rider on board is not much slower than the same very good rider on his good F4 bike so saying they are too slow is bollox (29s on a 50cc fark)
You can buy an RS50 and build a very competitive bike for not much money ( A grade Tim very nearly took out the GP this year on one )
You can do what I did and buy an ancient Honda MTXR 50 and follow simple instructions and get 14 hp at the wheel
F5 riders are way cooler than F4 riders thus more attractive to the opposite sex
For 2T fans the bikes sound bloody awesome as they rev around 14-15K
They don't use much gas
For the trophy hunters out there you have a much better chance of getting one in F5 as apart from Nathaniel the rest of us are fairly mature

Cons

sorry cant think of any

[Henk]

Cons

Riding three classes is a killer.

You missed a couple of pros though

Riding F5 bikes at the slower end of the spectrum teaches you a lot about holding corner speed. On an FXR framed XR100 you should be holding the throttle wide from turn one to the horseshoe, then when you accidently hold it flat through the chicane on an F4 bike you work out that it can be done.

Run F4 and F5 and you get twice the track time for the same entry fee.

F5 bikes are way less physical to ride than F4 so you don't get as tired if you are a little unfit.

F5 bikes are huge fun.

[F5 Dave]

What I've been telling people for years, or my name isn't F5 Dave.





(Actually it isn't really, its just a made up internet name)

[Henk]

What I've been telling people for years, or my name isn't F5 Dave.





(Actually it isn't really, its just a made up internet name)

Change it by deed poll

[F5 Dave]

Well I tried. I guess I shouldn't have turned up to the registry office drunk and the ugly fat woman in the moomoo (sure needed to know) changed it to ; mylittlepony.

When I can scratch the $53 dollars up I'll change it back.
To Julian Bakdor. A proud name.

[Buttman18]

I had one huge front end slide that should have seen me picking bits of bike off the track but the bike is so low it just seemed to sort itself out, made me feel like Valentino :lol:
Looking forward to tomorrow and race day.

Well Vale crashed in the 2nd points race re-mounted and finished behind his Nemesis (fast Fred) :facepalm:

We need more entrants in Auckland F5 as the turn out was rubbish yesterday, if it were not for team ESE bringing a spare it would have been pitiful.

Pro's for building an F5 bike

You can chuck an XL/XR/CB100 in a discarded FXR chassis and you have a very reliable bike that will not get you into trouble on the corners
You will be racing against riders who have been at it for years and wont take you out fighting over 17th position
The pace of a good F5 bike with a very good rider on board is not much slower than the same very good rider on his good F4 bike so saying they are too slow is bollox (29s on a 50cc fark)
You can buy an RS50 and build a very competitive bike for not much money ( A grade Tim very nearly took out the GP this year on one )
You can do what I did and buy an ancient Honda MTXR 50 and follow simple instructions and get 14 hp at the wheel
F5 riders are way cooler than F4 riders thus more attractive to the opposite sex
For 2T fans the bikes sound bloody awesome as they rev around 14-15K
They don't use much gas
For the trophy hunters out there you have a much better chance of getting one in F5 as apart from Nathaniel the rest of us are fairly mature

Cons

sorry cant think of any[/QUOTE]


Ill be back in Jan with my little RG50, i'm stuck in Dubai until Christmas

[F5 Dave]

Now there's a man with a disturbing screen name.

[cotswold]

Ill be back in Jan with my little RG50, i'm stuck in Dubai until Christmas[/QUOTE]

Rob and Culley have been working on their RG50's they have them going pretty well, it will be good to get more out there

[Yow Ling]

Well Vale crashed in the 2nd points race re-mounted and finished behind his Nemesis (fast Fred) :facepalm:



So why was everyone so wound up about the new rules when nobody bothers to follow them ?

[Bert]

So why was everyone so wound up about the new rules when nobody bothers to follow them ?
:clap::clap::clap::killingme:killingme:killingme:c lap::clap::clap:

Knee jerk reaction or response to the events of the GP maybe????

[F5 Dave]

We should make the rule that you have to crash at least once in any long race and practice how to get it done and back on losing the least time and not damaging anything.

[TALLIS]

there will be two more 50's campaigning within the next few months from the gpr stable! things are heating up!

[mr bucketracer]

there will be two more 50's campaigning within the next few months from the gpr stable! things are heating up!hell yer , pops another drink down

[TALLIS]

hell yer , pops another drink down

it will be like the gp125 of 1995, only 50cc!

[cotswold]

:clap::clap::clap::killingme:killingme:killingme:c lap::clap::clap:

Knee jerk reaction or response to the events of the GP maybe????

Umm my bars never touched the ground so there
:no:

[cotswold]

it will be like the gp125 of 1995, only 50cc!

Number 21 may be in the mix and #4 will be 18bhp by then, TZee is still fettling away so it could be a fantastic GP with nothing but 2T's buzzing around 14-15k, Mr Fast Ford senior is looking keen on the F5 bikes and we all know he pushes on, he knocked 3 seconds off from race 1 to race 2 by tweaking the carb on Fast Freds spare bike, could be a contender.
Ken needs to get his clutch fixed and F5 Dave should have his mojo back by then, GPR get those bikes ready and make sure the cooling works this time and maybe someone can give Nathaniel a run for his money.
I should invite the European free tech boys although their rules are a bit more relaxed re after market bits, would be nice to see the Jawa's and Conti's mixing it up with the fast Derbi's though.

[cotswold]

Chris Altys Jawa
Matijn Wobbens Derbi
Daz Courtny Eatons Spondon

[cotswold]

Here is my new motor, it came in a bucket so must be ok

[cotswold]

https://www.youtube.com/watch?v=YHKZ8IXEnRU


The NSR going ok

[TZ350]

Sounds Great.

[andrew a]

That dose sound very good.

[cotswold]

I am having some work done on my fancy new head and as there are no points rounds for a while this is the perfect time to do it.
Roger supplied the head for me for which I am very grateful as VHM no longer make them.
The piston looks good after 2 rounds of racing and the bore looks as good now as before use.

[F5 Dave]

So that's a blank insert. Or are you building the hell high compression engine?

[richban]

I am having some work done on my fancy new head and as there are no points rounds for a while this is the perfect time to do it.
Roger supplied the head for me for which I am very grateful as VHM no longer make them.
The piston looks good after 2 rounds of racing and the bore looks as good now as before use.


I saw the pics on facebook. Is that piston a dome top? Looks that way. I think the toroidal design was best for a flat top piston and the RSA style, steep wall bathtub good for the dome style piston. We run the later on the 300's and they seam to work well. Also you must be able to run a really tight squish on the 50. I would be going for .6. Should say will be going for .6 I have joined the 50 arms race and hope to have mine flying for the F5 gp. RS50 that is.

[cotswold]

I saw the pics on facebook. Is that piston a dome top? Looks that way. I think the toroidal design was best for a flat top piston and the RSA style, steep wall bathtub good for the dome style piston. We run the later on the 300's and they seam to work well. Also you must be able to run a really tight squish on the 50. I would be going for .6. Should say will be going for .6 I have joined the 50 arms race and hope to have mine flying for the F5 gp. RS50 that is.

Rich we had .54 squish
Thanks for the info on head shape as I was going toroidal but a European mate and now you have said bath type, I'll stick a photo of his when I get home
Pleased you are putting a 50 together be great to see a grid full at the GP
YOu should leave the motor stock 👍🏻

[F5 Dave]

Good on ya Rich, pity the grids fill as I'm out. But I have a plan for a rider.

0.5 no trouble. Used to reuse base (2) gaskets. Too many times and you'd hear tikitatikitatikita as it closed up a tickle more.

[cotswold]

Here are 2 that were given to me by FB friends one being Roffe Heljefors and he should know as he makes these with a 10mm plug

[cotswold]

Other. Photo .......,,,,

[Bert]

Other. Photo .......,,,,

Very Yamahish... :2thumbsup

[Henk]

Good on ya Rich, pity the grids fill as I'm out. But I have a plan for a rider.

0.5 no trouble. Used to reuse base (2) gaskets. Too many times and you'd hear tikitatikitatikita as it closed up a tickle more.

If plan A falls through, I'll ride your bike, only chance I would have of taking it to Malcolm.

Anyone else planing on trying to collect the whole set? I know the hillbillies are building sidecars.

[cotswold]

Jan Theil posted this a while back and I forgot to note down which bike it was for, as Frits has his name all over it he may feel inclined to say ?

[husaberg]

Jan Theil posted this a while back and I forgot to note down which bike it was for, as Frits has his name all over it he may feel inclined to say ?

This is another one they did
It might help to leave a trail of breadcrumbs
316895316896
Frits posted the pipe dimensions of the most winningest 50 in Europe as well a while back

316900

Plus one of Wobs from memory for I know not what
316901

[cotswold]

This is another one they did
It might help to leave a trail of breadcrumbs
316895316896
Frits posted the pipe dimensions of the most winningest 50 in Europe as well a while back

316900

Plus one of Wobs from memory for I know not what
316901

So as mine is pretty much square if one were to use an appropriate bit o maths could one use this as his template?

[husaberg]

So as mine is pretty much square if one were to use an appropriate bit o maths could one use this as his template?

That would be a question I would ask the resident physicist he would I think welcome a non Ryger not really Aprilia question I imagine.
I say yes , not I am not really that clever

[cotswold]

That would be a question I would ask the resident physicist he would I think welcome a non Ryger not really Aprilia question I imagine.
I say yes , not I am not really that clever

Not sure Frits reads this section so I hi jacked Robs page to see if I could direct him here

[Frits Overmars]

Not sure Frits reads this section so I hi jacked Robs page to see if I could direct him hereNo, I wasn't aware of this section. Jeez! Another 20 pages to read :facepalm:.

[cotswold]

No, I wasn't aware of this section. Jeez! Another 20 pages to read :facepalm:.

no need to go back that far, it's just the page before this one that has the diagram of yours that needs a little math

[richban]

Rich we had .54 squish
Thanks for the info on head shape as I was going toroidal but a European mate and now you have said bath type, I'll stick a photo of his when I get home
Pleased you are putting a 50 together be great to see a grid full at the GP
YOu should leave the motor stock ����



Ha ha standard. No fun in that.

I like the sound of this most winniest pipe Frits has posted.

We used this shape for the 300 to hit an MVS of 38.

316904

Also this worked really well. No real back to back test so can't confirm the best option.

316902

[Frits Overmars]

no need to go back that far, it's just the page before this one that has the diagram of yours that needs a little mathI like to know what I'm dealing with so I had to read the full 20 pages.


So as mine is pretty much square if one were to use an appropriate bit o maths could one use this as his template?In case you're not only interesed in the pipe but also in the combustion chamber pictures, here is how to distinguish them.
Look for the filename top left and if that doesn't help look at the value of X1: that's the cylinder bore.
X1=70 was a chamber for a Suzuki 500 cc twin.
FOSCYL01 = 125 cc FOS cylinder
A125HEAD = Aprilia RSA/RSW125

Pipe GARTWIN was the Garelli 125 cc twin: six straight world titles. But this pipe is 30 years old and you would have to convert the dimensions to a 50 cc engine.
Save yourself some work and start with the FOS Exhaust Concept that I posted somewhere on Kiwibiker.

By the way, I won't be looking into this thread on a daily basis; I need my two hours of sleep each night.

[cotswold]

I like to know what I'm dealing with so I had to read the full 20 pages.

In case you're not only interesed in the pipe but also in the combustion chamber pictures,

By the way, I won't be looking into this thread on a daily basis; I need my two hours of sleep each night.

It's ok Frits I am not a serial poster but do like to post when I change something.

It was the combustion chamber shape I am interested in at the moment, my pipe seems to work well enough for now but will be re visited after I have finished tinkering.

Thank you for taking the time to look, it is only due to the help of my friend Jenne Smit and of course TZ that the bike runs as well as it does, saying that there would be no bike if not for big John Steer

[cotswold]

If plan A falls through, I'll ride your bike, only chance I would have of taking it to Malcolm.

Anyone else planing on trying to collect the whole set? I know the hillbillies are building sidecars.

put a dremill to your 100 and cam it

[kel]

So as mine is pretty much square if one were to use an appropriate bit o maths could one use this as his template?

This is the standard offering and exactly what you'll get (unless you supply your own design). You do have to keep in mind this design was optimised for unleaded race fuel not the dirty leaded avgas we use. Sketchy machined up the first batch of these about a year a go. I was hoping to see some back to back test results from the RG50's :wait:

[cotswold]

This is the standard offering and exactly what you'll get (unless you supply your own design). You do have to keep in mind this design was optimised for unleaded race fuel not the dirty leaded avgas we use. Sketchy machined up the first batch of these about a year a go. I was hoping to see some back to back test results from the RG50's :wait:

I have just been given a set of drawings for a head by an engine tuner out of the uk, I have tried a couple of times to send them to you but not working for some reason, they are specific to my piston but still need tweaking for the deck height.

[kel]

I have just been given a set of drawings for a head by an engine tuner out of the uk.
Got it. I like the ribs for added cooling.
What about fuel, is this insert designed for a motor running Avgas? I've seen it asked on Pit-lane.biz what the optimal chamber shape might be for Avgas but I haven't seen an answer.

[cotswold]

Got it. I like the ribs for added cooling.
What about fuel, is this insert designed for a motor running Avgas? I've seen it asked on Pit-lane.biz what the optimal chamber shape might be for Avgas but I haven't seen an answer.

I'll ask him and get back to you

[cotswold]

Got it. I like the ribs for added cooling.
What about fuel, is this insert designed for a motor running Avgas? I've seen it asked on Pit-lane.biz what the optimal chamber shape might be for Avgas but I haven't seen an answer.

Mark just got back to me and it's 98 for this design so all good

[kel]

Mark just got back to me and it's 98 for this design so all good

You are already running unleaded then. Need to make the switch myself. Im sure with the fast burn, less ignition advance, lower compression, richer mix of unleaded that its got to be good for the air coolers. Elf MITS ...

[FastFred]

You are already running unleaded then. Need to make the switch myself. Im sure with the fast burn, less ignition advance, lower compression, richer mix of unleaded that its got to be good for the air coolers. Elf MITS ...

Lets not pussy around with that cheap toxic carcinogenic unleaded 91-95-98 shit people get from the local petrol station, lets go totally open fuel and brew up something decent with the now legal Elf MITS.

316928

[richban]

So now I have joined this 50cc arms race. Actually its back to where it all started truth be told. First bike ever was an MT50 second bike GT50E. Me Bro had a 50E bucket.

Anyway Back to the question I was going to ask. What is the best HP anyone here in NZ has got from there 50? anyone ever had 18hp? See as I am not very light I figure 18hp would be just the ticket on my new RS50. So that is the goal. I will post the disappointments as I go. Maybe I will start a new thread for the build.

There is not a 4 stroke left in the shed. The transformation is complete. NSR300, CAGIVA raptor 125, RS50 and TF/RS100 project. Oh god what happened to me.

[F5 Dave]

I'm impressed.

I was aiming at 17 for the Derbi but second cut only got 14.6. But the head is rubbish shape in a rush, and I don't know why I left the ports so conservative all those years ago (sat unfinished for close to a decade). RG was only 14. Less towards the end as ovalised a bit.

[speedpro]

[QUOTE=richban;1130917492]So now I have joined this 50cc arms race. . . . . .
There is not a 4 stroke left in the shed. The transformation is complete.QUOTE]

Carrying on with a certain tradition I'm expecting the first thing to do would be to fit an 80cc kit to the 50.

Welcome to the side of goodness and light by the way.

[richban]

[QUOTE=richban;1130917492]So now I have joined this 50cc arms race. . . . . .
There is not a 4 stroke left in the shed. The transformation is complete.QUOTE]

Carrying on with a certain tradition I'm expecting the first thing to do would be to fit an 80cc kit to the 50.

Welcome to the side of goodness and light by the way.

Ha ha thanks Mike.

Nah no 80 kits for me. Really keen to go nuts with the 50. Or should we say 53 ;] New stock cylinders are super cheap. The cast ones anyway. Also the Ali versions are too bad. But looking at the low res images you can see why they are quite cheap.

Anyway Ignitech on the way, FOS pipe on the design, push the comp and the revs, What could possibly go wrong.:innocent:

[richban]

I'm impressed.

I was aiming at 17 for the Derbi but second cut only got 14.6. But the head is rubbish shape in a rush, and I don't know why I left the ports so conservative all those years ago (sat unfinished for close to a decade). RG was only 14. Less towards the end as ovalised a bit.

Just put it on a different dyno!

[mr bucketracer]

Just put it on a different dyno!14.6 is the most i'v heard off , dave is a master

[cotswold]

So now I have joined this 50cc arms race. Actually its back to where it all started truth be told. First bike ever was an MT50 second bike GT50E. Me Bro had a 50E bucket.

Anyway Back to the question I was going to ask. What is the best HP anyone here in NZ has got from there 50? anyone ever had 18hp? See as I am not very light I figure 18hp would be just the ticket on my new RS50. So that is the goal. I will post the disappointments as I go. Maybe I will start a new thread for the build.

There is not a 4 stroke left in the shed. The transformation is complete. NSR300, CAGIVA raptor 125, RS50 and TF/RS100 project. Oh god what happened to me.

You have evolved

[TZ350]

14.6 is the most i'v heard off , dave is a master

Team ESE have dynoed a few 50's when I can find the original posts I will paste them below.

Fixer 13.6 hp


The ESE boys might have only half a clue, but it's a good half. And they have a functioning dyno now. With the addition of a small aluminium plate to raise the barrel, a small mod to the exhaust manifold and a little fiddling with the ignition timing, my Aprilia RS50 with it's Conti pipe and Doppler top end has gone from 10hp to 13.6hp. Woo hoo! Evidence below:

297225

Cotswald touching 14



Thanks Tee Zee for letting me put the 50 on your Dyno, ... happy with the nearly 14, could you post the graph for me as I forgot to take a photo in my haste to get home and strip the bee atch.
Sure,

310162

There you go.

Gigglebutton ... Av gas Red line, NOS Blue line.


237930237929

After a bit of a thrash on the dyno....... Red is the old curve, Blue new.
Well worth the hours worked on it. Next step a better ignition. Thanks guys

Buckets4me 14hp


288388 288389

There are a few F5 projects on the go, this is Buckets4me and his RG50. And as far as the Team goes, his pretty much sets the bench mark.

NedKellys 12hp


NedKellys 50.
294606294602

11.0 red line is Ex opens 87 deg atdc duration 186 deg and Frits pipe.
12.0 blue line Ex opens 81 deg atdc duration 186 deg and Fritz pipe.

[cotswold]

https://www.youtube.com/watch?v=46zTXbTM8ZA

the onboard is taken from a classic 50 meaning it runs very skinny wheels and tyres but check out what can be done with a KTM cylinder on Ron Ponti cases with disc valve, 22bhp rocket ship.
I pinched the clip from the Free tech boys

[Bert]

https://www.youtube.com/watch?v=46zTXbTM8ZA

the onboard is taken from a classic 50 meaning it runs very skinny wheels and tyres but check out what can be done with a KTM cylinder on Ron Ponti cases with disc valve, 22bhp rocket ship.
I pinched the clip from the Free tech boys

Bloody hell... Lucky he has corner speed issues; else he'd leave them all for dead.

[richban]

https://www.youtube.com/watch?v=46zTXbTM8ZA

the onboard is taken from a classic 50 meaning it runs very skinny wheels and tyres but check out what can be done with a KTM cylinder on Ron Ponti cases with disc valve, 22bhp rocket ship.
I pinched the clip from the Free tech boys

Oh man that thing is fast. Sounds so good.

[TALLIS]

Take the straight out and he would be dead last, but I don't think it's in anyway the bikes fault! Geez it hauls

[cotswold]

Take the straight out and he would be dead last, but I don't think it's in anyway the bikes fault! Geez it hauls

He's limited by his wheels, very skinny tyres, old school brakes and 70's chassis

[richban]

Thanks Tim for letting me post here. This could be the start of a really great 50cc tuning resource.

So Here is a pic post race day on the little fatty.
317361

It handles really well this bike. Its just heavy and the stock suspension needs some love. They have a rather funky subframe arrangement that house's the rear shock. I have chopped the rear of the subfrtame and will chop the rest after I have made a new shock mount mini steel sub frame that I will hang an Ali seat / subframe off. That should loose a lot of weight.


Next will be the wheels. They are way heavy so will fit the super light 2.5 and 3 Marvics I have. That should be good for almost 10kg.

317362

That should get the weight down. So now for some more power. Looks like pushing the barrel up 1.5mm will put the transfure's at 115 and the exhaust close to 85 degrees.
317364

317365

I found this scooter pipe I brought ages ago to go with a 70m kit for my little commuter. After a quick measure I think I can get it very close to the Frits Malossi Pipe. So that is the plan untill the bank allows me to sort a new ali cylinder and some tools to port it. I will post up results as I go. Might be a we while as the Suzuki series is about to start and I will be busy riding this thing.

317366


Oh an one last pic. First 50 bucket back in 1987ish. It had a full fairing and slicks. It never really got used. Maybe once at Bay Park.

317367

[kel]

Sorry for the delay Tim, insert now drawn just need you to confirm you're happy with the spigot measurement and we are good to go

[cotswold]

Sorry for the delay Tim, insert now drawn just need you to confirm you're happy with the spigot measurement and we are good to go

That old head was optimised by TZ for a pretty good squish so that would be fine as a template.
:niceone: Thanks Kel

[Frits Overmars]

https://www.youtube.com/watch?v=46zTXbTM8ZA the onboard is taken from a classic 50 meaning it runs very skinny wheels and tyres but check out what can be done with a KTM cylinder on Ron Ponti cases with disc valve, 22bhp rocket ship.
I pinched the clip from the Freetech boysYou could have pinched the bike's power curve as well then. Here it is:
317597
The Freetechs and the Classics were racing together in that video. In the corners the Freetechs rule; on the straights they are handicapped by their wide tires and fairings and their far too high weight. After all, they're mostly Honda RS125 bikes with 50 cc engines. I'm still waiting for someone to build a proper Freetech50.
Weight is killing the current Freetechs' performance. Compared to the Classics, the best Freetechs are not down on power. Below is the power curve of a decent Freetech50.
317598

[cotswold]

You could have pinched the bike's power curve as well then. Here it is:
317597
The Freetechs and the Classics were racing together in that video. In the corners the Freetechs rule; on the straights they are handicapped by their wide tires and fairings and their far too high weight. After all, they're all Honda RS125 bikes with 50 cc engines. I'm still waiting for someone to build a proper Freetech50.
Weight is killing the current Freetechs' performance. Compared to the Classics, the best Freetechs are not down on power. Below is the power curve of a decent Freetech50.
317598

That is impressive, the europeans have it nailed, the British free tech lads are 17bhp or there abouts so we have plenty to do to catch up with them. We are slightly hampered by being unable to use some of the parts available to them.

Frits that free tech power curve, do you know what the engine was and whether it was reed or disc valve ?

[Frits Overmars]

Frits that free tech power curve, do you know what the engine was and whether it was reed or disc valve ?I happen to know a thing or two about it but I'm not going to spill the beans here; I'll leave that to builder-rider Barrie Raterink, if he ever discovers this thread (it took me a long time). But here are some pics.
317623 317624 317626

[cotswold]

I happen to know a thing or two about it but I'm not going to spill the beans here; I'll leave that to builder-rider Barrie Raterink, if he ever discovers this thread (it took me a long time). But here are some pics.
317623 317624 317626

I have seen Barry's bike on a different forum. Kawasaki disc valve engine, very nice

[richban]

Weight is killing the current Freetechs' performance. Compared to the Classics, the best Freetechs are not down on power. Below is the power curve of a decent Freetech50.


Weight a problem with my RS50. The frame looks light but I need to strip the bike to see if looks are deceiving. The swing arm is steel and heavy. I am thinking maybe something from a small MX bike could be modified. Time to buy a new AC / DC tig.

[kel]

Kawasaki disc valve engine, very nice
With the inlet moved to the opposite side to allow for large disk, larger carb and short inlet passage :niceone:
What model Kawasaki is the bottom end from?

[jasonu]

I happen to know a thing or two about it but I'm not going to spill the beans here; I'll leave that to builder-rider Barrie Raterink, if he ever discovers this thread (it took me a long time). But here are some pics.
317623 317624 317626

I sent him a heads up email. Hopefully he will have something interesting to contribute.

[cotswold]

With the inlet moved to the opposite side to allow for large disk, larger carb and short inlet passage :niceone:
What model Kawasaki is the bottom end from?

Ar50 or 80 I think as they were popular in the UK and europe

[Frits Overmars]

Ar50 or 80 I think as they were popular in the UK and europeLast time I checked England was an island in the North Sea, off the European mainland. Some people seem to pretend it is a continent of its own :p.

[cotswold]

Last time I checked England was an island in the North Sea, off the European mainland. Some people seem to pretend it is a continent of its own :p.

:laugh: Sorry Frits, I will put my hand up as an escaped Englishman, in my defence we were brought up to believe Europe started after an unpleasant boat ride.

[bartarie]

317779317780317778

Comming in ;)

Hi Frits,

Strange thing to see you in NZ ;)
You see Frits everywhere around the globe!

If you guys want to know a thing or two please feel free to ask :)

Greetings

B

[husaberg]

Comming in ;)

Hi Frits,

Strange thing to see you in NZ ;)
You see Frits everywhere around the globe!

If you guys want to know a thing or two please feel free to ask :)

Greetings

B

Welcome and Feel free tell us everything about the engine.:2thumbsup

[bartarie]

317789317790317791317792

Lol i could tell :) but i am fairly busy!

Well its actually a fairly simple mod,

I took a AR50/80 engine, converted into bore 40 stroke 39,7.
The studpattern modified to m7x56, so i can fit Derbi cylinder.
Because of 2 points i decided to rotate the barrel 180 degrees, first i like the strait exhaust concept of the Aprilia RSR (and RSW)
Second point was to keep the original base of the frame, wich has a downtube in the middle of the frame.
This is solved by the standard AR50 by making a duct wich is exiting to the right (DOF).
Because it would have a rotary disc valve inlet things doesnt really matter wether it was front or rear exhaust.
Because the original unitrak system was way too high i modified it, its a conventional dogbone conversion seen on much bikes these days.
Therefor i made my own rearfork, and added a vintage WP USD fork (35mm) and at the rear also WP.
It would be no coincidence, steering damper also WP. Seat is self-carrying Apia RSW.

The clutch is made of several modified parts from KX65 and AR50 standard 3 plate now 6 plate.
Cooling pump is bosch electronic, ignition is Zeeltronic.
Carby is 75 percent home built, made my own velocity stack, powerjet and slide.
Powerjet has PWM. Main jets are removed and i fitted a Lectron needle.

Barrel is an standard moped cylinder from Derbi slightly modified.
Tube is an "tubo 102" (Apia GP tube) Converted to 50cc dimensions.

This winter i might make an dry clutch for my bike.
If this is finished i'd like to make my new frame, its inspirated by JJ-cobas TB5 (alex criville 1989)
Shorter wheelbased, steeper steering angle. Shock fitted vertical instead of horizontal.
Also will have an RSW Carbon Seat to drop the weight :)

B


317793

[TZ350]

I like it ... :clap:

[lodgernz]

317793

What is the purpose of the plate over the cylinder head?

[husaberg]

317789317790317791317792

Lol i could tell :) but i am fairly busy!

Well its actually a fairly simple mod,

I took a AR50/80 engine, converted into bore 40 stroke 39,7.
The studpattern modified to m7x56, so i can fit Derbi cylinder.
Because of 2 points i decided to rotate the barrel 180 degrees, first i like the strait exhaust concept of the Aprilia RSR (and RSW)
Second point was to keep the original base of the frame, wich has a downtube in the middle of the frame.
This is solved by the standard AR50 by making a duct wich is exiting to the right (DOF).
Because it would have a rotary disc valve inlet things doesnt really matter wether it was front or rear exhaust.
Because the original unitrak system was way too high i modified it, its a conventional dogbone conversion seen on much bikes these days.
Therefor i made my own rearfork, and added a vintage WP USD fork (35mm) and at the rear also WP.
It would be no coincidence, steering damper also WP. Seat is self-carrying Apia RSW.

The clutch is made of several modified parts from KX65 and AR50 standard 3 plate now 6 plate.
Cooling pump is bosch electronic, ignition is Zeeltronic.
Carby is 75 percent home built, made my own velocity stack, powerjet and slide.
Powerjet has PWM. Main jets are removed and i fitted a Lectron needle.

Barrel is an standard moped cylinder from Derbi slightly modified.
Tube is an "tubo 102" (Apia GP tube) Converted to 50cc dimensions.

This winter i might make an dry clutch for my bike.
If this is finished i'd like to make my new frame, its inspirated by JJ-cobas TB5 (alex criville 1989)
Shorter wheelbased, steeper steering angle. Shock fitted vertical instead of horizontal.
Also will have an RSW Carbon Seat to drop the weight :)

B


]

Any more detail on the carb I must say it looks pretty epic.
So it has no overlap on the fuelling circuits other than the PJ which is electronically pulse controlled.
I didn't see a tps, is it inline an RGV250?

[bartarie]

The lectron needle could be used standalone, works pretty good.

The pwm works great, at mid-range it seems you cannot choke the engine in fuel. It gives you a lot of confidence, t feels great. During the whole season i believe i just once adjusted the needle. (During a demo on a big airfield). Just to be sure and because it was a demo.

A TPS is not nescesarry, just place the exit of the PJ on 75% of the height of the throttle slide.
Just like yamaha does on the tz125 and honda on the 96/97 cr250.

Dont make things un-nescesarry complicated you know.

OMT

i am very negative About using a "on off" style PJ it is way Too rough, for sure on a 50cc.

[bartarie]

Oh plate,

Plate is to hold my det counter sensor snug in place while using 10mm Plugs instead of 14mm

[chrisc]

In the corners the Freetechs rule; on the straights they are handicapped by their wide tires and fairings and their far too high weight. After all, they're mostly Honda RS125 bikes with 50 cc engines. I'm still waiting for someone to build a proper Freetech50.
Weight is killing the current Freetechs' performance. Compared to the Classics, the best Freetechs are not down on power.

Okay, I'll bite. I'm curious to know more about what you'd consider a proper freetech50 Frits.

Can you use MX engines in the freetech50 class?

[sonic_v]

Okay, I'll bite. I'm curious to know more about what you'd consider a proper freetech50 Frits.

Can you use MX engines in the freetech50 class?

Yes to MX engines.

http://www.freetech50.com/?t=en&p=page&s=reglement

[cotswold]

Okay, I'll bite. I'm curious to know more about what you'd consider a proper freetech50 Frits.

Can you use MX engines in the freetech50 class?

The KTM 65 with the 50 cylinder seems to be popular with some in the uk
I am plumbing in a 2nd radiator for tamuranui not sure if I've got the flow correct

Frikkin picture is upside down again, this is pissing me off as it's fine everywhere else

[husaberg]

Frikkin picture is upside down again, this is pissing me off as it's fine everywhere else


:clap:Turn up computer the other way.
318234

[TZ350]

I am plumbing in a 2nd radiator for Taumarunui not sure if I've got the flow correct.

Should be in at the head and out at the bottom of the cylinder for max head cooling.

[F5 Dave]

Disagree. You have it going through the engine the right way as every engine I've seen, but through the rads in reverse. If the pump was strong enough it wouldn't matter but why fight thermosyphoning action? Hot in at the top.

coolest enters the low part of the engine to keep charge cool as possible and ideally exits the head at ideal temp if you have enough cooling.

[cotswold]

thanks guys......................

[kel]

Why two radiators? I have none, bike seems to go alright most of the time.
Taumarunui must be one of the hottest bucket meetings temp wise, bloody bike has failed their twice from thermal melt down. Maybe a radiator under the seat isn't such a silly idea ;)

[richban]

Why two radiators? I have none, bike seems to go alright most of the time.
Taumarunui must be one of the hottest bucket meetings temp wise, bloody bike has failed their twice from thermal melt down. Maybe a radiator under the seat isn't such a silly idea ;)

Do you run an egt kel?

[kel]

Do you run an egt kel?

Not yet. Have bought a couple of these http://www.ebay.com/itm/252006895656?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT will have it set up for the GP.

[cotswold]

Why two radiators? I have none, bike seems to go alright most of the time.
Taumarunui must be one of the hottest bucket meetings temp wise, bloody bike has failed their twice from thermal melt down. Maybe a radiator under the seat isn't such a silly idea ;)

Mainly because the man that owns NZ's winningest 50 told me I should and because it makes sense as mine was made for a bike with 4bhp and it now has more than triple that and revs its tits off must be making more heat than it used to.

[richban]

Not yet. Have bought a couple of these http://www.ebay.com/itm/252006895656?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT will have it set up for the GP.


I will never race a 2 stroke without one. Saves engines and body parts.

[TZ350]

Previously I said I would post pics of the mods done to the TZ400 that won at the Shorai Challenge, so here are some of the modified head and new water circuit.

From the pump water enters the rear of the cylinder below the welded on top plate, this forces flow around over the transfers then up into the front of the head via holes on each side of the Ex duct.

This water is then forced to flow around the inserted head, and out at the highest point, with an auto air bleed back to the top of the crossflow rad.

Follow the link to read Wobs post on his water circuit and to see the pictures.

[cotswold]

I will never race a 2 stroke without one. Saves engines and body parts.

I just bought a couple so when they arrive I will be asking dumb questions

[F5 Dave]

Only thing I learnt was on a 50 the header is so narrow you have to be careful not to stick the probe in so far (said the alien to the farmhand) as to overheat the fat edge. Do a dyno run without it and then fit it. Make a blanking plug so it can be removed for the test.

Temperature reading just kept climbing and lost 3hp. Went back next day once I'd fashioned a plug and hp came back. Put on the shelf and forgotten. Wish I'd tried pulling it out a bit further. Oh well.

[richban]

I just bought a couple so when they arrive I will be asking dumb questions

Good move. They don't tell the full story but it will make jetting a lot more simple. And when you see the temp go down rapidly pull the clutch in.

[richban]

Only thing I learnt was on a 50 the header is so narrow you have to be careful not to stick the probe in so far (said the alien to the farmhand) as to overheat the fat edge. Do a dyno run without it and then fit it. Make a blanking plug so it can be removed for the test.

Temperature reading just kept climbing and lost 3hp. Went back next day once I'd fashioned a plug and hp came back. Put on the shelf and forgotten. Wish I'd tried pulling it out a bit further. Oh well.

Good point! I wonder if just fitting it futher down the pipe would be the way to go. The reading would not be as fast maybe but with the data logged it should still tell the fuelling story. It would be interesting to here from anyone running an etg in a 50?

[jasonu]

Mainly because the man that owns NZ's winningest 50 .

Who is this man? Pete Sales perhaps?

[cotswold]

Who is this man? Pete Sales perhaps?

I am talking in living memory, modern times, this century though 7 times is a touch impressive, the last time was a quarter of a century ago. :whistle:

[cotswold]

50 cc with a 12 mm carb
http://youtu.be/q6FJ0vbUj6c

[jasonu]

I am talking in living memory, modern times, this century though 7 times is a touch impressive, the last time was a quarter of a century ago. :whistle:

Cheeky buggar.
Who then? David/Nathaniel Diprose comes to mind.

[cotswold]

Cheeky buggar.
Who then? David/Nathaniel Diprose comes to mind.

yes David took a look over my very buckity 50 and said the engine was exceeding my radiators ability to remove the heat.

[richban]

OK, so the motor is out and on the bench. With the cast barrel and gear oil its weighing in at 15.5kg. I think I can knock a couple of kg of that.

Looking at the cases down the intake duct I can see lots of sharp edges that I will attack soon. Before I do I will measure the case volume and see where its at. Just waiting on the gaskets and seals to turn up and away we go.

[TALLIS]

OK, so the motor is out and on the bench. With the cast barrel and gear oil its weighing in at 15.5kg. I think I can knock a couple of kg of that.

Looking at the cases down the intake duct I can see lots of sharp edges that I will attack soon. Before I do I will measure the case volume and see where its at. Just waiting on the gaskets and seals to turn up and away we go.

Did you manage to get a dyno run in as is?

[F5 Dave]

No he had some excuse or other. The other 50 we put on we found 2hp in 20 minutes before running out of adjustment.

[richban]

No he had some excuse or other. The other 50 we put on we found 2hp in 20 minutes before running out of adjustment.

Plenty of excuse to burn. Did you measure the case volume of your Derbi dave?

The first dyno will be the base line. It would have been maybe 8 or 7 hp.

[F5 Dave]

No, the Derbi was a rush job spread over 8 or 9 years.

[TALLIS]

Since the 50 is going so well, and is basically being used as the town bike, I thought I should be prepared.
Where are you boys getting your rg50 pistons?

[F5 Dave]

Um. . . Phil Turnbulls?:confused:

[Bert]

Since the 50 is going so well, and is basically being used as the town bike, I thought I should be prepared.
Where are you boys getting your rg50 pistons?

RMX50 piston :)

[TZ350]

Where are you boys getting your rg50 pistons?

Off Ebay

318784

The Wiseco Suzuki JR50 and Kawasaki KDX50 piston is a direct replacement for the old RG50 piston.

[richban]

So now have all the bits I need to do the first build on the AM6. Seat of pants build that is.
318793

The plan! Use the new mega race 30hp ali cylinder (stage 6 sport cylinder really) I brought from Europe. :msn-wink:
318791

It actually looks ok. Honda sort of layout.
318792

But the exhaust duct looks really small at first glance compared to standard. The cylinder will need to be raised about .9 of a mm to get the transfers opening around 84 deg atdc.

First thing I will do is port the cases there seams to be loads of big sharp edges around the place. I will post some pics when I get stuck in over the weekend.

[TALLIS]

Off Ebay

318784

The Wiseco Suzuki JR50 and Kawasaki KDX50 piston is a direct replacement for the old RG50 piston.
Thanks Rob, great.

[TALLIS]

The plan! Use the new mega race 30hp ali cylinder (stage 6 sport cylinder really) I brought from Europe. :msn-wink:



I hope the box dosnt say race on it, not in English anyway. looks nice tho!

[richban]

I hope the box dosnt say race on it, not in English anyway. looks nice tho!

Ha ha. No the word race was not on the box. Well it took me 2 hours to clean up the port windows. The nikasil was pushed over the ports quite a bit. The exhaust port exit is way small compared to standard. Also the transfer and boost port ducts are different from the cases. I think this cylinder is for a later model Derbi. But is says it fits the AM6. That is ture, it dose fit but not so good. I think after I match it all up there will be quite a bit of case volume. Maybe. I will cc the cases when its all back together and see where I am.
318803

[F5 Dave]

Piston looks good except pin is pretty low.

Strange duct but would suit a transition insert yeah?

[sonic_v]

So now have all the bits I need to do the first build on the AM6. Seat of pants build that is.
318793

The plan! Use the new mega race 30hp ali cylinder (stage 6 sport cylinder really) I brought from Europe. :msn-wink:
318791

It actually looks ok. Honda sort of layout.
318792

But the exhaust duct looks really small at first glance compared to standard. The cylinder will need to be raised about .9 of a mm to get the transfers opening around 84 deg atdc.

First thing I will do is port the cases there seams to be loads of big sharp edges around the place. I will post some pics when I get stuck in over the weekend.

Does the exhaust flange have a diameter of 28 mm? This is what the standard cylinder is.

[richban]

Does the exhaust flange have a diameter of 28 mm? This is what the standard cylinder is.

Yep 28mm. The exhaust duct exit is way smaller than standard though. On the standard cylinder it transitions form the port oval to around 24mm cross section area on exit. The new one is way smaller. It should give me lots of scope to adjust it. So a good thing I think.

[richban]

So I have split the engine. I must say it's a rather heavy duty little thing. Quite impressed how well made it all seams.

I have started porting / matching the cases to the barrel. It all looks quite straight forward. The barrel has no dowels to help line things up. I need to sort that so I can be as accurate as possible when grinding away.

As you can see there is a bit of dead space that needs filling between the barrel and cases. On the inlet side I plan to blend this into a nice big fat radius. I will also radius the duct entry on the barrel. Looks like I will end up with more case volume than it had as standard. I will cc it when I am happy with all the case work.

318926

318927

318928

I did have a mad idea that it needs a dry clutch. We will see.

[cotswold]

a big thanks to those involved with helping me get this former beach toy which would have had 1/2 the manufacturers claimed HP when I first got hold of it up to a respectable nearly 14.
the latest to become involved would be Kel, he drew up my new head inserts and Kerry who made them for me, you boys rock
Thanks boys

even upside down (wtf) they look sweet

[seymour14]

Be good to see it in action at the GP. The F5 should put up a fantastic amount of riders this year me thinks!

No worries.

[richban]

a big thanks to those involved with helping me get this former beach toy which would have had 1/2 the manufacturers claimed HP when I first got hold of it up to a respectable nearly 14.
the latest to become involved would be Kel, he drew up my new head inserts and Kerry who made them for me, you boys rock
Thanks boys

even upside down (wtf) they look sweet

Nice one. I will be there soon. I have just been in the shed with the grinder and diamond files putting a nice radius on the transfer ducts and boost port. What comp is that. I was thinking of going 15:1.

[F5 Dave]

That's a good start for av. I'm about 15.6

[cotswold]

Nice one. I will be there soon. I have just been in the shed with the grinder and diamond files putting a nice radius on the transfer ducts and boost port. What comp is that. I was thinking of going 15:1.

fourteen point one

[richban]

fourteen point one

Are you on the fence? What fuel are you going to run? Seams Hi for pump and not enough for Av. I think!

[F5 Dave]

That's still rral safe for pump. Even 15 would be fine for lc 50 on pump. I could easily run more but at some point you juggle the comprise of stinger and spark lead vs compression.

[cotswold]

Are you on the fence? What fuel are you going to run? Seams Hi for pump and not enough for Av. I think!

half and half

[F5 Dave]

Back in the day of leaded pump gas I used to run 17:1

That gas was good. Better than AV for power production and despite many experiments of com and shape, jetting and ign I never matched it with same spec below.

[mr bucketracer]

half and halfthats what i like running ,all my 2 strokes i run at 14 to 1 like all the fast 50s of the 60s and 70s

[kel]

half and half

You now have 2 fuels with different burn properties mixed together. Leaded which likes to run lean with lots of comp and advance, Unleaded which likes to run rich with considerably less comp and advance. That's kind of like a Shandy for your motor
(just in case; Shandy = beer+lemonade, :nono:)

Plus the head insert is for 98 -

Mark just got back to me and it's 98 for this design so all good

[mr bucketracer]

You now have 2 fuels with different burn properties mixed together. Leaded which likes to run lean with lots of comp and advance, Unleaded which likes to run rich with considerably less comp and advance. That's kind of like a Shandy for your motor
(just in case; Shandy = beer+lemonade, :nono:)

Plus the head insert is for 98 -with there powers combined we have captain planet

[richban]

with there powers combined we have captain planet

Ha ha.

Which setup makes the most toque sooner in the rev range yah reckon? Lower comp pump gas or mega hi comp Av gas. We are fat kart track racers after all. Corner exit is everything.

[kel]

Which setup makes the most toque sooner in the rev range yah reckon? Lower comp pump gas or mega hi comp Av gas. We are fat kart track racers after all. Corner exit is everything.

With unleaded you will lose some mid (at the same rpm) but it can give you a wider power band, more revs, and more hp. A 50's kart track corner exit speed would be all about clutch slipping out of corners, lower rev torque is less important than keeping on the pipe therefore unleaded wins.

[richban]

With unleaded you will lose some mid (at the same rpm) but it can give you a wider power band, more revs, and more hp. A 50's kart track corner exit speed would be all about clutch slipping out of corners, lower rev torque is less important than keeping on the pipe therefore unleaded wins.

Hummm. Well after riding my stock 50 at kaitoki the only time I needed to slip the clutch was when I messed up a gear change. A quick shifter is sitting in the box ready. Got to worth its weight in gold on a 50. It was a game changer for me on the 300.

[cotswold]

reverse cylinder, disc valve converted Derbi 50 getting leak tested in the tub.

This is being built in Pomgolia by Warren Harvey

[husaberg]

reverse cylinder, disc valve converted Derbi 50 getting leak tested in the tub.

This is being built in Pomgolia by Warren Harvey

Out of interest, do you know what size disk it runs?

[cotswold]

Out of interest, do you know what size disk it runs?

no idea but i could ask him, it is a carbon fibre Emot part

[husaberg]

no idea but i could ask him, it is a carbon fibre Emot part

It is I guess his standard conversion part then.
http://www.emot.nl/webwinkel/index.php?act=viewCat&catId=27

[cotswold]

They have it so damn good in the Uk bike wise, many to choose from, if I had a bigger slush fund I would import some of these.
This one is race ready freetech style and is 900 quid

[seymour14]

They have it so damn good in the Uk bike wise, many to choose from, if I had a bigger slush fund I would import some of these.
This one is race ready freetech style and is 900 quid

We'll take 5. :Police:

[cotswold]

I have decided to bucketise my rear shock as the spring is way too hard, no sag at all and next to bugger with me sat on it. The old chassis had a TZR250 shock bodged into it and it worked real well so I am going to cut 1 coil out of it and fit it into the pit bike shock. What could possibly go wrong :rolleyes:

[TZ350]

Cutting a coil out will make it harder.

[mr bucketracer]

I have decided to bucketise my rear shock as the spring is way too hard, no sag at all and next to bugger with me sat on it. The old chassis had a TZR250 shock bodged into it and it worked real well so I am going to cut 1 coil out of it and fit it into the pit bike shock. What could possibly go wrong :rolleyes:hope thats not a zxr400 shock..noooo

[cotswold]

Cutting a coil out will make it harder.

The coils are wider apart on the TZR , should I just compress it to fit as I thought that would make it stiffer ?


The pitbike coils are 12.5mm, 13mm apart and 140mm long


the TZR 11mm, 22mm apart and 160mm long

They both have 5 active coils
Now im confused

[cotswold]

hope thats not a zxr400 shock..noooo

TZR 250, I have the swing arm as well but it's destined for the scrap man as it will never get used

[diesel pig]

TZR 250, I have the swing arm as well but it's destined for the scrap man as it will never get used

What year? I may be interested:2thumbsup

[Bert]

TZR 250, I have the swing arm as well but it's destined for the scrap man as it will never get used

A bit late, but dont scrap it.
1KT sitting in my shed waiting some love...

[cotswold]

A bit late, but dont scrap it.
1KT sitting in my shed waiting some love...

ill take it to the GP and if someone wants it

[F5 Dave]

The important part of the calculation is, given coil diameter, the wire thickness and the active coils.


Think of a flat spring, like you mates ruler at school. Very bendy if you hold it at either end, but much stiffer with you hands closer together.

A spring is just convenient packaging of a leaf spring.

The fact you can't fit it is inconvenience.

[Sketchy_Racer]

I have decided to bucketise my rear shock as the spring is way too hard, no sag at all and next to bugger with me sat on it. The old chassis had a TZR250 shock bodged into it and it worked real well so I am going to cut 1 coil out of it and fit it into the pit bike shock. What could possibly go wrong :rolleyes:

Here's a handy spring calculator. Just measure up the springs and look at the calculated N/mm rate. It won't tell you what size you need but it will give you a good comparison of the two springs to see how close they are.

[husaberg]

I have decided to bucketise my rear shock as the spring is way too hard, no sag at all and next to bugger with me sat on it. The old chassis had a TZR250 shock bodged into it and it worked real well so I am going to cut 1 coil out of it and fit it into the pit bike shock. What could possibly go wrong :rolleyes:


Cutting a coil out will make it harder.

There is a semi professional way of making it shorter without cutting it and making it stiffer.
You make up a big long bolt compress the spring with a template top and bottom with flanges to keep it centered and simply pop it in the oven.
I will post the details tomorrow.

[Grumph]

There is a semi professional way of making it shorter without cutting it and making it stiffer.
You make up a big long bolt compress the spring with a template top and bottom with flanges to keep it centered and simply pop it in the oven.
I will post the details tomorrow.

I was told a couple of years back of a method which may apply here....

The timaru based group of car race guys who over many years have had much success at national level, wanted to race a datsun 1600SSS in production class races. They looked at it and said, ride height is way too high...rules say we can't change or modify the springs.
So while the engine and box were out being blueprinted, the car sat on old rims, stuffed full of sandbags - I'm told about a ton weight all up...
By the time the engine was done it sat about 1 1/2in lower - and there were no marks of heating on the original finish of the springs.
Puzzled a lot of scrutineers that did.

[mr bucketracer]

Now we are talking, non of you bucket boys would of keeped up with that guy if he was still alive319883

[seymour14]

Now we are talking, non of you bucket boys would of keeped up with that guy if he was still alive319883

Bet you wished you'd kept that and a few others too...

[mr bucketracer]

Bet you wished you'd kept that and a few others too...well that guy died and some fat guy replaced him so no skin of his nose lol

[husaberg]

I was told a couple of years back of a method which may apply here....

The timaru based group of car race guys who over many years have had much success at national level, wanted to race a datsun 1600SSS in production class races. They looked at it and said, ride height is way too high...rules say we can't change or modify the springs.
So while the engine and box were out being blueprinted, the car sat on old rims, stuffed full of sandbags - I'm told about a ton weight all up...
By the time the engine was done it sat about 1 1/2in lower - and there were no marks of heating on the original finish of the springs.
Puzzled a lot of scrutineers that did.

Setting the static Sag has a new twist.:innocent:
right I posted it elsewhere as well, but here is what I learnt 20 years ago.
400 degrees F and a couple of minutes under compression. Bobs your mothers brother.

[TZ350]

Now we are talking, non of you bucket boys would of keeped up with that guy 319883

Looks like a Mitsubishi Gallant, my mum had one new, that color too. Caused quite a stir when she turned up at Church with it, those anal Baptists couldn't get their head around a woman owning and driving a fast looking car, and a car that color to boot to. It was a time when women still wore hats and gloves to church. A Jap car, a lot of the men in the congregation had, had first hand experience with the Japanese in the Pacific.

319904

Mum could drive when she was 15 dad only learnt to drive when he was in his 30's, different times. I inherited it and my kids all learnt to drive in it. Thanks for the memories.

[F5 Dave]

Clearly its a Ratsun like Greg said. My cousin wrote one off, but yes they do all look alike. I had a car once. But only once.

It was a Vauxhall Victor and it looked like, well it looked like a piece of shit. Which was quite an accurate depiction.

[mr bucketracer]

not much difients in them 2 cars , mid chrome yellow

[chrisc]

Should have bloody known you boys were Datsun folk! I was into Datsuns for years before getting addicted to racing bikes. That car Scott had was a Datsun 160J.

Google image search beeoneoneoh and all of that will have a relation to the fairly successful Datsun/drifting blog I ran for years. The mustard coloured Datsun 1200 truck with the Nissan Silvia SR20DE engine swapped into it was my monster. Suuuuuuch fun. But this has no relation to 50cc race bikes...

[mr bucketracer]

Should have bloody known you boys were Datsun folk! I was into Datsuns for years before getting addicted to racing bikes. That car Scott had was a Datsun 160J.

Google image search beeoneoneoh and all of that will have a relation to the fairly successful Datsun/drifting blog I ran for years. The mustard coloured Datsun 1200 truck with the Nissan Silvia SR20DE engine swapped into it was my monster. Suuuuuuch fun. But this has no relation to 50cc race bikes...lol you have to add the sss to that (-;

[Grumph]

Suuuuuuch fun. But this has no relation to 50cc race bikes...

Agreed - but buckets is all about lateral thinking and the example i posted is a very cunning example...

The same group of Timaru guys had a Laser Sport which won the Championship run for them which ran for several years and even had David Lange driving one.
In fact they won two years running before officialdom caught on...and changed the rules.
They'd looked at the porting and said - shit those inlet valve guides are bad, how can we improve flow without removing material ?
At full lift there was at least 6mm gap between the spring retainers and the stem seals...so they pressed the inlet valve guides 5.5mm back into the head...
Worked a treat and i can verify from observation that it was worth about 60 meters down the back straight at Wigram.

Most car production class regs now say - original parts - in original position.

[cotswold]

Thanks to Roger for having the VHM copied, Kel for designing the insert, Seymour for the CNC magic, my mate Dave for cutting the thread I now have a decent combustion chamber shape, all I need to do is sweet talk team ESE into letting me pop over to make sure there will be no piston clipping the head nonsense and I'll be almost ready for the GP. (just need to sort out the shock , lose 20 odd kilo's and wind back the years to when I was 20)

[richban]

Thanks to Roger for having the VHM copied, Kel for designing the insert, Seymour for the CNC magic, my mate Dave for cutting the thread I now have a decent combustion chamber shape, all I need to do is sweet talk team ESE into letting me pop over to make sure there will be no piston clipping the head nonsense and I'll be almost ready for the GP. (just need to sort out the shock , lose 20 odd kilo's and wind back the years to when I was 20)

Nice one. I am starting my 50 assembly today. Its in a lot of bits. Now to remember how that gearbox goes in. And where did the ball bearing go. I think I will make it. Just won't be the bike I wanted to turn up on. We still be fun though.



Will post some pics later today.

[cotswold]

Nice one. I am starting my 50 assembly today. Its in a lot of bits. Now to remember how that gearbox goes in. And where did the ball bearing go. I think I will make it. Just won't be the bike I wanted to turn up on. We still be fun though.



Will post some pics later today.

you'll make up for it by riding the wheels off it

[richban]

you'll make up for it by riding the wheels off it

Hope so. Productive day yesterday. Got the bottom end all sorted. New main bearings at least. Then looked at getting the cylinder timed right. What a mission. It was sitting at exhaust 90 and transfers 110 with no base gasket. Thanks again glen for helping out yesterday. We took 1mm of the cylinder to get to 115 transfusers and at midnight last night I finished porting the exhaust to open @ 83 atdc.

Now to make a pipe close to the FOS dims as possible with what I have.

[F5 Dave]

Did you work out where you were at with the ign?

[richban]

Did you work out where you were at with the ign?

No. I can't change anything right now so just going to run it. I may have time to plug the ignitech on. Will see how I get on. Oh yeah. And thanks for the lend of the PWK 28. With an old FXR intake rubber it is going to work out great.


320031320036320035

[richban]

Engine back together. No carb rule for 50's :eek5: 40mm carb for a 40mm piston. Maybe not.

320084

[F5 Dave]

Can you fit two?

[cotswold]

Went into town tonight to see the boys from ESE to get a few pointers on how to set up my head insert.
TZ spaced the plug with a copper washer to get it around 4.5mm from the piston, we then cc'd the insert and it came in at 3.4ml which is what Kel designed it to be so awesome work Kel and Seymour.
The shock and it's 1000lb spring have been parted and Culley loaned a spring off an NF4 to try, just have to make up a centering cup

[F5 Dave]

Looks great. With the copper washer it will increase the heat range a stat so the CR8 will become a 7 where it should be a 9 or 10. Will burn a hole in the piston pretty quick if it makes decent power.

[cotswold]

Looks great. With the copper washer it will increase the heat range a stat so the CR8 will become a 7 where it should be a 9 or 10. Will burn a hole in the piston pretty quick if it makes decent power.

Dave, that plug was only for my engineer mate to use as a template for the thread, I have a couple of 10's on their way. I bought CR10EIX NGK but I seem to remember Wob's saying they could shit the electrode, any better plugs you could think of that dont cost $60 each (Denso)

[F5 Dave]

You're in my the four stroke plug realm now.

[richban]

You're in my the four stroke plug realm now.

After mucking around with subframes and finding various problems with suspension like they front is buggered and the back is buggered. The 50 engine will now be slotted into the NSR they both weigh the same so no big deal really. But I did like the short wheel base of the rs50.

[seymour14]

After mucking around with subframes and finding various problems with suspension like they front is buggered and the back is buggered. The 50 engine will now be slotted into the NSR they both weigh the same so no big deal really. But I did like the short wheel base of the rs50.

Still think you'll make next week? Times a moving quickly now.

[richban]

Still think you'll make next week? Times a moving quickly now.



Dyno tomorrow. Hell yes I will make it. Looking forward to seeing how it goes. It has never been on a dyno before so tomorrow will be the base line. Lets hope the line is the right shape.

[kel]

TZ spaced the plug with a copper washer to get it around 4.5mm from the piston,
the depth of the plug insert was to allow the unthreaded part of the plug to sit in the combustion chamber like this
320145
You gave the top secret design to the Griffiths :facepalm:

[seymour14]

the depth of the plug insert was to allow the unthreaded part of the plug to sit in the combustion chamber like this
320145
You gave the top secret design to the Griffiths :facepalm:

And I didn't even give you one billion dollars...

[cotswold]

the depth of the plug insert was to allow the unthreaded part of the plug to sit in the combustion chamber like this
320145
You gave the top secret design to the Griffiths :facepalm:

lol me and TZ looked at that and thought it looked a bit far down, when we measured the distance between the plug and piston it was outside TZ's comfort zone, so you are saying take the washer back out????

[cotswold]

And I didn't even give you one billion dollars...

you promised not to look while you made it..........:gob:

[richban]

Ok so we have a base line. We got it going with stock ignition and a blind guess with the main jet. 13.2hp @ 11500. and reved to 14k Big hole after peak power.


Hummm.


Ok we were going to fit the igntech anyway so did that. Few issues there, solved by Glen and google translate. Czech to english from the igntech site. Boom away we go.

Still same main jet and some ignition fiddling and 13.7hp still peak @ 11500. big hole blah blah blah. So we thought well lets try jet it. Changed to leaner main and then strange scrapping noise appears in engine. So that is where we left it. I am about to go up to the shed and do two things. 1 change pipe reducer from 13mm to 14mm. 2 find out what the bloody noise is. I am hoping its the clutch.

Anyway this thing revs to 14k happy. and makes 13.7 at 11/ 5. Still no proper cylinder head design and pipe is shithouse. A good start for a rush job.

[mr bucketracer]

Hope the clip did not come out. Did on mine. Never had it happen before

[F5 Dave]

Still super impressed. Way better than we could manage in the old days

[TZ350]

13.7hp still peak @ 11500

13+ at 11.5 super impressed ...... :drinknsin

[kel]

Still super impressed. Way better than we could manage in the old days

Um, something about didn't have bolt up goodness in the old days! You fucken oldies with you porting tools :killingme

[richban]

13+ at 11.5 super impressed ...... :drinknsin

OK so a little embarrassing. Seams It would like more than 400ml of gearbox oil for the clutch. I did talk about running a dry clutch but not quite like this. Opps! Engine is fine. Topped up with oil and rev rev argy little beast is back. On wards and upwards. I won't get time to do anymore dyno work so next tuning will be with egt and at the track.

[richban]

Um, something about didn't have bolt up goodness in the old days! You fucken oldies with you porting tools :killingme

Fuck your bolt on mate. I have spent days porting the cases and cylinder. If I bolted it straight on it would have about 8hp.

[F5 Dave]

Whoa, bad insomnia Rich.

[richban]

Whoa, bad insomnia Rich.

No time for sleep when your power curve is bung and the engine is on the bench.

[mr bucketracer]

Fuck your bolt on mate. I have spent days porting the cases and cylinder. If I bolted it straight on it would have about 8hp.cool ,i have days to catch up with my 3hour weid reed in + port jop , the head did take me awile to do at 2 hours

[F5 Dave]

Well we could have done better today. Head reshaped from the f-up it was before. But not the huge gained expected. But two big variables. Different dyno and also the av i had was that before my accident. That was April and was a month or two before. That makes it a year old sitting in a plastic container.

Still quick shifter set up and gear lever sweetly sorted.

[chrisc]

I'm surprised it even ran, or didn't blow up Dave

[F5 Dave]

I dunno, think it was 14.8 or 15.8 but my 50s have always been reliable. The RG was built in 04 and has has a ring every year and maybe 3 pistons, same crank, 14000 rpm overrev. New clutch basket inner. Probably the most reliable bucket ever to win like six gps.

[steamroller]

Fuck your bolt on mate. I have spent days porting the cases and cylinder. If I bolted it straight on it would have about 8hp.

They put out 8hp standard why not just use that barrel:eek:

[chrisc]

I dunno, think it was 14.8 or 15.8 but my 50s have always been reliable. The RG was built in 04 and has has a ring every year and maybe 3 pistons, same crank, 14000 rpm overrev. New clutch basket inner. Probably the most reliable bucket ever to win like six gps.

I meant with that stale fuel

[chrisc]

Speaking of which, I have a bit of avgas left from the nationals this weekend that someone is welcome to. Also about 8 litres mixed 30:1 with elf 976 too.

[Juho_]

Still same main jet and some ignition fiddling and 13.7hp still peak @ 11500.
...
Anyway this thing revs to 14k happy. and makes 13.7 at 11/ 5. Still no proper cylinder head design and pipe is shithouse. A good start for a rush job.
That's a great peak hp number, if measured / calculated power from gearbox or back wheel.

The Athena 50cc (old model, with T -exhaust port, same as you have), has "ok" transfer ducts as stock form.
I know two racing engines, that have the same cylinder with only some small modifications and combustion chamber machined for larger volume (to get the engine rev and actually make some power).
They had around 15hp@~11.8-12krpm from back wheel at Fuchs dyno, at their best jetting and ignition timing.
Both with PWK28, but with different inner rotor ignition systems and the other one with an aftermarket pipe (SCR RL50 ; other bike had a DIY pipe, but still made approx. same power at around same rpm's).

Do you have any molds of the transfer ducts..? Just curious.
I didn't have a chance to make vinamold molds from the transfer ducts, when I had Athena 50cc cylinder, that I ported for a customer.

[richban]

That's a great peak hp number, if measured / calculated power from gearbox or back wheel.

The Athena 50cc (old model, with T -exhaust port, same as you have), has "ok" transfer ducts as stock form.
I know two racing engines, that have the same cylinder with only some small modifications and combustion chamber machined for larger volume (to get the engine rev and actually make some power).
They had around 15hp@~11.8-12krpm from back wheel at Fuchs dyno, at their best jetting and ignition timing.
Both with PWK28, but with different inner rotor ignition systems and the other one with an aftermarket pipe (SCR RL50 ; other bike had a DIY pipe, but still made approx. same power at around same rpm's).

Do you have any molds of the transfer ducts..? Just curious.
I didn't have a chance to make vinamold molds from the transfer ducts, when I had Athena 50cc cylinder, that I ported for a customer.



Hi Juho.


That was at the back wheel. I am making a new FOS pipe this week so hopefully the engine will carry on making power up over 13k. It has no trouble reving. It just needs the pipe to make it all happen. No mould's sorry. This is very rush rush. After this race meeting I will pull it apart and to model in engmod.

Cheers Rich.

[mr bucketracer]

Speaking of which, I have a bit of avgas left from the nationals this weekend that someone is welcome to. Also about 8 litres mixed 30:1 with elf 976 too.you may want the non mixed stuff (-;

[richban]

Many hands make light work. After 4 hours of good times and smack talk. Andrew and I produced this little gem. All hand rolled and a little rush rush. But man does it sound amazing. All going well, this will fill the hole from 12 to 14 with big fat chunks of horsepower. We will see.



320245

[mr bucketracer]

Many hands make light work. After 4 hours of good times and smack talk. Andrew and I produced this little gem. All hand rolled and a little rush rush. But man does it sound amazing. All going well, this will fill the hole from 12 to 14 with big fat chunks of horsepower. We will see.



320245nice work rich

[cotswold]

Rich that 50 is looking scary good in such a short period of time, hate to think how many horses you will pull out of it given a year..........nz's first 20bhp 50??

Coolants, do any of you boys use one and if so which one. I got sold a bottle of Motocool expert by Motul as being track safe but after a bit of reading I am now unsure.
Waterwetter is coming tomorrow which is track safe but it's not what I was originally after.

[richban]

Rich that 50 is looking scary good in such a short period of time, hate to think how many horses you will pull out of it given a year..........nz's first 20bhp 50??

Coolants, do any of you boys use one and if so which one. I got sold a bottle of Motocool expert by Motul as being track safe but after a bit of reading I am now unsure.
Waterwetter is coming tomorrow which is track safe but it's not what I was originally after.


Water wetter works well. Also Motul Mocool is great. blue label concentrate.

Not sure about hp on the 50. I would be happy if I get in running nice. On that note I really need a rear RS sprocket above 48 tooth. If anyone has one they would like to sell or lend me. Please bring to GP.

[F5 Dave]

Penrite 10 tenths is tracksafe
There are two types of glycol apparently.

[husaberg]

Penrite 10 tenths is tracksafe
There are two types of glycol apparently.

ethylene and propylene from memory.
The poly stuff is dearer and sold as fashionable racing coolant for MX4 stroke race bikes.
http://www.engineice.com/

Propylene Glycol you can buy from a vets.
Its food grade 100 percetnt pure as its used treat ketosis in Cattle and sleepy sickness in Sheep (metabolic disorders that basically need a sugar hit)
http://www.revivalanimal.com/Propylene-Glycol.html

[cotswold]

well it made me sad,
my nice new head has been removed and replaced by the piece of shit original one due to a leaking fitting that i have no time to replace. The shock has a softer spring so at least that seems to be all good.
Next year :brick::cry:

[TZ350]

Can you repair the fitting, glue it in place with 5min Araldite.

[husaberg]

Can you repair the fitting, glue it in place with 5min Araldite.

Paging F5dave............

Note shouldn't you be suggesting ballazona or whatever it was?

[F5 Dave]

Not me. Be Devcon or JBweld.

[husaberg]

Not me. Be Devcon or JBweld.

Yeah, but I knew you would know just what to use;)

[F5 Dave]

Water wetter works well. Also Motul Mocool is great. blue label concentrate.

Not sure about hp on the 50. I would be happy if I get in running nice. On that note I really need a rear RS sprocket above 48 tooth. If anyone has one they would like to sell or lend me. Please bring to GP.
Sorry man I have a 45 only. My other 48-51 range runs on a carrier that's on the 50 currently.

[cotswold]

Can you repair the fitting, glue it in place with 5min Araldite.

Well thanks to Roger who had a couple more fittings made up looks like I'll be doing a back to back at the track :D

[Buttman18]

My Rg50 the night before the RNZAF 6 hour Mopedathon came 2nd in class behind an Aprilla 50cc

320517

[cotswold]

A mate from the Netherlands has sent me a late xmas present, means I will have to get another insert made up but should be worth it as this was built for his lad as his spare cylinder, his best one makes 17BHP so will be interesting to see where this one is at.

On from the GP disaster I have just started delving into what went wrong, I did find that when I rebuilt the carb the pilot jet was a 55 when I thought it had a 40 as that's what I had ordered, so I have rectified that, the other thing that was not really thought out was I had added a Scitsu tacho and some one mentioned it may have been interfering with my ignition??
I just compared the exhaust port on the new cylinder to the one on mine which (due to honda making the wall too thin) is pretty much maxed out and the Dutch Aluminium after market cylinder has a much bigger port which I will be unable to copy without some engineering.

[FastFred]

320753

Rag in the cylinder hiding the ports, very Rygerish.... :bleh:

[cotswold]

320753

Rag in the cylinder hiding the ports, very Rygerish.... :bleh:

Thats why the piston is still in the box too

[lodgernz]

Coolants, do any of you boys use one and if so which one. I got sold a bottle of Motocool expert by Motul as being track safe but after a bit of reading I am now unsure.
Waterwetter is coming tomorrow which is track safe but it's not what I was originally after.

According to someone on the ESE forum, the only coolant additive approved for MotoGP is GLYCEROL at 2 - 5% (with water of course).
NOTE: This is ****NOT**** Ethylene Glycol or Propylene Glycol or any kind of Glycol.
You can buy Glycerol at any pharmacy.
It acts as a rust inhibitor and a wetting agent. I've been using it for a year and it seems to work fine.

[husaberg]

According to someone on the ESE forum, the only coolant additive approved for MotoGP is GLYCEROL at 2 - 5% (with water of course).
NOTE: This is ****NOT**** Ethylene Glycol or Propylene Glycol or any kind of Glycol.
You can buy Glycerol at any pharmacy.
It acts as a rust inhibitor and a wetting agent. I've been using it for a year and it seems to work fine.

I have never heard of that one, neat
But in MNZ rules

10.13.2 Ethylene Glycol is banned from use in road race radiators.
Thus I assert Propylene Glycol is in NZ at least legal in MNZ events.
Funny enough you should be able to get pure Propylene Glycol at a pharmacy or even cheaper still from a Vet. (Its used for Ketosis and sleepy sickness treatment)
So unlike Ethylene Glycol you can feed it to pets with out negative effects.
I am not sure if its slippery though. Which is why (I think) the Ethylene Glycol was originally banned.

[cotswold]

................................

[richban]

got the 50 running last night with the new insert head but something odd has happened to the rev range, still if I can find where the revs have gone it should go pretty well, thanks TZ and Fast fred for your help

Like scott said on ESE thread. Must be massive comp? What comp is it? Also maybe the squish velocity is to high. Totally guessing with that but could be.

[cotswold]

Bought some Brisk plugs from Martijn at Emot as don't fancy having the NGK ones falling apart on me. These are the Brisk Silver race plugs and came well recommended, not too expensive at 12.50 euro's each

[mr bucketracer]

Bought some Brisk plugs from Martijn at Emot as don't fancy having the NGK ones falling apart on me. These are the Brisk Silver race plugs and came well recommended, not too expensive at 12.50 euro's eachi see you biding on my rd50 (-;

[cotswold]

i see you biding on my rd50 (-;

My daughter wants something a bit cooler than a scooter for her 1st bike you should stop bidding as you have enough toys already ☹️

[lodgernz]

There some nice cylinders available in Europe for RD50s. Just sayin'....

[mr bucketracer]

My daughter wants something a bit cooler than a scooter for her 1st bike you should stop bidding as you have enough toys already ☹️have not bid , if was the right price maybe

[mr bucketracer]

There some nice cylinders available in Europe for RD50s. Just sayin'....air cooled ones ? do you have a link?

[TALLIS]

have not bid , if was the right price maybe
No no... 50's are suppose to have cams, lots of cams.

[mr bucketracer]

No no... 50's are suppose to have cams, lots of cams.i guess they should :2thumbsup

[lodgernz]

air cooled ones ? do you have a link?

I was thinking of Polini and Malossi. They both do air-cooled and water-cooled RD/DT cylinders, but I suspect they were all big-bore.
Maybe you could make a fast RD70 or 80?

[sonic_v]

air cooled ones ? do you have a link?

Here's a standard one.

http://www.ebay.co.uk/itm/NEW-CYLINDER-BARREL-KIT-50CC-FOR-YAMAHA-RD50-RD-50-AC-/152030075144?hash=item2365b2d908:g:2cMAAOSwHQ9WV1p V

[dark art]

Airsal also makes a good alu/nikasil 45mm cylinder.
I´m sure you can find it a lot cheaper:

http://www.racing-planet.co.uk/cylinder-airsal-sport-yamaha-p-162390-1.html#.Vw8qyXr9ldg

[TALLIS]

My new Mickey mouse 50 :woohoo:

[mr bucketracer]

My new Mickey mouse 50 :woohoo:make it a hundy and we are 4 stroking :yes:

[TALLIS]

make it a hundy and we are 4 stroking :yes:

It's in the mail :shifty:

[Grumph]

Many moons ago there was a real CR110 Honda 50 in NZ. Dale Wylie picked it up in Malaysia for Bob Harris in ChCh. I think Dale won a NZ50cc GP on it at Ruapuna. Long since sold to an overseas collector.

[cotswold]

Can any one give me the cylinder stud spacings for their water cooled 50's, I have a project engine I am playing with and it has a 70 kit I want to ditch and replace with a 50, mine is case reed with studs spaced square 52mm

[husaberg]

Can any one give me the cylinder stud spacings for their water cooled 50's, I have a project engine I am playing with and it has a 70 kit I want to ditch and replace with a 50, mine is case reed with studs spaced square 52mm
Google told me
http://www.mopedarmy.com/wiki/Moped_and_scooter_stud_spacings

he told me this too
http://www.apriliaforum.com/forums/archive/index.php/t-242814.html

Useless factoid is the XR200 and 125S and H100/MB100 all have the same stud spacing's.
I have no idea why...........
If anyone does please write the reason on a $20 note and post it to me.

[cotswold]

[QUOTE=husaberg;1130966954]Google told me
http://www.mopedarmy.com/wiki/Moped_and_scooter_stud_spacings

he told me this too
http://www.apriliaforum.com/forums/archive/index.php/t-242814.html



http://www.mopedarmy.com/wiki/Moped_..._stud_spacings

Cheers Husa but this only tells me what wont fit , I already found that one. I was hoping that the Aprilia RS had the same spacings and one of our Euro friends confirmed it for me

[richban]

So it it an AM6 engine Tim?

I have just started getting my 50 into engmod. A few lessons already. My reeds don't have enough area to make the power I want. Also pipe needs a small adjustment. But that timing of 192 / 130 is hard to beat.

[cotswold]

So it it an AM6 engine Tim?

I have just started getting my 50 into engmod. A few lessons already. My reeds don't have enough area to make the power I want. Also pipe needs a small adjustment. But that timing of 192 / 130 is hard to beat.


No Rich it's a cvt project, I have on the plans

[richban]

No Rich it's a cvt project, I have on the plans


Yuck. Gears are the future. I can see the advantages. I have raced an auto scooter, its a different ball game as far as riding goes. My advice is look into rear bake systems that will give max control. Its all about the rear brake to tip in and keep mid corner stability. But after that its all a bit boring. Fast boring though.:shifty:

[cotswold]

Yuck. Gears are the future. I can see the advantages. I have raced an auto scooter, its a different ball game as far as riding goes. My advice is look into rear bake systems that will give max control. Its all about the rear brake to tip in and keep mid corner stability. But after that its all a bit boring. Fast boring though.:shifty:

It's just another project I fancy trying, not a replacement for the Honda

[F5 Dave]

So it it an AM6 engine Tim?

I have just started getting my 50 into engmod. A few lessons already. My reeds don't have enough area to make the power I want. Also pipe needs a small adjustment. But that timing of 192 / 130 is hard to beat.
31* blowdown is not much at all. You'd have to have mondo ex area above the transfers to make that work. I've been running 196\128 on the single Port, but even on the triple with same timing the symptoms are blowdown limited. (Though the auxs are way small, I did them 10 yes ago before I'd seen an RSA barrel).

Heck in the old days I ran 202 at 12000. But clueless then. As now.

[richban]

31* blowdown is not much at all. You'd have to have mondo ex area above the transfers to make that work. I've been running 196\128 on the single Port, but even on the triple with same timing the symptoms are blowdown limited. (Though the auxs are way small, I did them 10 yes ago before I'd seen an RSA barrel).

Heck in the old days I ran 202 at 12000. But clueless then. As now.

Engmod is saying 192 to 194 all Good. 196 loose power. 198 loose more power. Not messed with the transfer timing yet. This is all based on the pipe it is currently running. The Malossi pipe Frits so kindly supplied.

[F5 Dave]

At what peak revs? You're T port with barrel?

Most gp bikes were around 33 deg. But single port is what we had to play with until recently so needed much much more.

[richban]

At what peak revs? You're T port with barrel?


T port, 14K