Water cooling and unlimited carbs for 125s

[TZ350]

It seems to me all the front runners are on FXR150’s, :scooter: what could this mean?

Maybe its time to allow unlimited or 28mm at least, carb’s on F4 125 two strokes and possibly water cooling too. :rolleyes:

I have some RGV250 cylinders just begging to be run with a rotary valve bottom end. :yes:

Then the rewards of unlimited horsepower would be mine. :first:

Bugger actually learning to ride!

[quallman1234]

Do you have any idea how quick GP125's are? I do, stuipdly quick for what they are. (120mph +)
(watercooled 125cc 2 strokes 32mm carb i think?)

Seriously tho, the limits atm are fine imo. Take F5Dave's bike for instance. It cleans up all the other bikes at slipways (admitally might struggle on the big tracks)

[Bert]

Rather than heading for bigger 2-strokes. why don't we enable older (pre95 or 98) 80cc mx motors into the fold. I would guess that there are plently of them around and parts are still very cheap. but have a carb limit of 24mm.

Over in Aus they have let them loose and by all accounts it has leveled things up between the 150 fours and the smelly twos.:clap:

here are the NSW Rules:
http://www.ozbucketracing.com/rules.html

There are some very well presented bikes. :niceone:

Two cents again.
Bert

[koba]

Naa, leave it as it is, the rules are all nice and simple.

Also the really fast two strokes DO go LOTS faster than FXR's there is an example in the vid of the BOB that K14 posted up, the old KV100 MASHED everything down the straights.

Aussies are dicks, the current NZ rules kick arse coz they cater for many many different approaches.

[Pumba]

Your bike is already a bloody rocketship in a straight line, you just need to get it around the corners faster :bleh:

[Bert]

I have some RGV250 cylinders just begging to be run with a rotary valve bottom end. :yes:

Then the rewards of unlimited horsepower would be mine. :first:

Bugger actually learning to ride!

Scott Griffiths attempted that in the late 90's with the attempt to beat the likes of F5Dave and Ray Wilson. but with limited success. he used a XL 100 bore (~50mm Dia) and cut the ports out, mounted on a GP125 motor if i remember rightly.. just an idea for you.

Bert

[Skunk]

Personally I think the carb rules for 125's should be changed to 28mm. Stay with air-cooled though. If we get a consensus here we could submit it to MNZ.

[Skunk]

Naa, leave it as it is, the rules are all nice and simple.
Also the really fast two strokes DO go LOTS faster than FXR's there is an example in the vid of the BOB that K14 posted up, the old KV100 MASHED everything down the straights.
Aussies are dicks, the current NZ rules kick arse coz they cater for many many different approaches.
That 'old KV' is a well developed rocket. Lots of careful planning and tuning. I believe it's also temperamental and peaky. Agreed with you about the Aussies.

[Kickaha]

Personally I think the carb rules for 125's should be changed to 28mm. Stay with air-cooled though. If we get a consensus here we could submit it to MNZ.


Agreed.....

[Bert]

Naa, leave it as it is, the rules are all nice and simple.

Also the really fast two strokes DO go LOTS faster than FXR's there is an example in the vid of the BOB that K14 posted up, the old KV100 MASHED everything down the straights.

Aussies are dicks, the current NZ rules kick arse coz they cater for many many different approaches.

Point one True most of the well built ones do. but it is a dying art.

Point Two also true. Yes the current rules are good, but I guess where i was coming from was the possibility for improvement to the formula. My old sh!tter (which I have had now for 15 years & don't ride it as much as i should) is as old as me 1978 TS100. yes it still go's strong (when i can get it going), but I offen look at it and think maybe there are other options out there which are cheaper and easier, which may encourage more people to come back or start in the sport.

Last point maybe they are dicks, but that is your view. but they also have a better development plateform for younger riders. esp now with Troy introducing the metrakits and young rider race schools at philip island....
Could buckets be this for New Zealand. I think so. you only have to look at the young guys like luke and glen they started in buckets if I'm correct.:whistle:

Ok seem people don't like this idea again, I put it back on the shelf for another couple of years...

B

[Bert]

Agreed.....

Second that.

[speedpro]

That 'old KV' is a well developed rocket. Lots of careful planning and tuning. I believe it's also temperamental and peaky. Agreed with you about the Aussies.

I've ridden that "old KV" in a 2 hour years ago. Apart from falling off three times(see, falling off is nothng new for me) I remember it as being wicked fast but very easy to ride. I don't remember it being tempermental or particularly peaky. I've known the Steadmans for a very long time, Peter owns the KV, and I haven't heard of too many problems with these KE/KV buckets.

It's always interesting to compare performance of modern buckets with those from say 15 years ago. There would be very few, 3 or 4 maybe, nowadays that would keep up at something like an Ohakea GP. That's the problem I suppose with running on kart tracks - there isn't much need for serious engine devlopment. At a GP you could easily expect 6-8 buckets at least as fast as the KV.

[Buddha#81]

Ban all two strokers from bucket racing.....they smell (so do the bikes), they destroy the enviroment (not like my MotoFXR, which emits daisys out the exhaust) and the odd one bloody fast.

I vote it aint broke........

As a side note, i wouldn't mided a visit to aussie for a trans Tasman Challenge with superlites...... we get to keep our slicks!

[Slingshot]

A change in rules for 125cc two-smokers will kill it for those of us running 100cc two-smokers.

[Buckets4Me]

how bout we drop the cc for 4 strokes to 140cc again :dodge:
instead of letting 2 strokes get bigger carbs :angry2:
or an unlimited class
same cc rating but unlimited mods to engine no rules on carbs etc
lets see how good the 2 smoers realy are :2thumbsup

[Skunk]

I've ridden that "old KV" in a 2 hour years ago. ... ...I don't remember it being tempermental or particularly peaky.
I stand corrected - third hand info...

[F5 Dave]

Funny how people think my 50 is fastest bike in welly. It’s only fast once in motion (don’t slow down). For example in the weekend I was comprehensively dragged at the starts by not only an FXR but also a Long-chin. How embarrassing!

As far as allowing 125cc watercooled, hmm, let’s think about this. Nigel’s bike is a sleeved down RGV. How fast do you think it would be if it was 25% bigger?
RGV puts out say 55hp at the rear in road trim. 1/2 that (not that simple but you get the idea) is 27.5hp. Then tune it. Let's dismiss that shall we?

The 80MX idea is bad as they get ridden until junior totally shrapnel’s them, so you’d have to buy a going one & from there just start substituting newer & newer engines until it is totally expensive & all other bikes are uncompetitive.

28mm might be better for the aircooleds.

I fear no 4 stroke.

[Skunk]

Funny how people think my 50 is fastest bike in welly.28mm might be better for the aircooleds.
Fast - yes. Quick - no. Well ridden - yep.

[speedpro]

how bout we drop the cc for 4 strokes to 140cc again :dodge:
instead of letting 2 strokes get bigger carbs :angry2:
or an unlimited class
same cc rating but unlimited mods to engine no rules on carbs etc
lets see how good the 2 smoers realy are :2thumbsup

About the 140cc thing - it either makes a lot of work to allow FXR riders to legally compete or a lot of cheating. It makes no sense to make it difficult to use pretty well the only modern bike available for bucket racing.

The other bit you brought up - read the rules! You also need to check up on just how fast the old school 100cc 2-stroke F4 buckets were. The "old KV" is a good example and I seriously doubt it has had any performance enhancing work done on it in 15 years. My old #6 was an air cooled 100cc bucket which made a healthy 22.5rwhp. I've seen Nigel's RS/RG 100cc watercooled bucket produce 27.5rwhp on Brett Robert's dyno. The "dark side" has a slight advantage on tight tracks with better drive in certain places but on a faster track a "good" 2-stroke will clean them up. It does seem that the dark side's 150cc limit is a good balance from the performance point of view. Pete Sale has even thought of ressurrecting his CB125 reasoning that the extra capacity would allow it to be competitive without being so fragile.

[Skunk]

My feeling is the 100cc watercooled is equal to the 150 four stroke but the aircooled 125 needs a slightly bigger carb in these times. Yes it's possible to make a fast 125/100 two stroke but who is when the 150 is sitting there ready to go? Not many - and generally only the 'old schoolers'. By encouraging the two strokes the 'art' will not be lost.

[nudemetalz]

Funny how people think my 50 is fastest bike in welly. It’s only fast once in motion (don’t slow down). For example in the weekend I was comprehensively dragged at the starts by not only an FXR but also a Long-chin. How embarrassing!


And why can't a Long-Chin be good off the mark....... :chase:

[Bren_chch]

a fast 100cc 2stroke will always beat a fast 150cc 4stroke :devil2:

I think the rules are perfect! putting a 28mm carb on a well built 2stroke 125cc motor will destroy every 100cc 2 stroke. hmm actually i've got a 125 engine here, yeah i vote for 28mm carbs! :clap:

[nudemetalz]

I think the rules are perfect! putting a 28mm carb on a well built 2stroke 125cc motor will destroy every 100cc 2 stroke.

That's exactly right.

If the rules do change, then I'm changing to a 125 2-stroke as well because the Loncin 145 will be so outclassed .

[F5 Dave]

a fast 100cc 2stroke will always beat a fast 150cc 4stroke :devil2: Yes. But a Kart track does make it a different prospect a bit.


I think the rules are perfect! putting a 28mm carb on a well built 2stroke 125cc motor will destroy every 100cc 2 stroke. hmm actually i've got a 125 engine here, yeah i vote for 28mm carbs! :clap:
Hmm, hard to say, carb size, if you wanted to build an utterly grotesque 100 you’d bang on a 34mm carb (why not? RS125s run 39-41mm).

Mathematically it works out that a 24 has ½ the area of a 34. Bear in mind that is for a 100, a 125 could live with a bigger carb.

A 28 is 2/3 the size of a 34. Seems a little fairer.

Maybe a bit of sour grapes, my 125 I gave up on as I didn’t think it came up to as high potential as I thought it should have, so I blame the carb a bit. I should have tried a 28 just for comparison, but I didn’t have the time. DC’s Big bore MB 120 or whatever does show you can make a fast 125 though.

Could be the engine I chose wasn't the right direction. The ports were a little weird. I mean it would have killed Tony's same engine 150/125 I would have thought, but it's hard for me to compare as I've only really run my 125 at Taupo (exploded in practise at BOB in '07). But was revving too high for not enough go to continue development. & it had a nasty habit of expiring, some of that was my fault.

[SHELRACING]

I'm with Buddah, stinky two strokes should be banned or at least subject to emission controls:yeah:

BUT seriously, The two strokes at Mt Welly and Taumarunui the FXR's seem fairly evenly matched. I've had some great battles with TZ350 and PUMBA recently ( Two FZR's and a GP125 ) all 3 bikes had their own advantages and Disadvantages.
At the end of the day it was so close that it was down to who had the biggest Kahoonas....

That makes great racing. You don't have to win to be having a great race...

Leave the rules as they are, go hard, do your best, have fun
:Punk:




Ban all two strokers from bucket racing.....they smell (so do the bikes), they destroy the enviroment (not like my MotoFXR, which emits daisys out the exhaust) and the odd one bloody fast.

I vote it aint broke........

As a side note, i wouldn't mided a visit to aussie for a trans Tasman Challenge with superlites...... we get to keep our slicks!

[Pumba]

BUT seriously, The two strokes at Mt Welly and Taumarunui the FXR's seem fairly evenly matched. I've had some great battles with TZ350 and PUMBA recently ( Two FZR's and a GP125 ) all 3 bikes had their own advantages and Disadvantages.
At the end of the day it was so close that it was down to who had the biggest Kahoonas....

Still not sure if I am comfortable you commenting on the size of my kahoonas, but seeing how I won the weekend the must be the bigesst:first:

[koba]

What I like about the rules as they are is that they cater for so many people and approaches.
I have an NSR frame that (one day) is getting a bucket engine.
I can go LOTS of different ways with such a machine and I like that.

I also like that anyone I know who isn't into the tinkering and fucking about so much can just go and buy an FXR, nylon it up and go for it without having to worry about developing it heaps.

I have chosen the smoky path after seeing the "old KV" in action but after riding an "old CB125" last weekend I also have eyes for a tight tourque tuned 4stroke for really twisting tracks.....:shifty:

This whole situation is fostering development of a broad range of tuning skills in the youf of today. (I hope anyway)
While I'm not THAT young its still better than nothing.

Not too sure about the 125 28mm carb thing as I dunno enough about the 125 path.

[nudemetalz]

Actually I have to admit, Tex on his GP125 & on my Longchin were fairly evenly matched at Kaitoke, although it may have been more to do with our riding then anything else.

[Buckets4Me]

About the 140cc thing - it either makes a lot of work to allow FXR riders to legally compete or a lot of cheating. It makes no sense to make it difficult to use pretty well the only modern bike available for bucket racing.



thats the point make it expensive to run an fxr :bye:
my job here is done :done:

:wari:no more fxr's:wari: :bye:

:Punk: :2guns::shutup:

[Kickaha]

Actually Skunk while you're getting the carb ruling changed can you get the Fuel ruling changed so we can run Methanol in single cam, two valve four strokes:msn-wink:

[bucketracer]

Actually Skunk while you're getting the carb ruling changed can you get the Fuel ruling changed so we can run Methanol in single cam, two valve four strokes:msn-wink:

Nitro for two strokes and is there anything in the rules that prohibits Nitrusoxide.

While working on my 12500rpm GP100 engine I have found that if I take the std 22mm GP100 carb and offset it in the lathe, with two pases it can be bored out in an elongated shape 25.5mm wide by 27mm high. This leaves very little disruption on the sides from the slide cutouts and I also tossed away the idle screw that pokes into the air streem. Not quite a 28mm flat slide but getting closer.

28mm carb for 125 2/strokes. Good idea, anyone know how to get the rule changed.

[speedpro]

so we can run Methanol

I've tried to get Methanol allowed in another class. There is/was a real opposition to it within the MNZ old guard based on the death of that guy who was running it in his 2-stroke at Pukekohe. Never mind that his bike seized because a bit of bog fell out of the hole they had made in the transfer ports allowing air in. He was running Methanol, he died, Methanol is bad. They might have a bit more common sense now, that was a while ago.

[speedpro]

At Ohakea some years ago there was a XL125S engine in a sidecar that ran a good dose of nitro. It had a real bark to it and went well. They were trying it out as they were entered in the sidecar class at Wanganui on the bucket sidecar. There was a couple of bucket sidecars entered that year. They made the "real" sidecars look pretty stupid going through the kink and a few other places. Unfortunately the nitro motor blew up whilst testing a few days before Wanganui so they used a normal motor. The other guys turned up with a KX500 engine in their sidecar in the end. It was tied in knots every time they gave it some gas and the frame had to be welded after every race. Fun to watch though, from a safe distance!!!

[speedpro]

I don't recall clearly but I think before bucket racing became official that 100cc 4-strokes in open could run "fuel" or forced induction.

[TZ350]

I ran methanol in my air cooled Suzuki TR250 late 70's it made all the difference. Pulled out of corners better, ran stronger down the straights and made good power all day.

But I did find that the latent heat of evaporation of straight methanol made the motor run to cold. Cold motor, fuel does not evaporate, runs lean, more fuel colder motor, leaner still, round and round untill raw fuel is dribbling out the exhausts.

The trick is to blend the methanol with something else to get a balance between refrigeration from the latent heat of evaporation of the fuel and a good working temperature for the motor. I settled on a 50/50 mix of methanol and acetone at 20/1 oil ratio.

For those who want to know. If you can run your 4/stroke at 14:1 on methanol you can then run it at 18:1 on acetone but you cant effectively increase the compression ratio on a 2/stroke running alcohol.

Alcohol for two stroke, yes please, one rule for all. :banana:

[Kickaha]

I've tried to get Methanol allowed in another class. There is/was a real opposition to it within the MNZ old guard based on the death of that guy who was running it in his 2-stroke at Pukekohe. Never mind that his bike seized because a bit of bog fell out of the hole they had made in the transfer ports allowing air in. He was running Methanol, he died, Methanol is bad. They might have a bit more common sense now, that was a while ago.

Cal Raybon at Puke on the ex Geoff Perry TZ

Post classic can still run it in four strokes so I don't see why we cant

[k14]

Cal Raybon at Puke on the ex Geoff Perry TZ

Post classic can still run it in four strokes so I don't see why we cant
Anyone got some lying around? I can try it out next weekend at ruapuna in the cb :)

[TZ350]

Cal Raybon at Puke on the ex Geoff Perry TZ

Post classic can still run it in four strokes so I don't see why we cant


It was Cal but on a Suzuki TR500 from Colman's Wanganui as I remember it, quite possibly Geoff's old bike. Joe Lett was the tuner and was spannering it on the day. The moral is, that if you can't get your own Harley racer out of customs in time, be wary of loners. Joe was absolutely devastated, although thats racing, I don't think he ever rarely got over it.

[speedpro]

My mate runs methanol in his race car. Funny stuff to tune when you start getting close to the limits and "stand back" if you cross the limit. He's torched the end of an alloy head once. You could pretty well get your hand inside the cylinder through the hole. Mind you at 11+:1 and 40psi shit happens. He's also scorched all the hi temp HPC coating off one header and melted the pyro.

[TZ350]

Cal Raybon at Puke on the ex Geoff Perry TZ

Post classic can still run it in four strokes so I don't see why we cant


Post Classic pre 72 can run Alcohol in 2 & 4 strokes. So the very bike that bit Cal can still be run on dope.

Pre 82 4 strokes can but 2 strokes not, I expect this is to help mechanically preserve the TZ's and level the playing field for the 4 strokes in pre 82.

I once setup a TZ350 on Alcohol and Nitrus Oxide for fun but never found a straight longenough to push the button. I bottled out, probably the smartest thing I have ever done.

[Kickaha]

It was Cal but on a Suzuki TR500 from Colman's Wanganui as I remember it, quite possibly Geoff's old bike.

Yeah sorry I knew it was a T something or other :lol: and it was supposedly Geoffs bike



Alcohol for two stroke, yes please, one rule for all. :banana:

Nope four stroke only to even the performance up, level playing field and all that bullshit

[F5 Dave]

. . .
While working on my 12500rpm GP100 engine . . .
My brain skipped over this & it popped back in focus.

So this is the peak revs it will ever reach, or peak power & say 750 over-rev?

You will need to do some quite fancy re-engineering to get it to stay together at these revs if you really expect it to survive over 13,000.The old TS’s would never do these revs, the cranks were not capable & I suspect the GPs are similar.

For a bit of a laugh the stock TS flywheels were so heavy that at race tuned revs they would shear off & break cover, shooting off like a ball bearing spun by a airline trick, except a bit more dangerous.

I know someone who made a crazily over-square GP by destroking it so he could run modern 125 piston & spin it crazy. Never really worked.

Or are you going off the tacho, which will be about 2000 rpm optimistic?

[speedpro]

25.5mm wide by 27mm high.

This is going on to a 100cc 2-stroke, right? I wrote the rule deliberately with the wording "carburation equivalent to a single 24mm carb" to stop racers doing this sort of thing, or using a couple of 24mm carbs, etc.

[speedpro]

Dave is right. The Suzuki cranks are crap. Even rebuilding with all new rod and bearings for some reason the big ends don't seem to last, on the TS100/125s anyway. That was only turning them at about 11,000rpm though as the pistons didn't look favourably on going much faster in the TS barrells with the reduced support at the back once all ported. GP motors may be better in that regard. The Honda cranks are definitely best being good for up to 14,000rpm.

[F5 Dave]

. . .The Honda cranks are definitely best being good for up to 14,000rpm.You must have had a 'lucky' one in the sidecar.

[speedpro]

and #6 though that wasn't revved quite as hard as the sidecar. There is a limit though - see avatar.

[F5 Dave]

Bugger, missed that op, I should have asked if that one had spun to 14,001.:doh:

[Buckets4Me]

Dave is right. The Suzuki cranks are crap. Even rebuilding with all new rod and bearings for some reason the big ends don't seem to last, on the TS100/125s anyway. That was only turning them at about 11,000rpm though as the pistons didn't look favourably on going much faster in the TS barrells with the reduced support at the back once all ported. GP motors may be better in that regard. The Honda cranks are definitely best being good for up to 14,000rpm.

well mine is holding up ok 4 years on now and only a slight crack in the piston
it's seen 11000+ rpm and 4 2 hour races
anoher one hase been spun up to 13500 and a micron but ran lean lol
since then it's done ok and realy pulls like a school boy
I wonder how different the gp is over the ts ??? the ts is piston port ????

oh yea the bike hase also had many bad gear changes going down instead of up:blink: :shit:

but never rapped a rod around the crank yet !!!!! :Punk: am more use to the reverse gear change now

[Kickaha]

Dave is right. The Suzuki cranks are crap. Even rebuilding with all new rod and bearings for some reason the big ends don't seem to last, on the TS100/125s anyway.

The dodgy old four strokes seem to last ok though, my GN spent a considerable time with 12000+ showing on the rev counter, it took two season before a valve let go, the crank was still ok

[bucketracer]

Thanks for the input. I have looked for rod kits on the net and it looks like Suzuki used the same rod kit for a lot of 100/125's. So it looks like the GP rod kit is no better then the TS/TF's etc., and a bit limited you tell me. :mellow:

Now thinking about a RGV (50stroke/56bore) Rod and piston kit, but then it will be a 125 and I will be limited to 24mm carb. I can still bore the 100's 22mm carb to 24 as I have't hacked into yet. :)

[speedpro]

A while ago Suzuki superseded all their 100/125 rods to just the one model which happened to be the RM rod. It's a good one as is the silver plated big end bearing they come with. I expect they will be pricey compared to say a Pro-X equivalent.

[bucketracer]

A while ago Suzuki superseded all their 100/125 rods to just the one model which happened to be the RM rod. It's a good one as is the silver plated big end bearing they come with. I expect they will be pricey compared to say a Pro-X equivalent.


Thanks for the tip. But RM?? is it ok to use this rod????

[Buckets4Me]

if it's a replacement for the gp125 then I guess it's a go :shit:
being a road bike spare part and all

[bucketracer]

How come the 4 strokes can rev so high compared to the 2 strokes???

[Slingshot]

How come the 4 strokes can rev so high compared to the 2 strokes???

I'm guessing but it may have something to do with a 4-stroke only having a power cycle every two revs of the crank.

[F5 Dave]

and the word about the Tacho. Often they are so far wrong when they get up in the range as to be laughable. Friend's MB50 that spun up to 17,000, -or so he claimed :rolleyes:

[nudemetalz]

I'll bet your 50 gets around the 12-12.5K range, Dave.
Certainly sounds like it !!!

The Loncin engine, when I programme the tacho correctly to read it :crazy: , revs to around 11,000 before there's no more usable power, although I've seen 12,000 a few times (at Kaitoke, overrev between the short corners).

[F5 Dave]

Yeah but the 50 has a shorter stroke so can put up with more. Even so if you show an RG50 13,000 on a regular basis it will expire in short order. Actually mine revs higher still, but it's still all road parts, just from several different manufacturers.:msn-wink:

If you put your bike on a dyno you will see how optimistic most tachos are. The R6 of last year revved to 17,000. Or 15,500 genuine, so don't automatically assume electronic tacho is correct.

[Buckets4Me]

what about a Micron 3

they seem prety good
all the cart guys use them

[nudemetalz]

True about the optimistic tachos, however, I reckon the tuned Loncin would be about right in the reading (well approx).