FXR150 engine modifications?

[hmurphy]

I have searched the forums and haven't found what I wanted. I might be able to but it would take a lot of reading.

Basically... how do I get more performance out of my FXR150 engine? It is now a 156cc engine with hot cams and I am running it on avgas (because a couple others told me I should). The bike is faster than it was when it was stock but not by a massive amount really.

So... what have other people done from here? Raise compression etc? I don't know how it all works with the FXR engines and I don't know how much it will cost. I don't want another 10hp, but another 3 - 5 wouldn't hurt.

Cheers

[Moooools]

:crybaby: Waah waah waah my bike's not fast enough. :violin:

You could try to port it yourself and fit a high compression piston.
Or send it to someone along with a big pile of cash. Maybe your friend Gavin? :innocent:

I'm sure someone will be along with some more useful and specific advice.

[koba]

I have searched the forums and haven't found what I wanted. I might be able to but it would take a lot of reading.

Basically... how do I get more performance out of my FXR150 engine? It is now a 156cc engine with hot cams and I am running it on avgas (because a couple others told me I should). The bike is faster than it was when it was stock but not by a massive amount really.

So... what have other people done from here? Raise compression etc? I don't know how it all works with the FXR engines and I don't know how much it will cost. I don't want another 10hp, but another 3 - 5 wouldn't hurt.

Cheers

Break into Rich's garage with it and do the old switcheroo with his last one?

[hmurphy]

Fucken genius Malcolm.

[richban]

The more air / fuel getting pumped through the more power. Little bit of porting, bigger valves, not to much compression don't want to loose top end. There you have it. More power. Oh and get the fueling and exhaust right. Go to it.

[hmurphy]

Awesome. Where/who do I go to for that stuff? Any decent places or people in town?

[Shorty_925]

Should add 40kgs to yourself and run a stock motor :brick:

[F5 Dave]

:crybaby: Waah waah waah my bike's not fast enough. :violin:
. . . .
That's gold.

Actually in the Richban vids Gavin's bike did seem quite quick.

Just use the Fishie approach. Open the throttle & don't close it till its too late & make it anyway. repeat.

[F5 Dave]

Should add 40kgs to yourself and run a stock motor :brick:
I could retort with 'make it 15 & run an engine 1/3rd the size of everyone else'.

[Buddha#81]

chase as much hp as you like it wont make up for riding skill. There are a couple of young guns down here on fairly standard FXR's that constantly give us the learn.....unfortunatly one seems to think he wasnt fast enough so has gone to a CBR!

[hmurphy]

So you're saying I don't have enough riding skill?

That may be the case but I still think another 5hp might be nice. I personally think it's pretty obvious that I'm losing a fair chunk on some of the straights to the likes of Gavin's, Richard's and Andrew's bikes. I can also see where I need to improve by watching the videos, and places where I make a bit of ground, but I'm still riding below a 43 sec lap on Kaitoke and that keeps me happy.

[Buddha#81]

So you're saying I don't have enough riding skill?


Might be.....but that would be rude when i dont even know ya:innocent:.......Fishman seems to go ok with a poxy Luncheon:sick:. Maybe look at handling first?:yes:

[richban]

Funny shit. Well this is motor racing and it is most certainly not an even playing field.

Asking how to make your bike go faster from your option is a little dodgy. You can't really believe anything I tell you for one.

[F5 Dave]

Might be.....but that would be rude when i dont even know ya:innocent:.......Fishman seems to go ok with a poxy Luncheon:sick:. Maybe look at handling first?:yes:
yeah he did that & copied Fishies setup.

Have a look at Richbans vids, the first one. You will see Hamish pop through several times making up for Rich's Millenium Falcon riding like an Injun hiding behind the horse:blink: (actually shown well in Avatar) Unique style, but can't argue with it working.

[Ivan]

if you havent done anything allready get the suspension set up properly you can chase all the power in the world but if the settings dont allow it to handle nice its a waste, get as much weight off the frame to that will make a differnce

bigger carb jetted properly with the ports done would give you abit even if its just cleaning the ports up and taking out any impuritys in them quite a few guys i know who built hot rod dirtbike engines reckon dont polish the inlet port leave it rough as the fuel and air mix better some guys say polish it tho i guess it comes down to what looks better on a dyno.

exhaust system if you havent done it,

another option to the compression raise is look at getting a copper headgasket made half the thickness of your standered one good thing with copper is you can glow it red and cool it down and reuse it again to, was something i got taught when i was working for a mechanic

[F5 Dave]

yeah those big clumsy frame spars should be the first things to go.

pass the hacksaw Eugene.

[hmurphy]

So does anyone know or recommend where I can go or who I can go to for the porting and bigger valves (or any other little tricks to the FXR engine)?

[F5 Dave]

Yeah Rich's bro. .. . Course that might depend on if Rich pays him more to take a dive & discredit his name.

[F5 Dave]

Other sensible option is Pete Sales in PNorth Total MC.

[F5 Dave]

Or Ivan, -if he can decide whether to polish or roughen it. . .

[hmurphy]

Has a good carb, will dyno when the other engine shit is done to tune it better. Exhaust is too noisy at the moment and will be replaced. Standard header pipe is on the bike. Bike handles better than an FXR. I don't have the experience or skill level of Fishy yet but I am trying. So where or who do I go to that can help with 5 more hp?

[hmurphy]

Oh thanks Dave. I would do Kelford Cams (Richard's bro) but that will cost a bomb with the shipping (like last time). Ideally something local would be perfect. I can do Palmerston though. Good excuse to visit my family.

[richban]

Yeah Rich's bro. .. . Course that might depend on if Rich pays him more to take a dive & discredit his name.

He would do what ever you pay him to do. No team orders their. He has done it before. All he tells me is I better get shit together coz there some hot engines out their.

A 5hp gain is a lot when you are starting with 19 or 20. Don't go to the dyno unless you want a number that is useless at the end of the day. You have a key to a track. Thats a very good thing. Hit the books. Go to the library and get the Graham Bell 4 stroke tuning book. Look at intake and exhaust. Yes port it but I can tell you now the standard head is capable of flowing 27ish hp. The valves are the big problem. Bigger is better where they are concerned. But it will cost.

[hmurphy]

I'm only interested in the Dyno for tuning the carb accurately but if you think going to the track and testing is good enough then that suits me. I have done that with this motor and I think I have it about right ish. How much do the valves cost and labour roughly?

[Clivoris]

You could get a CBR200 like I've got. But I need it cos corners are scary and pies are friendly.

[Pumba]

...... I personally think it's pretty obvious that I'm losing a fair chunk on some of the straights to the likes of Gavin's, Richard's and Andrew's bikes.........

That may have less to do with outright horse power than you may think. Carrying a little more corner speed will result in carrying more speed down the straight which will give the appearance of more HP.

[hmurphy]

Call it what you like. It's a fact I'm down a lot of horsepower on a couple of the bikes out there. Yes I can find more speed round the track, Fish has proven that. I only came on here asking for how to modify my engine. No offense mate, I wasn't asking for riding tips in this thread but cheers.

[koba]

That may have less to do with outright horse power than you may think. Carrying a little more corner speed will result in carrying more speed down the straight which will give the appearance of more HP.

Righto,

To all the out of towners reading this:
Yes, normally more power isn't the answer. Yes Normally riding skills and handling count for heaps more.

This ain't a normal situation, Hamish is fast as fuck on Kaitoke, He could probably get a bit faster as rider, maybe, but power WILL improve his situation.

[richban]

Righto,

Yes, normally more power isn't the answer. Yes Normally riding skills and handling count for heaps more.

Malcom are you mental? Hang on, don't answer that. Power is everything. This is Road RACING. Not Trials. Even more important its bucket racing on a short track. Power is even more important. Wash out your mouth. There is nothing wrong with the quest for more power. But I will not mention another thing to Hamish coz I don't want him to beat me.:innocent:

[koba]

Malcom are you mental? Hang on, don't answer that. Power is everything. This is Road RACING. Not Trials. Even more important its bucket racing on a short track. Power is even more important. Wash out your mouth. There is nothing wrong with the quest for more power. But I will not mention another thing to Hamish coz I don't want him to beat me.:innocent:

My bike goes fine with it's lack of power, just look at the results I get on it...

Oh, as you were.

[Ivan]

Or Ivan, -if he can decide whether to polish or roughen it. . .

wow a guy asked for ways of getting more power i told him a few things i had been told by guys who built motors one was a guy who i respect who got a world record on his motor another used to be a mechanic in the world motorcross championships i just said what i had been told,

yet you choose to try and humiliate me like im thick or something???

[Buddha#81]

yet you choose to try and humiliate me like im thick or something???

Some moving targets are easy to hit!:love:

[F5 Dave]

wow a guy asked for ways of getting more power i told him a few things i had been told by guys who built motors one was a guy who i respect who got a world record on his motor another used to be a mechanic in the world motorcross championships i just said what i had been told,

yet you choose to try and humiliate me like im thick or something???
oh Ivan, dear Ivan. You wind up like a cheap clock. If you haven't noticed this is KB & taking the piss out of each other is sport. . . . Actually this is New Zealand & the rules apply pretty much the same.

[Henk]

Dave

This is a serious forum for serious racers, if you want to wind people up I'd suggest you take your piss poor attitude to

www.lemonparty.org

[koba]

Dave

This is a serious forum for serious racers, if you want to wind people up I'd suggest you take your piss poor attitude to

www.lemonparty.org


DON'T DO IT!

Especially if you are at work!

Eww! a new low.

I'm a bit worried about how you found that Henk...

[Henk]

Koba

That's been floating around for so long I thought everyone knew about it, there are a bunch of others just as disturbing but I can't remember them and was too lazy to look them up.

Handy site to send people to when they ask retarded questions and you want to have a dig.
Definitely not safe for work though.

[Buddha#81]

:sick::blink::facepalm::shit: thats there is just fooken wrong......hook line and sinker right there!

[Moooools]

wow a guy asked for ways of getting more power i told him a few things i had been told by guys who built motors one was a guy who i respect who got a world record on his motor another used to be a mechanic in the world motorcross championships i just said what i had been told,

yet you choose to try and humiliate me like im thick or something???

i like full stops they break up my train of though this helps people understand what i am saying and makes me seem like an intelligent human being.

[Str8 Jacket]

i like full stops they break up my train of though this helps people understand what i am saying and makes me seem like an intelligent human being.

Ivan is awesome!!

Unfortunately he is a ginga...... :eek:

[Moooools]

Ivan is awesome!!

Unfortunately he is a ginga...... :eek:

I have one of those in the family. Asked him if he could spot the exhaust port on an engine. Needless to say he couldn't find it, and thought the most logical place for it would be underneath the crankcase. I hope Ivan isn't that bad.:innocent:

But no matter how awesome you are you just can't sound it without propper sentence use.

[Arronduke]

I'm in shock....:facepalm:

Thanks Henk...

[quallman1234]

Surely increasing the compression a bit and tuning the carb, will get you a decent increase in power throughout the range. The carb def's needs tuning.
Dont you already run avgas, so you dont have to worry about changing gas?

Increasing the compression is easy, all you have to do is get someone to skim the head on a mill or use a thinner headgasket. Working out how much you need to take off shouldn't be too bad?

[richban]

Increasing the compression is easy, all you have to do is get someone to skim the head on a mill or use a thinner headgasket. Working out how much you need to take off shouldn't be too bad?

Don't forget to make sure the valves have enough room. Don't want to put them into the pusstion. Speaking of the Pusstion. The one you are running is cheap and shit. It will work fine as is, but you start making a bigger bang and it will need to be upgraded. Plenty of those pistons have given up and caused major engine death when more power has been asked of them.

[richban]

Dont you already run avgas, so you dont have to worry about changing gas?


If it's low compression maybe run 98 instead of avgas. Burn's hotter, makes more power. So I've been told. Problem solved. Cheaper init. Could be bullshit though.

[hmurphy]

Nah tuned the carb much closer to where it should be and is far more rideable. Pulls through a longer rev range and doesn't hate it too much when given lots of gas from low revs. Clears out at high rpm quite nicely now too. It's still nothing like the stock motor, full pin from almost stalling and it would love it. I will be calling up a shop this week or Monday next week about a few things and will see how I go. Will be interesting. Cheers

[F5 Dave]

Don't forget to make sure the valves have enough room. Don't want to put them into the pusstion. Speaking of the Pusstion. The one you are running is cheap and shit. It will work fine as is, but you start making a bigger bang and it will need to be upgraded. Plenty of those pistons have given up and caused major engine death when more power has been asked of them.
Using the pusstin to close the valves instead of spring pressure is actually a top tuning trick. Not having to use heavy valve springs & a mechanical valve closing. That's Desmodronic baby,. . . just applied from the other side, so one part doing two jobs. Colin Chapman would have been impressed.

[NOID]

POWER TO WEIGHT ...... put the fxr on a diet, there is alot of weight in the frame, if you sit down and look at some engineering/frame design books you may find that the frame could loose alot of it beef - im not sure what yourve already done but heres some simple cheap options, grind/cut off all non needed tabs and welds / cut off rear subframe and redesign/build from alloy. fibre glass tank with 2L fuel cell under. look into a Ti exhaust piping, lighter 17inch wheels. go for a run or eat less aswell, the less weight your engine has to push the better. :gob:

So to some it up become a midget with Ti framed, stock fxr engined bike and ull have no issues :shit:

[Henk]

He has already thrown the frame away and replaced it with one from a ZXR250 (I think) but he should drill some lightening holes in those huge spars. I'll bring a holesaw next time I'm heading down that way.

[F5 Dave]

and I'll pitch in a coping saw to play connect the dots:shutup:


and yeah lose some weight Hamish you porker:blink: Maybe get a haircut, clip your toenails real close. . .

[richban]

and yeah lose some weight Hamish you porker:blink: Maybe get a haircut, clip your toenails real close. . .

Pre race colonic and a good hard vomit! 2kg at least.

[F5 Dave]

I still don't think you'd find that much spare in him. I'm full of shit so I'd lose 3kg for sure.

[koba]

I still don't think you'd find that much spare in him. I'm full of shit so I'd lose 3kg for sure.

My before/after weighing experiments with the scales at work show that 300g is an above average yield.

[quallman1234]

My before/after weighing experiments with the scales at work show that 300g is an above average yield.

Which creates the question. Is taking a shit or taking a piss, the better way to lose weight.

[gatch]

Which creates the question. Is taking a shit or taking a piss, the better way to lose weight.

Both for maximum losses.

Or gains, depending on your perspective.

[F5 Dave]

don't forget to blow your nose & have a jack as well.

[Buddha#81]

Another KB thread dragged into the gutter! Good work fellow bucket people, love ya work!:Punk:

[koba]

Which creates the question. Is taking a shit or taking a piss, the better way to lose weight.

A Piss, usually aroud a pint (600ml) for a bladderbuster but with diligent training and focus it can be twice that.

[koba]

Another KB thread dragged into the gutter! Good work fellow bucket people, love ya work!:Punk:

Cheers, we get better at it all the time ;)

[Arronduke]

Dont forget to drink heaps of piss the night before as this will kill shit loads of brain cells and make your brain lighter... :beer:

Fill your tyres with Helium ... about 100psi and the bike will want to float.... now to think of it... oil is quite heavy...

[gav]

OK, just out of interest, any idea how much hp your bike has at the moment, Hamish?
One of the guys here managed to find 1.5hp just by getting the exhaust sorted after using a dyno. Had a pretty decent pipe on it to start with, well, you would've thought it was decent. He's now got around 20hp at the rear wheel. Are you all running the same gearing? Maybe try and swap bikes and see who is faster?

[Yow Ling]

OK, just out of interest, any idea how much hp your bike has at the moment, Hamish?
One of the guys here managed to find 1.5hp just by getting the exhaust sorted after using a dyno. Had a pretty decent pipe on it to start with, well, you would've thought it was decent. He's now got around 20hp at the rear wheel. Are you all running the same gearing? Maybe try and swap bikes and see who is faster?

And then got done at levels for being over 95db.

[koba]

I'm not sure about the power but the current pipe Hamish has definatley creates the noise. :facepalm:

[ajturbo]

So you're saying I don't have enough riding skill?

.

yeah.. you suck..:shifty::innocent:

[gav]

And then got done at levels for being over 95db.

Hahahahaha, and looks like he was back to square one with the pipe he ran at Greymouth. :innocent:

[richban]

Hahahahaha, and looks like he was back to square one with the pipe he ran at Greymouth. :innocent:

At BOB I saw a lot of megaphones of different shapes and sizes floating around. I still haven't managed to get one that works. Tricky bloody things. Will try another one soonish.

[Yow Ling]

At BOB I saw a lot of megaphones of different shapes and sizes floating around. I still haven't managed to get one that works. Tricky bloody things. Will try another one soonish.

Except for Wallys ones they are scientificly based on the style principle, no maths just have to look good, we got all the training we needed from American Chopper. Waldo has a book I think so thats why his are loudest. Mine are loosley based on Kickahas and there are 3 or 4 loosley cloned from mine, one day we will hit on the 11 secret spices and have 25 made in thailand from recycled razorblades

[kel]

Megas are great for noise but pointless on the FXR's with standard cams. From memory standard overlap at 1mm lift is only 3deg, the whole point of the mega is to suck during the overlap.
Of course knowing this doesn't stop me from running one, its ear drum splitting loud so its got to be good! (neighbours dont seem to think its very cool though).

[Dutchee]

Megas are great for noise but pointless on the FXR's with standard cams. From memory standard overlap at 1mm lift is only 3deg, the whole point of the mega is to suck during the overlap.
Of course knowing this doesn't stop me from running one, its ear drum splitting loud so its got to be good! (neighbours dont seem to think its very cool though).
And that's why we have an issue around the country with getting permission to run events.
If it's too loud for your neighbours to put up with, don't ask for the neighbours of tracks to put up with it. When we end up sitting in our garages making vroom vrooom noises because we're not allowed to ride anymore, believe me, loud bike owners will be having their picture up on the dart board so we've got something to do while "riding our bikes".

It ain't cool, it ain't clever and it's nothing new either.
Michelle

[richban]

Megas are great for noise but pointless on the FXR's with standard cams. From memory standard overlap at 1mm lift is only 3deg, the whole point of the mega is to suck during the overlap.
Of course knowing this doesn't stop me from running one, its ear drum splitting loud so its got to be good! (neighbours dont seem to think its very cool though).

Yeah, we are talking far from standard cams here. Its a funny one. I made one for the old engine that seamed to work, but no proof. Was really quite quiet. Next one made the ears bleed.

[richban]

And that's why we have an issue around the country with getting permission to run events.
If it's too loud for your neighbours to put up with, don't ask for the neighbours of tracks to put up with it. When we end up sitting in our garages making vroom vrooom noises because we're not allowed to ride anymore, believe me, loud bike owners will be having their picture up on the dart board so we've got something to do while "riding our bikes".

It ain't cool, it ain't clever and it's nothing new either.
Michelle



Well then that told someone.:shutup:

[Henk]

Rich, you need to run a stock "Stealth" pipe, quiet enough that the guy in front of you doesn't know you are there when you stuff it to them, god knows you don't need more power.

[timg]

Hahahahaha, and looks like he was back to square one with the pipe he ran at Greymouth. :innocent: Yeah, the mega scrapes a little on the right bend after the Ruapuna hairpin, and Greymouth is all right bends so the old one seemed like a good choice for the weekend :laugh:

[Henk]

Well then that told someone.:shutup:

We've had noise control at Mt Welly this year on a quiet practice day, and Roys Hill are out of action at the moment due to a noise complaint, the karts there are getting complaints because the PA is too loud. The one thing that is going to kill our sport is noise, MX and the rest of our dirt brethren have lost venues to noise already, the riverhead forest neighbors were complaining that the CHH chainsaws were too loud at one stage.

The only redeeming feature of Kels megaphone as far as I'm concerned is that it stops him turning right when we run the track clockwise and slows him down a bit because if he doesn't ease off it hits the deck and spits him off.

[koba]

Rich, you need to run a stock "Stealth" pipe, quiet enough that the guy in front of you doesn't know you are there when you stuff it to them, god knows you don't need more power.

It actually works quite well for me...

[richban]

We've had noise control at Mt Welly this year on a quiet practice day, and Roys Hill are out of action at the moment due to a noise complaint, the karts there are getting complaints because the PA is too loud. The one thing that is going to kill our sport is noise, MX and the rest of our dirt brethren have lost venues to noise already, the riverhead forest neighbors were complaining that the CHH chainsaws were too loud at one stage.




Shit that is bad. Do you guys police the noise to 95db and all that in AK? I have plugged up the end of my exhaust to try keep it within legal limits. Making another one that will be better (more quite) at the mo.

[richban]

It actually works quite well for me...

Loud is good when passing. Sketchy used to scare the shit out of me with his creeping up unheard passing. Worked in my favor when he almost crashed from laughing so hard. After I did the big sit up poo pants wobble.

[koba]

Load is good when passing. Sketchy used to scare the shit out of me with his creeping up unheard passing. Worked in my favor when he almost crashed from laughing so hard. After I did the big sit up poo pants wobble.

Fantastic, confirmation that the tactic will work on you.

Now where did I put that 20 horsepower?

[Henk]

Yep it's that bad. We're not nearly as militant about it as we probably should be.

[Dutchee]

I remember riding off-road years ago (probably the Dead Toad or something) and pooing my pants every time a guy on his CR500 came past. His was a stealth machine, and I'd only realise he was there as he gassed on at around my front wheel. Cracked me up every time.

Stealth bikes are cool, loud bikes aren't, and that's just how it is these days (and has been for many years now). There are old threads in here regarding similar things, so I'll shut up, drink some more vino, and leave you boys to it.

[Henk]

I remember riding off-road years ago (probably the Dead Toad or something) and pooing my pants every time a guy on his CR500 came past. His was a stealth machine, and I'd only realise he was there as he gassed on at around my front wheel. Cracked me up every time.

Stealth bikes are cool, loud bikes aren't, and that's just how it is these days (and has been for many years now). There are old threads in here regarding similar things, so I'll shut up, drink some more vino, and leave you boys to it.

Stephen Tapling on an old CR500, the year I got thid in the open two stroke class on my 360 at the toad he came second, and lapped me. He came past at about 2000 RPM and probably still making 35HP. The fact the he could ride didn't hurt

[husaberg]

Except for Wallys ones they are scientificly based on the style principle, no maths just have to look good, we got all the training we needed from American Chopper. Waldo has a book I think so thats why his are loudest. Mine are loosley based on Kickahas and there are 3 or 4 loosley cloned from mine, one day we will hit on the 11 secret spices and have 25 made in thailand from recycled razorblades

http://dairally.net/daihard/chas/MiscCalculators/DaiPipes.htm
http://www.mez.co.uk/mezporting/exhaust_length.html

[kel]

We've had noise control at Mt Welly this year on a quiet practice day, and Roys Hill are out of action at the moment due to a noise complaint, the karts there are getting complaints because the PA is too loud. The one thing that is going to kill our sport is noise, MX and the rest of our dirt brethren have lost venues to noise already, the riverhead forest neighbors were complaining that the CHH chainsaws were too loud at one stage.

The only redeeming feature of Kels megaphone as far as I'm concerned is that it stops him turning right when we run the track clockwise and slows him down a bit because if he doesn't ease off it hits the deck and spits him off.

I've cut the baffle off so all should be good now :2thumbsup

[F5 Dave]

I remember going to races at Auckland where they had the noise meter out & you had to do a lap or so each to pass before racing.

On the other side I remember at Ohakea having to do a ride-by of the tower to ensure you weren't making too much RF interference.

[kel]

I remember going to races at Auckland where they had the noise meter out & you had to do a lap or so each to pass before racing.

On the other side I remember at Ohakea having to do a ride-by of the tower to ensure you weren't making too much RF interference.

Ah the good old days, but it’s not always that simple. JC mentioned that the club has received noise complaints for weekends that we haven’t even been at the track.
Obviously we all have a responsibility to build bikes that are within the prescribed limits (mine is!), and rather than voicing the possible demise of the sport why not focus on compliance, enforcement and reporting. I would think that reporting the facts from the track along with Joe publics untruths would be exactly what council would want to see.
:Offtopic: did someone say FXR engine modifications?

[F5 Dave]

:Offtopic: did someone say FXR engine modifications?
Yeah remove the Cams, put some pegs in the pistons, drill some holes in the barrels & run some sort of driven pump to aid cylinder filling rather than waste an extra engine stroke doing it. Then lets talk about your cheating oversize engine. back to 125 & 24mm carb please.