2 strokes and emissions | GTAMotorcycle.com

2 strokes and emissions

CaMBo

Member
Ive riding dirt bikes for some time love 2 strokes to death the cheap reliability and easy rebuilds are the **** but im wondering if I can some how swap a big 2stroke like a kx500 or cr500 into a streetbike frame something like a sv650 or maybe something smaller and a little lighter would be even better but you get my idea if I was to do this over the coarse of some time obviously is there a way to even get it to pass emissions or am I better off finding a old school 2 smoker street bike
 
It depends on what you mean by "pass emissions." There are no emissions testing programs in place for motorcycles in Canada... or anywhere in the world, as far as I'm aware. So there is no form of regular emissions inspection that you would fail by changing the motor on a bike. I can't remember the letter of the law anymore, but I believe it is worded that changing any part of the emissions systems of a vehicle is not allowed. It is unlikely that there is an interpretation that would allow you to get away with swapping a 4 stroke with a 2 smoke... legally. The enforcement of such laws is spotty and irregular, however, so as long as you managed to get someone to sign off on a safety certificate, it is possible that it would never come up. Getting bikes with engine swaps insured can be substantially more difficult, or impossible (no personal experience and haven't heard any recent stories).

For interest's sake, you might want to look at this RZ350 a forum member is building: http://www.gtamotorcycle.com/vbforum/showthread.php?180770
 
I've only ever dealt with the Environmental Protection Act with respect to emissions, but that's more for cars and catalytic converters. I'm not aware of anything that would prohibit a swap like this... but I'd be interested to find out, in case anyone turns anything up!
 
The HTA doesn't say anything about it, but your insurance company might have a thing to say about whether they will insure a "modified" vehicle.
 
Yea my insurance is already somewhat bad due to a bad stint riding my 300exc on the road :( and a few speeding tickets a while ago was planning on building a bike over the coarse of a yr when my abstract is clean again :( but I can see the difficulty getting one insured, I was rather thrown off the rz350 due to its age but there is some aftermarket support for them just thinking it would be somewhat slow for road use/short highway
 
The HTA doesn't say anything about it, but your insurance company might have a thing to say about whether they will insure a "modified" vehicle.

I think the emissions stuff that I'm thinking of (if I'm not making it up) is federal and not provincial, does that sound right?
 
I think the emissions stuff that I'm thinking of (if I'm not making it up) is federal and not provincial, does that sound right?

Federal law specifies emissions equipment standards required on new vehicles offered for sale in Canada.

Provincial law covers emissions equipment on vehicles operated within a given province. Ontario's laws prohibit removing or tampering with emissions equipment to render it less effective.
 
Yea my insurance is already somewhat bad due to a bad stint riding my 300exc on the road :( and a few speeding tickets a while ago was planning on building a bike over the coarse of a yr when my abstract is clean again :( but I can see the difficulty getting one insured, I was rather thrown off the rz350 due to its age but there is some aftermarket support for them just thinking it would be somewhat slow for road use/short highway

An RZ350 is hardly "somewhat slow" ... and at least they'll withstand continuous high speed operation! Dirt bike engines aren't designed for those load conditions. In the early days of "motards" when people converted dirt bikes for road use (no longer legal) they blew up regularly when people rode them on the highway. Vibration control isn't a strong point of a big single, either.

For a street bike, just get something four-stroke, counterbalanced/multi-cylinder and reliable (not a dirt bike engine) ... A modern bike with everything engineered to work together properly will work better and stay together longer than any homegrown mongrel ever will ... and you can insure it. The two-stroke might be easier to rebuild, but the four-stroke (outside of motocross dirt bikes, which are too highly stressed to live long) is less likely to ever need a rebuild.
 
Yea I would agree as a road machine a 4stroke multi cylinder bike would be most practicable and reliable BUT the sound of a 2 stroke calls to me always :( had a rmz450 for abit had to sell and get my 2 stroke back theres just something about the simplicity the sound and RAW power out of the tiny engines I love them -.- the pick would be mostly a weekend hooligan/fun machine not a commuter so rebuilds and wrenching isnt a big deal. been doing my research on rz350's there's abit of aftermarket support for em like borekits and cranks might go check one out on the weekend and that weight is nice dont really want a modern 400-600lb bike seeing as im 5'10 and 145 not the biggest guy
 
...dont really want a modern 400-600lb bike seeing as im 5'10 and 145 not the biggest guy

If you mean you can get more out of a small bike because you're lightish, then I can understand that. If you mean regular bikes would be harder to throw around, though, my favourite ride to date is a ZX-11D (close to 500lbs) and I only weigh 125
 
rg is a little to expensive for me they got for around 15k easily I can get my hands on rz's 2-5k easily and do the wrenching myself an I do mean I think I would get the most out of a smaller bike and especially a 2stroke. I would make the transition from dirt to pavement a little easier allowing me to feel more comfortable with the bike quickly.
 
I could see why can be lasy with a zx11 dont even have to shift :p and being 125 you dont find it a little cumbersome at times?
If you mean you can get more out of a small bike because you're lightish, then I can understand that. If you mean regular bikes would be harder to throw around, though, my favourite ride to date is a ZX-11D (close to 500lbs) and I only weigh 125
 
I could see why can be lasy with a zx11 dont even have to shift :p and being 125 you dont find it a little cumbersome at times?

Nah. Only if I absentmindedly parked facing downhill and I had to waddle it out, then things got tricky. Otherwise city riding & centrestand were no problem. Even picked it up solo once or twice :p
 
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I've only ever dealt with the Environmental Protection Act with respect to emissions, but that's more for cars and catalytic converters. I'm not aware of anything that would prohibit a swap like this... but I'd be interested to find out, in case anyone turns anything up!
Almost no insurance company will touch a bike (or car for that matter) with engine mods.

That said, most people just don't disclose their mods and hope they never get caught.
 
An RZ350 is hardly "somewhat slow" ... and at least they'll withstand continuous high speed operation! Dirt bike engines aren't designed for those load conditions. In the early days of "motards" when people converted dirt bikes for road use (no longer legal) they blew up regularly when people rode them on the highway. Vibration control isn't a strong point of a big single, either.

For a street bike, just get something four-stroke, counterbalanced/multi-cylinder and reliable (not a dirt bike engine) ... A modern bike with everything engineered to work together properly will work better and stay together longer than any homegrown mongrel ever will ... and you can insure it. The two-stroke might be easier to rebuild, but the four-stroke (outside of motocross dirt bikes, which are too highly stressed to live long) is less likely to ever need a rebuild.

My RS125 survived Ottawa and back at 140+.

There was another 2 stroke thread on here somewhere recently where I brought up the reliability of 2 strokes and rebuild costs and everyone in the thread told me people are switching back to 2 strokes for reliability and lower maintenance costs. So confusing.
 
4-stroke motocross engines are much more expensive to keep running than the equivalent 2-stroke was. But those engines are very highly stressed. They're both designed to last a certain number of hours, but then the 4-stroke requires a much more expensive overhaul.

Back off the stress level and then the 4-strokes last exponentially longer. The pistons and piston rings have a much more favorable lubrication situation, the rolling-element bearings in the bottom end of a 2-stroke inherently have a finite life and hydrodynamic bushings (4-stroke) are not subject to this, 4-strokes have a much better situation with regards to piston cooling (e.g. oil jets spraying at the bottom of the piston - can't do that with a 2-stroke). The 2-stroke has its piston rings crossing the intake and exhaust ports on every revolution; 4-strokes don't have this issue.
 
4-stroke motocross engines are much more expensive to keep running than the equivalent 2-stroke was. But those engines are very highly stressed. They're both designed to last a certain number of hours, but then the 4-stroke requires a much more expensive overhaul.

Back off the stress level and then the 4-strokes last exponentially longer. The pistons and piston rings have a much more favorable lubrication situation, the rolling-element bearings in the bottom end of a 2-stroke inherently have a finite life and hydrodynamic bushings (4-stroke) are not subject to this, 4-strokes have a much better situation with regards to piston cooling (e.g. oil jets spraying at the bottom of the piston - can't do that with a 2-stroke). The 2-stroke has its piston rings crossing the intake and exhaust ports on every revolution; 4-strokes don't have this issue.

Thanks. I didn't realize there was much difference between the engine in a motocross bike vs any other bike. From taking a quick look at some info on a Honda CRF450X I see they recommend oil change and valve clearance check every 1000 km. I can see how that could get expensive and irritating if you ride it a lot.
 
Actually the crf x models still are better than the r models ( full moto x race bike). The valves need checking more often than 1000 km. A lot of my friends ride these 4t mx bikes as trail bikes. More often than not, by the time they check the valves, they have to replace them not shim them.

Sent from my iPhone using Tapatalk
 
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