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Bumpin up the cc's on xr200r?

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So since there hasn't been much activity going on in the 80-200 forum, I started cruisin and reading the 150-230 forum. 

Today I read a post about a 150, with a kit that bumps it up to a 225? Through all my reading here, all I can really recall for the xr200r, there's the powroll 218 kit, and I think I remember something about a 240?

My question is, how is the 150 able to be bumped up 75cc's, but the 200 at most jumps 40cc's? Is there a bigger kit, or is the 200 motor even capable of handling a bigger setup? I'm just curious about future possibilities. 

Also, what's the difference between the crf150f, and the crf150r? 

Daniel

Edited by Daniel627
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The CRF150/230 engines have greater center to center distance between the crank and tranny mainshaft so they can have a longer stroke than the XR/XL/ATC family of engines. A stock stroke on a 230 is longer than what Powroll can do to a XR200 crank.  The CRF230F head gasket is the same part as the late XR200.

The CRF150R engine is a small water cooled version of the bigger CRF250/450 engines. 

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Ahhhh I gotcha, makes perfect sense. I just thought I'd ask since I have no knowledge of the 150/230 really. I'll look more into the available builds for the 200 after I spend time on the fresh stock motor and feel I'm ready for more power. 

Thanks for clearing up my confusion Chuck

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LoL on not smoking out the neighborhood anymore. Mine has a fresh bore on it, I believe he bored it to 65.5. If I remember right he said he just went .5mm over, and I think it was at stock. I think it has about an hour total run time on it. I got the gear and plate that was recommended for my downshifting problem, just been too damn hot to think about messing with it. I'd never ridden an xr200r before I got this one and had it rebuilt, so I didn't know what to expect, or know a difference in power. 

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The 150R is a modern race tuned engine with water cooling, short stroke, large bore and 4 valves. Very powerful but with shorter life. It does not interchange with the CRF150/230 series.

The early (03-05) CRF 150F is just a downsized 230 with a shorter stroke and smaller bore. These engines as well as the XR200's are limited in bore size by the cylinder stud spacing. You can bore it a little, then you have to start increasing the stroke to get more displacement. 

The later 06 to present 150F is an entirely different motor sharing no parts with the 03-05 engine. The 06+ engine has roller rockers and is lighter and slightly more compact even though it shares the same engine mounts. One significant difference is that the cylinder studs are spaced further apart which allows the use of a much larger piston. That engine is able to go from 150 to 225 just by installing a much bigger piston without increasing the stroke.

I think this engine deserves more attention. There is no one currently stroking it and very few cam choices are available. Even with e-start its about 10 lbs lighter than a 230 engine.

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On 7/27/2017 at 7:51 PM, Chuck. said:

The CRF150/230 engines have greater center to center distance between the crank and tranny mainshaft so they can have a longer stroke than the XR/XL/ATC family of engines. A stock stroke on a 230 is longer than what Powroll can do to a XR200 crank.  The CRF230F head gasket is the same part as the late XR200.

The CRF150R engine is a small water cooled version of the bigger CRF250/450 engines. 

Chuck,  I think the crank to mainshaft distance is the same because I've swapped primary gears sets The rod clearance issue is just related to gear diameter right where the rod swings. The CRF 6 speed gearset is spaced differently without the internal kicker gear. The offending gear just moved a little to the side allowing more rod clearance.

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8 hours ago, arthur6 said:

I just saw an XR200 on Craigslist, the ad said it was bored to 300.

probably 1.00 mm oversize piston,same as 100 cc's lol

You see it all the time on craigslist,people have no idea

 

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Kinda like what I saw recently. Someone selling an xr70, but in the item description they say it's a 60cc bike, yet you look at the pictures and the graphics clearly show "xr70" on it. Not sure if it's not paying attention to the typo, or they're just that dumb lol

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I converted my '85 XR200 to a 250. Bought the cylinder and liner on eBay, trimmed 6mm from the taller 250 cylinder, modified the sleeve slightly to avoid contact with the crankshaft counter throws, and it bolted right on. Faster yes. But it really needs a 250 head and carb to get the full feeling. As an alternative to boring it, consider modifying your 200. Port the head slightly, modify the exhaust, use a iridium plug and jet the carb real good.

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