Yamaha YM1S with Lifan single...need suggestions! - Page 2

makenzie71 · 10-30-2011, 02:32 AM

Things I learned and did this evening...

I was going to pull the jug and piston off my 250 Hi Bird quad and swap them to my 200cc dirtbike motor. Found out it won't really work.

The 230cc (labeled 250) engines are (bore and stroke) 67X65 mm.
The 198cc (labeled 200) engines are 63X62.5 mm.

What I would have gotten was a piston comng up 2.5mm shy of the compression mark. I didn't want to deck the jug that much, and it would have only gotten me another 10~15cc or so.

The heads are itnerchangeable.

I did deck my 200 jug base .010", ported and polished the head a little meaner, and got it all ready to go. I lost one of the wrist pin retainers for the piston, though, so got to wait for that before I go any further.

Weldangrind · 10-30-2011, 03:46 AM

That looks so right! 8)

Does the valve cover actually hit the backbone, or the support tube underneath it? If so, perhaps that can be manipulated out of the way.

Weldangrind · 10-30-2011, 03:49 AM

Quote:

Originally Posted by makenzie71

What I would have gotten was a piston comng up 2.5mm shy of the compression mark. I didn't want to deck the jug that much, and it would have only gotten me another 10~15cc or so.

Out of curiosity, are the connecting rods the same length? If not, perhaps the longer rod will make up the difference. If they are, then can you swap the crank over as well? You'd get the extra 30cc out of it.

makenzie71 · 10-30-2011, 11:35 AM

I actually didn't get that far lol. It was a matter math.

Now that I'm thinking about it I am considering splitting the case of this 200 I have and seeing how the transmission is setup...I would like to see if I can just swap the transmissions between it and my 230cc quad motor.

Probably over thinking everything about it. Probably better to just do the decked jog on my 200, do the basic power adder mods, and live with my 18~20hp until I get an opportunity to get a more powerful motor...and, for some reason, I really want to stick with these Chinese models.

I need to find one more engine just to play with. I'll get me one of the 230cc ones and see if we can go a mm or two over on the bore or whatever.

Maybe a turbocharger...lol....

10-30-2011, 02:32 AM	#16
makenzie71 Join Date: Dec 2008 Posts: 412	Things I learned and did this evening... I was going to pull the jug and piston off my 250 Hi Bird quad and swap them to my 200cc dirtbike motor. Found out it won't really work. The 230cc (labeled 250) engines are (bore and stroke) 67X65 mm. The 198cc (labeled 200) engines are 63X62.5 mm. What I would have gotten was a piston comng up 2.5mm shy of the compression mark. I didn't want to deck the jug that much, and it would have only gotten me another 10~15cc or so. The heads are itnerchangeable. I did deck my 200 jug base .010", ported and polished the head a little meaner, and got it all ready to go. I lost one of the wrist pin retainers for the piston, though, so got to wait for that before I go any further. __________________ http://www.duncandesignsstudio.com/justinsoddprojects/
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10-30-2011, 03:46 AM	#17
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	That looks so right! 8) Does the valve cover actually hit the backbone, or the support tube underneath it? If so, perhaps that can be manipulated out of the way. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
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10-30-2011, 11:35 AM	#19
makenzie71 Join Date: Dec 2008 Posts: 412	I actually didn't get that far lol. It was a matter math. Now that I'm thinking about it I am considering splitting the case of this 200 I have and seeing how the transmission is setup...I would like to see if I can just swap the transmissions between it and my 230cc quad motor. Probably over thinking everything about it. Probably better to just do the decked jog on my 200, do the basic power adder mods, and live with my 18~20hp until I get an opportunity to get a more powerful motor...and, for some reason, I really want to stick with these Chinese models. I need to find one more engine just to play with. I'll get me one of the 230cc ones and see if we can go a mm or two over on the bore or whatever. Maybe a turbocharger...lol.... __________________ http://www.duncandesignsstudio.com/justinsoddprojects/
	0