What is the differnce.....Need Advise...

[topoortorideon4]

I was looking at the stuff to rebild my 200m top end and I dont under stand the differnce between the compessions std, 10.25:1, 12:1? Which of these would be high compression or standard. Or would I have to use race gas with these like 12:1 or 10.25:1. If I rebiuld my motor should I put a new rod in it too or is that the least of my concerns. And do any of you know the approx. cost of replacing all the berings in the bottem end including the crank

[Vealmonkey]

12:1 is high compression and you would have to use "race" gas with it's higher octane rating. !0.25:1 is more like standard compression. Unless you really want to make the bike a racing type machine, stay away from the high compression piston because it puts alot of strain on the engine and shortens engine life. If you want to improve the trikes performance, I would first look into a higher performance cam, air filter and a nice exhaust pipe. With a hard tail frame once you get up over 50mph or so, it gets squirrely anyway. If you really want better performance, you would be better off going with a 200x. Unless you are running on a relatively flat surface, the hard tails get a nasty bounce at speed. I don't know much about the 200m frames, but if they are buillt like the 200s frames, you could always try and graft a 200x rear swingarm section so you could have rear suspension. Just a suggestion.

[topoortorideon4]

I have an old 185s racing cam would that work? What abou a 200x cam? The thing is I want more power not so much speed. I like speed but for my M it does it for that machine. Would it work if I put a 200x rear end in my 185s?

[thefox]

For the compression, std. is Standard compression which on a 200m is 7.6:1. I would go with the 10.25:1 compression piston. It is a nice upgrade, you will be able to notice the power difference but it will not require the race gas. The higher compression piston will really help the low end power that you want. If you want to shift toward more top end power then you would be looking at swapping out the cam. A 200x cam is the next step up then the XR200 cam, followed by an aftermarket cam (depending on the type of aftermarket cam of course).

Do you need to replace the rod? Well that depends on what shape it is in now which you can't really tell without taking the motor apart. As long as the machine has been taken care of (never run with very low oil) and you don't hear any rod noise now then you probably don't have anything to worry about. Replacing the crank bearings is a good idea but again they may be ok still. I bought new bearings ($20) and had them pressed on my YTM crank ($40) but then you are splitting the case, not just doing a top end job.

As for the rear end, you can put a 200x on the 185s but it would require some cutting, grinding welding and fabrication skills. If you try it make sure to take pictures so others can follow later.

[topoortorideon4]

I might try it sometime. The thing that worries me is finding the piviting point. How do I find it?