xr 200 engine upgrade

[smokinp]

I have a 1985 200x with a auto clutch 200cc engine and a 12:1 wiseco piston,my problem is that I want more power and I need some help.I am thinking of putting in a xr 200 engine with a 10.25 or 12:1 piston,cam of some sort,exhaust and a bigger carb.do you guys think that I should try to mod my 200 engine or go to the xr engine?I have some 18 inch tires coming so I will see how those fair...

[xd 200x]

where did you get yopur piston i have the same setup

[smokinp]

www.wiseco.com

[tdup]

I built my xr200x a little over a year ago. I love the mod. I am using the 6 speed transmission from the xr. The xr piston which is a higher compression than the stock 200x, the x jug and head and the 26mm xr carb and intake. I also chose to run the 200x cam with my set up for a slightly lower torque curve over the xr cam. I do a lot of hill climbing and tight trails so I am running an 11 tooth front sprocket. With the 6 speed gear box 6th is almost identical to a 5 speed running a 12 tooth sprocket. But you have a much lower first and better gear selections between, which can come in very handy for an over 200lb rider in tight hilly trails. I ride alot so I can also say that this is a good reliable set up. In the riding I do I have only ran it out in 6th for any distance a couple of times. I think the motor could handle a 12 tooth sprocket but I think it would take quite a while to rev out in 6th.

[smokinp]

can you post some pics?

[smokinp]

Hows does this setup sound...xr 200 bottom end(what has to be done to fix the kickstart to go the right way?)xr200 carb and intake with a 12:1 wiseco piston and bored .20 over to freshen up the engine .my question is what is the best head setup to use?the 200x or the xr 200?

[3WheelsForever]

That sounds perty good. Although the intake will not work because on a dirt bike the intake is angled so the carb will clear the rear shock i believe. I have heard that the 200x has bigger fins than the xr 200 head. But I would just stick with the xr. It has a hotter cam and Im guessing the valve springs are stronger because of that hotter cam.

[tdup]

The intake from the xr200 worked perfect on mine. I tried to port match a 200x intake to match the 26 mm carb. It makes the landing to thin by the o-ring and doesn't seal well. You will need the xr intake for it to work right. I used the x head. I think the xr heads all had compression releif systems but not 100% for sure on that one. There are 2 ways to do the conversion to keep your forward kick. First you can use the whole xr bottom end. you will need to split the cases and install the 200x short main kick start shaft in place of the xr long shaft. Then use your 200x side cover and reversing gears and kicker output shaft as normal. You will also need to use your 200x stator set. The xr stator set does not have a lighting coil. If you are going 12 to 1 compression get an aftermarket cam to reap the full benifits of the compression. Also 12 to 1 will not run very well on pump gas. 10 to 1 will give you a noticable jump in compression while maintaining pump gas use. The 2nd method of conversion is to use you 200x cases and replace the complete transmission set including the shifting barrel with the xr set. again put the short stub shaft onto the xr's main kick starter gear before assembly. Good luck with your conversion. It is worth it.