185/200/200x/xr200 top ends

[fordrangerracer]

I'm gonna take a wild guess that 185,200,200x and xr200 top ends are all interchangeable? But on a 185 would you notice any power to upgrade to an xr200??

And would you notice any power from the bigger 200x head without the cylinder?

[Stephon_xr500]

I know the 185 and 200x top ends are interchangeable I just built a 185 bottom end and cylinder with 200x head. I'm hoping it gives some more power but I haven't got it running yet to find out.

[fordrangerracer]

That's what I was looking for mostly. Just swapping heads, I know in a car/truck it will give more power but trikes not sure lol. if you really think about it, technically it should because the dip, n not sure what its called, is significantly larger. Therefor giving easier flowing intake and exhaust. But I'd like to know how much of an increase before I go through all that trouble! haha

[Flossyb20]

Cam covers are a little different on each, some have compression release, some don't, but they'll all bolt up to the head.

[RyanZD]

185 and 200 are interchangeable 200 defiantly has more bottom end power though....

[fordrangerracer]

Well, what I'm looking for is on my Xl185 going up hills it doesn't have quite enough power to get up in 5th. Just looking for a little more. I was also thinking about getting my stock cylinder bored and getting a 200x head. Can I have it bored .40 over? And if I would do .40 what size piston would I need?

[muthey]

you lost a zero in there lol you mean .040 over, .40 over you wouldn't have a cylinder left, if you look on ebay they sell piston kits with rings when you bore a cylinder you always bore it to match the piston, so first your best off having a shop look to see how much you will need to bore it to clean any warping out. Then you can know what size piston to get. Also from what others on here have done the xr200 head gives the most improvement of them all.

[fordrangerracer]

Yeah muthey I did lose a few zeros! lol. Well my plain is either a 1986 200x engine since it has the 6spd or I'm just going to build my 185 with and XR200 carb and head and a 200x cylinder with a 12:1 piston. My next question is will i actually notice any power from these mods? And is 12:1 too much, should I do 10:1? And just keep in mind this is for the road! :P

[muthey]

you will definitely notice a difference, but 12:1 is a little extreme unless you plan on racing 11:1 is about right for a higher performance motor. I believe I read on here somewhere that if you go 12:1 you end up having to run race fuel, or it pre detonates, not positive on this but hopefully Howdy or Fabio will pipe in and confirm or correct me on this. For some reason I think yamaha's are running 11:1 as a standard and I run regular gas in mine

[fordrangerracer]

Alright well thats one thing I definitely don't want is pre-ignition. had the timing a tooth off one time and every dang time you kicked it'd come back hurt like no end!! Just like my buddies XR500 if the carb isn't adjusted perfect it'll about break your leg! But anyways for now I'll just stick with the head and carb and do a little more research on the cylinder and piston. I really appreciate your help everyone!