can the ds valve be butted?? i was talking to a local cycle shop yesterday due to valve shims, one of the valve were to tight and i needed a shorter shim, i went to road and track in edmond ok and talk to john (i believe), the shim i had was a 205 and i was looking for a 200, he talk to me about how he doesnt think they make shims that small, he looked thru a couple of catalogs to see if he could order some and there werent any, the smallest he could order was a 230s, he asked if the valve could be butted, cut 30 or 40 thousanth off the top of the valve to give me some adjustment area, getting into a 230 shim or some where around that, has anyone done this or does anyone know if it can be done to the stock valves
thanks

 

Two options - shorten valves stems, which will cost you a head gasket ($50) and the time/labor removing valves and having them shortened, Or you can have the shims you got ground down to the desired spec.

I just picked up some shims I had ground by my local machine shop an hour ago - I needed thinner ones than are made by anybody too. It cost me $15 to have all four ground to the spec I needed, and it doesn't interfere with hardness - they're hardened all the way through, not just case hardened. Just don't grind thinner than the lip on the bucket is in depth, of course.

I bought the shim-under-bucket conversion kit from Web - thinnest shims made are 2.00. Well, that was still too thick, because stupid Web made the bucket tops .012" thicker than the stock buckets!

Ideally, the valves would shortened .020" or so, so that you can once again adjust over time by changing shims, but if I pull my head again and remove valves, I plan to go back together with stainless valves, and I don't wanna spend the dough right now. $15 per adjustment, aint bad - I can live with that until I do the other.

 

that was something i was thinking about doing myself, i have a friend thats a machinist and i was going to ask him if he could shave like 3 thousandths off one of my old shims, i too have the under bucket shim set up, i dont know if its form web or not the name on the packages are kibblewhite precision machining, so due to the newer buckets being thicker, thats whats causeing the problems for us,
thanks

 

I agree with replacing the valves if the head needs to come off. Not necessarily bigger but SS valves to replace the original intakes, especially if you plan to run race cams and springs. Personnally I would consider this a must any time you plan to remove the head but then I tend to err to the side of durability.
Obviously Rotax used these valves when the engine was designed to be a motorcycle engine and never reconsidered upgraded valves for the quad engine. I wonder if that has changed??

 

I just had my head and manifold port matched after 120hrs. on the stock motor, and did all my upgrades at the same time. Over the course of that 120hrs., I never had to adjust my exhaust valves, and only had to adjust the intakes .002" on one occasion after 40hrs. I was surprised at how well the stock valves and valve seats held up - it all has maintained a like-new condition after 120hrs. of hard and high rev riding, 'cause I've had the CDI most of this time.

But, with the spring kit I now have, and the race cams, I expect to see more wear faster - with the potential for valves to start folding over time from slamming shut so much harder, which will decrease clearance. I'm very curious to see how long the stock valves last with my new mods - I'll be watching valve clearance like a hawk for a while.

 

They make a 2.00mm shim get them from a Kawi dealer. They are for a KZ 500 or something like that. Yeah it sucks I needed a 1.95 so I ended up grinding a 2.00 down to a 1.95 it is difficult to do and I don't recomment it.