Hey all, goin to be boring my 89 KDX 200 out +2mm this or next week via Langcourt, and I noticed the main exhaust valve is kinda close to the cylinder wall...will it clear with 2mm overbore or wil I have to do something to it? What would have to be done if it will not clear the piston? Please, any help is appreciated! :)
Problems with main valve with +2mm?
- Thread starter beefking
- Start date
canyncarvr
~SPONSOR~
- Oct 14, 1999
- 4,005
- 0
EG's big bore takes the 200 to 225, and that isn't a sleeve.
He DOES make required changes to the main flapper....I don't know what that process is.
What about your head? If you don't change the oem head volume along with the bigger bore, you're going to have a self-destructing machine on your hands.
From other posts of yours, I'm sure you know that.....so I'm stating an obvious point I'm sure. Rather safe that sorry . ;)
From what EG says his big bore process is, I understand him to do SOMEthing with it....again......don't know what/how.
Does langcourt 'fix' the port timing with the overbore? Hope so.
Let us all know how it comes out! 2mm give you less than a 220 piston spec, so what piston are you using? Is it coming from langcourt, too? Hopefully they have the piston they're matching your bore to??
Good luck!!
He DOES make required changes to the main flapper....I don't know what that process is.
What about your head? If you don't change the oem head volume along with the bigger bore, you're going to have a self-destructing machine on your hands.
From other posts of yours, I'm sure you know that.....so I'm stating an obvious point I'm sure. Rather safe that sorry . ;)
From what EG says his big bore process is, I understand him to do SOMEthing with it....again......don't know what/how.
Does langcourt 'fix' the port timing with the overbore? Hope so.
Let us all know how it comes out! 2mm give you less than a 220 piston spec, so what piston are you using? Is it coming from langcourt, too? Hopefully they have the piston they're matching your bore to??
Good luck!!
- Jan 8, 2000
- 3,331
- 1
I just sent the cylinder for my '91 200 out to have it re-plated because I was told that it can't be sleved.
- Thread starter
- #6
Well I already have the piston, its a Wiseco. I was originally going to get just the standard (or 1 size over) Pro-X piston kit, but it was actually more expensive for me and harder to find. And since i would have to replate ANYWAYS, might as well bore out too. :)
I just email'd Fredette (frpoffroad.com) and asked them about the main valve as well as the head volume. I was under the assumption that with the 2m overbore the stock head volume would be fine, maybe just have to advance the ignition a degree or two I'm thinking. Doing the replating and 2mm only brings the CC's up to around 212. There must be a way to do this somehow, or else they would not supply a 2mm piston eh?
I just email'd Fredette (frpoffroad.com) and asked them about the main valve as well as the head volume. I was under the assumption that with the 2m overbore the stock head volume would be fine, maybe just have to advance the ignition a degree or two I'm thinking. Doing the replating and 2mm only brings the CC's up to around 212. There must be a way to do this somehow, or else they would not supply a 2mm piston eh?
- Thread starter
- #7
OK well I just took a few pictures to make this all make a little more sense...(god i love this camera! :) )
Here you can see the cavity where the main valve sit/rotates in. ( the valve itself )
The thickness of the wall where the valve sits is 3mm max. and a shade more than 2mm at the thinnest. ( see picture )
Here you can see the main valve installed. In stock bore, the closest that valve could get to the piston is about 2mm. The new bore wil bring the wall towards the valve not even .75mm, so clearence is not a problem.
But again, do you think there will be enough material there so that it won't crack???
Here you can see the cavity where the main valve sit/rotates in. ( the valve itself )
The thickness of the wall where the valve sits is 3mm max. and a shade more than 2mm at the thinnest. ( see picture )
Here you can see the main valve installed. In stock bore, the closest that valve could get to the piston is about 2mm. The new bore wil bring the wall towards the valve not even .75mm, so clearence is not a problem.
But again, do you think there will be enough material there so that it won't crack???
