Hi everyone.. hope youre all good and had a good summer.
I like my bike to be stock but the one thing Ive always wanted to do was get the squish corrected. I'm hoping for a little more oomph all over... I assume thats what would happen. I dont imagine it will be a big difference but every little bit helps on a stock bike. Anyone had this done and what benefits did you see? Wonter is nearly here so it would be a good time for me to have it done.
Also, I seem to remember someone here offers the service... i cant remember who though?
John
Read this article,
http://www.3cyl.com/mraxl/aylor/heads/heads.htm
That is a good brief description of the squish band and the value of the correct clearance and angle. The picture is of a Kawasaki combustion chamber which doesn't have as defined a squish band as the RD squish band. Optimum squish clearance for the RD 400 is from .034" to .038" and anything over .040" is excessive. The squish band angle needs to push the fuel mixture out of the edge of the cylinder into the center so that is no fuel trapped at the edge of the piston that can ignite/detonate and cause damage.
Most engine tuners can turn heads and adjust squish bands. Scott Clough, Chuck Quenzler come to mind immediately. Maybe Ed E, but I'm not sure he has the equipment to turn heads.
Lyn Garland
Ive been looking into it and I like the idea more... but Im pretty sure the heads will need to be dowel pinned. These heads can slip around a lot and that would defo mess up an even squish band all the way around.
I just gotta find some one to do that can do that too... and see what else this kind of work entails. I'm hoping to keep the current bore and pistons... and dont different pistons have different angles on them?
I'll have to start emailing people to see what all needs to be done to do this.
It's pretty simple. When Chuck does squish on 350s he uses 400 gaskets. No need for a dowel/pin. You can verify squish with a piece of correct size solder. Not sure how much a .5mm bore size would effect squish, but Chuck has said his heads are good for a few bore changes.
I had all the same questions. :toot:
Garrett can do head skim and combustion chamber mods as well.
Last time I met up with him a few months ago, he was working out the CNC programming for RD head mods.
https://gra2strokes.com/headwork/
Super clean work as always.
Thanks guys,
Ive emailed chuck and garret.
I want to keep the bike stock as I really like the powerband for bombing around town but I'm hoping cleaning up the squish will give it a little more zip. I imagine pushing more charge into the combustion dome should do that.
John
The best thing is a proper squish band reduces the chance of detonation and seizure. Those two things typically happen when you're twisting the grip and enjoying the high speed ride!
Me again!
Right now I get NOS Yamaha pistons of ebay when I need them. Just curious... is there any benefit to switching to Wiseco pistons before getting the work done? I think the dome angle is different and would need to be known before cutting squish.
TY
No input on dome shape.
The advantage of Wiseco or Wossner forged pistons is that they are stronger for higher powered engines. If your RD is stock it's probably not necessary.
I think that the Wisecos are more readily available for RD350s than stock.FWIW
i run prox when i can (stock equivalent cast). its a good idea to know what you will be running before sending heads to be reshaped. there's -zero- downside to getting heads corrected, except cost. but its money well spent. :twocents:
Aftermarket pistons are usually copy the same dome shape as OEM.
That said, I would just run banshee / RZ pistons with the middle tang on the intake removed. Pro X are readily available, well priced and the larger windows do make a difference.
Thanks for all the excellent advice everyone!
Fingers crossed the border is open and I get to come meet some of you in Deals Gapp this spring.
John - Ottawa