Eastside told me that that don't even use an exhaust gasket. They bolt the pipe directly to the head.

 

NASTY GEARBOX SUPPORT FAILURE on 2004 Xterro!!!


Whelp, looks like i get to try the warranty process.

Was riding in the snow covered dirt today with the kids. We were
out for quite a while! Great fun...

Anyway, I backed it into a small shallow ditch, put it in forward,
and wheels spun in the mud,snow, dirt mix, then when they caught on
the harder dirt I heard a BANG and a nasy clacking and spinning
sound. All power was gone on the wheels. Got out expect to see a
broken chain, or one of the gearbox issues discussed before, but
what I got was a whoosey.

It appears that the connection from the gearbox supporting arm to
the engine case failed. I found the bolt that goes through the
crack case of the engine into the supporting arm and it was sheared
off.. but it sheared at a point inside the crankcase and took that
section of the case with it!

In the end I guess I'm not sure if the crankcase failed or the bolt
that inserted into the crank case because both are damaged. The
fact that the bolt is sheered tells me it was most likely the bolt.

What resulted after this was absolutely nasty.... of course I was
under power at the time when it let go, and when the supporting arm
is allowed to run free watch out!!! instead of the wheels and chain
spinning, once the gearbox is allowed to break free it spins!!! and
everything attached to it spins as well. It chewed up and
shattered the plastic case around the gearbox, the supporting arms
were twisted like you would not believe as they banged agains the
rear swing arm and the drive shaft. The reverse cable was sheared
off from hitting part of the rear swing arm.

What a mess!!!


I'm waiting to get pictures of all this... batteries are charging
now for the camera.


KPX is gonna love this one!


Edit... pictures are posted on my picture page


-Steve

 

I guess you could try it but I wouldn't recommend it, there is just no way to effectively seal it without one. Even with one, I usually see where it is leaking when I take the pipe off. The stock gasket does not work well at all with the eastside.

Went ahead and milled .035" off the head, noticed it shaved most of that flattened portion of the combustion chamber off. I got a little worried it may not be as efficient so I got the dremel out and ground one back on it. Used the gasket and drew a template and tried to duplicate the shallow angle the yerf head had on it. Bolted it back on and it starts quicker now, doesn't have to turn over as many times. Probably has close to stock compression now (I would guess) no pinging. I did notice that there is not much adjustment for the cam chain tensioner now that the head is closer, also advanced the cam a little more.

Runs great! there are going to be some unhappy 250 buggies out there if I catch them on a hill! Low end grunt is now at an all time high, I can climb anything with enough traction, even accelerates on a moderate hill now instead of struggling. Tried some insane hills that 4wd quads were hesitant to go up. The only times I couldn't climb (the REALLY steep hills) is when one of the wheels would hit a large root or rock either causing the front end to reach for the sky or the back tires to spin. Its a little unnerving when it feels like you are going to flip over backwards. If you haven't been to turkey bay, it is just one huge hill after another with ruts everywhere, tight trails, rocky hills, muddy hills, roots and trees everywhere, oh yeah and lots of hills.

I am very pleased with the results, milling the head added nothing on top for me. The larger valves is where I saw an increase in higher rpm, the higher compression added the bottom end power. I don't think I personnally would want to take any more off the head, I would be afraid the tensioner couldn't handle the extra slack and I don't want to worry about detonation. It still needs to be jetted correctly, seems to rich again, is it possible milling the head reduces airflow slightly?

Also, a while back I noticed I have 2 base gaskets, probably to reduce compression from the factory. I could have went with a thinner single gasket and got good results but was afraid of effectively raising the piston in the cylinder and causing problems by the ridge created from the rings. I may be a little overly cautious, if the engine didn't have as many hours on it I would have done this. Also, I would recommend milling the jug so you wouldn't screw up the combustion chamber but I had no way of doing this myself, the head was much easier and would be in my control with no wait time.

Kelly

 

If you mill the jug, you'll remove the lip that holds the sleeve in place. Without the lip, the sleeve would be free to travel downwards towards the crankshaft. [img]i/expressions/face-icon-small-shocked.gif[/img]

 

Hey Kell.. that's awesome. We have the same engine... wonder what just milling the original head would give us without valves of the yerf.


Do you have access to a machine shop, or do you have yer own mill??



-Steve

 

Thats good to know!

 

If you look back "several" pages you will see raptoraz's review on his kpx's head after he milled and ported it. I think he says it increased torque on the low end, probably worth the effort if you climb steep hills, I can now stop on a very very steep hill and start again with the wheels spinning). Keep in mind it is still a 150 but it's got way more low end grunt (more compression) and the top end (because of the larger valves) has that pep that it needed. There is No way the 250's I rode with could keep up with it, it is now fun to ride. Top speed is still the same old 30-35mph but it reaches it way quicker.

We have a cnc router table which is VERY accurate, I just made a jig that uses the valve cover holes to bolt to and then clamp the jig to the table. I then make sure it is perfectly level and mill it down with an aluminum cutting bit and cutting fluid. Takes me about 30 min. mostly making sure it is level and the clamping/jig surfaces are clean and clear of imperfections. On mine I milled .034" then took the last .001" off a little slower so it would leave the smoothest finish possible.

 

Wow... very cool info. Thanks Kell.

 

bump for r6

 

Been busy. No R6 conversion as of yet. Also tossing around the idea of ditching my Blue one in favor of a Rhino.