Performance Engine Mods and E start

Guide seals were replaced when torn down. Never had a leak down test, but it's going to get one before I put it away for the winter.

"Hard to believe the cylinder would still be in spec if all the cross hatching was worn away."

I think that is exactly what went wrong. I had a friend who has worked on / rebuilt bikes his entire life work on the engine. We measured and it was "border line"....he's a old school 2 stroke, and air cooled XR guy though, and well...maybe his version of "borderline" might have been OK for those, but not a newer style 4 stroke. I also put a LOT more miles on then he does, and I did get 2,000 km's out of it without a hint of smoke/oil burn.

I'm chalking it up as a personal learning experience for myself....lol

Guess I'll know for sure after this spring, and I'll see what the leak down comes out at with the dealer here

Well I've started my rebuild/upgrade.

Decided to go with motor out of frame. Got it out today.

Took about 2hrs.

I put YZ cams in my 08 and it runs much better. It has more low end and is acutally easier to ride. I dunno about a high compression piston.

I put one in an 03 YZ450 that I run on the ice and flat track. It is pretty snotty now. I don't think I'd like it in the woods.

The YZ cams made the e-start not work as well. Sometimes you can feel it gets hung up on a compression stroke and won't move the piston.

I use the kick start on the bike when it's cold and the e-start after it's warm.

I put YZ cams in my 08 and it runs much better. It has more low end and is acutally easier to ride. I dunno about a high compression piston.

I put one in an 03 YZ450 that I run on the ice and flat track. It is pretty snotty now. I don't think I'd like it in the woods.

The YZ cams made the e-start not work as well. Sometimes you can feel it gets hung up on a compression stroke and won't move the piston.

I use the kick start on the bike when it's cold and the e-start after it's warm.

wait so your bike was never like this when it had the regular wr450 cams in it????i just picked up a used wr450 and it gets hung up on tdc with the estart quite a bit and is making me wonder if i have these cams in mine.....any way to tell??

wait so your bike was never like this when it had the regular wr450 cams in it????i just picked up a used wr450 and it gets hung up on tdc with the estart quite a bit and is making me wonder if i have these cams in mine.....any way to tell??

They all do it. I was hoping maybe the YZ cams would eliminate this for me but I guess not.

They all do it. I was hoping maybe the YZ cams would eliminate this for me but I guess not.

alright got ya....sorry

They do it but it's worse with the YZ cams.

But the bike runs so much better I don't care.

When it hangs up you just use the kick starter.

BTW if your battery isn't in good shape it will do it more often.

I use the kick start on the bike when it's cold and the e-start after it's warm.

That's interesting. Mine does the opposite(06 yz cams). It will start cold with e-start really easy, almost as soon as I touch the button, but it's a bit finicky when warm/hot. I've figured it out though, all I need to do when it's warm is give it a 1/8 twist of throttle, pull the hot-start lever and hold the button down a little longer than usual. Starts up 99.9% of the time using that approach. Makes me think that a bit of tinkering with the jets would sort it out, but the bike performs really well otherwise, so I just live with it as-is.

I think I'd leave that one alone. No WR450 I have ever owned started easily on the button when cold.

Jetting is a big part of getting the estart to work with the yz cam. I have my bike jetted pretty good with an open pipe. So long as the bike is warm the estart works fine. It works cold aswell but I dont like to wear the batt down.

I think I'd leave that one alone. No WR450 I have ever owned started easily on the button when cold.

Mine always started fine hot or cold before I installed the yz cams, but I do have an open pipe on it.

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