YFZ stroker "issues" - please HELP!!

[sosbe]

Irecently decided to stroke my 05 YFZ. I went with +3 mm Hot Rods crank and rod with a CP 14:1 compression full race piston. All new bearings, and I sent the clutch cover to Sparks to have the oiler mod performed and also put a high volume oil pump in it. I put everything together by the book only to find out it didn't have neutral.it did run though, started with no problem. So I pulled it back out and tore it down again and noticed the shift drum wasn't right. I replaced the shift drum and put it all back together and now it will barely turn over. When I pull the spark plug out it snaps it over like a brand new battery should. My valves were adjusted before I tried starting it the first time so I don't think its a clearance issue. I am 99.9% sure my timing is right.
It will crank over, but when it gets close to TDC it comes to almost a complete stop. Very sluggish. I pulled started it and it did run, but I had to stay on the throttle to keep it running. As soon I let off it instantly dies like its seizing up, but it spins freely without the plug in it. I'm stumped and lost. I've thought and thought and I'm on the virge of tearing it down again or taking it to YAMAHA and paying to have it taken care of. Please help if u have any suggestions. Thanks guys.

[Ride1Rob]

I say timing... especially with that much compression :eek2: . Check it and see what you got.

[sosbe]

Ok man. I'm really hopin that's it. I really don't want to pull it apart a 3rd time. I've been pissin with it for a month now waitin on parts and I just want it to be done. I live 30 minutes from the badlands here in indiana and now that its warmin' up I haven't had anything to take.
Ill check what kind of compression I have and play with the timing a little bit and let u know the results. Thanks man!!

[Ride1Rob]

No problem! It's not anything down in the motor as it turns when the plug is out. The valves have to open at a certain point to help releive case pressure and with that high compression of a piston one tooth off will do that. Make sure that it's SPOT ON! Even take pics of it and post it if you think it's right so we can take a look at it.

[sosbe]

Ok. Ya the manual doesn't really match what it actually looks like.kinda looks like an H with a vertical line after it. I've got it set dead on the vertical line. Is the notch supposed to be in between the 'H' ?

[Ride1Rob]

Try to get the flywheel notches lined up right in the middle.

H l This is how the notches should look on the flywheel.

It'll move a tad either way when you're messing with the cam chain.

[Fast350ex]

Check and see if the cams circlips are aligned properly with the groove in the cap.

Also, check the runout on the cams.

[sosbe]

Got'r goin boys!! Starts easy - runs smooth - and after I play with the jetting a bit - she'll run like a raped ape. Thanks for everything. O ya - it was the timing. I was off one tooth on the exhaust side so when it hit TDC it was locked up in there tight as a drum.

[Ride1Rob]

:muscle:

[MAaudioX10]

I sure hope you had that CP piston machined for that oil upgrade. With a stroker crank, CP pistons are known to contact the oil squirter. The additional 3 mm of stroke is added to the bottom of the stroke and, CP piston have an x-forging under the piston.

I'd make sure your squirter isn't broken in two.

[sosbe]

Well, I didn't have the piston machined, and Ive been running the living dog**** out of it and havent had a problem with it yet. The shop I purchased the parts at is highly experienced in performance upgrades and race motors. I would hope that they would have informed me of this issue before I handed them $500 for a piston and jug. Who knows, maybe I just got lucky.

[MAaudioX10]

Errr....luck has nothing to do with it. You wouldn't have an immediate effect from the squirter being busted in two....what you will have is a low oil pressure situation.

Low oil pressure destroys the crank bearings on the HR stroker cranks( I've been through 2). My last build, I ran a CP race piston with a stroker crank and, the piston was not machined. The squirter was broken in two.

It's your bike man.....just don't say I didn't warn ya.

[Ride1Rob]

:eek: