J-Madd

Depends on what kind of riding your gonna do on the '06.

Before you drained your coolant, was it low? If it was topped off, it's doubtful that an o-ring was leaking....and the only o-rings that would let coolant get into the cylinder are the 2 around the domes. You can probably find an oring to fit the domes at an autoparts store. I hope that is your problem, but I'm skeptical. Let us know if that fixes it. If not, I'd say it could be the stator. They fail suddenly for no reason.

Yep. Anyone want to buy a 68 mm stock stroke Cub, pistons, domes (20cc) and trued/welded crank if I can't do this?

I searched and have found limited info on how to go about doing this. I already have a 4 mil, but I was wanting to make my stock stroker a 4 mil as well. I know Cubs are cast for a particular stroke, just wanting to know how to make it work and put the port timings were they need to be. This will be for mainly just drag racing. Any suggestions would be appreciated.

Yeah, that's kinda what I thought. They have a limit listed in the rules section on their website, but it's probably a copy of rules from other parks. Thanks!!

Well, I went ahead and ordered a spacer plate. I haven't gotten around to re-measuring. Port heights and durations are over my head. When we put the motor together, we'll find out!!

Around 3 - 3.5 psi in 4-snows (22x11x8) turned backwards, of course.

If the head gasket was leaking, water would be beaded up on the end of the plug when you remove it. Had a bad crank seal been ruled out yet? Exhaust pipe on the bad side stopped up? Good luck and keep us posted. edit: Oh yeah...........I didn't notice if you had swapped plug wires left to right. That would completely rule out it being an electrical issue if the problem persists on the right side.

I had to put caliper in the exhaust port for it to fit inside the cylinder........and its tapered, so I probably didn't get the reading that I was looking for.

I thought for sure it would be your slides. If I could find one of my first posts, it would be just like this........and it turned out my slides were in backwards when I got it. Maybe you could lean the needles a notch and see if that works. If not, take the reeds out and make sure that they didn't come loose, or that nothing fell in the intake and is holding them open. I dropped a screw in mine once and rode around for a while before I figured out the problem. It was keeping the reeds from closing all the way. Unlikely scenario, but worth a look. You'll get it figured out eventually.

It seems to fall off a little if I short shift it........probably b/c I go from spinning like crazy, then hit a higher gear and it hooks and steals some rpms. I just need more practice.

The stealth factor is out the window, unfortunately........the cylinders are polished. I measured from the head mounting surface of the cylinder to the top of the exhaust port and transfers and they measured about 34 mm and 44 mm, respectively. I don't have better measurements b/c the battery is dead in my digital caliper, only I can only measure 1 mm increments without the display. If more precise measurements are needed, I'll get them this evening. thanks!!

What gearing are you running? You gotta 1-5 override? I barely hit 4th gear with wedges, running 14/42, no override.

I'd appreciate it!! Thanks. BTW, what times are you running on that track? There were 2 triples (750 cc air cooled 2 stroke engines) that came to my race that only ran in the 4.70s at Bonne Terre (they never made a decent pass at our track due to jetting/ignition or some type of problems). I couldn't believe that they couldn't run faster than that by the looks of both bikes.........they looked mean! I'm gonna have another race in Kennett in the next couple of months or so; and may try to have races regularly if you wanna come up and race with us.

I've been to St. Joe state park (Park Hills, MO) a few times and there were plenty of bikes there with loud out of frame pipes. Now I have some, and wonder if their still as lenient on the limit (86dB)..........no one was under THAT limit at all. I can change back to IFs if I have to. We're going August 18th and 19th.

There's some on e-bay right now. If I find them again, I'll edit and post the link.

Your slides are in backwards.

How do I measure the port heights? Do I measure from the the top of the cylinder to the top of the port? Please elaborate :thumbsup: . I can fix anything on these things, but I don't have a clue about that :shoothead: . Thanks.

That's what I had one jetted at with similar mods, elevation, temp, etc..

I've got a set of ported cylinders that were allegedly ported for 4 mil longrod motor with a spacer plate. If I put a motor together and use cut domes, the port timings would be off, ........right? How can I tell if it was ported for the plate or not? I don't trust the person that these cylinders came from. Thanks.

A friend made one for me from some metal mesh that you can use for a BBQ grill, it cost a couple of dollars at Wal-Mart.

Just seeing if anyone has a flywheel that is already lightened, just lying around. I don't want to buy one and then have it lightened if I don't have to.

I thought bone stock HP was around 32 or so. 04-05 YFZs are around 36 or 37 (not sure about 06-07). Either way, I agree that about these mods being about 50 hp, and its easy to get even more than that.

Will do. Everyone is already asking when the next one is gonna be. The track will be a little better next time, and it'll be a little more organized, I hope. BTW.....I raised up the back end of mine to keep the chain from rubbing, and ran my best time of 4.78 right before we took up the lights. Those tripples never did get their jetting right on one, and had ignition problems on the other, but they'll probably come back next time. Oh yeah, and no one thinks Danita's was stock. There's more talk about that Outlander than any other bike that was there! They couldn't believe how fast it was.

Take the ring off of the piston and place it in the cylinder. Then push the ring into the cylinder with the top of the piston a little ways to straighten the ring up (make it perpendicular with the cylinder wall), then check the distance between the ends of the ring with a feeler gauge. I don't remember what the gap should be, but someone else will, I'm sure. If its too big, that may be your problem...leading to piston slap.