J-Madd

Brake pads usually aren't the weak link in stopping on dirt. The tires locking up and sliding is what keeps if from stopping. You should be able to get on the brakes hard enough to lock them up (though I don't like to do that, can get kinda hairy.) If not, you may just need to bleed the brakes.

Just file off the top of the piston the width of the exhaust on the exhaust port side. You'll have to calculate how much for 2 degrees.

Did you fix the problem that caused your last motor to fail? You mentioned water pump, but it may have been something else.

I have a set of like new chrome Fat Bastards if anyone is interested.

Get a Clymer manual. You'll need to set the eccentric adjuster thingy when you replace the shaft. The manual makes it simple.

If not, the clutch would be fully engaged all the time. The bike wouldn't even move.

Seriously? How long would that take do ya think?

Oh, and when you kick start that thing, be sure and kick all the way through, giving it throttle at near the end of the kick. Don't pussy foot it. If it kicks back it will break stuff. I actually put my 16 Mil Twister 78 mm bore on remote start because it broke all kinds of shit; and I didn't want to take another chance.

(I didn't read those links) I like to get the needles close before ever going down the track. You can fire it up and rev it up. If it won't clean out or doesn't sound crisp keep going a 1/4 turn out on the needles. It should rev clean and rpms should climb if you hold the throttle at about 1/2 to 1/2 open. I set them on the verge of lean hanging at the track sometimes. Once the needles are close, make some passes with the pjs wide open and then begin closing them a little at a time until it runs clean. Some people drill the barbs and pjs out to about 0.096". If that's the case, you may have to close the pjs quite a bit. When you get to where they're about 1 turn open or less, each 1/8th turn takes away a lot more fuel (a lot more sensitive than when they're 2 or 3 turns out). I've seen a small turn be the difference in burning a plug strap and running fat when they're drilled out and that far in.

Roll Out (circumference)

I have some BB/SF Silenced shearers. I don't think they fit a DM though. If you haven't bought that motor, I have a turn key 421 Cub with pipes and carbs that will run 3.8s on that chassis. Little to no tuning needed, Where do you race? That track in Mississippi? I'm 100 miles from Memphis.

Nope

Sounds like an issue with the trueness of the cylinder deck or head.

Degree your motor and see what the exhaust duration is. On drag ported stock cylinders its usually 200+ degrees. If so, CPIs would be your best bet.

Do you have an override? If not, are you gonna use 6th gear? If your using 6th 15/45 would be ok. Otherwise, I'd go 15/43 or 15/42.

Get the bar down and your e.t. will drop. It must be flexing a lot.

Yep, with your mods, that's about all your gonna get out of it. I'm sure that's a half mile run down a paved road to get to that speed.

Your wheelie bar is too high. Makes a good pic though.

21 cc on a 72 mm (or whatever) bore is small. Throw in a positive deckheight and that's even worse.

I like holeshots or OEM YFZ450 tires.

You can just by a cheap assortment of orings from any autoparts store and find the one that fits. It's not a special oring. BTW Stock clutch setup (billet basket at most) is good for 99% of engines out there, imo.

You may have to replace the transmission shaft. Yes you have to split the motor.

www.rebelgears.com. They make their own, as well as lighten, rear sprockets. I'm sure they can lighten the countershaft sprockets they sell.

It would be great if it had 60 ft (and 330 ft) times. I don't see how you can tune without 60 ft sensors. I'm betting you could lay down a whole lot better e.t. with less mph. For example: Lets say you run 3.80 @ 84 mph on a 300 ft track. Hypothetically suppose you ran that on out to 500 ft @ 84 mph (no additional acceleration). That e.t. would be 5.4 seconds if I did the math correctly. You could run a 4.2 (@84 mph)in 300ft in the same scenario and still run 5.8 in 500 ft. NOT at all knocking the time slip. I think your 60 ft times are waaaay up there. But if you're gearing to get the mph out of it, that happens.

As long as you know all the formulas its not terribly difficult, but I've long since forgot calculus and physics. The squish ranges mentioned must be in the ballpark, because that's what a lotta folks run.