Is this normal?

[kdeal]

QUOTE (Canniboomer @ Oct 25 2009, 04:03 PM) <{POST_SNAPBACK}>

say what kdeal?....there are at least 6 reasons why a crank could be pinched too tightly, and any tightly-squeezed installation will cause some left-side bulge of the crankplate race -- while it smashes hard-pressed against the rollers and plastic outer bearing cage,...which could hold out the gear by many thousanths.
But OK, he has now stated that the crank sideplay is OK and not pinched, so those causes are now ruled out.

One other thing just to mention...the primary-gear inner O-ring? Did you happen to slip the new one over the crankshaft?...instead of inserting it inside the gear? I have run in to that question before on a phone call, where a guy was looking at the parts catalog and did not yet notice the inner-gear placement for that O-ring.

Boomer,

You cannot squeeze the left side of the crank any further than the bearing and cartridge plate is going to allow you to do so. So, the right side crank bearing is a moot point. If there was a problem it was with the crank having mismachining or the gear not going all the way on.

[Canniboomer]

No matter how tightly the gear is mated to the crank, or pre-squeeze installed on the crankplate, that gear will bulge out MORE when the plate is installed with a too-tight crank. You are ignoring the effect of intense side pressure on the bearings at less than zero side clearance, from many potential causes.

That is apparently not HIS problem, agreed,..... but it's certainly not off base to mention.

[kdeal]

All you are doing is taking out the .007" or so that is the crank side play. Being a rebuilt crank and with no shims I would hope that is not the issue....

There is at least an 1/8" gap there, far more than a tight crank.

[cannondale27]

I think once cranknut is torqued on everything will be right in line since it is not right according to the 1st pic.Make sure you do a leak test.

[Canniboomer]

QUOTE (fast moto @ Oct 25 2009, 12:03 PM) <{POST_SNAPBACK}>

..... The bearings are the same ones that were in when I took the crank out.....

It's also possible that the crankplate mainbearing has some axial wear. Here is a crank that came out of
a 2003 Moto. The plate bearing looked OK and the left race was not very dulled. But, you can see how the crank was allowed to move leftward enough to scuff the stock TDC bolt (with stock TDC spacer).

Both motors pictured above might need a second look at the left mainbearing for side wear. Those gears should not actualy rub with any friction. They should barely clear each other, and not pinch at a feeler gauge or a sheet of paper slipped in there.

Gently tamping the crank to hard left and then hard right would also be a good check, so you know about where those cranks are sitting (in the sideplay range) when the photos were taken. If gently tamping the flywheel to move the crank full left causes pressure between those gears, then you might need to change the mainbearing.

Since fast-moto has a steel pump gear, you would expect the primary gear, and the backside of the pump gear
to show some amount of "shine" if they were actually rubbing there before.

[fast moto]

What is the correct amount of crank side play and what is the best way to measure it?

[cannondale27]

.011" +- .003". Is acceptable. It is measured with a dial indicator mounted on block and measuring to the end of crank with nut and all crankplate bolts torqued minus crankplate gasket. You just move crank in and out and take measurement of the difference. Some go tighter but I think they are messing with potential failure.