Crankshaft Play?

[r2palmer]

How much side-to-side play is acceptable for a Blaster crankshaft? I HATE pulling the cases apart and would much rather just use the existing crank if I can....
The crank has almost zero play when I pull & push up & down on the connecting rod. Nice and snug that way.
But the left and right play is significant, at least a milimeter on each side. It doesn't "wobble"; the connecting rod doesn't tip at an angle left/right. It just slides to the left & right a bit when I intentionally push it left & right.

Is side-to-side slop ok as long as the up/down measure is real snug?

I'm on a REALLY limited budget, so all I'm looking for is something that'll work ok. I don't need to race the machine; it's not pretty; I don't need or want to brag about how cool it is or about all the fancy aftermarket mods it has (it has none), and I don't need to depend on it to get my kids to the hospital or anything. I just want to do occasional trail riding with my kids without the piston seizing or breaking or without the rod shattering through the cylinder wall.

Thanks.

 

[fioz600r]

The side to side play is ok as yousaid 1mm each way. Its the up and down you have to worry about. But you said yours is good, I think youll be fine with your crank.

Also welcome to the site.......

 

[brandoz28]

my almost brand new wiseco is only slightly tighter than that

 

[fioz600r]

my almost brand new wiseco is only slightly tighter than that

See your good LOL............I:I

 

[xjma]

The crank is supposed to be able to float to the side a little bit either way, that's normal. You don't want any pressure on it from the side. If there is any up or down play, then that is an issue.

You say there is no wobble at all and that is good. If it doesn't wobble side to side at all that means that the bearing is still tight like a tiger.

Throw a little oil on it while you've got it apart so that it's lubed when you start it up. Lube the piston and the jug before you assemble that too.

 

[fioz600r]

The crank is supposed to be able to float to the side a little bit either way, that's normal. You don't want any pressure on it from the side. If there is any up or down play, then that is an issue.

You say there is no wobble at all and that is good. If it doesn't wobble side to side at all that means that the bearing is still tight like a tiger.

Throw a little oil on it while you've got it apart so that it's lubed when you start it up. Lube the piston and the jug before you assemble that too.

Good recommendation have some reps.......I:I

 

[OConnor Racing]

The side to side play spec is .016" - .028" total, not on each side. Push the rod all the way over to one side then stick a feeler gage in it and see what you have. A mm on both sides is not good.

 

[r2palmer]

If the side to side play is greater than .028 inches, what sort of damage would that set me up for?

This engine already seized one piston with less than 3 hours on a fresh rebore; but the piston was used (sorry, I'm a cheapo, don't have much cash) and the wear marks on the cylinder wall looked to me like the cylinder bore wasn't true, almost like they rebored it a little weiner-eyed and off-center (took it to a $35 rebore shop because of the price).

So I got a replacement cylinder now and had a really good machine shop do it up right ($175 for the boring & new piston kit). Now I want to put it all back together but I dread the thought of splitting the cases again and putting in a new crank.

I do have two good cranks as spares, and a new set of crank bearings. I have three Blasters and a bunch of spare parts, so parts availability isn't the problem.

Problem is, last time I split a case open I had a hell of a time getting everything apart with my hand tools; was afraid I was going to break everything; then when I bolted everything back in, I couldn't believe there wasn't a gasket between the two halves; and I developed an oil leak there that was hard to seal.

I probably should replace the crank... I was just hoping some gurus here would tell me everything will be OK if I leave it intact. But I think the play is more than .028 inches so it's probably way out of specs for side to side play.

 

[ricekiller1985]

when you put the cases back together you need to use yamabond or an equivilant. I like the yamabond myself I have used other brands but the yamaha stuff seems better to me. you just put it on the surfaces that touch and it seals it up.

 

[brandoz28]

yeah i used yamabond as well and no leaks here

i used an automotive harmonic balancer puller, a decent sized screw driver, and a small hammer to split my cases. all hand tools on my porch

 

[OConnor Racing]

I use 1194 case bond for the center cases. Excessive connecting rod side clearance will put unnecessary stress on your piston and rod. It's like playing Russian Roulette. You may get away with it but sooner or later................boom. It's not worth the chance. Trying to save a few bucks now could lead to a complete catastrophe later.