Thread: JP Double Roller Crank Gear Question

I went to put my Crank Gear on the crank and it no way no how wants to slide on by hand. The stocker slid right off, assumed the new one would slide on. Assumption is the mother of all F up's, but dang.. Is there a trick? Is it a press/tap on? I searched and someone said use some fine grit paper to smoothe burs, but I see nor feel burs...

Also checked the cam sproket... With the key properly seated, the cam sprocket will go about 3/4 way on...

XP Cam...

OK shew, scare over!!!! Set went on PERFECT!!! Just a little tapping... I do have a bit of rubbing on the oil pump cover, but it's not machined down so I'll be taking it to the machine shop Monday to have it done. I heard if you get the chamfer done on the crank sprocket that clearance isn't an issue anymore but they lied.. LOL

After installing, everything is sinched down and there is absolutely NO binding what so ever. Slight movement back and forth on each sprocket and the chain is nice and snug with a bit of movement. Very pleased with the JP set, not just gotta get the pump cover machined down a bit.

You do know that JP double rollers have a problem with snapping, right?

Chain snapping or the crank sprocket? I know people have issues that don't get the chamfer right, when the chain fits TIGHT on the sprockets it puts added stress on them.

The chain snaps.

I don't think I'll have that issue, from the facing of the block to the outer edge of the chain (facing the block) I have 2/16" all the way around. Looked like the crank sprocket was a little closer then the cam, but no same gap. Only rubbing I had was the oil pump cover, which is being taken care of. I'll be able to test fit again in a couple days probably, working on everything else at the moment.

One of the things that helps chains snap is deflection. Meaning if the chain is not straight and one gear location of the chain is closer to the face of the block than the other.

Originally Posted by BillBoost37

One of the things that helps chains snap is deflection. Meaning if the chain is not straight and one gear location of the chain is closer to the face of the block than the other.

I other words. If you install it correctly you shall be A-Okay.

I believe this to be true!! And spacing is equal from the block facing all the way around, I have a little back and forth play on each sprocket with tells me there's no binding (if one sprocket was further in or out the chain would be tight with no play), and it seems nice and snug. Seems to be done correctly!!

I would urge you to read this thread before buttoning up your motor.

ClubGP Message Forum troubleshooting

GTPower... is the chain still different on the JP's. Thought I read a while ago that Rollmaster bought them. Which might make the chain the same as rollmaster.

I have read that as well. I don't think they are the same anymore. Possibly at one time they were??

I read that post a while back. Isn't it from '09? I do know the chain is a Rolon chain, see it stamped all the way around on the outer links...

One would think quality control has taken over since, or at least somewhat.. For every bad post I found regarding JP I found good ones to.

Rollmaster bought JP, or vise versa... There are two different chains, but like Bill said most of the issues were before the buy out/merge. AND it has a lot to do with how they are machined and installed one would think. I mean slapping it in, doubling up on your timing cover gasket and calling it a day would be a HUGE mistake I'd think.

That's a good point. I still wouldn't risk it. I've never seen a rollmaster break.