I've always used a 5/16" drill for 3/8-16 threads. Not exactly sure what % of thread that gives you, but I've never had threads pull out on anything using a 5/16" bit.

I think I opened up the holes in the sprocket to 3/8" so the fit was as tight as possible between the bolts and sprocket. Can't remember... I've slept since then.

 

00XJ we are talking about drilling through the sprocket to let the 3/8 fit snugly in the sprocket, not the pilot hole for rethreading the hub. I think that is the confusion. FYI: 3/8" threads - 5/16 pilot = 1/8" of thread (1/16 all the way around) which isn't a whole lot when you think about it. Fortunately, the threads holding isn't the issue, even with the stock bolt.

The machine shop drilled 23/64 holes in the sprocket and told me that the holes were already stretched too big to be used with a 3/8" bolt. They were indeed, quite oval shaped and the sprocket was pretty mangled anyway, but John@Raceway called and told me to speak with Eugene who is shipping my parts out today and I got some news.

I hope I'm not speaking out of turn (wasn't told to hush.)

The sealed axle bearings have a tube between them (which we have discussed here before) and it is to keep lateral presure from transfering to the inner race of the axle bearings. Some people have been having issues with drag because the bearings were very tight which contributes to the issue we are having. He said that the factory is moving to a tapered bearing (like is used on cars) which better absorbs lateral load and doesn't require the tube between the two axle bearings. It's slightly thinner than the flat bearings, so one would have to remove the tube between the two bearings and cut a small spacer off of it for both sides. This would need to be a pretty precise cut, but you could sand a little to make sure you get it right, and if you screw up, there is a ton of extra tube (you would only need about 1/8-1/4" of spacer per side.)

Sounds like a plan. He is also aware of the issue with the bolts being too small for the holes in the sprocket, and they have gone to bigger bolts at JetmotoUSA. I'm going to be sending him pictures of my axle carrier, sprocket, and the bolt I pulled out of the axle bearing (hopefully tonight.)

Never fear, Jetmoto/Raceway are on the job =)

I'm seriously going to put an alarm on my digital camera, I get it back, put it up, go take a nap, and the wife has it taking the 1,000,000th picture of our Pitbull in a cheerleader outfit.... the horror. Maybe she will let me have my camera back again tonight.

I need to figure out who it was that did something with the stock chain tensioner. I think someone did a spring relocation to either put more presure on the chain or (hopefully) spin it around so the chain doesn't hit the damn axle. *shrug*

-JNY

 

Ok, I see. I simply drilled a 3/8" hole in the sprocket. There was NO slop. Just go up to a 7/16" bolt maybe? I posted up about the bolts being too small for the sprocket holes awhile back.

I know what you mean about a digital camera coming up missing. My wife has two horses, and there are NEVER enough pictures of them!

I posted about relocating the spring on the chain tensioner. I drilled a hole in the arm about 1/8" from the bottom, and fed the end of the spring into it. That way it isn't under the arm catching on weeds/sticks, etc... The spring needs to be much stiffer. I hope Jetmoto will offer one soon.

I got tired of the chain slapping on the chain guide, even when it is properly tensioned. It drove me crazy! I mounted a pad on the top and bottom of the guide made out of UHMW. I countersunk the holes as deep as I could to keep the chain from rubbing on the screws, and used flatheads to attach them. No more, or very little slap now and when it does it isn't near as loud as before.

 

I'm waiting on the axle carrier, bearings, and sprocket to get here and I'm just going to use the new sprocket because the threads in the hub are already tapped.

I don't know if a stronger spring would help the tensioner because of it's design. If it was mounted on the top (pushing up) it wouldn't be an issue would it?
What is UHMW? I'm going to drill a hole in the tensioner arm while I'm waiting for parts.

Looks like it's going to be the middle of next week before my parts get here, and then I have to cut spacers out of the pipe in the middle of the axle (which I've yet to get out.) So maybe I'll be riding by next weekend. I don't know how easy it's going to be to make those spacers.

-JNY

 

UHMW is a plastic. Ultra High Moleculer Weight. It is sorta like nylon, but softer, and is self lubricating.

Part of the problem with the tensioner "we" are having now is the smaller drive sprocket. It has caused the chain to be closer to the top and bottom of the swingarm/chainguide because of the smaller diameter of the sprocket. The chain has to be tensioned pretty snug, or the tensioner dosen't have enough "swing" to remove the slack in the chain. You could put a roller on top of the swingarm, but you need the tensioner on the bottom since it is the slack side of the chain.

 

Yeah, I never thought of that man. Great points.

If the rear spring wasn't so soft it wouldn't be as much of an issue, but if the rear spring didn't fully compress at roughly 1/2 of the rear shocks compression, then the chain issue would be even worse. It's a blessing and a curse =(

-JNY

 

<div class="FTQUOTE"><begin quote>Originally posted by: 00XJ

UHMW is a plastic. Ultra High Moleculer Weight. It is sorta like nylon, but softer, and is self lubricating.



Part of the problem with the tensioner "we" are having now is the smaller drive sprocket. It has caused the chain to be closer to the top and bottom of the swingarm/chainguide because of the smaller diameter of the sprocket. The chain has to be tensioned pretty snug, or the tensioner dosen't have enough "swing" to remove the slack in the chain. You could put a roller on top of the swingarm, but you need the tensioner on the bottom since it is the slack side of the chain.</end quote></div>


Its a type of Polyethelene Its the stuff they make milk jugs out of.

Great points and observations 00XJ!

 

I was just digging around my work and found some 8mm Flathead screws. I think im going to c-sink the stock sprocket and see how it looks. Ill post a pic when i get it done.

 

We need to stop the China Crap. Quit buying...Sellers...Got to be other ways to sell foreign crap. Thay are crap unbalanced & i'm lamed due to the cheap crap imitation design. Screw the China there due for as done to Japan...Then again we got there crap but much better Than China ******...Basically if theres no parts replacement data base its black market...for you or me usa citizen weve been thrown in jail.

 

GIZTMO
Very eloquently written![img]i/expressions/face-icon-small-confused.gif[/img]