belt drive problem

I have a belt drive , unknown mfg. It has a ball bearing in the clutch and there is a lot of wiggle between the basket and the center. I do not think it is possible to take the wiggle out. I am running zero shims on the mainshaft and the back of the clutch lines up pretty well with the front pulley.
The belt is slightly loose but not bad.
Trans is bolted up tight.
The belt wants to walk off the sprocket...20 revolutions and the belt drifts outward about 1/4". I want zero.
Does the floppy basket allow the belt to drift outward? At speed does it even out and not become a problem? If not what is the solution? somehow cock the trans in the cradle? I could get the dual draw bolts but would that really do the job?

You have definitely got to use the double gearbox adjusters

You might pull the clutch basket and examine the bearing; probably needs to be replaced with a high quality roller type, perhaps M.A.P., Norvil, or other belt primary makers sell good ones. Or, you could spec it and order it from a bearing house.

Re: mechanic problem

seen it before
BAD ball bearing...or a worn out clutch center or belt drive basket.
With the primary cover OFF,
run the engine,
when you put it in gear,
(so far so good)
Start to pull the bike with the clutch, if you SEE the basket move forward and twist and the belt shoots off to the left.
The ball bearing is likely bad and bad sleeve bearing don't help either.

Double adjuster is not an issue until you keep the basket from flopping around "excessively".

I've done lots of BD starting in 1988, to bad you don't even know the type of belt drive which may give you a clue as to who made it.

HTD or AT10 ??????????

if I had your problem I would first order in and install a left side threaded gear box adjustor so you have the ability to get the belt running true, and after doing that if the belt wondering still persists then yes look to the clutch locating bearing, etc as the solution

can we assume you have at least removed the clutch plates and put a tightening socket on the hub nut, and if you go that far you may as well then see if you have crushed the cir clip

in other words do all these easy things first, maybe you will get lucky and not have to replace the bearing, etc

I pulled the clutch off and set it on the bench. The everything is new, perhaps not even 100 miles on it.
The circlip in the mainshaft is in perfect condition.
The stepped washer is located correctly.
There is no slop in the basket to the center
The bearing is firmly mounted on the center and basket, it is not rattling in the basket or the center.
It appears that the bearing itself is loose as a goose and allows a lot of wobble by the time it gets to the OD of the basket. In this case , cocking the trans in the frame is not the way to go.
I had the same problem in my Goldstar and due to its age, hard life as a dirt bike, and the rather flimsy mounting plates, I had shims in four places to allow the Hayward belt drive to run true.
First step is to find the maker of the belt drive.

the belt is a Gates 880 powergrip GT2 8MGT round teeth
68 T basket
32 T front pulley

"It appears that the bearing itself is loose as a goose and allows a lot of wobble by the time it gets to the OD of the basket."
Seen that before....

" In this case , cocking the trans in the frame is not the way to go."

On my combat I only run one tensioner......on the left.

Your belt sounds like HTD family/profile

Typically you remove all mainshaft shims since they serve no function in a belt drive.

All of the current manufactured bearing I have seen have been "loose as a goose" They don't make them like they used to.
I would suggest a second adjuster. Jim

Hi, may be a one dot bearing could help ........!

clutch-bearing-clutch-centre-fit-t12490.html

marinatlas said:

Hi, may be a one dot bearing could help ........!

clutch-bearing-clutch-centre-fit-t12490.html

Click to expand...

I should have said "All the modern SEALED bearings I have seen were loose." The unsealed bearing is available with a tighter fit but they don't last in a dry primary. Jim

Hi G81

I dont think it can only be me, but You really didnt need your final quote!

"So there are opinions and there is real world, product test data. I normally go with evidence and not opinions.

I think we all know that your product is good, everything CNW produce would be on most peoples buy list. However, 100 kits brilliant. Me, I have a Bob Newby belt drive kit thats been on my bike since 1994. Never failed, never caused a problem, never changed the belt! Embarressed to say its only done 25,000miles in that time. Bobs made a lot of kits. Tested? Real World?
I think so. But many other people have produce good kits. I run Maney items on my Race bikes,(Nortons)

Joining the party nearly 30 years late ( The first belt drive I saw was on a race triple in 1988)
I would expect your product to be far better.

Just an opinion

Chris

Chris said:

Hi G81

I dont think it can only be me, but You really didnt need your final quote!

"So there are opinions and there is real world, product test data. I normally go with evidence and not opinions.

I think we all know that your product is good, everything CNW produce would be on most peoples buy list. However, 100 kits brilliant. Me, I have a Bob Newby belt drive kit thats been on my bike since 1994. Never failed, never caused a problem, never changed the belt! Embarressed to say its only done 25,000miles in that time. Bobs made a lot of kits. Tested? Real World?
I think so. But many other people have produce good kits. I run Maney items on my Race bikes,(Nortons)

Joining the party nearly 30 years late ( The first belt drive I saw was on a race triple in 1988)
I would expect your product to be far better.

Just an opinion

Chris

Click to expand...

Chris

Actually the bulk of your above comment is not an opinion, but a statement. And, a good statement at that. You have stated that you have a Bob Newby belt drive, that is almost 25 years old with 25,000 miles on it, and it has performed flawlessly for you. A statement of fact that the Newby belt system is a good and proven design. I like that kind of information.

The opinion of mine, which you quoted in your comment, should be taken in context with the thread it was originally posted. There were "opinions" in that original thread that called into question on whether the Poly Chain Gates belt was the best choice for the CNW Electric Start Conversion. I was simply saying that the opinions of the people questioning the belt decision was contrary to the product testing and success of the product over the last three years. We did not originally design the belt drive as a stand alone belt drive system, but as part of a Electric Start Conversion with a belt drive. So we wanted to use a belt with less width to fit into the system. The Gates Poly belt is 21 mm wide, which is much thinner some of the other belts discussed in this thread or the original thread which you took my quote. It fit in our design, and had the strength we were looking for in the design. After the system performed well in both our in-house tests, and purchased systems in the field, Matt at CNW asked if we could launch the belt drive as a stand alone system.

So, thirty years late, well yes, been busy with other manufacturing work during that time. Is it far better than other belt drives? Well that would be an opinion that would have to come from others. Is the CNW belt drive far better as part of a electric start conversion, again another opinion that would be best given by consumers and not the manufacturer.

I believe there are many good Norton aftermarket components out there. I run Maney parts on my NYC Seeley Norton. I run a TT 5 speed gearbox. I have three Nortons with Full Auto heads. I have been a machinist and mechanical designer for 50 years, and I really try my hardest to do "quality" work. But, others do quality work also. But I generally make my decisions based on real world reviews (like your review above on the Newby Belt drive) and not on opinions of people that have no experience with a particular design or component.

With Respect
John

Hi John

Thank you

succinctly put. You are right, in relation to the best belt for your usage, I agree. I probably didn’t read it as such, ie others disagreeing. Belt drive with electric start is the future. We are all getting older & I cant see us wanting to give up on our bikes.

With respect


All the best Chris

Chris said:

Hi John

Thank you

succinctly put. You are right, in relation to the best belt for your usage, I agree. I probably didn’t read it as such, ie others disagreeing. Belt drive with electric start is the future. We are all getting older & I cant see us wanting to give up on our bikes.

With respect


All the best Chris

Click to expand...

And, best to you too, Chris