Belt'agedon

Dear Nortonists,

This forum is about sharing experience, and I am truly sorry if I hurt anybody with this material :roll:
Almost everything has been discussed about Belt drives, but I have a doubt about the cause of the following. I thouroughly followed the fitting instructions of this norvil 30mm belt, or so I thought...




If I refer to this site : http://isccompanies.com/june-2010-under ... t-failure/
I am on the too low tension side. Any thougts ?

Cheers

Xavier

Or too tight.

Sprocket misalignment? How many miles was it on your bike?

Oh thats a Key Point, around 600

Done that so got that logo image on a T-shirt now. I'd most suspect the flanged sprocket with un-flanged sprocket wobble failure mode with help from grit entering decorative mass saving ventilation holes. Ie: enough clutch wobble that belt edges rub-work against the full pulley flanges till the tooth roots anchoring removed and speed-ed up by road grit. Either over or under tension could also be part of the belt edge separation. Grab clutch basket and see if any detectable wobble as I must also understand what happened to yours so I can avoid it in mine, again. Check radial run out now too as only takes one good over tight event to cause a candy cane'd main shaft. Ugh.

Hummm, no ventilation holes, run-out/wobble, still to be checked !

Could also be a faulty belt from new, is your belt kit a steel pully system or a alloy pully system, I was running the steel pullies from RGM and have done 12,000 mies with it before my belt lost about 3 mm with the belt not running true, I brought the alloy belt drive kit from RGM for my project bike but decided to put it on my Norton and a double ajuster, last week I went to fire my Norton up and my belt is starting to do the same thing trying to run off the front pully, my inner case has been open up at the back so I can see the belt running on the clutch pully, the belt was adjusted right and running true then I notice it started to pull to the outside of the pully when I had a look inside it has gone to lose for some unknown reason with only about 2,000 miles on it, but it has damaged the belt.

The alloy kits has also caused the bike to have a few more vibrations than the steel kit, I feel it more in the foot pegs when ridding, I have decided to go back to the triplex chain as I had no problems with the chain only with the wet clutch I had problems with and because the inner case is open at the back I am going to just spray chain lub on it when it needs it, but I do have another inner case to put back on if this don't work.

Ashley

looks like it has been running out of alignment. from this picture I would guess it has been running off the back side of the clutch drum or you don't have one of the guide plates on the front pulley as it still has a narrow strip of teeth left on it.

Xpongebob said:

Xavier

Click to expand...

Peel's creeping up clutch wobble rubbed belt to death on front pulley plates was in total dry sealed case no venting so grit is just an accelerant not a causal agent. As for triplex or drive chain wear and tear I can tell ya there are two wide apart camps if ya observe enough the reasons, one to keep an oil slinging dripper on it or run dry as a bone. If not at one extreme of the other - chain wear definitely increases. In primary oil helps cool chain runing over hot crank sprocket and its own friction plus to keep its internal produced metal grit flushing out. Lube friction reduction is the least important reasons for oil in chain. Racers have gotten away with dry chain for a while so keep an eye on it for missing links before a row of em let go, while experimenting for the rest of us. Peel's alloy drive was detectable aid in mass and shifts and response with nil effect on vibration. The only other thing I can add on this is my rather poor opinion of AMC sleeve bush lubrication in lower gears.

Hee Hee Hee.

Might have needed the dual gearbox adjuster to micro adjust alignment?


Installed...


I used these to align the pulleys. It was Bobs idea and a good one.

Torontonian said:

Hee Hee Hee.

Click to expand...

I was laughing at the dry rubbing warning, not sure what you were laughing at. :mrgreen:

Sorry , I laugh at all Norton disasters then try to figure 'em out. Belt defective. Belt too tight . Belt mis-aligned. Clutch mainshaft circlip crushed or broke. Mainshaft bushes worn out.

Hi Bill,

What you're saying is interresting, cause the Norvil setup for a mk1 does'nt need the back guide plate on the front pulley.

Anyway, I've just ordered the dual adjuster in order to clear onze possible cause, even if alignement didn't seem to be faulty at first....

Subsidary Question : this kit uses Htd belt, can it be replaced by a Polychain, or profile is different ?

Cheers

Do'h if any one expects a belt to stay put for long without dual adjusters fixing it down square after diddled to stay on w/o front plates on. I'm from Florida where we watched submarine races under moon light beaches, ugh think about blown sand rubbing things raw. Anywho each of these diaster reports helps my own mechanical ego getting caught out by such a simple straight forward gear head machine that can burn rubber in a few other places than tires. In case it might help others think less of me, do note that once a horrific tug is put on shafts better check the shafts or expect another wobble off of belt sooner than later til the whole drive train interconnected lesion sinks in. There's a saying that might apply...

Hi Xavier,

Hope it can help: In most of french industrial hardware shops selling belts, pulleys etc... you can have your belt made to order, much cheaper and of as good quality as those got from Norvil, RGM ... and other Norton parts providers.

Yours should be of AT10 profile, which is a standard one. It means that a 980 millimeters long belt has 98 teetht(one per centimeter).

Mine on my Dominator is a AT10 / 27 mm wide.

Back to your problem: too tight /misaligned / rubbing against something?

Bonne chance

Laurent

What you're saying is interresting, cause the Norvil setup for a mk1 does'nt need the back guide plate on the front pulley.

Click to expand...

Why? Is that how Norvil supply them now? Mine is from 2003 and went 20,000 miles (31,000 km) at least until the same thing happened. It has both side plates on front pulley. From what I see on the Gates website (how to determine failure modes) mine had been too tight when it was installed and some early damage had been done together with some oil contamination.

like keith said all the norvill drives I have Sean it should have 2 guide plates with the inner one retained with counter sunk screws and there in is one of your troubles

Xpongebob said:

Hi Bill,

What you're saying is interresting, cause the Norvil setup for a mk1 does'nt need the back guide plate on the front pulley.

Cheers

Click to expand...

I will not install one without the dual adjuster as most of them will have alignment issues without it. yours was not running fully on the pulleys as evidenced by the narrow strip of teeth left on the belt.

Xpongebob said:

Hi Bill,

Anyway, I've just ordered the dual adjuster in order to clear onze possible cause, even if alignement didn't seem to be faulty at first....

Cheers

Click to expand...

Deleted

Keith said:

Why? Is that how Norvil supply them now? Mine is from 2003 and went 20,000 miles (31,000 km) at least until the same thing happened. It has both side plates on front pulley. From what I see on the Gates website (how to determine failure modes) mine had been too tight when it was installed and some early damage had been done together with some oil contamination.

Click to expand...

In fact, I must precise that having a Maney Crankcase I don't have enough clearance for the backplate, and the front pulley, reporting the problem to norvil they took my front pulley to the lathe, and told me no backplate was needed. So I guess my engine is closer to a mk3 ?