Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Aftermarket timing belt failiure

Well, I am sure many will be interested in my experience with the aftermarket timing belt from Big Dog Motorcycles (X-Wedge Cam Belt 2009-10 WOLF models & Morgan 3 Wheeler) Note that they no longer appear to be selling this item.
I had it installed at 18350kms and today at 20352kms it broke.
Being after market and looking a little less robust than the original I had been regularly checking it. at about 200kms prior to this it looked fine. In fact, it still looks good overall barring the huge break!
If you are running one of these, you may need to keep a spare handy! I for one will be buying one from a preferred supplier.

Unlucky but feel reassured it's a non-interference engine.

Thanks for the heads-up. I do have one of these Big Dog belts on my spares shelf but have always been sceptical about its robustness. In light of your experience I think I'll just carry it as a spare and not rely on it long term.

2000km / 1200 miles of life obviously points to the belt being 'not fit for purpose'. Have you let Big Dog know about the breakage? I'd be interested to hear what they say.

This week, I also had a broken belt despite it being an original Gates. I found this on the crankshaft pinion when doing the roadside repair. Absolutely no idea what has caused this damage. I can't imagine that parts of the broken belt could cause this damage.
I ordered a new pinion and a new spare belt. When carrying a new belt, please be sure you have all the necessary tools to repair the road.

The failure that Laurens shows in his photograph above is, I believe due to the fact that the timing sprockets appear to be "Sintered" or produced by a process known a "Powder Matallurgy".
In this process metal powder is compressed into a mould and then heated to allow the metallic grains to fuse together. The process has to be very closely controlled to ensure maximum strength in the finished component and if the powder is not properly fused together this can result in the final component having less than the required strength.
I recall some time ago people were experiencing failure of the keyways in the pulleys for the same reason.

The following website has the details :-
https://www.pm-review.com/introduct...tering-in-the-powder-metallurgy-process/

regards
Keith

Another good reason to have a clear viewing window in the belt cover. You would be able to see particulate before the failure, hopefully.

Those driving gear teeth appear to be wider in the area of the damage, which would tend to indicate a very solid object passed between the belt and the gear. Are running spacers on your front cover or is there any opening that could have allowed a foreign object to enter the timing case?

Yes, the normal spacers but they give only a slot of 2 mm.

Was this Big Dog belt one of the early type (GF reinforced) or the 'improved ' later type that had Kevlar reinforcement?

Prompted by this thread, have just looked at our timing belt - probably ~10-12000 miles (was changed when we had Chassis/Centa/...etc done at the factory. No markings on it (worn away).

We have an S&S spare (S&S 106-0571)

What are current thoughts/experiecne on belt life and recommended mileage to change??

Breakage is more a hassle than a risk given the non-interference nature of the engine - or is it a case of running until it breaks unless regular inspection shows obvious degradation....??