It was all going so well, 3 fantastic weeks in the US and Back out for a ride today. 50 miles in a clanking from the trans and lack of drive. Well I nursed her back 13 miles blaming new ferodo plates (replacing worn surflex with pointed drive dogs). But looks like it sumped badly last few wks and the new belt couldn't take it. Previously the belt had suffered several oil soakings and survived several cleans. This one has done maybe 9,000 miles and although from norvil is a different brand, not a Gates as original. What is strange is that when the original failed in May 2012 no amount of tightening would get me drive. This one despite being coveted in oil got me away from dead stops ok but acted like an auto on lockdown. It is also loose and no way should it have got me home.....time to fit one of those white oil resistant belts or go back to chain....I can guess the opinions headed my way. Will attach pics later....
belt drive 2nd failure
- Thread starter Keith1069
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More and more examples of the diminishing advantages of belt drive over chain. Clean and shock-absorbing are the only positives I can see. If you have to run it in oil to lube E-start workings or if leaky seals at either axis means an oil-resistant belt is necessary, there goes the clean thing. Then there's the cost to be considered. So an oil-tight, kick-only motor might see a small advantage. For all else, bupkis. Think I'll dance with the girl that brung me.
Thanks Dave, yes I will be looking for an oil resistant belt. I did see some in my size recently (8 x 30mm)but not length (920mm) Will have to research. Its my fault for not draining the sump but the original Gates got oiled several times in 25k miles. This one has 8.5k on it and its the first oiling it's had!! Leaving the primary to drain is probably not an option I'd take. I am just so surprised that this belt went so quickly. I wish I'd noted the make but the printed name has rubbed off.
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Danno said:
Unfortunately a belt is not as shock absorbing as a chain. The glass fibers in a belt can not stretch without breaking. A chain on the other hand has all those pins with a cushioning layer of lubricant around each pin. That gives a chain a considerable cushioning effect. Jim
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Besides checking with belt makers and vendors that guarantee any 30 mm belt is ok for at least 80 hp &or 8000 rpm belt translation speeds they also assured me that oil or ATF will not bother belts, so hope all the *assumptions* of reasons for failures is correct or may get a 3rd and 4h let down and back to messy ole heavy chain gang. If hobot is full of hu hu on heat, tension, power - speed handling and oil exposure please alert all the ignorant auto and cycles out there about ignorant use of cam belt drives. These belts do fail too after a time, though apparently less than chains wear so they get away with enclosed heated oil bathed high stressed narrow belts over smallish pulleys as long as nil grit and pulley wobbles. BTW on 18+ inch slow water crossings with unsealed belt I found its possible to get enough water forced under belt unevenly even at low rpms to hydro plane wedge belt right off a pulley w/o side plates but can slip it too-lless back on and carry on fine again. Very few solvents work on tire or belt rubber but acetone and relatives and then so slow needs heat and high concentration or long time to matter.
Thanks Hobot, I just Googled and Brecoflex is the one that guarantees?? oil resistance and 2.5 x life. Waiting on supplier to see if he can get a 920mm. He advertises 880mm which means adding a link back in the final drive chain or a new one.........maybe opening out the gearbox adjuster holes as well. I was hoping for a straight swop though. Weathers just improving here again at 65F and was hoping to ride not fix stuff. Been thru 95F Orlando, 65F Toronto, San Fran and Monterey and back to 95F Orlando with rain and snow at the Canyon and melting snow in Yosemite.....
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One of Peel belts was 880 but found I could not get it slack enough to start with for the parts expansion d/t Peels HI Heating (could only touch fingers an instant on primary, tranny or drive chain) w/o altering stuff like you mention so removed it. If you can detect any basket deflection All bets off till fixing AMC box first. If basket stable then you have a murderous mystery for sure.
Can ya image-in how much power thrills and time it takes to heat air cooled rear drive chain til too hot to handle, well neither could I till Peel engine combo against all advise woke THE FucK UP. Yet after a hand full of drive train failures only drive and rubber trouble Peel ended up with was poor ole tires lack of mileage and traction-heat endurance. To get Peel to her peak about destroyed me and her in every way so over whelmed to keep one Commando pure Norton no brainer operated like a wiser mature old fart should.
Can ya image-in how much power thrills and time it takes to heat air cooled rear drive chain til too hot to handle, well neither could I till Peel engine combo against all advise woke THE FucK UP. Yet after a hand full of drive train failures only drive and rubber trouble Peel ended up with was poor ole tires lack of mileage and traction-heat endurance. To get Peel to her peak about destroyed me and her in every way so over whelmed to keep one Commando pure Norton no brainer operated like a wiser mature old fart should.
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Keith1069 said:
You do really need to sort out how the oil is getting in there and stop it. If you want another Gates belt buy one from an industrial belt supplier and you'll find they sell them considerably cheaper than any bike spares place will. I swapped my Gates belt because I thought I ought to rather than because the old one had a problem. It was over ten years old and still fine. I think I paid about £20 for the new one.
Ian
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If you are wet sumping it shouldn't be getting into the primary case. What is your breather situation?
I don't think the oil is the primary cause of the failure. Are you SURE the belt isn't too tight?
I don't think the oil is the primary cause of the failure. Are you SURE the belt isn't too tight?
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The belt system is designed to be run in a dry primary.
The primary is not intended to be a sump for oil from the motor or transmission.
Seals are readily available and fairly easy easy to replace.
So why are these incidents considered belt-drive failures?
:roll:
If you run a chain in the primary and forget to put in oil, highly like it breaks before you would like.
Title of post would be "Primary chain failure"?
Just makes it sound like the component was to blame when in fact improper maintenance was the culprit.
The primary is not intended to be a sump for oil from the motor or transmission.
Seals are readily available and fairly easy easy to replace.
So why are these incidents considered belt-drive failures?
:roll:
If you run a chain in the primary and forget to put in oil, highly like it breaks before you would like.
Title of post would be "Primary chain failure"?
Just makes it sound like the component was to blame when in fact improper maintenance was the culprit.
Onder
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Because the belt failed! But of course I get your point that something caused the belt to fail.
Id be all over making sure it isnt too tight when it gets hot. They really do change quite a bit from cold.
I run a 850 mk2 and it is dry and sealed. Worry more about grit than heat but then Im an older type who
tries to control himself more often than not.
No idea what service life is in the real world. It may well be 5k is the limit of complete safety. If so at
20 quid I cannot see that as a show stopper considering most of dont do much more than that in a year
and if we did I still dont see the cost as significant. If I as still 23 it would be.
It is a bit like rear tires. Mine has 1200 miles on it and it is shockingly worn. I rarely can get more than
3500 miles out of one and they cost three times the belt.
Suspect we just have a consumable. Think of the Commando as a warbird. How many hours did they
stay at the front lines? Not very long, they were replaced with a fresh one. Fresh as in brand new.
Id be all over making sure it isnt too tight when it gets hot. They really do change quite a bit from cold.
I run a 850 mk2 and it is dry and sealed. Worry more about grit than heat but then Im an older type who
tries to control himself more often than not.
No idea what service life is in the real world. It may well be 5k is the limit of complete safety. If so at
20 quid I cannot see that as a show stopper considering most of dont do much more than that in a year
and if we did I still dont see the cost as significant. If I as still 23 it would be.
It is a bit like rear tires. Mine has 1200 miles on it and it is shockingly worn. I rarely can get more than
3500 miles out of one and they cost three times the belt.
Suspect we just have a consumable. Think of the Commando as a warbird. How many hours did they
stay at the front lines? Not very long, they were replaced with a fresh one. Fresh as in brand new.
I have two bikes with Bob Newby belt drives and clutches. No complaints, but no complaints about the stock oil filled Commando chain drive primary either.
The main advantages with the belt drive on the 650 ss were that it solved the problem of the forever leaky tin primary and also the slipping stock clutch. It is also much lighter than the stock setup, though this probably isn't too important with most standard type road machines. The weight saving of the NEWBY is a lot because of his drilled alloy clutch drum and alloy hub, however the belt drives which utilize a stock heavy Commando clutch are not going to save nearly as much weight.
One advantage for racing- a belt letting go at high speed is not great but a primary chain letting go at high speed could be fatal, certainly more potential for both bodily and vehicular damage there.
Glen
The main advantages with the belt drive on the 650 ss were that it solved the problem of the forever leaky tin primary and also the slipping stock clutch. It is also much lighter than the stock setup, though this probably isn't too important with most standard type road machines. The weight saving of the NEWBY is a lot because of his drilled alloy clutch drum and alloy hub, however the belt drives which utilize a stock heavy Commando clutch are not going to save nearly as much weight.
One advantage for racing- a belt letting go at high speed is not great but a primary chain letting go at high speed could be fatal, certainly more potential for both bodily and vehicular damage there.
Glen
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I personally justified the cost very easily, all it took was a constantly oil leaking pre Mark3 primary no matter what I tried to stop it
replaced the big O ring gasket multiple times, tried all kinds of sealants in combination, bastard still kept leaking
for that reason ALONE, and because I was no longer a teenager on minimum wage and lived frugally I could afford the $500 for the belt
instant relief, it was worth it to me, and what I found was that I liked the way the belt "felt" compared to a chain, it felt lighter and smooth when I shifted, and another big bonus I had not anticipated was that with no oil in the primary none could foul my clutch plates
so yes, for me, I am very happy with my dry belt primary, and I have no problem at all justifying the $500
Oh I certainly do. Its not often it does it and this is the first time since the new belt went in May 2012. Main oilseal carefully installed with keyway covered, no nicks on crank and primary tappings sealed. It is engine oil BTW. I believe it sumped heavily (3 wks standing)and I over revved it which can overcome the seal. It shouldnt but it does.
Main seals renewed every bottom end rebuild (stripped this winter to do rings and add timing side lower drain hole).
Very careful on this Dave, runs at 30mm total. The original Gates suffered severe abuse from overtightness, runout and several oilings. Each time it was cleaned and re-used, eventually failing at 25,000. I believe the failed belt is a Contitech. Breather is a marine brass one way from Norvil. It works well and comes off the std 850 timing case outlet (750 with 850 cases).
Its also possible that I need new clutch and drive pulleys. They are worn and may have accelerated the demise of the belt.
The oilproof? one I found is from Brecoflex but have not located the correct length yet.
Thanks for comments.......
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