Cambelts - before changing

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
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anton88
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year: 1989
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Cambelts - before changing

Post by anton88 »

Right, first job now the bikes home is to change cambelts. Ive some on order, waiting for the postman. Heres some pics of the condition when i took the covers off :

The centre / crank pulleys:

Image

The horizontal belt:

Image

The vertical belt:

Image

The bike had been standing for quite some time before i took it home, and no idea when belts last changed, but there didnt sem to be any major concerns or damage to them. However, there is a load of crap around the vertical cam pulley - not sure if its old rubber or oiley dirt (any way it will all be cleaned away nefore the new belts go on) :

Image

Image
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Finnpaso
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Re: Cambelts - before changing

Post by Finnpaso »

I am QUESSING now, that someone have tighten too much those belt cover screws, then that rubber start to turn and it can hit to belt and grinding start. I noticed thiskind one time, when i turned those screws too much and then that rubber part started to turn and belt touched that rubber and started to make some noise.... I opened immdiatelly covers and find small part of rubber gone away already... As I say, this is quessing..... :thumbup:
Antti http://www.youtube.com/watch?v=HeKOh3XoXPg&NR=1
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Desmo_Demon
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Re: Cambelts - before changing

Post by Desmo_Demon »

anton88 wrote:However, there is a load of crap around the vertical cam pulley - not sure if its old rubber or oiley dirt (any way it will all be cleaned away nefore the new belts go on) :
Chances are, that is rubber from the belts. I've seen this with my ST2 when I went 12k miles without adjusting the belts. I adjust the belt tension every 6k, now (the bike has 36k miles on it and I only do valve adjustments every 12k as the valves have settled and I skip a valve check/adjustment).

What happens is that the belts stretch and get a little loose. When the engine is not up to operating temperature, the belts are still a bit more loose than they should be. When you go riding and chop the throttle, the belt flexes and hits the belt cover. If you inspect the smooth part of the belt, you'll probably see a groove where it has been hitting the cover.


This is what my belts looked like when I got my Paso....

Image

Image
2002 Ducati 748 monoposto
1998 Ducati ST2
1996 Suzuki GSXR-1100
1994 Bimota DB2
1988 MegaPaso 916 project
1987 Ducati Paso 750
1985 Harley FXEF
2001 Ducati M900ie (wife's)
2000 Yamaha YZF-R1 (wife's)
1998 Ducati ST2 (wife's)
1994 Suzuki GSX-750R (wife's)
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Finnpaso
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Re: Cambelts - before changing

Post by Finnpaso »

It can be also so, as U say.... :thumbup:

Also all pulley(and "lead rollers" bearings) must be roll easily without too much friction. I have seen many Ducatis, what have lost those bearings and then its again bad thing.....and very harmfull to belts..... :smoke:
Antti http://www.youtube.com/watch?v=HeKOh3XoXPg&NR=1
KTM 990 Adventure -08 metal dark grey
Paso 750 -89 red/metal grey
907IE -91 red/metal grey
907IE -91 red
2xST4S -02 red/metal grey
ST2 -01 red/metal grey
Volvo V70 Bi-Fuel Classic/titanium
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ducapaso
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Re: Cambelts - before changing

Post by ducapaso »

This might also be the right time to make an accurate ceck to the bearings and wonder if it's bettere to upgrade to roller/bearing alike newer desmodue :thumbup:
have a nice ride, Nicola

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20YearOwner
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Re: Cambelts - before changing

Post by 20YearOwner »

Changing belts, its really and easy project when you have the manual. Also go to Ducatitech.com and see the video.
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jcslocum
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Re: Cambelts - before changing

Post by jcslocum »

anton88
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Re: Cambelts - before changing

Post by anton88 »

Thanks for the tips Guys. Upon closer inspection, its definitley a mixture of dirt and rubber, but i think its accumulated over quite some time.

I havent fitted the new belts yet, as the engine is coming out for a thorough clean degrease and bit of paint before checking and replacing any parts. I can see that the vertical belt has been rubbing on something (not by much), but cant see where yet - should be able to see where once its all clean.
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Re: Cambelts - before changing

Post by Mc tool »

wouldn't hurt to change the oil seals behind the cam pullies , probly should do the ones in the clutch too
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