VBB clutch problem.
Post Reply    Forum -> Not-So-Modern
Author Message
Member
VBB2T 177
Joined: 23 Apr 2019
Posts: 7
Location: Hong Kong
Sat Aug 10, 2019 7:04 pm quote
With some background first.
Upgraded to 7springs clutch. Removed rib on case clutch cover.
New 3 plates clutch disc. Soaked over night. SAE80 gear oil. New basket. New separate bush and pressure washer. Clutch separate test is good. There is a washer between the crank bearing and 0.5mm gap to the clutch gear.

Clutch disengage and engage fine. Gear change is fine. Roll free in first gear. The problem is only when start moving from stop in first gear the engaging is not smooth and create loud grinding noise. The bike will suddenly lurch forward no matter how slow I release the clutch level. As soon as the bike is moving then 2nd / 3rd gear the problem gone.

If I step on the rear brake, in first gear, give it little throttle and release the clutch in half way, clearly hear the grinding noise and the bike wants to jump forward (instead of pulling forward).

I removed the clutch again and again did not see any grinding marks or abnormal sign. Exchanged 2nd set of new clutch plates behaved the same.

I researched online everyone said itís the oil, dry clutch plates, soak the plates, cable adjustment, even primary Cush drive. I have actually upgraded to DRT 23/62 so itís new Cush drive.

Anyone has some ideas to help me to determine what caused the problem? Much appreciated.
Molto Verboso
Joined: 26 Oct 2015
Posts: 1570

Sat Aug 10, 2019 8:31 pm quote
It could be that the clutch arm shaft is fouling out on the clutch itself. It would take a few miles or so for any wear to show up on any of the surfaces.
Member
VBB2T 177
Joined: 23 Apr 2019
Posts: 7
Location: Hong Kong
Sun Aug 11, 2019 2:45 am quote
whodatschrome wrote:
It could be that the clutch arm shaft is fouling out on the clutch itself. It would take a few miles or so for any wear to show up on any of the surfaces.
Included the video with the noise.
Pls see the descriptions.

Anyway the clutch arm and the actuator shaft looks fine. Have been running few hundreds kilometers with that noise. Just not sure what caused the noise.

My next try maybe 4 plates clutch / carbon plates, different springs, any through?
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1363
Location: London UK
Sun Aug 11, 2019 2:55 am quote
Did you fit a new steel thrust washer under the clutch? If so what thickness was it?
Member
VBB2T 177
Joined: 23 Apr 2019
Posts: 7
Location: Hong Kong
Sun Aug 11, 2019 4:19 am quote
Jack221 wrote:
Did you fit a new steel thrust washer under the clutch? If so what thickness was it?
Hi Jack221

The thrust washer was new from SIP which said 0.5mm. I didnít measure it but I tested it before putting the clutch plates in. The clutch cog gear can rotate freely without touching at the clutch back plate. New bush / tight fit as well. Any throughs are welcomed. Thanks!
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1363
Location: London UK
Sun Aug 11, 2019 7:04 pm quote
Not the one in the clutch but the one under it.
https://www.sip-scootershop.com/en/products/washer+clutch+32x158x155+mm+_48334000
If this is worn or too thin. It does exactly what yours is doing.
Member
VBB2T 177
Joined: 23 Apr 2019
Posts: 7
Location: Hong Kong
Mon Aug 12, 2019 1:57 am quote
Jack221 wrote:
Not the one in the clutch but the one under it.
https://www.sip-scootershop.com/en/products/washer+clutch+32x158x155+mm+_48334000
If this is worn or too thin. It does exactly what yours is doing.
Thanks for the information. I will look into it. I will try using a different washer to test.
Member
VBB2T 177
Joined: 23 Apr 2019
Posts: 7
Location: Hong Kong
Tue Aug 13, 2019 2:35 am quote
Some update.

I got sometime with my bike today. I started up the engine, remain the bike in stable position, shift into 4th gear (that generate less torque on rear wheel when I lock it up by the rear brake). I released the clutch lever until I hear the noise, I hold it and twist the throttle. As I was holding the throttle and clutch lever position, the noise continue. Until 15-30 seconds later, the noise disappeared.

Then I put into 1st gear and drive it normally. Seems the the clutch plates were ďbreak-inĒ and no noise anymore. The feeling of the engaging is smoothen. The clutch plates may have been heated up and burnt out. Not sure yet. I am waiting it to cool down and test again. I will then go out for a longer ride.

Stay tuned.
Enthusiast
1972 Vespa GTR, 1963 Lambretta LI 125
Joined: 05 Nov 2018
Posts: 62
Location: Halifax, England
Tue Aug 13, 2019 11:24 am quote
It could be and it's a long shot but it happened to my scooter, one of the crank bearings.
I had an issue where when I started the engine there was a grinding noise, and when I pulled the clutch the tone changed.
Turns out the flywheel side bearing cage had split and was starting to dissolve the bearing.

If it is you will know soon enough as the engine will die, just like mine did.
Missouri Loves Company Rally   vespa scooterwest scooter west Motorsport Scooters   AF1 Racing Vespa Austin
Post Reply    Forum -> Not-So-Modern
[ Time: 0.2340s ][ Queries: 23 (0.0301s) ][ Debug on ]