[ChopperCharles]

So my SCR has developed a weird issue. Sometimes when I’m decelerating, and I get down to a slower speed and almost stopped, I hear a clicking from the transmission or front pulley area. It’s speed dependent, not rpm dependent. If it starts making the noise and I kill the motor it still makes the noise until I’m stopped. It’s intermittent, but appears to happen when I slow down rapidly. However I’ve also heard it briefly when pushing the bike around in the garage.

I put the bike on a lift and removed the sprocket cover, but I see nothing wrong. Rotating the wheel with the bike on the lift doesn’t reproduce it. In fact it happens maybe 30% of the time when I decelerate hard - it’s not something I can reliably reproduce.

I’m not sure if it’s because I’m unloading the rear suspension, the front sprocket bearing is bad, or what. I have the belt adjusted a little on the loose side, 9mm deflection at 10 pounds on the gauge with the bike on the side stand. (Spec is 6-8mm). The belt deflection is still 1cm (10mm) when the bike is on the lift and the suspension is fully extended.

It’s actually pretty loud. Almost embarrassingly loud. If you’ve ever tried to start an 80s virago, the noise is as loud as that horrible starter gear smashing about. But rhythmic according to speed instead of the virago’s frenetic bang-crunch-whirr-bang.

Any ideas? I’ve found a few posts from XV950 owners with the same problem, but nobody ever figured out what it was or put forth a resolution.

~2000 miles, recent oil and filter change (15w40) and the bike was quite hot.


Charles.

 

[Schu]

On deceleration, especially with engine braking, your belt tension switches from the upper run of the belt down to the lower run of the belt. When your slack is all on top it is trying to wrap around the smaller driven pulley and may be trying to climb up on the grooved teeth. It may be the clicking you hear as it almost climbs a tooth and slips back into the groove. It may get louder as it actually gets closer to climbing a tooth and staying there! Do the belt grooves look ok or are they losing their edge?
This is all theoretical because I've never owned a belt drive bike prior to my SCR. But I have experience with mechanical design and have seen this with synchronous belts and chain drives when tension is not properly set to accommodate the reaction of the reversed load. Don't forget you did alter your swing arm geometry when you changed to longer rear shocks.

 

[srinath]

Also suspension travel on the bike (bolt/scr) is severely limited because of the belt drive. A suspension that does move (travel) is likely going to reduce belt life. In fact having that hard as a rock suspension and my extra padded seat makes me feel better after I un "Bolt"ed my SCR.

 

[ChopperCharles]

Hrm. Ill remove the sprocket cover and I’ll see if I can rig a mount for my phone to video the front pulley.

Teeth on the belt look fine.

New from the dealership the belt was so loose it had inches of travel... and it never made a sound like this.

Maybe I need to figure a way to mount that tensioner I bought after all. Or look harder into a chain drive conversion.

Charles.