I am getting a weird noise at take off in the lower rpm band. I can pull in the clutch and let it idle or rev it up and I hear nothing. The motor has to have a load on it to emit the noise. It is quiet when the motor is cold. As the motor warms it gets louder.

My initial reaction was that it is the clutch but I am wondering now if it is the CCT's. Bike is original with 22K on it. I have done all maint per manual and change oil every 3-4K miles. I heard the niose starting about 500 miles ago and changed the oil @ 400 miles ago hoping that the fresh oil would calm it down. It seemed to help for a short 100 miles or so. The clutch and tranny is shifting great with no slippage.

What do you think? I am going to order a set of CCT's just to be careful but the probelm just does not make any sense.

Oh, yes. I had it painted @ 6-700 miles ago and they left a vaccum line unhooked under the tank. I thought that it may be a vaccum line but they should not have gone into any of the motor.

 

You may have an exhaust leak. Check where the header connects to the head.

 

That's how mine was. I don't know what you mean by "weird" noise. Mine sounded like a loud tapping at takeoff. Wouldn't do it everytime. Higher up the rev range it disappeared. Would only do it under load. Changed the CCTs and it has been gone since. It would tap about 10, 15 or so times. When I tore the bike apart I found the rear cylinder skipped one tooth on the cam sprocket timing and the rear CCT hung up. As soon as I inserted the tool to unload it, it snapped to tension.

 

And there's why I don't like auto ccts.. especially when they really are not needed. More parts to go wrong for no reason.

 

Yes, it sounds like a slight tapping noise. I thought that it may be the CCT's. I will leave her parked until I get some manual CCT's.

 

Carb slides are tapping. It's completely normal. At higher rpm you shouldn't hear it because the slides are high enough and the vacuum pulses close enough that the slides won't drop to the bottom.

 

Why would I just notice it a few hundred miles ago?

 

You know, I noticed my bike is making a similar noise. It sounds like a clicking or tapping sound. Mine also started making the noise about 500 miles ago. When the engine is cold it sounds nice and solid with no noise. Once it's warmed up, it clicks like crazy at low rpm and once I reach a higher rpm it stops. I thought it might be the valves since I have about 29k on it now. I don't know much about the CCT's or if these bikes have maunal or auto CCT's.

Can someone explain to me a little more about the CCT's on these bike? Are they auto or manual and are they hard to replace? I would really hate to go through all the trouble to do a valve adjustment and it's not the problem.

 

I thought valves too when I first heard the noise but I just had mine checked at 18K. They were still dead on.

 

Mine does this but the clacking noise has become so much that I can feel the bike shudder a bit. The frequency tells me it's not rpm related, but wheel speed related.

I tightened the chain with the new tire recently and it still does it, although the chain did loosen up quickly, so maybe it's got some bad links.

I adjusted the valves and manual ccts a few weeks ago, but no change. Started faintly maybe 5K ago. The bike is just plain wearing out at 32K miles. The engine was so quiet when I bought it at 21K, I just don't get it. I may try switching from 15w40 to some 20w50.

 

Since it's wheel speed related... Try taking the clutch cover of and cleaning the cavity... Usually full of goop... At the same time get the chain of clean it lube it and then look for kinks/bad links... Check the rear wheel bearings and when re-installing check alignement of the rear wheel with a caliper or similar, the lines on the adjusters are useless...

Mayby someone can give more pointers... But those are the obvious ones...

 

The carb slides do make a ticking/tapping noise at a bit above idle... It's noticeable, but only if one is paranoid and are looking for a noise...

And that might explain the reason why you discovered it some 500 miles ago...

 

The stock CCT's are automatic... and prone to failure when you least want them too.... If you are at 29k and havent had problems and not replaced them I'd say it's a good time to swap for a pair of manuals... And at the same time you can do a tad more work and check valves at the same time... It's not that hard and you will likely still have the cover of on atleast one cylinder to confirm TDC on the right stroke... So taking the other of aswell isn't that much more work...