"Hissing" Noise in 5th gear... Snake nest?

[davisbm2]

So my Magician is nearing 1,000 miles. It has given me every issue imaginable, expect for the fact the engine seems pretty darn good (so far).

However, since day one I have had a very odd issue in 5th gear. When the bike gets hot 5th gear makes a hissing sound. In my head I imagine things expanding and rubbing in ways they shouldn't.

As soon as you drop to 4th it goes away, and occasionally it can be difficult to shift down, almost like the lever is not "catching". This can be annoying at a stop light but if I reach my hand down and jiggle the shift lever it almost always shifts down.

So do I have a lemon? A bike still being broken in? Is this sound common? Or do I have some really pissed off snakes stuck in my gearbox.

[Chineeske]

Is it also difficult to get your bike in Neutral?

If so, it probably needs a clutch adjustment.

Other than that... well, I don't know which engine your bike has but when I opened up my CB250 clone I saw that Mr. Honda uses steel sprockets for pretty much everything in an engine, while the Chinese enginebuilders don't mind to use plastic () as sprocket material...

But a 'hissing' sound has normally nothing to do with gearing...

[Ariel Red Hunter]

Originally Posted by davisbm2

So my Magician is nearing 1,000 miles. It has given me every issue imaginable, expect for the fact the engine seems pretty darn good (so far).

However, since day one I have had a very odd issue in 5th gear. When the bike gets hot 5th gear makes a hissing sound. In my head I imagine things expanding and rubbing in ways they shouldn't.

As soon as you drop to 4th it goes away, and occasionally it can be difficult to shift down, almost like the lever is not "catching". This can be annoying at a stop light but if I reach my hand down and jiggle the shift lever it almost always shifts down.

So do I have a lemon? A bike still being broken in? Is this sound common? Or do I have some really pissed off snakes stuck in my gearbox.

I'm surprised that this problem showed up at a thousand miles. Could it be the rear chain being too slack and dragging across the swinging arm?...ARH

[Megadan]

I agree with at least checking the clutch adjustment. These engines are notorious for having a little clutch fade as they get hot. I often readjust my clutch a little once the bike gets hot because of it. If your clutch is already adjusted on the loose side when cold, it will almost certainly be etremely loose once warm and you can have difficulties with down shifts and neutral.

How old is the oil and what is the level reading at? If you haven't changed it recently, I say do an oil change and see if you have any larger shavings or chunks of metal in the oil or filter screen.

I also agree with checking the chain, not just for tension, but for front to rear alignment. Sometimes you can get some odd noises from sprocket misalignment, and in this case the countershaft sprocket being in an overdrive gear might be causing some strange vibration resulting in the noise.

[davisbm2]

What do you mean when you say "loose" in terms of clutch adjustment?

I think of clutch fade as things actually getting tighter. For example, the clutch works great, until the bike gets hot and things expand. Once things have expanded, I hear that hissing noise which in my mind sounds like things that were once within tolerance have now expanded out of tolerance.

I have done a lot to bikes, but I only know the basics of transmissions. I have adjusted the clutch lever so that I have oh, 1/4" of play before the clutch engages.

Should I tighten the clutch lever to have nearly no play? Is it possible that these bikes can only go so long and get so hot before things start to get way out of tolerance?

The hissing noise sounds a lot like something spinning making slight contact with something else.

The transmission has always been very chunky and clunky. When I shift down coming to stop light into say 2nd gear the bike gives a loud CLUNK and creates a whirring noise. That's with the clutch PULLED IN.

[JerryHawk250]

Originally Posted by davisbm2

What do you mean when you say "loose" in terms of clutch adjustment?

I think of clutch fade as things actually getting tighter. For example, the clutch works great, until the bike gets hot and things expand. Once things have expanded, I hear that hissing noise which in my mind sounds like things that were once within tolerance have now expanded out of tolerance.

I have done a lot to bikes, but I only know the basics of transmissions. I have adjusted the clutch lever so that I have oh, 1/4" of play before the clutch engages.

Should I tighten the clutch lever to have nearly no play? Is it possible that these bikes can only go so long and get so hot before things start to get way out of tolerance?

The hissing noise sounds a lot like something spinning making slight contact with something else.

The transmission has always been very chunky and clunky. When I shift down coming to stop light into say 2nd gear the bike gives a loud CLUNK and creates a whirring noise. That's with the clutch PULLED IN.

Try setting the clutch with about 1/8" or less play when cold. When it arms up the play will increase.

[pete]

since you say the noise only happens in 5th gear....
I am wondering if you have a poorly machined gear..
spur gears are noisy at the best of times.. the gear
teeth heel and toe as the rotate in mesh with each other..
in 5th gear you have the biggest driver meshed with the smallest driven..
so they are going to have the biggest heel and toe effect of all the gears..



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