High pitched whine when clutch engages

[ptm]

The good news is that after months of working on it since I bought it in December, I went for my first ride on the 750 - wow what a difference from the 400. I've never ridden anything but the 400 so it's going to take some getting use to...but it's going to be fun

The bad news is this noise.

No noise idling in neutral just sitting there. Pull in the clutch and put it in gear and still no noise. Start to let the clutch out and as it engages it sounds like I have a supercharger - high pitched whine - almost a whistle - with a little rough edge to it.

Bike has 36,000 miles. Clutch? Transmission? Bearings?

 

[focus frenzy]

is the noise only as you engage in gear or does it do it while riding in gear?

if it is while riding, check to see if the chain is rubbing any thing or if anything is rubbing the chain (shafties rule)
it could be the countershaft bearing, ride it and pay attention and see if the whine gets faster with road speed or engine speed.
see if it changes or goes away when going from pulling to coasting.

 

[Jethro]

check to see if the chain is rubbing any thing or if anything is rubbing the chain (shafties rule)

There is a different whine related to owners of shaft driven bikes. It is them trying to justify the benifits of a shaft drive! Boo yak sha!

 

[ptm]

I don't think it's the chain. When the bike is stopped, the noise starts as soon as I start to release the clutch, before it is really even moving much. As it starts to move the noise does change with engine/road speed. I didn't notice it much once I got going, but it may have just been covered by other sounds. This was just my first brief ride in the neighborhood to see how everything worked. When we get another break in the rain I'll pay more attention to it.

Thanks

There is a different whine related to owners of shaft driven bikes. It is them trying to justify the benifits of a shaft drive! Boo yak sha!

:lol:

 

[focus frenzy]

could be normal, hard to say with out hearing it and with out having a previous history to know if this is new or if it has always been there.

 

[SqDancerLynn1]

maybe the clutch drum bearing is noisey or the drum is loose

 

[earlfor]

I dont think its normal Leon. My 79 750 never made a sound from the clutch side. I dont remember ever being able to hear it at all.

Earl

could be normal, hard to say with out hearing it and with out having a previous history to know if this is new or if it has always been there.

 

[ptm]

I guess I'll wait until I can do a few more test rides - maybe this weekend if the weather cooperates. I don't plan to go far (or very fast) yet until I get more confidence that everything is OK.

What should I look (or listen) for? Any specific things I should try that might narrow down what the problem is?

Thanks

 

[Anonymous]

It wouldn't hurt to spend the 5 bucks on a gasket and take 2 hours or so to look through the clutch.

Does it sound like a manual transmission car going quickly in reverse?

Steve

 

[ptm]

It wouldn't hurt to spend the 5 bucks on a gasket and take 2 hours or so to look through the clutch.

Yeah, I'll probably end up doing that. The problem is I've never been through a motorcycle clutch, so I'm not sure what to look for. I can generally tell when a bearing is bad, but it would be nice to have some idea what to look for. I've got several manuals so I could just follow the disassembly and inspection routine...

Does it sound like a manual transmission car going quickly in reverse?

Not really, it's got a little of that sound if the car was going really fast, but it's got more of a whistle sound to it. It really does sound like a supercharger. I'm trying to figure out how I can record it and post it so you all can hear it.

I should be able to get out this weekend for some more rides. We'll see what other clues I come up with.

 

[ptm]

Well, more info. The noise is there whenever there is a load on the engine. Like I said earlier, when I first engage the clutch, starting from a stop is when the noise starts. It's there pretty constantly except when I back off on the throttle - then it stops. Get back on the throttle and it starts again. Other than the noise it seems to run really well - it starts easily and pulls very strongly. Doesn't smoke and the plugs look good. The oil pressure light never comes on when the engine is running.

Finally pulled the clutch cover and there are a lot of little metal flakes in the oil on the bottom. 8O Not real fine like in metalic paint, much bigger. And they're gold colored like brass or bronze- not silver like alum or steel. Man, I hope this isn't serious. I ready for a break from the wrenching - I want to ride it.

I'll pull the clutch apart tomorrow and I'm going to drop the oil pan as well and see what's in there.

Any other thoughts on where to look and what to look for??

 

[Anonymous]

It's good thing you pulled the cover to check. Finding problems early is the key to escaping without begging for a loan.

If it was mine I'd start pulling parts and keep going until I found the problem. If you have metal particles there is wear and it should be obvious.

Start with the clutch pack and pull the plates and check them to spec and warpage.

Pull the clutch hub and inspect. Check the two bearings that the hub rides on.

You should now see the oil pump. It's driven by some gears that ride on bronze bushings. The entire clutch compartment should now be visible. Look it all over.

Just for the heck of it, I would pull the oil pan and clean it and the screen of any particles.

 

[ptm]

Thanks, Swanny. I know it's the right thing to do to prevent a catastrophic failure, and so far the weather is cooperating. I'll keep digging and see what I find. Part of the reason I'm looking for some direction is the color of the shavings - they must be bronze (I don't think there's any brass in the engine innards), and I don't know what bearings and/or bushings in the engine are bronze.

I noticed that getting the clutch basket off requires a special tool to hold it while you loosen the nut. Any tips on how to do that without the Suzuki tool or access to welding equipment?

Thanks

 

[Anonymous]

Thanks, Swanny. I know it's the right thing to do to prevent a catastrophic failure, and so far the weather is cooperating. I'll keep digging and see what I find. Part of the reason I'm looking for some direction is the color of the shavings - they must be bronze (I don't think there's any brass in the engine innards), and I don't know what bearings and/or bushings in the engine are bronze.

I noticed that getting the clutch basket off requires a special tool to hold it while you loosen the nut. Any tips on how to do that without the Suzuki tool or access to welding equipment?

Thanks

As for taking off that nut (if I remember correctly), I engage the tranny then use a piece of 2x4 to keep the rear wheel from turning (insert through from one side to the other). This should lock the hub for you.

I think the hub rides on some bronze bushings for the needle bearings. Again, not entirely sure since it's been a while since I've been in there. Just keep pulling parts. You should be able to find the wear relatively easilly.

 

[ptm]

Pulled the oil pan and it looks great - a little black sludge toward the front and back, but not too bad. It's clean in the middle, and no sign of any metal flakes. I cleaned it in a pan with kerosene and no flakes hidden in the sludge.

I haven't yet pulled the oil screen, but if there was anything it should be on the pan side, right? And that side looks good. I'm assuming the oil is pulled from the pan through the screen and to the pump where it's pushed through the engine.

Pulled the clutch and disassembled, and, other than the springs being right at the limit, it looks perfect - the plates are well within spec, there are no grooves where the tabs on the plates hit the sides of the basket, and the bearings hardly look worn - the flat one at the end of the shaft coming from the clutch has a little fine black dirt in the corners, but it's not gritty at all and th rollers look fine.

I pulled the gear off the oil pump and again, everything looks great. The washer between the gear and the pump is fine.

Any thoughts what to look at next? :-k

 

[Anonymous]

I'd check the debris with a magnet to determine if it is a shredded plated fastener. The cam lobes are usually stained this colour but if the sound is coming from the clutch cover it probably isn't them. When my clutch started dumping filings into the oil they all went over to the oil pan side because I use the side stand a fair bit. I think the black crud in the clutch is normal, it works like a centrifuge and cleans the oil a bit.

Steve

 

[Anonymous]

Yea, the screen is just to keep the bigger pieces from getting to the oil pump. The pump is located before the filter and you don't want chunks of metal getting into it.

Hmmm, let's back up a sec. What kind of debris do you have? Big shavings or little bitty ones?

I'd check the debris with a magnet to determine if it is a shredded plated fastener.

That's a good idea.

I would of expected you to find something by now. The basket, and plates all look good? Bearings. Hmmm. You could pull the oil pump now that you are right there. Check for scoring inside the pump.

There isn't a whole lot of stuff you can inspect unless you crack the cases and I'm not sure you want to do that.

I'm not sure you can feel anything by turning the input shaft to the tranny either. If you want to try that I'd take off the chain (pull the sprocket) and then try feeling what's going on in the tranny. Any bad noises in particular.

You've got me stumped right now.

I just remembered that when I pulled mine apart there were some shavings inside of it also. I looked high and low and couldn't find anything wrong. I did notice that there was a lot of casting flashing on the cases however. I just attributed it to some flashing breaking loose and went on with the rebuild. It was aluminum pieces and I did debur the cases after that.

 

[ptm]

Thanks for the input. I was hoping to find something really obvious, but it really looks good. Either it was used mainly for longer distances, or the previous owner was really easy on the clutch - or he was hard on it and it was replaced not long before he stopped riding it and put it in storage - Other than the spring length, the parts look almost new.

The cams looked good when I did the valve adjustment. Some slight signs of wear, but nothing major.

As far as the flakes, They're already gone - I recycled the oil so I can't test them with a magnet #-o I should have saved some - must have been suffering from a mild case of dumb-dumb fever at the time. They seemed so obviously bronze colored, I didn't think to check at the time. They were definitely chips rather than a fine dust.

One other thing. I had run it about 150 mi since the initial oil change after I got it all back together. When I drained the oil from the crankcase it looked good. I let the pan sit for a while, drained most of the oil out then looked at what was left with a strong light, and I didn't see any sign of metal. However, I did the same thing when I drained the oil from the filter housing and the filter. When I looked at it under strong light I could see some very fine metalic, bronze colored dust in the oil, so something is going on...

I really don't want to split the case - that's way farther than I wanted to get into it this year. Ah, well. One of the challenges of buying a used bike from a distance. I'm still kicking myself over how much I paid for it - and to ship it here.

I think I'm going to put it all back together, run it a little more and see... I'll let you know what happens.

Thanks, again.

 

[Scrumper]

I know it's been some years since your last post on this subject but I just wondered if you ever got to the bottom of your engine noise.

My '79 GS750 has just started making a similar sound; high-pitched whine, almost deafening at certain speeds and it started right after getting a new chain and sprocket set fitted. Chain tension seems ok and nothing obviously rubbing, so I'd be interested if your investigations uncovered anything else. Cheers.

 

[Macmatic]

I know it's been some years since your last post on this subject but I just wondered if you ever got to the bottom of your engine noise.

My '79 GS750 has just started making a similar sound; high-pitched whine, almost deafening at certain speeds and it started right after getting a new chain and sprocket set fitted. Chain tension seems ok and nothing obviously rubbing, so I'd be interested if your investigations uncovered anything else. Cheers.

Must be the season, I'm looking to track down a similar noise on a GS450 I just finished. I've only put 15 miles on it so far but it rides great, I'm concerned about a "supercharger" whine it makes sometimes though, seems to go away once it warms up.

Maybe it's an 8 valve thing? I did rings on a GS1100 about a year ago and it had the same kind of whine, the owner said it was doing that before I worked on it though...right before he stole a brand new pair of gloves off my shelf...

I'll post back to this thread if I find anything, to me the noise sounds like it's coming from the top end so far but I haven't actually been able to have it make the sound while I'm off the bike so its a little hard to track down. One idea I'm going to look into is tach cable noise, both the 1100 and this bike use a mechanical tach.

/\/\ac