This does not sound good!!

[imnowhooked]

Finally got the carbs done thanks to the guidance I acquired here! Got everything together today, put in fresh fuel, & she fired right up!! I rode app. 6 miles holding on for dear life..(man does she run)..started hearing a noise which I thought was coming from the clutch, best described as almost a knocking sound but not quite as bad?? Anyway, eased her home about three miles & put her in the garage & let her idle, I can hear the noise on the right side( as you sit on the bike) but not so much on the left. I have fresh oil & oil filter & sight window shows full on center stand, I did put new clutch parts in & tightened everything to specs. Seems to be coming from cylinder head itself which can't be good ,but it is really hard to track down. Any ideas??

[gearhead13]

Is the noise there just at idle or is it still there at higher rpms (just off idle to 4-5k or so)?

[flyanimator]

do you have a mechanics stethoscope? really cheap at harbor freight(a couple of bucks or so). This might help you find where the noise is comming from. Don't have much experience with these bikes as i'm a newbie so I'll let the veterans here chyme in on what the issue might be. Just thought this could help you find where the noise is comming from so you can narrow down what it could be.

[49er]

If your engine has the 8 valve head, it's probably just excessive cam endfloat. It's usually pronounced at idle and up to 2000 rpm ,when the engine has warmed up. It's not terminal, just annoying as hell.

Go to Basscliff's site for a fix that I perfected some time back.

[imnowhooked]

Do you think this could be the problem?? When I took the carbs off a couple weeks ago the intake boots were in bad shape, I do have some on the way but they are not here yet & being somewhat impatient & having the carbs ready to go,I had the bright idea to grab the electrical tape & wrap the ends where the clamps are & tighten the clamps..(it is a 16 valve).. with hopes that it would hold just for a day or two(I know..I know... I know..go ahead, I deserve it) I tracked down the noise & it was coming from #4 intake boot, I took the carbs back off & lo & behold, where the tape was had "caved in" & a tight strip of electrical tape had closed off app. 1/4 of the flow. I am assuming that since I made it about 6 miles before it started making any noise that the pressure "sucked it in" & caused my noise. I know nothing got in the cylinder because all the tape was still intact & no pieces of rubber were missing. Hopefully my boots will be here tomm.& I will find out for sure if that was the cause of my noise. What do you think... or could I be way off?

[mike-s]

That is a bit of a Bodgy bros fix. Personally i would have run the bike and actually used something akin to a starter assistant that contains highly flammible ether (one brand is aerostart) or even wd40 and see if spraying it around the carb boots or block (it may be the o rings between the boots and block, not the boots themselves that are shot) does anything for the engine revs aside from possibly making the operator slightly woozy. when i tried to rule out carb boot problems in the past i actually used old zip/cable ties, cut the locking mechanism off the end, wrapped them around the securing point on the carb boot, used a bit of electrical tape to secure it together and THEN used the boot clamp over the top of it to try and ensure that there was going to be a secure grip onto the carby.

I think that the worst you'd get from the method you did was just a lot of induction noise as the air vibrated the tape as it was drawn past at high speed. I would suggest seeing if the noise stays after the boots are replaced and take it from there.

[imnowhooked]

The funny thing is...it was running fine. I figured if it had an air leak it would not be running as good as it was, if the new boots make it run better than it was I will be real happy. This engine does not have the o-rings, the boots just slip over the ports & clamp down...I too believe it was the induction noise blowing by the tape, glad someone said what I was thinking..makes me feel better! Hopefully find out tomm.

[mike-s]

The funny thing is...it was running fine.

That can be taken as a "good thing" i guess.

I figured if it had an air leak it would not be running as good as it was

You'd be getting symptoms of the revs continually rising when you come off the throttle (i.e. stopping at traffic lights) and generally being a recalcitrant so & so and consistently inconsistent in its behaviour.

if the new boots make it run better than it was I will be real happy. This engine does not have the o-rings, the boots just slip over the ports & clamp down...I too believe it was the induction noise blowing by the tape, glad someone said what I was thinking..makes me feel better! Hopefully find out tomm.

yeah it has o rings, between the boots and the head!! Just make sure you have some included with the new boots, there's a fair chance you will though.

[BassCliff]

yeah it has o rings, between the boots and the head!! Just make sure you have some included with the new boots, there's a fair chance you will though.

Hi,

Mr. iamnowhooked is correct. For the 1980 GS750E, there are no intake boot O-rings.



#26 are clamps. #24 and #25 are right and left intake pipes.

You get a noise on the right side? Are you sure it was tape flapping around? (Tape! Ha!) It's not clutch rattle is it? Keep us informed.

Thank you for your indulgence,

BassCliff

[imnowhooked]

Oh, by the way,thnx 2 everybody that offered advice !! & I am sure it is not clutch rattle Mr BassCliff, once I really checked it out it was obvious it was coming from the #4 intake boot(highly obvious). It sounds strange to me but I hope that is the problem as I was able to move the strip of TAPE back & forth with my finger. HOPEFULLY my boots will make it here tomm. & I will know for sure. I will be sure to let everyone know.

[mike-s]

Oh, my mistake, i didn't realise that they incorporated using clamping at BOTH ends on some models, im used to it being bolted to the head at one end and the clamp only being used at the carby end.

Please return to your regularly scheduled viewing.

[BassCliff]

Oh, my mistake, i didn't realise that they incorporated using clamping at BOTH ends on some models, im used to it being bolted to the head at one end and the clamp only being used at the carby end.

Please return to your regularly scheduled viewing.

Not to worry there Mr. mike-s. I'm still learning this stuff too. I'm grateful that the members here are patient and forgiving with me. I learn something new about these classic motorcycles every day.

Hey, Mr. iamnowhooked. Have you replaced your boots/O-rings yet? Is the noise gone? Please keep us informed.

Thank you for your indulgence,

BassCliff

[850 Combat]

I too would vote for clutch rattle. It can be remarkably pronounced when the carbs are out of synch, or it there is any other reason for the motor not to be running smoothly.

[imnowhooked]

Not to worry there Mr. mike-s. I'm still learning this stuff too. I'm grateful that the members here are patient and forgiving with me. I learn something new about these classic motorcycles every day.

Hey, Mr. iamnowhooked. Have you replaced your boots/O-rings yet? Is the noise gone? Please keep us informed.

Thank you for your indulgence,

BassCliff

Nope...hopefully in the next couple of days. The suspense is killing me! It has been in the mid 70's since Friday & supposed to be 80 & rain tomm., I dont care if it is a hail storm..If I get them, I will ride!! Maybe tomm??!! I will let you know the outcome soon as I get them on.