Working with a BUZZ

[79XS11F]

OK this BUZZING in my handlebars that makes use of the rear view mirrors has got to be corrected. The only thing different from last year when the bike did not buzz is that I have returned the bike to stock specs with the only major change being the installation of a full stock exhaust system. That exhaust is not touching the frame anywhere, is mounted in stock rubber grommets at the rear foot peg supports and of course attached to the head at the exhaust ports. the main stand and side stand contact it while riding but they also have stock grommets. This buzz goes away at 4500 RPM. It at its worst while accelerating. Even the fuel tank BUZZS but I can stop that if I pinch the tank with my knees. I can do nothing to correct it in the handlebars. This BUZZ is not present while at an idle.
Today I loosens all the engine mount bolts and allowed the engine to "settle" and then torqued all the mount bolts as per the manual and in the order listed in the manual. A test drive indicated no improvement. I will check the head bearings tomorrow to confirm that they are set up correctly.
Is there anything i could have done while putting in the clutch or stator that if over looked could lead to an out of balance situation that would not affect the way the engine runs? This BUZZ in the rear view mirrors will occur even when the bike is on main stand if I give the throttle a twist.
Rob

[79XS11F]

bump .. no ideas guys ...

[petejw]

I was getting a buzz when my carbs
were out of sync, actually they had holes in the
diaphrams, repaired them and the buzz went away.
i also get vibrations when the cam requires adjustment.

[79XS11F]

you mean valve clearance adjustment right? I was also wondering if the times being out a little could cause it.
Rob

[petejw]

quote:
you mean valve clearance adjustment right? I was also wondering if the times being out a little could cause it.
Rob



no, i was meaning the cam chain.

[79XS11F]

OK I will check that stuff out as well.
Thanks
Rob

[prometheus578]

"Interesting..."

An engine vibration issue...
Just reread your post several times... noticed the clutch and stator reference.
Recalled that some Kawa Vulcans... the bolt that holds the stator sometimes backs out. Stator then wobbles on the crankshaft, quite a mass on metal it is, and causes vibration(and a knocking if really loose) You may want to explore this.
Stator is a precision,tapered fit to the crankshaft. Do not oil the crankshaft end when putting the stator back on, as this makes it easier for the stator to loosen.
HHmmmm.... now that I think of it...
I've been chasing a vibration on my XS850. Found the exhaust header against the frame. Did a little creative bending, which helped, but the main vibration was still there.
Typing this reply, I recall that I had to remove the stator when replacing the cam chain. I may have to recheck my work, as well, as I don't recall the vibration prior to the surgery.

[79XS11F]

well I have come to the conclusion that the engine must be missing in spite of good readings when I color tuned it. This "BUZZ" is at it's worst while accelerating but alway present accept at idle. From what I can see there is no fuel starvation going on because there's always fuel in the lines so I am thinking electoral. I have new coils on her, new plugs (2nd set) and new pickup coils. So I guess I will have to give her the once over yet again to find out what this is. It is annoying to say the least. i did notice that the engine does not seem to vibrate as much as the bike it's self if i put my hand on a side cover and give her a twist but the exhaust note does not sound consistent.
Rob

[olebiker]

Rob my maxim buzzes making the mirrors unclear. If I take my hands off the bars the tank buzzes as well. Because I haven't done much other than ride the thing I thought maybe they all have a bit of that. It doesn't bother my hands like a small bike will so I haven't worried about it but I would like to know if you find a cure.

[79XS11F]

well the thing here is that the only BIG difference to the bike was switching out the exhaust system from 4 to 1 to stock. The same engine did not cause this buzzing when i used it in this bike that first summer that I had the bike. I have checked very closely and the exhaust system is not contacting the frame anywhere. I do know that the rubber engine mounts are not the same ones I had used because the originals are still on the hop up engine.
If I am lucky it is just a combination of old engine mounts and hardened rubber grommets at the foot pegs exhaust mounts. I do however want to fix it or at least confirm that the bottom end is not toasted. I may have to try to switch them out with out pulling the engine but that would still involve removing the carbs, exhaust etc.
I will post when I get it resolved if I can even do so.
Rob

[79XS11F]

Question

OK .. I just adjusted the head bearings because there was a "Little" play there but doing that did not remove the "BUZZ" I feel while riding. There was however an improvement.


QUESTION When I hung the exhaust system I applied the right amount of torque to the head exhaust stud bolts. It didn't seem like they were very tight at the spec torque so I did tighten them down somewhat more. Could that be causing the exhaust systems frequency to somehow get into the bike?
Rob

[olebiker]

Rob I can't imagine that being the case. Do you feel this while you are not moving or only while driving?

[79XS11F]

At idle is OK but always there once underway and more noticeable while accelerating. goes away at 4500 to 5000 if held study but returns above and below that RPM range.
Rob

[chopwatchagot]

How are your valve springs? If they are out of spec they could be creating some different harmonics. The inner and outer springs are designed to cancel out each other's vibrations (harmonics) and maybe yours are out of tune.

[olebiker]

Originally posted by 79XS11F
At idle is OK but always there once underway and more noticeable while accelerating. goes away at 4500 to 5000 if held study but returns above and below that RPM range.
Rob

Really you need to rev it up slowly in neutral with the clutch in. If you don't get anything then you are on the right track with wheels,steering head,anything that moves when the bike rolls but not sitting still. It is a process of eliminating various systems. The reason I think it is a good place to start is because of the progress that you made with the head bearings. I hope this makes sense to you.

Carl