not your normal Vibration issue. OVAD, TB's, nothing works..

[elmosisu]

Hello all. I just returned from a 4000 mile trip on my '04 Rockster that was very enjoyable, with one glaring exception that is driving me to the point of possibly selling my bike.

It all started during my 18k service, that I did myself ( along with my 6k , and 12k services, the last couple of years). My bike has been flawless for the three years that I've owned it, and I saw no reason to expect anything different for the next 3 years, and my previous services ( valves TB's fluids..etc) went great, with great results. I am very anal about being PRECISE on all the things that I do with the Rockster. My bike has always been a source of pride to me, and others look to me to help them service their BMW's and other makes. I'd call myself a good mechanic, with basic tools, and a good ability to understand how things work ( although my fat fingers seem to get in the way )

After the 18k, ( and about 1 week before my big trip) the bike picked up a strong Buzzing vibration in the handlebars and footpegs from 3800 to 5000 RPM. Okay.........no big deal, right? TBs must be out. I go to check them and they are set like I normally would do , Mercury guages at idle and at 3000 rpm with no load.

I then thought that I must have not done the valves correctly............no problem.............I spend an hour to carefully redo the valves ( perfectly, mind you) and resync the TBs............

no change. still a very harsh vibration in the handlebars and footpegs.......very noticeable at 80mph cruising speed.

I'm starting to get worried at this point.....my trip is days away, and I don't have time to get to a dealer. what do I do?

I rigged up my mercury gauges to my tank bag with duct tape and wires, in an attempt to mimic a TwinMAX, whe I can check the TB's under load and during real use condidtions. SO.......down the road I went with my "contraption" working like a charm. ( boy.....di I get a few weird looks !! )
I was able to watch my vaccuum change as the rpm's and load changed, and I attempted to "dial out" any imbalance in the 4-5k RMP range under load. I though I'd solved the problem, as there was some adjustments that I made to the TB's.

WRONG. still vibrates like a weed wacker................F*CK %*$(#@

I'm either going on a 4000 mile trip with a carpal tunnel syndrome machine, or I have to cancel.....................

I have to go on this trip!!!!!

One other point of notice..............I observed that my vaccuum changed significantly between one cylinder to the next, depending on load and speed.......ie at 3000rpm and light load, the right cylinder would show higher vaccum, but a 5000 rpm and medium load, the left would now show higher vaccum....................I thought my guages were screwed up, so I switched to the remaining two tubes of the carb stix, and got the same result!! difficult to balance TB's.............

I took off on a Saturday, doing approx 500 miles a day from WA to MN via Hwy 2, trying to ignore my "Buzz Bomb", with little sucess...........my hands went numb frequently, and I was denied some of the relaxation that a road trip like this will give me..............

I got to my Brother's place in Grand Forks ND ( he's an airhead guy), and quickly asked hime if I could use his feller guages and Carb Stix, to try and salvage the last half of the trip from the "BUZZ in the bars" . I found that my OVAD and TB's were spot on, even after 1500 miles of 80-90 mph cruising.

I changed the valves to slightly tight on intake and slightly loose on exhaust, hoping that ANY change would alter the harmonic being set up by the motor...............

you guessed it................no change.............vibes. Even my brother commented on the vibrating bi*ch, and said I should get an airhead, and i wouldn't have these types of problems.....................I ignored him

so...................I'll cut to the chase.............


6 total times to open the valve covers and re-adjust.........probably 20 attempts at TB sync.

I even chaged the oil back to BMW oil, thing that my oil was doind something to it.

I stopped into Big Sky BMW in Missoula Montana, to see if they could help. they were very busy, but offered to TB sync my bike. They said that it needed no adjustment, and they'd have to book me an appointment to realy check out the bike............I rode off to my home in WA.

so...........here I sit after a 4000 mile trip, with a buzzing BMW, that I want to sell, because I'm stumped.

I suppose that I should take it to the dealer, but I will be very upset if they say that they can't find anything wrong with it............ ( everything IS in spec!!!! )

why is my bike viberating? ( it is definitly engine speed related...not tires, or something else)


is the strange TB vacuum indicitive of an air leak?........I've tried to find one.........but can't

what did I do during the initial 18k service that might have done this?


my wifes Moto Guzzi is looking pretty good right now..........


hElp Rick

[Xray28]

If you had a dirty (just a little) injector or other fuel delivery system componet on one side you may be synching your TBs to something that is not inherently balanced. Do you remember if you had to adjust the TBs much when you did the 18K service?

Twin spark right??? another possibility is a spark plug that isn't firing properly (bad plug internally or bad wire). This could manifest itself at higher RPMs because at slower speeds the other plug in the cylander may be masking the problem.

[CycleRob]

elmosisu,

If the vibes are severe, you have one cylinder who's output is weaker than the other. When your first synch and valve adj re-check was perfect, you should then look elsewhere. It could be a gummed injector nozzle with an imperfect spray pattern, a leaky Hi-Voltage plug wire, a too high (cap/wire) secondary resistance, an intake manifold air leak (throttle load synch settings were diff), or a burnt valve (do a compression or leakdown check).

My best guess, with today's fuels and 18K miles is a gummy or partially clogged fuel injector. The "dirt" may even have gotten there by entering the open end of a seperated Quick Disconnect at service time.

Keep the bike . . . . find & fix the problem !

[beemerphile]

If she were mine, I'd screw in fresh spark plugs, add a couple of ounces of Seafoam to a full gas tank and make the trip. If that didn't work, I'd start looking for an air (vacuum) leak in the induction system.

- Lee

[riceburner]

check all the bolts.

maybe the engine mounting bolts have come loose on one side?

You sure the wheels are correctly balanced? (have you had the tyres changed recently?)

Do you use any SLIME or Ultraseal in the tyres? Make sure you didn't put the wrong amount in (I once double shotted the front - I'd forgotten I did a pair of tyres, then when I replaced just the rear I put SLIME in both - of course that meant the front was double filled - the bike vibrated like a bastard).

If the vibes are only really noticable at higher speeds I'd suspect one of the above tbh rather than the engine itself.

[Boxer]

add a couple of ounces of Seafoam

Lee, I don't want to hijack the thread but this may be pertinent to his problem as well. I was discussing Seafoam with another rider this weekend, who rides an R65. I had told him I had used some in a full tank of gas and afterwards my bike began vibrating more at around 4K rpms. This was AFTER a meticulous valve adj and TB synch. He asked if it would not be better to just take off the injectors and clean them rather than running the gunk in the line through them with the Seafoam in the tank.

I had to just shrug my shoulders, because I don't know the answer to that.

I DO know that my bike has begun a noticeble increase in vibration at the dreaded 4K area. Added to the mix however is the fact that I removed my can and replaced it with just an exhaust tip. I still have the cat converter.

I think I'm going to put my can back on and see what happens with the vibrations then, but will the Seafoam clean out sufficiently to make such a noticeble difference in the engine dynamics?

[elmosisu]

I did a detailed shakedown of the tires/ wheels, and definitly ruled them out as the cause. I even had my rear tire changed on the trip, and know for a fact that I can lightly reproduce the vibe at a standstill, by revving the engine quickly to the RPM range that the vibes show up at. it buzzes quite noticeably, but under load, at hwy speeds is when it shows up the most. I did remove the bottom ( secondary) plugs, when I did my valve adjustment, and thought that that might be the culprit, so i switched plugs from one side to another. no change.

I will get a new set of plugs this week, and throw in some injector cleaner.

I'll see if I can get a compression tester as well.

the power is still good, and there is no change in the operation of the bike, prior to the viberation showing up, so............

any other ideas that might be an issue?


I'm wondering if there is an air leak entry point other than the obvious TB mounts and air tubes?

thanks Rick

[beemerphile]

He asked if it would not be better to just take off the injectors and clean them rather than running the gunk in the line through them with the Seafoam in the tank.

I had to just shrug my shoulders, because I don't know the answer to that.

You are not running the "gunk in the line" through the injectors. It is not like clogged arteries, but the gunk, if it exists, is stuck somewhere in a tight place (most likely the injector) blocking the proper passage of fuel. In dissolving the gunk, it frees the passage and allows the fuel to flow properly. A good off-the-bike cleaning of the injectors would work also, but Seafoam is an easier fix. The best objective evidence of a fuel injector issue is to remove the injector and observe the spray pattern. If there is a good uniform pattern there is no need for Seafoam, or cleaning, or anything else as it is not the problem. I've never known an unnecessary cleaning to hurt anything. The only way I can imagine a cleaning to "cause" vibration would be if the bike was previously tuned to compensate for the imbalance. If so, then removing the cause of the imbalance may cause it to be out of tune when clean.

... but will the Seafoam clean out sufficiently to make such a noticeble difference in the engine dynamics?

In my experience, yes.

[beemerphile]

I'm wondering if there is an air leak entry point other than the obvious TB mounts and air tubes?

Rick,

The vacuum plumbing to the charcoal canister is a potential source for a vacuum (air) leak. If the canister has been removed, the the blocking plugs could be leaking or lost in space.

[Xray28]

you wrote :so i switched plugs from one side to another. no change.

I don't know about you, but my fanny isn't sensitive enough to tell if the weaker componet of the torque profile is from the right or left side. Too many miles in the saddle I guess So switching plugs might just be moving a symptom rather than changing it.

[elmosisu]

Okay........Okay.............

This week I will get new plugs all the way around, and throw in some seafoam.


My gut feeling is that it won't help, but if it does.................I'll buy myself a beer ! ( only because I can't realy by you guys one)

[elmosisu]

So.............. I've gotten plugs, Done my OVAD 9 times now ( no kidding )
set the TB's With 3 different sets of merc gauges and once by a dealer ( during the trip)

I've pulled the injectors and looked at the spray pattern. It seems like they are both doing the same, even spray ( that was kinda cool to do )

I've gotten in a fight with my wife, because she thinks I spend too much time "tinkering and revving" the bike in the Garage.......



the vibes ar still there. I'm not liking the bike. I have an appointment with the dealer.............I feel that I've failed on this one.


Any other ideas? I'm not counting anything out.

again, the vibes appear at 4000 rpm, and are engine related. they get stronger when the motor is put under load ( accelerating from 4000rpm up)

[NHighCotton]

Long shot,...... have you inspected the air filter?

Are you sure you did nothing out of the ordinary during that 18K initial service?

[KHaynes]

Check every part of your cable cams on the throttle bodies. I could not balance my RT correctly until I removed a tiny piece of gravel under the left cable. It was an instant cure.
Also when you do your throttle sync, are you ensuring that both throttle plates are closed and neither cable is tight before you start?

[Beemeridian]

78

[Acpantera]

Check the alternator belt and make sure no chunks are missing, after all other suspects are eliminated I would look at the clutch disc and pressure plate.

[elmosisu]

I will check the Throttle cables and alternator belt. thanks

I don't see any gravel in the throttle cable pulleys. I know that one would have definitly caused a problem.