driveline vibration

[Big_Iz]

I have noticed a droning vibe when accelerating -- equivalent of what I would call a driveshaft vibration on a car. If I let off the throttle, it immediately goes away. Obviously difficult to describe in words, but let's call it a brrrr....rrrrr....rrrrr that increases with speed, but only when on the throttle (anything above a "light" acceleration).

 

While I was changing the dogbones, I spun the back wheel around in the air, didn't feel anything loose, didn't notice any kind of looseness in the bearings (wheel mounted).

 

From my search, I didn't note any common problems as such, so I'm looking for any wisdom on a place to start. Bike is new to me, has done it since day one for me, tires are pretty new, bike has about 32k miles and appears to have been well maintained and not abused.

 

Thanks,

Iz

[Seaking]

that sounds kind of familiar.. it's similar to what I'm experiencing (I was thinking it might have been the carbs out of synch or chattering clutch plates?)

 

However, does your vibe happen in all gears at all speeds, mostly when adding more throttle to engine? Do you feel this vibe in the floor boards as well as in the grips? Not high freq like a hand buzz but more in tune to the tire rotation or engine revs?

[saddlebum]

based on your discription I would be thinking too much gear lash between the pinion and crown gears in the rear drive unit. this is usaully caused by worn out bearings. Drain the oil from your diff into a clean container and see if looks silvery. Another possibillity is lack of lubrication on the rear wheel drive splines. On my bike I had the threaded end snap of the pinion gear shaft, the bike would still drive but I had that vibration.

[Guest tx2sturgis]

This is a symptom (vibration under acceleration) that is noticeable when the carbs need to be synchronized.

 

Try that first before you do anything else. I bet it will fix it. This should be done about once a year...others will have different intervals in mind, but for me, thats about right.

 

If you plan to keep the bike for a while, its worth it to buy your own synchronizer. There are several on the market, and most will run you around $100 or so. You will also need a LONG screwdriver. If you dont want to bother with it yourself, or wont have the bike very long, then it might be easier to have a shop do it...but you wont save any money that way. The dealers like to make this sound like a big deal and charge accordingly.

 

Its not that hard to do. There are some technical articles describing the procedure here. Good luck.

 

 

 

 

Edited May 27, 2011 by tx2sturgis

[Big_Iz]

I have yet to check the carb sync, so I can't comment either way on that option. I am, however, inclined to look more at the driveline because of the way the vibration happens. Since the vibe isn't constant and continuous while under acceleration, kind of a 4-beats-on, 4-beats-off, my instinct says I have a bearing problem somewhere.

 

All the input is very much appreciated,

Iz

[Condor]

Another place you might want to look at is rear tire cupping due to low pressure???

[FuzzyRSTD]

I have yet to check the carb sync, so I can't comment either way on that option. I am, however, inclined to look more at the driveline because of the way the vibration happens. Since the vibe isn't constant and continuous while under acceleration, kind of a 4-beats-on, 4-beats-off, my instinct says I have a bearing problem somewhere.

 

All the input is very much appreciated,

Iz

 

Go to Honda shop first, get a small tube of Honda Molly 30 grease. I would remove the rear wheel and grease everything, gears/fingers in the wheel and rubber and also the drive shaft splines. I would also change rear wheel diff grease/oil. I would also do the sync right after the grease job.You can find all of this info in the teach library, step by step with pictures. I did all and if I can do it, anyone can. Remember the clip ring in the finger piece. Do not forget to put it back in like someone here did. No not me.....The drive shaft can sometimes be a problem getting back into yoke at motor end. But you learn this by how it feels. Make sure your bike is left in gear before this procedure. The first time took me a few times, and the last time about a week ago, it went the very first try. These fine people here will help you all the way through.:cool10:

Fuzzy

[Big_Iz]

Removing the rear wheel and final drive was next on my maintenance (make sure PO did his job) list anyway. I guess its possible that the carb sync could create a harmonic that would shudder its way through the drivetrain though -- hadn't really given that enough consideration yet.

[RedRider]

Just a thought (not knowing how long you have owned your Venture) --

 

If you had been riding a V-Twin prior to the Venture, you may just be changing gears too soon and bogging the engine. This engine likes to run at high RPMS. Don't change to 5th gear until 60 or 65 MPH (some will say 70). You can get 90+MPH in 3rd.

 

RR

[Big_Iz]

I have owned a wide variety of bikes, recent few being my current 2nd bike (VStrom 1000), VTX 1800c, GL15000, Pacific Coast on back to a '85 VMax almost 20 years ago. I do find myself short-shifting the RSV, partly because I haven't modified the baffles to quieten it up. To answer your question, I have only had the RSV for about a month now.

 

The vibe happens in the mid range RPM, as I don't get on the throttle at lower RPM, try to never lug it around.

 

Its all good, I'm loving the bike and this certainly isn't a deal breaker.

[BradT]

you may just be changing gears too soon and bogging the engine.

 

This is what I was thinking. Try hitting the rev limiter in first and second a couple of times, this will help tell you where 6,000 Rpm. It is possible you are bogging it and not aware.

 

Brad

[Guest tx2sturgis]

Since checking the carb synch is such a non-invasive first test...why not humor me?

 

 

If the carbs are not synched, that v-four under your tank will vibrate under acceleration, as 1 or 2 cylinders are pulling harder than the other cylinders. Its a well known symptom of the carbs being out of adjustment.

 

If you really feel like its mechanical...then go ahead...spend some money on bearings or gears or clutches or something.....

 

 

 

 

 

 

[Big_Iz]

Since checking the carb synch is such a non-invasive first test...why not humor me?

 

I like the way you think

[Seaking]

That's the hard part of asking for help... "describing accurately" what your bike is doing or what you're feeling.. Is it drive line or carbs? How one person interprets it is different than another person and how they describe it in text is again totally different

 

My buddy was telling me his bike would lag when he dropped the hammer at highway speeds last summer.. almost like it would pause before spooling up.. he'd tried to imitate the sound the bike would make but it didn't make sense to me. I test drove the bike and couldn't duplicate his problem. Yesterday when testing his bike to see if his was making the thumping vibes I'm experiencing, he asked if I could hunt for that problem he's had since last summer.. and it's a slipping clutch... argh.. I should have guessed it last year.. ergh

 

but as tx2sturgis suggested, start with what costs less in time and effort and work your way up unless you definitely know what it is.. You'll get a good carb synch out of it anyway

[Big_Iz]

Posting an update. I finally got around to doing the carb sync. One was WAY off (3-4 full turns of the sync screw). The engine runs smoother, exhaust melody is not so choppy, and the vibration as originally described is reduced.

 

But its not gone.

 

My next step is to complete some maintenance on the rear wheel and final drive. Check all the bearings for any slop, lube everything up, change the final drive fluid, and make sure all is tight.

[V7Goose]

Posting an update. I finally got around to doing the carb sync. One was WAY off (3-4 full turns of the sync screw). The engine runs smoother, exhaust melody is not so choppy, and the vibration as originally described is reduced.

 

But its not gone.

 

My next step is to complete some maintenance on the rear wheel and final drive. Check all the bearings for any slop, lube everything up, change the final drive fluid, and make sure all is tight.

First, I'll say your original problem sounded exactly like a carb sync problem.

 

But your description of how far off it was does not ring true. It is impossible for me to imagine any of these bikes where a carb sync screw could be "3-4 full tuns" off. Even with really BAD sync, one full turn of any of the three screws is a LOT. Are you sure you did it right? Does the sync stay on at both idle and high RPM? Do you know that the tech manual is WRONG on the sync procedure (so you must follow the instructions on this site, NOT the Yamahaha manual)?

 

If the specific symptom is significantly better after your sync, this strongly suggests the problem was the sync, but if it is not completely fixed, that also suggests the sync is not correct.

Goose

[Big_Iz]

Agreed on the 3-4 turns. Let's put it this way, I use a single-tube home made manometer with some mid-weight oil in it (same thing I have used on every bike for the past 10 years). When I hooked it up to the right front/rear carbs, the front one sucked the tube completely out before I could shut it down. Trust me, it was further off than I have ever seen one before -- usually, the oil will glide up one side until they are adjusted and balanced out, but this was just plain stupid.

 

Anyway, I do plan to go back and redo the sync again just to make sure its good.

[V7Goose]

Agreed on the 3-4 turns. Let's put it this way, I use a single-tube home made manometer with some mid-weight oil in it (same thing I have used on every bike for the past 10 years). When I hooked it up to the right front/rear carbs, the front one sucked the tube completely out before I could shut it down. Trust me, it was further off than I have ever seen one before -- usually, the oil will glide up one side until they are adjusted and balanced out, but this was just plain stupid.

 

Anyway, I do plan to go back and redo the sync again just to make sure its good.

I know you think you can do the job with the tool you have, but in my opinion, you absolutely cannot.

 

The interaction between the linkage screws on these carbs is so great that I believe it is all but totally impossible to do a proper sync without a four-cylinder tool. Any attempt to do this job with even a two-cylinder tool is a total waste of time. You may be able to get it a bit better, but you cannot get it right within any wild imagination of the time and number of re-checks it would actually take moving the vacuum connection from one port to another. This bike does NOT have a single cylinder that is the reference point and to which you match the others.

 

I have synced the carbs on literally HUNDREDS of these bikes, using several different tools (but all with four vacuum connections). You may not put any stock in that experience, but I am confident in what I say. Good luck.

Goose

[Big_Iz]

No discount whatsoever to your experience and I know I don't have the right tool for the job at hand. My response was simply that a previous hand had somehow buggered the sync up pretty bad.

 

I did, however, lose the nice "big cam lope" that was playing a tune before

[Big_Iz]

Goose, thanks again for your prompting. When I went back in with a 4-way sync tool, it was close, but still a bit off. I'm sure I don't have it exact, but its getting better.

 

Ran a quick jaunt up to the main office last night, 4 hours (half on the NJ turnpike), and it is running more smoothly than previous. Once I get done with checking the valves, setting the float levels and mixture, and new plugs, I will reset the sync again.

 

But back to the original question, the droning vibration on acceleration still exists. So the search continues.