Bonneville America Forums Forums Technical Forums General Tech Engine vibration - need experience

My bike is at the service dealer for a follow up after 904 BB install. I've noticed a problem since the BB I can't figure out. After all the major work was done (install of D&D Cycles BB kit with Wiseco pistons), I noticed a slight vibration primarily 3400-3600 rpm. I could feel it in the pegs and it wasn't there before. As I broke in the BB it seemed to get worse as I put miles on it. I took it easy the first 500 miles staying 5-5.5K or below, then opened it up the last 350 miles occasionally.

You can feel the vibration even sitting still in neutral running up and holding the 3200-3800 rpm range. It also seems to be worse with heavy throttle. It never vibrated before that I could notice, and now having to hold 4th around town in the bad range is annoying. You can't avoid that range. I absolutely love the added torque and power but wish there was an answer for the bad vibes.

The shop said they have checked the carb sync, valves and jetting. They even pulled the top end and checked the pistons. They said the balance shafts are not adjustable and they can't think of anything else to check. They don't seem to think there's a problem and/or it's not that bad. It's really noticeable to me and my wife has complained that she now feels vibration in the sissy bar that's never been there. I'm really counting on some of you experienced wrenchers for some input. Could carb synch cause this? Is it just a factor of the added power and torque? It scared me because it appears to have increased with mileage. First, just the pegs, now tank to sissy bar. My '71 Triumph didn't vibrate this bad. Help!

General trouble shooting:
Ensure all the stuff is torqued up to specs and while doing so ensure any related bushings are in place (if there are supposed to be any). Rear motor mount, exhaust pipes to headers, crossover pipe, front motor mount, etcetera.

Still vibrates excessively?
Then one at a time: consider resetting the cam chain tensioner. Ensure the camshaft backlash gears are tensioned. Pull the left engine cover and inspect the clutch basket. Did you have the clutch springs upgraded?

I don't have the BB nor am I freaked. Hope this helps.

Moe, I would think they checked the mounting, but I'm passing your suggestions on to the shop. I specifically asked about your cam checks. It does seem like it could be something off or loose due to the fact it gradually increased. Thanks, I appreciate any possible suggestion that might have been overlooked.

This may be way out in left field but have you inspected the baffles in your SS to see if maybe the packing is burned through on one side?

Do they think it's a problem too? On the old bikes when I would put the 10.5:1 pistons in you got a little more vibration due to the higher compression. But in those engines there are no balance shafts. Maybe one of the BB guys could tell you if they had any more vibration after their BB job.

i have no vibration at all. bike is a smooth as stock. i don't even know where you would begin to look. possibly bad bore job? D&D should know, but may be worth talking to carlos at British customs or bill gatley. i KNOW they would have a good idea whats causing it

Frank

When I initially did my BB I had a real bad vibe in the same rev range as you. I rechecked the bolts when I changed the break in oil I found the front engine mount bolt was loose. after I retightened the vibe was still there but not as bad. I have just put it down to the harmonics of the larger capacity and higher compression ratio. After a few rides / miles I dont notice it anymore. It has just become part of the feel.

I got a note from them. They said the cam tensioner was automatic and the cam gear tensioners were ok. They plan to recheck all mounting bolts tomorrow. They've done a bunch of these and I can't imagine a bore problem, but no suggestion will be taken lightly. They also plan to do a new dyno run tomorrow. The one done after the BB showed leaning above 5500 rpm. They may want to up the main to the next size.

.Mine had the same vibration right untill I blew it up with 1000k on it,8200 dollars later it still vibrates more than ol ladys stock speedmaster.Perhaps they just run that way,mine vibrates less now but still not smooth like stock.They,at the shop told me my starter drive was bad,but could it have been somthing to do with the ring gear.Just somthing for them to check and like Brett says I don't notice it till I get on my ol ladys bike.

idk guys i don't think it should vibrate much more then stock unless you have a stroker crank in it without the factory balancers. i don't want to make you worry but i also don't want to see you get stranded somewhere.

Frank

Frank, I am concerned as well. They didn't change the stroker and I certainly don't want it to blow up. What's interesting to me is that it gradually increased during the 850 miles I put on the BB. I could live with a little bit more vibe than stock because I love all the added power/torque. I just don't want any trouble or have it annoying to ride.

Also, the oil/filter had been changed not long before the BB. Should it be changed again now that I have 850 miles on the BB or can it wait until next service?

I've never thought running clean oil through a dirty filter was a good idea. Did you have them check the exhaust flanges and clamps as well just to remove the less obvious sources of vibration?

i put 200 miles on my bike, then changed the clutch, oil, and filter yesterday and have put another 50 miles on it. i know they say wait 500 but even with 200 miles on it the oil had a lot of what looked like fine metal powder in it.

Frank

Frank, I'm not worried about getting stranded anywhere. I put 5500km on around Tasmania and Victoria over the Xmas break and other than a minor fuel issue my bike ran strong and reliable over the whole 15 days. during one leg of the trip out in the middle of nowhere we sat on 150km/h for almost an hour straight, without a worry. probably the most fun I have ever had with my clothes on!

You shouldn't be able to see any fine metal in the oil at all, period. If you are, something is wearing.

Regarding the vibration, it appears from the others with BB kits that they vibrate more. Since the pistons are larger and probably heavier the counter balance shafts can't handle it. Unless someone with a BB kit can state that they don't have any vibration it appears it will be normal.

The metal flake in the oil scares me though. Keep a close eye on the witness hole. Hopefully this is just due to breakin but the filter should take it out.

i have the 904 and i dont get any more vibration then i did stock. and the pistons felt lighter to me then the stock ones did, and they should seeing as they are forged

Frank

If the new pisons DIFFER in weight from the originals (yes, lighter as well as heavier), then you WILL have an additional level of vibration - the reciprocating masses of the crank/pistions and the balancer shafts are essentially a tuned assembly to eliminate vibration - alter one factor (i.e. the piston weight) and you will have lost the tune.

Just one of those things you have to put up with - the only solution would be to re-design the balancer shafts to compensate for the changed piston mass. Just my 1$ worth.

I don't think mine vibrates anymore then before my wiseco BB either.
Are you sure it's a rpm related vibration and not a misalignment of the rear wheel that occurs only when moving?

Pat, I'm sure it's not wheel related. I can feel it in neutral running up to the 3500 range. I'm picking it up this afternoon. They are doing a final dyno run and check. I've passed on all suggestions and have run out of ideas.

I will post an update after riding. Thanks for all input and I'm still open if anyone has another idea.

make sure to post the dyno #'s

Frank

MAJOR DEVELOPMENT! I went to pick up the bike today. They had run the dyno and felt it was already set up the best it could be overall. The dyno still showed leaning at the highest rpms. They put my 130s back in and ran it again. The result was better near redline but not as good the entire range below 6000. They decided to put the 125s back in which I agree with. I'd much rather have it the best it could be in the range I use the most.

They were going to bring the bike around front when the starter broke. The actual mount for the starter gear in the engine casing broke. It turns out this has been a problem for Triumph and the mounting has changed in later models. D&D feels they can get it fixed on warranty even though mine has expired. Good thing as just about the whole engine has to be torn down and replaced. I'll have a new engine with the 904 pistons. I will have to break in all over again.

There is a possible good side. They plan to check and possibly balance parts that go back in the engine. The factory can't take the time to do this in assembly resulting in some stock bikes vibrating more than others. I checked out a new 07 stock model while there and it vibrated similar to mine. So, I'm out of a bike for another week or more, but I feel like I have a much better chance of having my cake and eating it too. If they are able to get the bike to run as smooth as it did initially, but with all the improved power and torque, I couldn't be happier.

I don't have a new dyno print out, but it should be almost identical to the one done before. The only change from my post BB install dyno is they changed the 42s to 45 pilots to tame decel popping and help bottom rpm leaning. The bikes been running great like this for the last 850 miles. I'll really miss the bike with the weather so nice, but I'm glad the starter gear broke there and not out on the road somewhere this weekend. Once all back together and running, I'll post results.

I feel good for you since it seems like this will bring a good conclusion to the current dilemma, however:

Quote:

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The actual mount for the starter gear in the engine casing broke. It turns out this has been a problem for Triumph and the mounting has changed in later models.

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now I feel bad for my '04...

Time for someone to figure out a kick start

hopefully they cover the expense, goodluck and i hope you get it back done right and quickly

Frank

Anybody else ever have a problem with starter mounts breaking??? Starter problems as a whole? If the case mounts broke I would think the starter was engaged while the engine was running. Can't figure any other way for the mounts to break unless the starter drive was stuck in the engaged position and spun while the engine was running till it seized.

Did the shop state why the starter mounts broke?

It's interesting that Marty stated earlier he had problems with his starter drive. He also had a vibration which appears smoother now. Common failure and symptom???

Man I don't like that news,lthins is the first I have heard of any starter problems. I hope that means it is rare. Where exactly does the case break? Where the starter goes through into the primary?

Ian, from what I could tell it's part of the engine body that holds the idler gear shaft in place. It's a socket tube like mounting just to the right and up from where the starter comes through. The top half of the socket was broken off.

You can see it clearly on the last page of the Clutch chapter in the shop manual.

Thanks a lot for that info. I'm already a worry wart! Ahhh well....

This is only the second time I've heard of this problem. The other time I was at the dealer and they were working on a brand new 2005 that happened too. In 2005 they had never seen that problem before. I guess it's a major PITA when it happens. I'm crossing my fingers that it won't happen to my bike.

See this link, with pictures, of the starter shaft race castings breakage....says it all, and so far I believe Triumph is fixing beyond warranty expirations.

http://www.triumphrat.net/modifications-...t=starter+shaft

Robin, thanks for the posted link. That's exactly what happened to mine. I'm 8 months out of warranty, but the dealer feels it won't be a problem getting it covered. Triumph has fixed this on later models, but I dont' know when the change occurred. The link shows a 865 and mine is a 790. It is a MAJOR job to change out the entire engine casing.

I asked could I have push started the bike if it had happened out riding. Yes, you could push start, but you could risk having metal parts cause further damage. I'm now wondering if it gets loose before beaking. If so, it could be an explanation for the vibration that was slowly increasing.

Bob, just wondering what weight of engine oil were you using when you had the breakage? I know that using a heavier oil will damage the nylon gears in the oil pump. The owner's manual recommends synth 10w-40, so perhaps a heavier oil would give more resistance when starter cranking thereby stressing the starter shaft race casting. Also, when you had the breakage, was the bike cold, or still warm?

D&D has done the oil changes and only uses the recommended synthetic oil. The bike had been started just 15 minutes before. I had asked them to check the front brake pads while in the shop and they forgot. I was there when they started it and pulled it back into the shop to put the pads on. They put the pads on and when they tried to start to bring the bike around front - it broke.

D&D sent an e-mail saying Triumph is covering the repair on warranty and the parts are on the way. Boy, what a relief! It will be a week or more before I probably get it back. Hopefully, they'll find a way to ease a bit of the vibe when they put it all back together. I hope none of you have to deal with this starter problem. It could cost a lot of time and money. I wonder just how common this is.

I hope not common and caused by a bad casting or something. I wouldn't care if there was a kick start option. My financial situation at the moment would mean I would have to open the primary and pick out the parts and put it back together and push start it.

I'm glad Triumph helped you out under warranty. If it is a common problem I would hope there would be a recall and a fix for it.

I know that thought did cross my mind, I guess rather than a full fledged recall , make it a service bullitin to cover the cost when a broken one is brought in for repair.

hey ram,

where is the portion of the case that snapped? I'm interested because frank and I noticed that on my 07 speedmaster, the left side case cover and the top of the case behind the jugs are little more beefy. it makes it hard to get my left carb bowl cover off. I'm just curious to see a picture to determine if that is the reason for the beefier engine cases.

thanks,
tony

Tony, if you were to remove the left cover there's a tube like part on the engine casing that the idler gear shaft fits into. There's also a corresponding part of the cover that secures the shaft's other end. The part that broke is the top half of the mounting on the engine casing but not on the cover. You can see this on the last page of the clutch chapter in the shop manual (if you have one). The end top half of the tube socket broke allowing the shaft to lift and no longer allow the idler gear to engage the starter gear.

They would have to recast the casing to improve it and they may have beefed up other fittings when they made the change. I assume it would have some sort of inner steel sleeve or something to make it stronger.