Model 94 vibration

[matt glascock]

Hi All, Here's the new happening. On my daily rider (1972 Model 94 Wombat), the bike has developed a fine, high-frequency vibration. Not a rattle, per se, but a noticeable vibration felt only through the handle bars not present before. The engine runs as well as previously and there are no accompanying noises. Motor mounting bolts are spec-tight. The one recurring issue is a consistent loosening of the exhaust mounting nut - even after replacing the crush gasket. Where should I look next? Finally, should I stop riding it until I get this sorted out? As always, thank you!!

Best,

Matt

[racerclam]

The crank halves may have tweeked a bit . I always weld them after being trued , the 125s are good at tweekng.

Rich

[matt glascock]

Will I damage the main crank bearings if I continue to ride the bike as is or do I need to get the crank rebuilt now? Thanks Rich!

[hodakamax]

Hey Matt, the number one cause of vibration is the flywheel. I would check that first. Second I would check the other end of the crank for things loose. This symptom brings to mind a fun discussion we had quite a while back concerning the same subject. It went on for many pages and many opinions were discussed even bets were placed on the outcome. Ideas went from cracked frames to who knows what while bypassing the obvious. A different flywheel was finally tried and the problem was solved. I did win the bet but I haven't collected my beers yet.

Rich's advice is always good and that may well be the problem, but first I'd check the flywheel carefully for any problems or damage. Sometimes the only way to tell is to try another unit and at least eliminate that as a cause. In the case mentioned above the flywheel was checked for run out, balance and being true but still shook.

Another opinion for the day!

Maxie

[dirtsquirt74]

I have owned my model 94 Wombat for many years. Back in the day when I rode it regularly, it had no vibration. Even though my motor didn't vibrate, I came across a bracket that Pabatco brought out to solve the vibration problem and bolted it on my bike. Could be all you need to do is to order up a Pabatco bracket and bolt it on your motor. I am sure some of the prior dealers remember that bracket.

Richard Schwarz

[viclioce]

Check your front wheel bearings too. ; D Victor

[matt glascock]

Hey Maxie, that's a great suggestion. Happily, I just so happen to have a spare flywheel in the parts stash so on it goes tomorrow. Is there a technique by which the original flywheel can be properly balanced? I like to have a spare. Thanks to you too, Victor. I did replace the front and rear wheel bearings about 600 miles ago, but will pull the wheels and check them out as well. Gets me off my duff for a repacking to boot! And finally, thank you too, Richard. I'd like a bit more information regarding the bracket you mentioned.

Best,

Matt

[viclioce]

Hey Matt. What happened with that 250 T Dog you were trying to buy on eBay?

I would suggest that you contact EBay directly regarding the sellers behavior. EBay won't want to get in the middle of a breach of contract dispute and may well pressure the guy into delivering the bike for the amount of the winning bid. Contracts consist of an offer and an acceptance. Both exist here. Arguably, you could sue the seller in Vegas and EBay for breach of contract.

Anyway Matt, I think he just changed his mind about selling it for $500. Someone must have told him it was worth more, and he regrets posting it as he did. Too bad. You should report the transaction to eBay. They do in fact mitigate disputes, and if nothing else the can black list this guy from eBay. Worth pursuing. ; D Victor

[matt glascock]

You are absolutely right, Victor, and it really pisses me off. In the original ad, the seller even said that the original tank was worth more than the starting bid price of $500. What really galls me is that if you bid but fail to pay, ebay will really ding you. Apparently not the other way around. I looked into opening a claim, but listed on the page to do so, the cancellation of the sale was already listed as such and that the incident was "closed". I may try again but right now I', so angry I could spit nails. That tank looked brand-new. The same 250SL is now listed for bids beginning at $1950. I won the first auction for $510 fair and square. RIPOFF!!!!!!

[viclioce]

I would contact eBay and ask if they want to deal with you directly or your attorney? That should get their attention mighty quick! Then lay out what you want, to make the deal go through! They should st least listen. They aren't stupid and know what it could lead to. You just have to let them know that's where you're headed if they don't force the guy to honor the contract to sell it at the winning price.

[matt glascock]

That's what I'll do. Good call. I'll report the outcome.

[viclioce]

Glad you're going to pursue it! I figure the least they will do is blackball the seller. People need to learn! Breach of contract is breach of contract. Even if they think "it's just eBay!" Good luck!

Oh and please remember, this was NOT legal advise. Just a friendly opinion! ; D Victor

[viclioce]

The thing to tell eBay is he canceled the sale AFTER the auction closed, with you as the winning bidder. NO ONE ELSE BID. Let them know that you did not retract or withdraw your bid and you rightfully won the bidding. They may be thinking you did one or more of the above. ; D Victor

[matt glascock]

Hi Victor, you are absolutely 100% correct. This is a breach of contract pure and simple. The seller has claimed (whined) to Ebay that he listed the bike incorrectly as a "collectible" rather than a motorcycle, they bit, allowed him to cancel the auction that I won, and relist it. They gave him a pass. Here's what I think - someone told him that he got slammed and he developed acute seller's remorse and pulled the plug on my win. Anyway, I'm out on a killer deal on a 250 SL. Double standard by ebay and a total ripoff. I hate them. Imagine what would happen if you reneged on ponying up the dough for an auction you won. They'd probably cancel your account. Bogus.

[viclioce]

The term SleazeBay comes to mind.....

[viclioce]

So did you work out the vibration issues??? ; D Victor

[matt glascock]

Hey Victor, Sleazebay for sure. I hate it, but it remains an important resource for finding parts. I swapped out the front wheel for my other 94 with brand new bearings and replaced the flywheel with the one in my parts stash. The problem persists. A crank rebuild may be in my future unless you have any other ideas. In other news, ebay informs me the cancellation is legit. So much for that "completed auction is a legally-binding contract" BS. Thanks for your help and support, Victor!

Best,

Matt

[Roddy boy]

Is the vibration constant through out the Rev range? If it only appears at specific revs, and only noticeable in the bars, then it may just be a harmonic vibration. Cure is some bar end weights or internal slugs

[matt glascock]

Roddy boy, AHA! Yes, its felt through the bars and NOT throughout the rev range. I checked it out. Lets say I'm at a stoplight and I blip the throttle for no other reason than its COOL. As the revs wind down the vibration appears and disappears at around the quarter throttle region. Maybe I'm just setting up some type of sympathetic resonance at that RPM. I'm not familiar with the weights or slugs you mentioned. Any suggestions? Thanks to you and the gang!

Best,

Matt

[Roddy boy]

Most newer bikes have internal bar weights to keep the buzz out of the bars. If you take one out, as I did on my KLR, the harmonic vibration is immediately noticeable. They are usually tapped for a retaining bolt that spreads it out a bit and insures a tight fit. I would bet that any metric bike shop will have a set for 7/8 bars. Any bike wrecker will have tons of then. Try a couple different sizes and let the forum know if it works out. If you are going to add a set of Bark Busters, they come with external weights that bolt on between the hand guard and the bar end

[matt glascock]

Thanks Roddy! I'll try some out and report.

[hodakamax]

Hey Matt, your vibration problem is starting to concern me. Is this something that has started recently or always been there? Vibration problems at certain RPMs are almost always associated with the rotating crank assembly which includes the flywheel and clutch. There are always vibrations embedded in rotating masses and some can be magnified by things like loose mounts or cracked frames. Also a failing bearing could be suspect. It may be time to check out the crank assembly for failing bearings and alignment as Rich said and a check of the frame for cracks. True that bars vibrate and can be cured by weights but we don't want to cover up a problem deeper in the engine. Just my opinion! Hope this helps.

Max

[matt glascock]

Hey Max, I'm glad you rang in again on this issue. I don't want to mask an evolving problem. The bearings and bushings (all) were replaced 800 miles ago so hopefully they are ok. I have not inspected the clutch but did exchange test the flywheel with the one from my parts stash (possibly suspect) with no improvement. I did the same maneuver with a known good flywheel I pulled from my other Wombat. Again no improvement. I did loop the bike out on a steep climb out but the both of us hit dirt only, albeit pretty hard. The only thing noticeably tweeked was my pride. The vibration developed about 4 or 5 rides later. Do you suppose its a real possibility I incompletely cracked something that progressed over the next week. I will go over the frame and motor mounts with a fine tooth comb and pull the clutch for an inspection. If nothing is revealed, it looks like a crank rebuild will be in order. After that, I'll try dampening the bars. Great suggestions, Maxie. I'm on it!

Best,

Matt

[taber hodaka]

I have seen gas tanks develop a vibration, cured by a foam wrap on the frame under the tank. ---Clarence

[matt glascock]

Thanks Clarence, I'll need to check that out. I had the tank off for sealing a while back and used a thin foam tube over the frame but i'm not sure it provided a snug fit to the tank. I'll dig into that tomorrow.

Best,

Matt