I have recently pick up a major vibration. feel it in the floorboard mostly. I believe there is something going on with the engine or drive train. change plugs and plug wires. help very little. adjusted clutch. still the same, but shifts better. wonder if there is something going on with the carb or fuel system. maybe a weak coil? I don't want to just throw money at the problem, so any advise would be of help. the bike is a 1990 tour glide with a stock evo engine. thanks

 

If the front engine mount goes bad you can feel more vibration, and the front engine mount is not an extremely expensive item to replace. I think the current part number for our 90 FLHTCU was 16207-79D and it cost about $41.85 ( plus shipping) at Zanotti. I seem to remember there was a lot of confusion by various individuals on which way to turn it, some manuals were wrong and some installed it up side down, there was a posting somewhere with the proper way to install it but I haven't found it yet. There might still be "B" and "C" models available as well which will probably be cheaper. I think the original was part for the '90 was "16207-79B" . I think "C" was actually smoother but did not hold up well, so Harley went to the "D" model. A lot of guys that have the front mounts replaced on their newer Harleys will complain they vibrate more with the newest "D" mounts as opposed to the "C" but the "D" hold up better. I think the "D" is better than the "B" mount. Of course there are several after market products available.

on edit: this will give you an idea:




I once had a compensator nut tightened by a HD dealer and I was told by the dealer that having it loose created a lot of vibration, I was pretty new with the Harley at the time and did not notice it over normal vibration.

 

Is it on both sides and only noticable in the floorboards?

There's lots of other things you can check, but I've found these 2 areas the most common cause of floorboard vibration on Dressers.

The exhaust has to "rock and shake" with the engine and takes a lot of movement so anything out of order can make your flooboards tingle. Check the exhaust mount on the transmission side cover. Also look where the rear down pipe intersects the pipe going back. There is a welded gusset support and they can crack there over time as well as where the rear pipe splits near the head. The brace that supports the left pipe above the starter should be checked. Check the v-clamps on the mufflers. I've seen flanges break and even had one muffler break between the flange and muffler body. Not saying you need to remove everything, but DO check all over the entire exhaust with a "fine tooth comb." I know most would think an exhaust leak would be noticed and something would have to be about to fall off, but believe me - "been here and done this"

A loose (less than tight) floorboard bracket will do it also. The right rear support is the worst for it and the most difficult to tighten. I've seen several that were loose from the factory, even though most were installed with locktite. They wear into the frame just enough that you can't wiggle by hand, but sure makes your feet feel it. It's easiest to remove the boards from the brackets when checking/tightening them and yes, they can get loose even if they've never been off.

PS great post pajoe Like I say - learn something everyday thanks!

 

thanks, I will check these area for problems. how will I know the engine mount is bad? also, it is smooth around 50 to 55mph, but once I get up to 60 it begins to vibrate alot. used to be smooth all the way up to 75-80 mph. I thought something was amiss in the engine, but maybe i'm looking in the wrong place. both floorboard vibrates. it is so bad I started back riding my kawi 900 again. really need to find the problem. thanks

 

Since both have bad "vibes" it's probably not a footrest bracket issue. And not to say there couldn't be other issues, just that exhaust things I mentioned are the most common.

Maybe someone has a better cheat, but best way to check the front is to remove it completely. Look for signs of the center bushing separating from the rubber and/or the rubber cracked, separating from the metal.

Check the alignment adjusting links also. There is one on top of the engine just like at the front mount. You'll have to pull the tank(s) for that one. They seldom give up, but can wear out at the ends over time.

 

check the exhaust and all look good there. I took it on a 100 mile trip today to see if I could better describe the vibration. it seams to me it's all through the bike. handlebars, floorboards, seat. listen to the motor and It appears to be running right. I didn't feel or hear a skip or anything. purr along just fine. I quess I'll bite the bullet and replace the front mount. or they known to go bad? It's probaly as old as the bike. I'll let you know if it fixes it. thanks

 

Don't you know that all Harleys vibrate. Its probably just the nut holding the handlebars.

Hope you find the problem Bro.

Mark

 

Yes, they go bad. They have a tendancy to get soaked with engine oil, because when the filter gets changed (unless some sort of trough is used), the oil runs into them. Couple that with the inherent viberation of the V-twin, environment, etc., they just wear out.

 

It can also be the signs of a bad cam bearing. That would be an expensive symptom if that's actually it and it's not addressed. I'd be tempted to spend the 20 bucks for a bearing and gasket just to be sure, assuming you're confident the vibration is originating in the engine before dropping money on an engine mount. I don't know why I didn't think to mention this earlier and a vibration is about the only warning sign they give...

PS: just looked again it's a TourGlide and the filter is under the trans on them so they don't get soaked at every oil change, but I can certainly see where a case-mount filter type engine would have a problem...

PS# 2: Just looked a 3rd time so make that 30 bucks for gaskets since the rocker boxes got to come loose (stock engine, non-adjustable pushrods)... I need to go to bed too tired to think straight apparently

 

Assuming that the exhaust is not touching the frame, saddlebag mounts or flooboards/floorboard mounts, and after you've replaced the front motor mount if you still have the problem. You might want to do a compression and leakdown test. A weak cylinder will cause a vibration thatwill drive you nuts.
You state that you recently picked up the vibration. What did you do to the bike before it started??? Is the primary chain and final drive adjusted to specs? Hope this helps.