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Old 10-02-2012, 05:08 PM   #69781
deathu
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Hi,

I recently had a chance to swap bikes for a few miles with a buddy, he has a '96 model, mine is a '98. One thing struck us both, which is the huge difference in the level of vibrations between the two bikes, which are after all the same model. The first thing he said after riding my DR was "dude, your bike vibrates a lot". Also I felt his bike vibrated MUCH less.

To give an quantitative example, on his bike I was doing 110km/h (68mph) in the 4th gear and felt it was not asking much, the bike could easily do more. On my bike, if I go over 110km/h in 5th gear I feel that i'm asking too much from the engine. Notice the difference, at this speed his bike was in 4th gear and felt butter smooth, mine was in 5th and felt stressed.
Ok, there is a small difference in gearing, I am running 15/43 while he is using the stock 15/41 gearing. The gearing difference is minimal however.

Apart from that, both bikes are almost stock. Stock carbs, snorkles in place, performance pipes installed to save weight.

The difference between the two bikes was absolutely huge, this seriously got me thinking maybe something is wrong (maybe valve timing, maybe the balancer is not installed coorectly, who knows what else....). I would say that, for example in 4th gear, his DR ar 110km/h (68mph) is as smooth as, or smoother than mine at 80km/h (50mph).


So I am asking you, how fast should a stock DR go and still feel smooth?
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Old 10-02-2012, 05:13 PM   #69782
Emmbeedee
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Quote:
Originally Posted by deathu View Post
Apart from that, both bikes are almost stock. Stock carbs, snorkles in place, performance pipes installed to save weight.

The difference between the two bikes was absolutely huge, this seriously got me thinking maybe something is wrong (maybe valve timing, maybe the balancer is not installed coorectly, who knows what else....). I would say that, for example in 4th gear, his DR ar 110km/h (68mph) is as smooth as, or smoother than mine at 80km/h (50mph).


So I am asking you, how fast should a stock DR go and still feel smooth?
Did you check the chains to see if one was bad and the other good? Back when we used Chain Wax, I could hear the chain on my wife's Monster when I was riding behind her. Switched to proper chain lube and a new set of chains and sprockets and never had that problem again.

A tight or kinked chain can make such a big difference to a bike's feel.
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Old 10-02-2012, 05:14 PM   #69783
barko1
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Smooth is awfully relative so pretty hard to give anything but a subjective answer. Mine seems fine at 70 mph, until I get on my Concours 14 then I remember what real smooth is. Perhaps you have bad or improperly torqued engine mount bolts??
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Old 10-02-2012, 05:32 PM   #69784
deathu
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Quote:
Originally Posted by Emmbeedee View Post
Did you check the chains to see if one was bad and the other good? Back when we used Chain Wax, I could hear the chain on my wife's Monster when I was riding behind her. Switched to proper chain lube and a new set of chains and sprockets and never had that problem again.

A tight or kinked chain can make such a big difference to a bike's feel.
The chain on my bike has under 1000 miles, installed with new cush drive rubbers and sprockets, and also with sufficient sag. I know how much problems an incorrect chain setup can create... had serious chain issues on one of my other bikes. By comparison the chain I installed on the DR is very quiet... actually I couldn't hear it at all, even when I had the stock muffler.

Quote:
Originally Posted by barko1 View Post
Smooth is awfully relative so pretty hard to give anything but a subjective answer. Mine seems fine at 70 mph, until I get on my Concours 14 then I remember what real smooth is. Perhaps you have bad or improperly torqued engine mount bolts??
70mph, in 4th or in 5th gear? My buddy's bike felt really smooth in 5th gear up to around 85mph (130-140km/h). I know this is a subjective matter, but common sense applies I think... there's no way my bike would go over 120km/h without feeling it's going to disintegrate really soon.
Thanks for the engine mounting bolts tip, I'm going to check that.
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Old 10-02-2012, 05:48 PM   #69785
acesandeights
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Quote:
Originally Posted by deathu View Post
...
So I am asking you, how fast should a stock DR go and still feel smooth?
I typically haven't been over 80mph and very seldom. I've actually never been on the interstate on my bike, all rural highway, rural road and dirt. When I have cranked it up a little to pass a car on the highway I've gotten to 80mph in 5th and it was smooth. It felt very smooth in fact; HOWEVER, I recently put knobbies on and whoa! what a difference. It's night and day. The knobs are squirrely, vibey, etc. I ride 5 - 7 days a week. Rode one day at 80mph, the next with knobs and wow.

I don't know if your bikes are set up the same other than gearing, but realize you're turning about 5% higher RPM at any given speed. If your tires aren't the same, it could account for a LOT of vibes compared to more road oriented tires.
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Old 10-02-2012, 06:11 PM   #69786
deathu
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Indeed knobby tires do add some vibration, but the vibration I have is much worse than that caused by knobby tires alone. I currently have Pirelli MT21s on the bike. If I grab the clutch lever at speed and let the engine idle, the vibration level drops significantly, even though the bike is still rolling at 110km/h on those MT21s. This makes me think that the actual source of the worst vibrations is the engine itself, unless I am overlooking something...
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Old 10-02-2012, 06:12 PM   #69787
doug s.
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Quote:
Originally Posted by deathu View Post
Indeed knobby tires do add some vibration, but the vibration I have is much worse than that caused by knobby tires alone. I currently have Pirelli MT21s on the bike. If I grab the clutch lever at speed and let the engine idle, the vibration level drops significantly, even though the bike is still rolling at 110km/h on those MT21s. This makes me think that the actual source of the worst vibrations is the engine itself. Am I overlooking something?
maybe the counterbalencer is off?

doug s.
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Old 10-02-2012, 06:18 PM   #69788
wee-twin
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On my recently acquired DR I get vibes under load such as acceleration or climbing a hill. I already checked motor mounts, but I am suspecting chain. Bike had 14 countershaft sprocket when I bought it. Only 7000 on bike. Any ideas how to tell if chain/sprockets are causing this? Oh, I checked the cushdrive and rear bearings.

wee-twin screwed with this post 10-02-2012 at 07:10 PM Reason: More info
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Old 10-02-2012, 06:30 PM   #69789
deathu
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Quote:
Originally Posted by doug s. View Post
maybe the counterbalencer is off?

doug s.
This deffinitely is one of the possibilities I am thinking about. Until now I understand that the possible causes may be:
- enine mounts not torqued correctly
- counterbalancer off by a few teeth (I don't know the history of the engine, I don't know if it was opened or not)
- valve timing may be incorrect (camshaft may be off by one tooth? would the engine even work in this situation?)

Any other possible causes?

LE. Just rode from work to home, and I did a new test. Got to a speed where the vibrations were problematic, grabbed the clutch, let the engine idle for a second then revved it to about the same RPM it was running before, while still holding the clutch. The bad vibes came back, the same as under load. I think this eliminates the drive train as a possible cause...it must be the engine

deathu screwed with this post 10-02-2012 at 07:50 PM
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Old 10-02-2012, 06:46 PM   #69790
nigelcorn
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Joined: Aug 2007
Location: Henderson, NV
Oddometer: 793
Hey everyone, I'm hoping to get back into dualsporting after some time commuting on a street bike.

I have a 1990 Honda Pacific Coast 800 in pristine condition that I am looking to trade for a DR 650. I'm in the Vegas area, so if you know anyone nearby that is looking for a street bike, send them my way, thanks!
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Old 10-02-2012, 07:13 PM   #69791
ram1000
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Quote:
Originally Posted by wee-twin View Post
On my recently acquired DR I get vibes under load such as acceleration or climbing a hill. I already checked motor mounts, but I am suspecting chain. Bike had 14 countershaft sprocket when I bought it. Only 7000 on bike. Any ideas how to tell if chain/sprockets are causing this? Oh, I checked the cushdrive and rear bearings.
Does it have a high compression piston? Mine does and it is smooth until I use the power. Cruising its just fine.
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Old 10-02-2012, 07:38 PM   #69792
NordieBoy
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Quote:
Originally Posted by wee-twin View Post
On my recently acquired DR I get vibes under load such as acceleration or climbing a hill. I already checked motor mounts, but I am suspecting chain. Bike had 14 countershaft sprocket when I bought it. Only 7000 on bike. Any ideas how to tell if chain/sprockets are causing this? Oh, I checked the cushdrive and rear bearings.
Look down and see if the front of the chain is jumping around.

If the vibes smooth out under heavy acceleration, then it's probably the chain.
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Old 10-02-2012, 10:49 PM   #69793
Kommando
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Quote:
Originally Posted by deathu View Post
70mph, in 4th or in 5th gear? My buddy's bike felt really smooth in 5th gear up to around 85mph (130-140km/h). I know this is a subjective matter, but common sense applies I think... there's no way my bike would go over 120km/h without feeling it's going to disintegrate really soon.
Thanks for the engine mounting bolts tip, I'm going to check that.
I run over 90MPH (indicated) for miles at a time out west. With 16/46 sprockets, 90/90-21 front Shinko 244, and a 130/80-17 rear Kenda K761, the DR feels fine.
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Old 10-03-2012, 12:57 AM   #69794
Thumper Dan
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Location: Australia, Northern NSW
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Quote:
Originally Posted by deathu View Post
This deffinitely is one of the possibilities I am thinking about. Until now I understand that the possible causes may be:
- enine mounts not torqued correctly
- counterbalancer off by a few teeth (I don't know the history of the engine, I don't know if it was opened or not)
- valve timing may be incorrect (camshaft may be off by one tooth? would the engine even work in this situation?)

Any other possible causes?

LE. Just rode from work to home, and I did a new test. Got to a speed where the vibrations were problematic, grabbed the clutch, let the engine idle for a second then revved it to about the same RPM it was running before, while still holding the clutch. The bad vibes came back, the same as under load. I think this eliminates the drive train as a possible cause...it must be the engine
I remember on this very forum (the only one I really read ) and someone was having similar issues with vibration and thought it was the chain etc etc. It turned out to be dodgy cush drive rubbers. He replaced them and everything was fine again.

Its going to be a process of elimination unfortunately. Do the simple things like the chain sprocket replacement.......check. Engine mounts are torqued to correct spec.........check. Cush drive rubber replacement........check (you get the idea). If it isn't the parts that I just mentioned, at least you'll have spares and peace of mind that you've eliminated them. Not sure about the counter balance and how to remedy but maybe Jeff from procycle can chime in :)..

But please make sure you let us all know what happens so this library of info keeps building.

good luck
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Thumper Dan screwed with this post 10-03-2012 at 01:02 AM
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Old 10-03-2012, 02:28 AM   #69795
BergDonk
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Location: Snowy Mountains Oz
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Quote:
Originally Posted by Adv Grifter View Post
My DR clunks pretty good going into 1st also. The 1st to 2nd shift I do kinda slow, and that seems to help. Not much I know to make that clunk go away.

I know sometimes different oil seems to help. But (for me) as oil wears down seems the clunk becomes more severe.
I use Mobil One synthetic Car oil (for High Mileage cars) It has no friction modifiers. Been using it for 35,000 miles now.
I usually mix in about a half quart of Chevron Delo 400 (Dino oil) with the Mobil One. Seems to work well and shifting is better for about 1000 miles ... then clunk returns.
But I believe the Delo may help some .... Strictly seat of the pants call here. Good luck.
IMHO if you notice an improvement in shifting and/or clutch operation after an oil change then you are not changing your oil often enough as its breaking down and your engine is suffering as a result. Forget the Mobil 1 and just use the Delo 400. Not 400 LE, just 400. I also add a splash of Lucas stabilizer, about 5%, and change at up to 4,000 km intervals with no noticable change in behaviour.
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