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Discussion Starter · #1 ·
My 2002 RD07A is vibrating. Up to 4000 rpm things are normal: v-twin characteristic low amplitude vibration. But over 4000 rpm the vibes build in amplitude, such that by 5000 rpm there's enough vibration coming through both handlebars and footpegs to be uncomfortable even over short distances. I've checked, and the vibration correlates with engine speed, rather than road speed.

The bike had almost no use for 6 months up until this July, when I took it down to the Pyrenees. I had removed a ScotOiler, but not disconnected the vacuum line to the rear carb. This is when I noticed the bad vibes, which were not present before then. Most likely not plugging up the vacuum line to the rear carb was a factor. But I sent the bike to get all 4 spark plugs changed, and had the carbs balanced. The vacuum line is now removed, and the carb is now plugged up, so shouldn't be an issue. However the vibes are still there. (I've also recently tried to fit a K&N filter, which was a pig to do and I'm not entirely sure has a good seal. Not sure if that is relevant.)

Any ideas what might be causing this?

Iain
 

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whys the rum always gone?
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i'm sad to say i've no idea what's causing this Iain , i'm having the same kind of issues with the RD04 as your having but it would seem not quite so bad , so far i've balanced the carbs checked the choke plungers the next thing for me is the choke cables and re-set the fuel mixtures.

hows the bike running in itself does the engine feel healthy and pulling as well as before , my gut feeling is your issue is with the vacuum as you didn't seem to have the problem before this was played with.
 

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The Sultan of Bling
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May not be relevant at all but I had Insomnia down for get her first MOT since the rebuild, fitted the restrictive baffle specially for the occasion and she was vibrating like a massage bed in a cheap American motel :(

Back home, baffle out, smooth as silk.

Now the carbs have been set up specifically for the exhaust sans baffle so could it be the fueling?
 

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hi, Ive got a 1990 Africa twin with a vibration to, its there when stationary a 3 hour ride non stop is as much as i can do, my hands feel strange afterwards, the bike has a very loud after market silencer on it and im thinking this could be the problem ??????? 0 to 60ish is ok but 70mph ish onwards you can feel it through the handle bars and the tank. and clues ??????????????:confused::confused::confused::confused::confused::confused::confused::confused::confused::confused:
 

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it's about an hour......
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This may be completely off topic but here I go anyway. My @ had an annoying handlebar wobble which when holding on to the bars caused a vibration, but when I let go of the bars the wobble was very noticable and dangerous (IMO). It wasnt causing much of a problem apart from the vibration but I didnt like it so set along finding the root cause. I had the front wheel respoked, had new discs and pads put in, had the bearings checked and the wheel balanced. And nothing sorted the problem. Until I put a new front tyre on. Although there was plenty of wear left on the old K60 I had on it had worn funny and this was the root cause of the problem.

May be a completely different thing, but see if the bars wobble when riding without your hands on them.
 

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My 2002 RD07A is vibrating. Up to 4000 rpm things are normal: v-twin characteristic low amplitude vibration. But over 4000 rpm the vibes build in amplitude, such that by 5000 rpm there's enough vibration coming through both handlebars and footpegs to be uncomfortable even over short distances. I've checked, and the vibration correlates with engine speed, rather than road speed.

The bike had almost no use for 6 months up until this July, when I took it down to the Pyrenees. I had removed a ScotOiler, but not disconnected the vacuum line to the rear carb. This is when I noticed the bad vibes, which were not present before then. Most likely not plugging up the vacuum line to the rear carb was a factor. But I sent the bike to get all 4 spark plugs changed, and had the carbs balanced. The vacuum line is now removed, and the carb is now plugged up, so shouldn't be an issue. However the vibes are still there. (I've also recently tried to fit a K&N filter, which was a pig to do and I'm not entirely sure has a good seal. Not sure if that is relevant.)

Any ideas what might be causing this?

Iain


My initial thoughts are; if the bikes carbs were balanced with a vacuum leak (the unplugged scottoiler line) and then afterwards you plugged it, your carb balance is gonna be all out of whack! You need to get the inlet manifold takeoffs (where the scottoiler connection goes) blanked off properly (with a small bolt) and then re-check the carb balance with some good guages.

My second thought is, whilst doing the balancing, plugs, or air filter, you have disturbed or disconnected the TPS (throttle position sensor) that is on the RD07.


Bob :toothy5:
 

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I think these bikes just wear the tires funny. I'm getting a little wobble now as my tires are starting to cup with wear. My tires are wearing out on the sides faster than they are on the center. It really only does it when I'm in a turn and I take one hand off to wave or something. When I turn in at low speeds it almost feels like the front is going to fall in. I've got the engine buzz too, but not that bad and it pulls great all the way to redline (to me anyway). I'd like to compare it to a really well sorted AT just to see what I can do to make it better. :cyclops:

This may be completely off topic but here I go anyway. My @ had an annoying handlebar wobble which when holding on to the bars caused a vibration, but when I let go of the bars the wobble was very noticable and dangerous (IMO). It wasnt causing much of a problem apart from the vibration but I didnt like it so set along finding the root cause. I had the front wheel respoked, had new discs and pads put in, had the bearings checked and the wheel balanced. And nothing sorted the problem. Until I put a new front tyre on. Although there was plenty of wear left on the old K60 I had on it had worn funny and this was the root cause of the problem.

May be a completely different thing, but see if the bars wobble when riding without your hands on them.
 

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Handguards looped in the end of the bars? Non standard bars and pegs? Crash bars? Areas to look at as well as balancing carbs and tyres Iain. They do buzz. Find they run better at 80 than 70 on the clock with a standard pipe.
 

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Space Emperor
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I actually had a similar problem: had a stuck choke, and the carbs were balanced totally off to compensate for the choke. I then went on to remove the Scottoiler, blanking the vaacum holes, removed the choke and blanked it off, and then balanced the carbs, incl. idle screw. I soon wished I had not done anything all! The bike ran like crap, but improved a lot over time. It still doesn't run as good as before, and it now has considerably more vibration, mainly evident on my knees, when touching the tank ... I'm not sure what to do next either?

My second thought is, whilst doing the balancing, plugs, or air filter, you have disturbed or disconnected the TPS (throttle position sensor) that is on the RD07. Bob :toothy5:
Care to elaborate on the TPS, Bob? What is it, and does it require any adjustment?
 

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I actually had a similar problem: had a stuck choke, and the carbs were balanced totally off to compensate for the choke. I then went on to remove the Scottoiler, blanking the vaacum holes, removed the choke and blanked it off, and then balanced the carbs, incl. idle screw. I soon wished I had not done anything all! The bike ran like crap, but improved a lot over time. It still doesn't run as good as before, and it now has considerably more vibration, mainly evident on my knees, when touching the tank ... I'm not sure what to do next either?



Care to elaborate on the TPS, Bob? What is it, and does it require any adjustment?


On the RD07a there is a TPS (throttle position sensor) on the side of the carburretor body. I'M GUESSING, but this senses the position of the throttle and alters the advance of the ignition at specific revs (don't ask me what/how, cos remember I'm guessing!) so if it was knocked out of adjustment, damaged, or disconnected, I'd reckon on the ignition timing/dwell would be incorrect within a certain rev range. This might manifest itself in bad running or less fuel economy. Just an idea, but my suspicions do lay with chokes or possibly a vacuum leak.

Another guess, may be that one of your plugs or coils on one cylinder is not working, giving a weaker ignition compared to the other cylinder where both coils/plugs are lighting things up properly.


Just some ideas really.



Bob ;)
 

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Discussion Starter · #11 ·
Thanks for all the ideas. Some things I can rule out:
  • Wheels, Tyres - The >4000 rpm vibes are there, independent of bike speed or gear selected.
  • Renthal bars, Guards, Risers - Had all of these fitted for many years without the vibes.
  • Crash bars - Vibes there with and without crash bars fitted.
So what I'm left with is:
  • Choke - Bike has the original choke cables, so maybe I've got a stuck choke, plunger, etc.
  • TPS - Haven't been anywhere near it myself, but should be easy enough to check
Best head to the garage!

Iain
 

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Space Emperor
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Well, if the bike vibrates when on the centerstand, I guess you can rule out all other theories than the engine and the backwheel ...

I found this interesting read about the TPS: http://www.xrv.org.uk/forums/africa-twin/14697-its-most-amazing-thing-2.html which doesn't mention about vibes, but perhaps it will fix my rough riding with big pops on decelaration :)

I'm suspecting my front plugs are dying as happens a bit too often. Must be the intense heat down here.
 

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Born to Slide
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I have balanced carbs to good effect on my at but was thinking if your problem might be like one I had on my Moto Guzzi 1100 sport ( carb model) - a beast that needs everything right.

Ok balancing carbs is ok but in reality all it does is balance them at tick over or whatever you have racked it up to on the tick over adjustment.

However you have two carbs and they need to be to be lifting St the same time and rate. The Guzzi has 2 cables one to each carb so off with K&Ns and fingers into the mouths to feel the slide - get someone to slowly open the throttle and feel if they are synchronised - if not adjust the lazy carb. Now not quite the sane onand at but quite possible for there to be something in links etc that may do the same - worth a look whole you have things down.

You will need to balance and set tick over after.

Hope this makes sense and is of some use.
 

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Space Emperor
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I have balanced carbs to good effect on my at but was thinking if your problem might be like one I had on my Moto Guzzi 1100 sport ( carb model) - a beast that needs everything right.

Ok balancing carbs is ok but in reality all it does is balance them at tick over or whatever you have racked it up to on the tick over adjustment.

However you have two carbs and they need to be to be lifting St the same time and rate. The Guzzi has 2 cables one to each carb so off with K&Ns and fingers into the mouths to feel the slide - get someone to slowly open the throttle and feel if they are synchronised - if not adjust the lazy carb. Now not quite the sane onand at but quite possible for there to be something in links etc that may do the same - worth a look whole you have things down.

You will need to balance and set tick over after.

Hope this makes sense and is of some use.
Actually makes great sense! :thumbright:

I made a long tube with a bit of oil in it to sync the carbs, and I noticed that at idle, it was well balanced, but with a bit of throttle, there was no longer equilibrium. Will have to do as you suggest next time I have the tank off. You would just look at the throttle valves, and see if they move in sync, right? And how to adjust the lazy valve?
 

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Discussion Starter · #15 ·
...

So what I'm left with is:
  • Choke - Bike has the original choke cables, so maybe I've got a stuck choke, plunger, etc.
  • TPS - Haven't been anywhere near it myself, but should be easy enough to check
So I checked the choke plungers today (what a pain in the arse that is!) and they're both fine. Both seem to have weathered 50k miles and regular mud baths with no appreciable wear.

I also took a look at the TPS, which is still connected. I can't tell if its working or not, or adjusted correctly or not. So I'm not sure how to verify the TPS. Any ideas?

Iain
 

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KTM 990 ADV
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The way I used to sync my throttle openings on my old S3 400 Kawasaki triple was to get two flat wood lollypop sticks cut a very small v shape into one end of each just enough to slip over the needle and then let it rest on the underside of the slide and the air inlet of the carb. Then just twist the throttle very slightly to make sure that both are starting to open together, if not adjust untill they are. I dont know if the @ carb design will allow you to do this but if it will it works a treat. You may have to stand off the bike whist someone touches the throttle for you so you can see both sticks at the same time. But you have to be very light on the throttle rotation as its the very first sign of movement thats important. Hope this is of some help.
Tez
 

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My guess is carb linkage wear.

As linkage wears out, the carbs will no longer be synch at medium throttle opening......even if they are synch at idle...
 

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Space Emperor
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Hey Iain, what happened, did you get it fixed? Mine is vibrating like a mofo at the moment. Suspecting the linkage or a bad plug
 

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Discussion Starter · #20 ·
Hey Iain, what happened, did you get it fixed?
Hi Thomas

Haven't done anything in particular to fix it. However since I started this thread the bike now has a Remus silencer, Sachs suspension, new wheels with SM Pro rims and stainless spokes, and Rugged Roads crash bars. I can still feel some vibes, but with time and the modifications I can't remember if they're worse/better than before. It may have all been down to the 6 month layoff and me forgetting just how vibey the XRV is/was. I did a 3000 mile round trip to the south of Portugal at the end of last year, and as I didn't have a sense of humour failure with the bike I consider that the vibes are acceptable.

Iain
 
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