Hi folks,

My 85 K100 seems to be running OK.

It's got 20k miles on it.

I want to reduce the high speed vibrations as much as possible before a long trip.

I have a set of Carbstix that use mercury and 4 glass tubes.

If all the cylinders are within a reasonable balance, is it possible to just tweak them to get better balance without going through all the TB setup from the start?

Just to get them as close as possible.

Gerry

There are quite a few thorough posts here which cover this subject. Using Carbstix and the like, turning the airscrews, you are only synchronising the TBs at idle. This has little affect on 'high rpm' TB imbalance. It would be wise to avoid touching the locked-down 'adjusters' between the TBs without some measure of experience and a fancier bit of kit to do the job with. While it may seem like fiddling here is the magic bullet for the inherent and often chronic tingles at speed of the mighty K, you'd best attempt to lessen these vibes through other ways. Try tightening engine mounts, lubing splines, setting ignition timing - itself a mix of art & magic - and etc. Read on and good luck.

I see what you mean. After 30+ years of familiarity with the boxer twins, I inhereted this K bike and it's so different than the twins. While I love the power, it lacks the laid back cruising of the twins.

It's so technologically unfamiliar that I dread doing anything on it.

I'm afraid that one foul up and I'll be trucking it to some dealer who will rape my credit card.

I understand that doing anything, even checking the engine timing is complicated. But I'll investigate that and if I get brave, I try it.

Thanks,

Gerry

without going through all the TB setup from the start?

No!

and the begining is of rubber

I too am a long-time Airhead lover, since '76, but I dare say that if you stick with it, read, learn and absorb the incredible amount of totally accessable info contained here and in the forum's many varied and willing members, it wlll be a rewarding journey.

Hello Puccini,
I'm also new to the k-bike.

I just balanced my throttle bodies after replacing the rubber mounts beforehand.
The linkage between bodies is set at the factory so that the TBs all shut down at the same time.

The adjustment is the brass screw.

It didn't do anything for my 3,500 RPM +/- vibration, but it was another thing off my list of things to do.

Remember to balance all four of your vacuum tubes to one vacuum before you start adjusting anything - the steps should be in your vacuum gauge handbook.

The valves need to be in adjustment also before you begin.

You may want to have the valve cover gaskets on hand and the rubber mounts for the valve cover bolts (12) also as these may have perished over time.

The valve cover is an inch-pounds torque setting so don't over-do it.

Cheers, M

Like your operas by the way.

The major difference between the older twins and the K is only the electronic ignition/electronic fuel injection.
Both are mechanically built like a "Panzer"
The life span of the K bike is even greater than the one of the 'old' boxer because of technology advancement.
As Guest in the house (AKA TWB) said, we have numerous members ready to help.
If you are a little bit mechanically inclined, maintaining a K bike will be very easy.

zonenfeile wrote:



No!

and the beginning is of rubber

And of course a lot of beginnings is due to a hole in the rubber...

Always check before use!

Inge K.

Crazy Frog wrote:The major difference between the older twins and the K is only the electronic ignition/electronic fuel injection.
Both are mechanically built like a "Panzer"
The life span of the K bike is even greater than the one of the 'old' boxer because of technology advancement.
As Guest in the house (AKA TWB) said, we have numerous members ready to help.
If you are a little bit mechanically inclined, maintaining a K bike will be very easy.

I have to tell you that I am prepared to venture further, in the home maintenance realm, because of the help supplied by this forum.
Thank You!

[quote

And of course a lot of beginnings is due to a hole in the rubber..[/quote]

I have a Haynes shop manual for my K100RS and read through the section re tuning the TB. However, I don't see any mention of what the nomimal "base" setting of the little brass adjustment screws should be. On the old airhead BMW twins the Bing carb settings is 1 1/2 turns out from fully seated. Is that also true for the TBs on a 1985 K100RS?
After having the fuel injectors reconditioned, the engine doesn't want to start nor idle well. Prior to that, it started and ran like the proverbial top....

brickrider wrote:I have a Haynes shop manual for my K100RS and read through the section re tuning the TB. However, I don't see any mention of what the nomimal "base" setting of the little brass adjustment screws should be. On the old airhead BMW twins the Bing carb settings is 1 1/2 turns out from fully seated. Is that also true for the TBs on a 1985 K100RS?
After having the fuel injectors reconditioned, the engine doesn't want to start nor idle well. Prior to that, it started and ran like the proverbial top....

Have you checked the vacuum line from #4 Cyl to the Fuel pressure reg? Ditto the rubber hoses from the air box to the cyl's. I would suspect a vacuum leak after disturbing the fuel delivery. Does it back-fire on hard deceleration (lean)?

I'll check the Clymers manual and see if there is a base setting. If you have a set of vacuum gauges, put them on and see if one cyl is way out-of-wack with everything else (large vacuum leak).

Cheers, M

I have replaced all the rubber hoses in the fuel delivery system. They are new and consequently in fine condition. I checked the TBs with my mercury gauges and the they seem to be correct. One thing that I noticed however, turning the brass screw on the TB does not seem to do much -- on the carburetted bikes I'm used to, a small change in the adjustment screw is registered immediately on the gauges. Is this typical of fuel injection systems?