As part of the maintenance a TB synchronization was in order, as the last time (3years ago), using a comercial one, is deemed too expensive for the frecuency and the results obtained with the home made had been very good, so I got the required parts:
4 6cc descartable syringes
The 4 springs I used the last time (small enough to fit in to the syrynges)
Appropiate diameter hose
Small cardboard to fix the syringes
Wife´s heat glue gun

Assembled as per the pictures

On this one the vacuum distribution prior to synchronization


And here once synchronized

I put a drop of oil on the syringes to reduce friction.
Synchronization procedure is the standart for idle
Hope this helps
Best regards
JAP

very clever...could you feel the difference?

Hi, yes I felt it the last time, a noticeable vibration reduction reduction. During the the last rides, vibration was rising again.
I have not finish the bike yet, guess that I´ll need to change the gearbox seal.
Best regards
JAP

nice job.

Hello japuentes,
The rubber inside the syringes acually moves with the vaccum?

Ed

rotormotored wrote:Hello japuentes,
The rubber inside the syringes acually moves with the vaccum?

Ed

Yes, the vacuum tries to move the pistons inwards, and the spring tend to avoid it, more the vacuum more the inward displacement.
As all the pistons and springs are equal, when pistons are on the same position, the vacuum is the same.
Best regards
JAP

a verry nice and cheep solution jap ......thanks for posting this

it just goes to show ingenuity at work ...!

Nice job !
I may try it as I have access to syringes.

I tried to make a device from plastic tubes, water and so on. It didn't work because it was far to sensitive to differences in pressure and at one stage I got all the water sucked into the cylinder No harm done, but I had to abandon this approach and purchase a commercial unit.
It is a good tool but it has its limitation due to spring tension used and mass of metal rods(pistons) that vacuum has to move. Used with caution and care you can get a good result.

Two things :
a. balancing TB is influences what happens when the butterfly are in closed or neat closed position. This is where air flow is restricted and subsequently important. At open throttle the difference is negligible because the air volume is governed by the diameter of TB.
b. I managed to smooth my bike by eliminating air leaks around the TBs (top and bottom) and all air leaks in the air intake system (both boxes).

Brilliant !!!!

Go straight to the top of the class.

I have the commercial set and it would be interesting to see if there is any difference.

A really good job mate.

Ajays

Ned, you can reduce vacuum force with little plastic vents (aquarium use - very cheap) in each tube. Dont use water in tubes, use light red oil for automatic transmission. Its much more controlable and visible.

Regards

Ned wrote:
a. balancing TB is influences what happens when the butterfly are in closed or neat closed position. This is where air flow is restricted and subsequently important. At open throttle the difference is negligible because the air volume is governed by the diameter of TB.
.

Yes, this synchronization, using the bypass screws, is for the idle range only, while doing it you can see the pistons keeping it in the 950 to 1500 rpm range.
Over 1500rpm the vacuum is to low for the syringe/spring set I use and is not to be synchronized with the bypass screws but with the TB´s linkage ones.
Adjusting the TB´s linkage at home is considered a serious sin.
Best regards
JAP

Ingenious. I have a commercial set but with only two dials, used for my previous air heads so will give your method a go.

GMcQ

nino wrote:Ned, you can reduce vacuum force with little plastic vents (aquarium use - very cheap) in each tube. Dont use water in tubes, use light red oil for automatic transmission. Its much more controlable and visible.

Regards

Thanks Nino,
Yes, I see how that will work. At least it may give me sufficient time to pop the tube out before oil gets sucked into the cylinder.
Yes it will work once the balance is close to being equal. Unfortunately in my case it too unbalanced to keep trying. As it turns out, someone from UK was selling a system so cheaply that I just couldn't pass up the offer

I have a set of Morgan Carbtune gauges (made in sunny Belfast) if you need a lend, Gerard.
I found that they worked well on my current K but could never get a good sync on my last K until I shimmed the valves.
Doesn't make a noticeable difference to normal riding but tick over is a lot smoother and regular.

A good, innovative and cheap solution, JAP.

Comberjohn wrote:I have a set of Morgan Carbtune gauges (made in sunny Belfast) if you need a lend, Gerard.
I found that they worked well on my current K but could never get a good sync on my last K until I shimmed the valves.
Doesn't make a noticeable difference to normal riding but tick over is a lot smoother and regular.

Will take you up on the offer John when the weather improves. See you guys had a drop of snow.

Gerard

Nicely done I have a carbmate with the four taps to let you switch between 1-2,1-4,2-3,2-4, etc, bit more exxy than your really elegant solution! Wish I'd thought of that

I'm curious.. What is BMW's deal with saying 'DO NOT ADJUST THE LINKAGES'? My K100 is WAY off synchronised when sitting at 3krpm, according to my carbmate. if it was a carb'd bike, i'd be adjusting it no problems at all. But folks seem to keep saying you need some kind of lab to do the TB's on the K?

When you adjust the brass screws you adjust the air flow through a bypass and the butterflys should be closed.
When you open the throttle the bypass is effectivly out of action and the air is going through the main part of the TBs and that puts each end of the bypass at equal pressure so no air goes through it. The adjustment of the butterflys don't usually get far enough out to cause any problems and when the butterflys open the vac should be the same or close.
Even a crook coil can effect the air going through at speeds like 3000rpm at no load.

Rick G wrote:Even a crook coil can effect the air going through at speeds like 3000rpm at no load.

Oh good point! I'll check it out on the weekend

crook coil will just make it miss won't it?....

Klompy the grey brick wrote:crook coil will just make it miss won't it?....

Good point, will it missing cause it to suck more air? Probably not! ??

It may make it miss but quite likely will cause imcomplete combustion and so the system may not scavenge properly or at all and more or less air in so less or more vac. You wont get a good pulse at the collector so that will affect the exaust dump etc etc

Adjusting the throttle plates at home is eminently doable. If the mods wish to make it a stick so I don't have to write this down every six months as seems to be the current situation, I will share my experience. Btw, I learned at the elbow of a gent who built and tested the prototypes of the K100 and K75. His technique is sound.

In my experience, over time, the difference between TBs seems to grow, such that to achieve balance while one TB might have the bypass screw only 1/2 turn out from fully bottomed, another TB might have the bypass screw unscrewed a couple of turns from fully bottomed. This is due to mechanical wear of the throttle shaft and plates over time. It happens.

I have also found that a careful TB balance can reduce vibes at operating speeds. Just my experience. You might have a different opinion, but very often when the bike picks up a gritty vibe at moderate speed I put the carb sticks on the TB spouts and, sure enough, it is out of balance. Touching up the balance very often reduces the vibe.

Rendrag wrote:Nicely done I have a carbmate with the four taps to let you switch between 1-2,1-4,2-3,2-4, etc, bit more exxy than your really elegant solution! Wish I'd thought of that

I'm curious.. What is BMW's deal with saying 'DO NOT ADJUST THE LINKAGES'?...

I have an opinion on this ... yes you need a flow bench to accurately set the butterflies and balance the unit, ie all 4 TBs are in synch before they bolt them on the bike. After that, small adjustments are made using vacuum adjustment/bypass screws to compensate for slight differences in performance between cylinders. Yes, they are all slightly different even at the factory assembly level.

The bench flow setting is ABSOLUTE and should not be messed with because if you can't balance the system using the carb balance procedure, something is wrong. After all two adjustments bring into play two variables.

Yes, u can adjust it all but all that you are doing is "balancing out" a problem that should be fixed not "tuned out". Just my 2c worth