How are you balancing the carbs?

[matsmith749]

My r80 1984 paris dakar tribute bike has had mikuni carbs fitted - as part of re-commissioning I've been looking at the carbs.

Full clean & rebuild kit done, but idle & throttle pickup a bit too lumpy / vibratey.

Got the idle setting dialed in - but not sure I have the perfect way to balance properley.

I've got no vaccuum take off ports on these carbs, so I've made it up - would appreciate any better advice than me going freestyle!

What I did:

Remove the air pod filters so I can see the slide, backed off the throttle cables to zero on the top of the carbs - then set the idle.

Daughter took over throttle duty, and while twisting slowly I observed one carb slide whilst holding a finger against the other - and set the cable adjuster so that they both start moving at exactly the same time.

Then swapped over - finger on the other / watched the other slide to confirm.

It feels pretty smooth now - is there a better way? Just out of interest - before I started adjusting, left carb slide was rising 5mm (ish) before the right carb slide moved - no wonder it felt lumpy!

 

[Stirlingmoz]

You could always use one of the snail type vacuum gauges.



At idle, stick it the back of one carb and then swap to other side and compare readings.

No vacuum take off port required

 

[scooter paul]

My r80 1984 paris dakar tribute bike has had mikuni carbs fitted - as part of re-commissioning I've been looking at the carbs.

Full clean & rebuild kit done, but idle & throttle pickup a bit too lumpy / vibratey.

Got the idle setting dialed in - but not sure I have the perfect way to balance properley.

I've got no vaccuum take off ports on these carbs, so I've made it up - would appreciate any better advice than me going freestyle!

What I did:

Remove the air pod filters so I can see the slide, backed off the throttle cables to zero on the top of the carbs - then set the idle.

Daughter took over throttle duty, and while twisting slowly I observed one carb slide whilst holding a finger against the other - and set the cable adjuster so that they both start moving at exactly the same time.

Then swapped over - finger on the other / watched the other slide to confirm.

It feels pretty smooth now - is there a better way? Just out of interest - before I started adjusting, left carb slide was rising 5mm (ish) before the right carb slide moved - no wonder it felt lumpy!

Back in the Stone Age that’s pretty much how I used to balance, say, Bonneville twin carbs. My carb balancing tool was two lollipop sticks. One under each slide. Watch them move as the slide went up.

 

[barny]

Similar to above, I would start with a drill about 3mm and drop the slide down to that,adjust the cables to that point so they are both opening the same amount and synchronized at that point. Then adjust the idle. DON'T run the engine with drills in place.

 

[matsmith749]

Thanks - I’m liking the sound of something like lollipop sticks, that’s a great idea.

Feel like that would be quite a bit more accurate than my eyeball & finger combo

 

[dean0n0]

I used pencils.