vacum testing

[Wayne1960]

Guys is there a forum topic that describes how to vacuum test Mikuni 26mm carbs? if not can anyone point me in the right direction?

[chrisu]

There is

I did one

[Wayne1960]

Hi Chris

can you recall the title?

[chrisu]

it was a few years ago.

if you pm me i'll send the word doc version I did.

Maybe it only went into the magazine - can't remember to be honest

[ADRIAN H]

in downloads page of the site below - link to MIKUI VM tuning manual

http://www.classickawasaki.se/

[Wayne1960]

Thanks Adrian the Mikuni in the downloads is different to my VM26

[RALPHARAMA]

I take it that by vacuum testing you mean synchronising the carbs using vacuum gauges?

I am planning in the not too distant future to be making a video tutorial for http://www.bikerstoolbox.co.uk, just waiting for the star of the show to be well enough! I can't shoot video and demonstrate stuff simultaneously I have tried I'll be demonstrating at least two types of balance systems and I'll most likely use my Z1000 or Z900 for one!

It's not rocket science:
1. Remove all the carb tops (3off 4mm screws)

2. Remove the caps off the vacuum take-offs and connect the vacuum gauge pipes to all four in line.

3. Warm the bike up and set it running at the tickover speed. You might have to adjust it more than once as the procedure continues.

4. Decide on one pot as being in the midway through it's adjustment and then balance the others to this. Traditionally (don't know why) No 3 was considered this one and on some bikes it was sealed. You will need a carburettor adjusting tool which essentially is a 10mm socket on a tube with a 'T' handle at the top and a long thing screw driver running down the middle. Engage the socket bit on the lock nut and turn it anti-clockwise to release the nut and then make the adjustment with the screwdriver bit until the measurement between the carb you are adjusting and the first one is the same reading. You might start with 3 & 4. You can then move to the next carb and adjust the screw until that is reading the same as the first two, obviously lock the the locking nut each time. As you adjust each carb it will often up set the tick over so you often need to keep adjusting it.

If you find it is taking a longish time, which it might for your first attempt fire up a biggish fan in front of the engine for cooling.;

Cheap dial gauges are shite and are unreliable (usually blue) and inaccurate. I always use a high end electronic Vacuum Mate, but this is not cheap I make a good part of my living fettling bikes so it's well worth me owning and it also determines dynamic vacuum which highlights all sorts of engine faults include poor valve seatings etc.

For carb syncing the best value for money is the Carbtune Pro II. Sadly the nanny state has banned the original Carbtune which used mercury! Most accurate physically possible

If you need any of the above they are all on my website and if you're a PUM you can apply for a Discount Account

[Wayne1960]

Thanks for that and really helpful. I'm looking forward to giving this a go.
What do you recon on me making a tester using bottles and pipe? Looks like it will do the trick or am I cutting corners?

[chrisu]

+1 on the Morgan carbtune

[RALPHARAMA]

Thanks for that and really helpful. I'm looking forward to giving this a go.
What do you recon on me making a tester using bottles and pipe? Looks like it will do the trick or am I cutting corners?

Why risk trashing a classic engine for the sake of a few quids worth of tools you'll need every year.

[Wayne1960]

Ok thanks

[chrisu]

Thanks for that and really helpful. I'm looking forward to giving this a go.
What do you recon on me making a tester using bottles and pipe? Looks like it will do the trick or am I cutting corners?

Why risk trashing a classic engine for the sake of a few quids worth of tools you'll need every year.

Ralph - the voice of reason................