Carb balancing

[Coyote]

My plan to give bikes a break is not working.

The VFR is running worse than I remember. The front right cylinder is running as if there's a hole in the exhaust, or it's not getting enough or too much fuel, I don't know. Something is happening that I'm not qualified to diagnose.

Looking through the Haynes manual I got for it, my bike is long overdue for a carb balance and it looks easy enough to do. It might help the bike run better. Only I don't have the gear. Can I get the gear cheap from anywhere or does anyone have some kit they're willing to lend me for the weekend?

[breakaway]

You can make a carb balancing kit, with a reasonable length of plastic tubing, water & food coloring.

Cut a piece of plastic tubing (4 metres long maybe? probably even longer) and then fold it in a U shape. Put colored water down it, and mount it on a wall or something like so:



While tuning the carbs, try to get the two levels in line with each other.

Then hook either end into the bike. Make 2 of these since you have 4 carbs.

[Coyote]

You can make a carb balancing kit, with a reasonable length of plastic tubing, water & food coloring.

Cut a piece of plastic tubing (4 metres long maybe? probably even longer) and then fold it in a U shape. Put colored water down it, and mount it on a wall or something like so:



While tuning the carbs, try to get the two levels in line with each other.

Then hook either end into the bike. Make 2 of these since you have 4 carbs.

Awesome. Was going to mention possibly making my own system but I thought I'd get laughed at

The water shouldn't get sucked into the engine, right?

Think I'll only need the 1 since the manual says to balance 1 carb with the one next to it, then the one next to the last, etc. I'll read it again to make sure though.

[breakaway]

The water shouldn't get sucked into the engine, right?

Nope, that's why you have a large amount of clear hose.

Think I'll only need the 1 since the manual says to balance 1 carb with the one next to it, then the one next to the last, etc. I'll read it again to make sure though.

Correct, my bad.

[Coyote]

Nope, that's why you have a large amount of clear hose.

Correct, my bad.

Excellent. I'll pull the bike apart to see what size tube I'll need, then head into Mitre 10 tomorrow.

I'm assuming the tube has to be an equal length from each carb?

[breakaway]

I'm assuming the tube has to be an equal length from each carb?

Negative.

[jonbuoy]

Carb balancing is supposed to be the very last thing you do, only do it when your 100% the ignition, carb jets and valves are A OK. Out of balance carbs will give you a rough idle and vibes as will a lot of other things. You'll only add another variable if you mess with them now.

[Coyote]

Carb balancing is supposed to be the very last thing you do, only do it when your 100% the ignition, carb jets and valves are A OK. Out of balance carbs will give you a rough idle and vibes as will a lot of other things. You'll only add another variable if you mess with them now.

Oh dear. Course this wasn't going to be easy.

I'll give the manual a further read. Though I'm pretty sure I'm incapable of dealing with carb internals.

Wouldn't be surprised if the charging system is the problem. Often the electrics will die for a second then come back to life. Lights go out, engine cuts out, etc.

[jonbuoy]

Oh dear. Course this wasn't going to be easy.

I'll give the manual a further read. Though I'm pretty sure I'm incapable of dealing with carb internals.

Wouldn't be surprised if the charging system is the problem. Often the electrics will die for a second then come back to life. Lights go out, engine cuts out, etc.

Checked your battery connections mate? Negative should clamp onto the frame somewhere. I honestly wouldn't fiddle with the balancing or any other carb screws just yet.

[Coyote]

Checked your battery connections mate? Negative should clamp onto the frame somewhere. I honestly wouldn't fiddle with the balancing or any other carb screws just yet.

Checked them several times. Doesn't seem to be the problem.

All the electrics are a mess on the thing. Wouldn't be surprised if the engine blows since the oil light didn't warn me.

[flyingcrocodile46]

Carb balancing is supposed to be the very last thing you do, only do it when your 100% the ignition, carb jets and valves are A OK. Out of balance carbs will give you a rough idle and vibes as will a lot of other things. You'll only add another variable if you mess with them now.

What he said.

Check/clean/replace air filter to see if that helps. Also try spraying some engine start around the carb connections to the air fliter and engine (while running). If revs increase, then you have a vacuum problem (air leak). (edit)... check that the spark plug caps are properly connected to the HT leads... if in doubt, try unscrewing the caps from the leads, trim 10mm off the ends of the leads and screw the caps back on.

[Squiggles]

Checked them several times. Doesn't seem to be the problem.

All the electrics are a mess on the thing. Wouldn't be surprised if the engine blows since the oil light didn't warn me.

Im still offering a GN for it


Yer, carb balancing is the last thing you should do, sort the rest of it, then the carbs.

[Katman]

As a lot of others have said, DON'T fuck around with the carb balance until you're sure everything else is ok.

[koba]

hey black man.
Bring it around sometime this weekend if ya want, just sort a time first.
May not be able to help but you never know...

[vifferman]

As a lot of others have said, DON'T fuck around with the carb balance until you're sure everything else is ok.

Yeah, what he said.
If/when you've got that sorted, and you can find someone knowledgeable and handy to help you with it, you can borrow my vacuum gauges. (Sorry - I don't have the time or inclination at the moment to personally help you).
Don't piss about with home-made ones - if you suck liquid into the engine, you could end up with more problems.

PM me when you're ready. By then I may even have some time/energy/kitchen passes to help you get sorted.