Carb balancing...

[bikemonkey]

When balancing the carbs do I leave the airbox off and take off the top carb plate to get access?

It seems stupidly hard to get inside the vee even with a angled screwdriver.

It's just taking the airbox etc off seems to me like it would upset the bikes intake and make balancing the carbs like it useless.

[CMSMJ1]

You do it from the bottom....all the top of the bike complete.

[bikemonkey]

Hmm guess I'll have to find a better screwdriver then, the one I've borrowed is quite chunky and won't go in the vee along with my hand.

Blowtorch and an old long flathead it is then

[Neosophist]

you wont turn them by bending a normal screwdriver.

Have the airbox on, tank on everything as normal.

Set the idle to just above normal.. i find 1500 good

http://www.carbtune.co.uk/bevel.html

something like this is excellent for the job but I just use my hands and a 7mm socket to turn the 3 screws, a deep reach 7mm is the best but ive used small ones no problem (but my hands are small)

be warned it gets roasting in the v so be prepared to burn your hands if you opt for that way.

[bikemonkey]

Managed to get them done

Used a 7mm socket like you suggested Neo, very tight fit and quite warm though!

Only problem I have now is my idle is still erratic if I set it below 2k rpm. I read somewhere this could be the plugs? Would make sense seeing as I have no idea how old they are plus they've had alot of abuse.

[Neosophist]

Managed to get them done

Used a 7mm socket like you suggested Neo, very tight fit and quite warm though!

Only problem I have now is my idle is still erratic if I set it below 2k rpm. I read somewhere this could be the plugs? Would make sense seeing as I have no idea how old they are plus they've had alot of abuse.

Not likely the be plugs.. not impossible if one is missfiring, but sicne you mention below 2000rpm most likely are.

1. air leak on carbs
2. dirty pilot ciruit on carbs (very common, even after a cleaning)
3. bad valve clearances
4. bad carb settings (float heights / mixture screws)

[bikemonkey]

1. I've changed the carb rubbers, but could there be an actual leak in the carbs themselves? And where would I look?

2. Possibly, would I have to send them to get ultrasonically cleaned if so?

3. Shouldn't be, I've just done them and they're all in spec.

4. Most likely cause when I think about it, I didn't check the float heights when I re-jetted and the mixture screws are quite lean at 1.75 turns out.


Will get a look at the float heights later today and if that doesn't help then I shall try a small adjustment on the mix screws.


EDIT: Would changing the float heights/mixture screws mean I have to re-balance the carbs after?

[vfrman]

You shouldn't have to mess with the balance unlesss you break the carb bank apart.

[bikemonkey]

Cheers vfrman


Got the float heights set, they were only one or two mm out on each.

Then got the bike started again and it was still erratic, plus I sprayed some GT85 underneath the carbs and the revs rose about 5-600 for a little bit and dropped back down again shortly after.

I'm now thinking the carbs have an air leak. The inlet rubbers are brand new and the carbs are seated perfect.

What does the carbs themselves leaking mean? New carbs, or a full replacement of all seals or something else?

[Neosophist]

Cheers vfrman


Got the float heights set, they were only one or two mm out on each.

Then got the bike started again and it was still erratic, plus I sprayed some GT85 underneath the carbs and the revs rose about 5-600 for a little bit and dropped back down again shortly after.

I'm now thinking the carbs have an air leak. The inlet rubbers are brand new and the carbs are seated perfect.

What does the carbs themselves leaking mean? New carbs, or a full replacement of all seals or something else?

The carbs thesmselves cant really leak unless you put a big hole in them. Never ever seen that.

If your spraying it on the rubbers then there not seated proprely, not tightened up enough or overtightened if it can suck the mixture past the rubbers.

You have put the screws and washers back in the carb balacning ports right?