Carb balancing

[marlbororman]

been reading workshop manual. Am i right in assuming this is the connection for the front cylinder?




Edit... I presume its the alen bolt just below the carb clamps in this pic ( roughly in the middle of the picture)



Also, i have a scott oiler, fed on a T peice, near the tank vac feed ( the pipe that always gets put on the overflow drain pipe ) Would i be right in assuming this is a good point to tap in for rear cylinder? i.e. unlug feed to scott oiler, plug gauge in?

It dont look bad job to do, plus got chance to borrow vac gauges Just not hundred percent on the connections

[tony.mon]

Yes, that's the front cyl take-off point.

If you've got a scotoiler fitted, half the job's done.
All you need to do is connect to teh front one, then you're away.

Remember that the fuel tap needs a vacuum, so you can't just disconnect it, as the level in the float bowls drops and you don't get an accurate setting, and after a while the engine stops anyway.
So raise the rear of the tank, and before you disconnect anything clamp off the pipe going to the tap from the tee piece.
Now disconnect the pipe from the rear cyl going to the tee, and use that to connect the balancer.

The clamped pipe stays on the tank, so that fuel will continue to flow properly.

Personally, I lift off the tank and reconnect it laying on the rear of the bike (careful, it'll slip off easily, a helper or strapping it on is a good idea) then connect the carb feeds the wrong way round (right to left) and the vac one's already there, of course, because you clamped it off and left it in place.
The two drain ones don't matter while balancing.

[marlbororman]

Yer already sussed i need to start the bike and clamp that vac pipe, or bike wont run properly. everything else i should be able to get i think without actually turning the tank round,Just undoing front bolts and rear bolt so i can lift slightly to get to the vac pipe. Just didnt want to connect into the wrong connection for the front. I understand everything else. Cheers for confirming what i already suspected. i Think i`ll give this a go, will pm my mate to see if he has the adapter to screw into the front take off point

[benny hedges]

much easier to do with the tank off as the balancing screw is a bitch to access with the tank in it's normal place....
the balancing screw is on the left, halfway along the tank - there's a clear pic of it in the manual.

you will need the engine at it's normal operating temp to get an accurate setting, and also increase the idle over 1500.

mine was absolutely miles out the first time i set it - surprising as it was supposedly serviced before i collected it from hunts
you will definately notice smoother running and pick-up once it's done.

if they are a mile out, it could indicate an air leak at the intake rubbers or a badly fitted or damaged carb diaphragm...
my gauge also has a scale that indicates possible engine problems depending on the level of vacuum... it suggested mine has a problem with cam timing, and inlet valves opening too early.
i checked this obviously and found it was fine, i think the reason i have lower vacuum than expected is due to the drilled slides a'la dynojet...

manual says the normal vac level is 20mm/hg but mine is more like 10

[marlbororman]

Well i cant really tell if they are out or not at the minute, as ive owned the bike since 2005/2006 and ive never had em done , im expecting them to be way out

I guess i`ll notice a big difference when ive done em. I just sms`d me mate but i guess hes at work coz he aint replied yet lol.

[sirch345]

Just to be completely different

For adjusting the carb balance on the Firestorm, now being familiar with getting to that awkward to reach adjuster screw/bolt on the Firestorm I find I don't need remove or even raise the back end of the tank.

I don't use a screwdriver to do this as this is more inclined to increase the rev's (which you don't won't) as you push the s/driver against the screw/bolt head. I use a 1/4 drive socket with the universal joint and a couple of extensions attached to a screwdriver type of handle. I find this works very well.

Chris.

[benny hedges]

just another tip - give it a good revving between adjustments and let it settle down before touching the screw again - makes a difference.
you might think you have it spot on until you rev it... miles out! ask me how i know!!!

just been at mine again cos i had a oil leak from the breather on the front cam cover... i think it's because of the breather covers that came with my k&n... i used the same covers with the bmc but it isn't doing me any favours so i've took them off.
daft idea imo, the breathers are there for a reason...

gone down a size on the mains as well and set the mixture up proper - the old way...
i pulled one plug cap off, set a high idle running on one cyl, then turned the screw til it idles at it's highest point.
same on the other pot.
dynojet recommend f&b 2 1/2 turns but the back one is nearer 2 while the front is set at 2 1/4.
when i ran it on both cyls the idle went up from 2k to 4 1/2 lol. before i set them it was huffing and puffing at 1200 - better response when snapping the throttle too, it was hesitating a bit with it set at 2 1/2 each.
giving it a clean then i think i'll go for a run out to rhyl to annoy some coppers seeing as i am all legal

[marlbororman]

well my mates sorted me out with a nipple for the front take off point, will get that fitted tomorrow, tank will be coming off anyway, to get at the pesky allen head blanking bolt cant get on it otherwise

[tony.mon]

That blanking bolt's a pain to reach.
Save yourself time and finger skin by taking off the airbox and lifting the carbs off, leave them attached by the cables and you can reach it easily.
Only takes a few minutes.

[marlbororman]

Ok, will do, well nipples going on and found a bit of pipe to stay on it, just need to dig summat out to blank the pipe off. Been busy editing video from today, its just uploading as i type

[tony.mon]

Blanking the pipe:
a bolt (leftover one from the end of the CCT's when you've replaced them does fine) with a smear of silicon round the threads.
Or a golf tee.

[marlbororman]

ok cheers.

[timber]

I saw a post somewhere on t'internet that suggested attaching a length of hose (about 8") permenantly to the take off points on both cylinders (when cold). Use a hose connector to connect the balancing tool (T piece for the rear cylinder take off) and blank off when finished (as suggested on this post).
This means you can connect the manometer quicly and easily, without getting burnt hands, and without having to remove the tank (just lifting it with the tool provided).
I know if i had'nt done this, there would have been some swearing coming from my garage!

Thanks to everyone for the information supplied on this site, i'd have been pretty clueless without it.

PS, my bike runs so much smoother after the carb balance, and it was'nt even out by much.