View Full Version : Carb balancing problems
echomadman
14-09-07, 06:10 PM
I tried balancing my carbs last weekend to sort out a lumpy idle and to see if the bike would stop popping/backfiring when idling. however i ran into problems.
I was using a set of carbtune gauges, basically the front cylinder pulled the rod right up to the top of the gauge and the rear cylinder hovered around 1/3 of the way up. no amount of adjusting made any improvement and pretty much just made the backfiring at idle worse.
Anyone got any ideas as to what could be causing it? i checked the hoses from the carbs to the gauge and they were fine.
yorkie_chris
14-09-07, 08:32 PM
See if theres loads of slop in the linkage arm, dizzyblonde had this problem where the pivot was worn to the extent that all the adjustment in the screw was used and the rear throttle was still shut tight.
Also, this is just a theory, but if the idle screw was set very low, and the adjustment very far in, then the rear pot would be opening and hence drawing air, with the front carb shut and just making lots of vacuum.
If you actually look at the throttles and check they are both open slightly when the throttle is closed then this should give you a bit of an indicator.
Please bear in mind that the above advice is given by me and may well be total rubbish :rolleyes:
Chris
Spanner Man
15-09-07, 06:52 AM
Morning all.
Ditto Yorkies advice on checking the linkage for wear. Also make sure the carbs are correctly installed, as any air leak could give you the symptoms you describe.
He's right about the idle adjustment too (clever cloggs). I have seen bikes where people, thinking it was the idle adjuster, have adjusted a balancing screw to the point where one cylinder is actually not running due to the butterfly in the carburettor being fully closed. It's an issue more commonly found on multi cylinder bikes, but check it carefully all the same.
Cheers.
yorkie_chris
15-09-07, 04:27 PM
(clever cloggs).
:D
But not that clever, can't even get mine to start...
Spanner Man
17-09-07, 06:43 AM
Morning all.
Still having trouble getting yours to go Yorkie? Have you bypassed the kill switch? & made sure that all connections (ignition switch etc) are clean, as don't forget that corrosion on terminals can allow voltage through, but not current. So your meter will read the voltage at say the ECU, but the corrosion will not allow adequate current through when under load.
Cheers.
yorkie_chris
17-09-07, 04:31 PM
Sorted it mate, exactly as you said, was a broken wire below the ignition switch.
No can on it at 11.30 saturday night, the exhaust full of fuel from trying to get spark and it fired up... muahaha ... nearly set my kecks on fire and mae my ears ring but sounded great!
Chris
Spanner Man
17-09-07, 04:50 PM
Evening all.
Good show Yorkie! I'm glad it's sorted at last:D
That explosion of fuel in the exhaust made you jump I'll bet! At least the neighbours didn't ring the bomb squad eh!
Cheers.
yorkie_chris
17-09-07, 10:41 PM
bomb squad eh!
Cheers.
My reputation preceeds me
echomadman
09-01-08, 12:08 AM
late with the reply but it turned out the choke plunger on the rear cylinder was jammed, choke was half on all the time.
I stripped and rebuilt the carbs and took the opportunity to drop in a jetkit while i was at it. bikes running much better now, no more popping and banging at idle, although its harder to start in the cold now.
yorkie_chris
09-01-08, 09:20 PM
Just shows you can't assume anything (like that they'd be working), to tell the truth when I've seen SV's do this its usually been held open just a fraction, not much effect on balance just running rich.
Apologies all for draggin up this thread, Recently went to get my own carbs balanced and was told my linkage arm was way to loose and it made the balance near impossible, i wont shock you all with the details of how they resolved this but it seem to have semi done the job, however i was advised to get this resolved. however i have no idea what the heck i should be replacing.
There a few folks selling carbs down in the for sale forum, but i get the feeling i need more than just the carb pots, do i need the entire housing around them ?
Pics would be great also,
yorkie_chris
29-01-08, 02:44 AM
You can get the linkage arm from suzuki for about £19
It tends to be the bushes in the arm that wear, not the shafts on the carbs themselves.
And the linkage arm i what controls the flow of juice in to the carbs ? is that correct ?
If so, then i could just replace it i guess, but i was told that there was what seemed to be sand around some of the carbs also, I guess untill i take as look my self i wont know.
Would have body have a part number handy for the linkage arm ?
And the linkage arm i what controls the flow of juice in to the carbs ? is that correct ?
If so, then i could just replace it i guess, but i was told that there was what seemed to be sand around some of the carbs also, I guess untill i take as look my self i wont know.
Would have body have a part number handy for the linkage arm ?
Look in:
http://www.alpha-sports.com/suzuki_parts.htm
dont want to see lazy here, but i've actually already been on there looking, but still have no idea what part i should be ordering, i've looked at the carbs and the carb fittings but cant identify the linkage arm sorry folks :(
ELR4ever
29-01-08, 10:43 AM
late with the reply but it turned out the choke plunger on the rear cylinder was jammed, choke was half on all the time.
I stripped and rebuilt the carbs and took the opportunity to drop in a jetkit while i was at it. bikes running much better now, no more popping and banging at idle, although its harder to start in the cold now.
Echomad,
Probably last thing you want to do right now, but, try a pair of those dual prong spark plugs, they are supposed to aid starting, and seem to do the job on mine. Cheers -D
dont want to see lazy here, but i've actually already been on there looking, but still have no idea what part i should be ordering, i've looked at the carbs and the carb fittings but cant identify the linkage arm sorry folks :(
I think it's called the lever assembly, part
13553-19F00 (http://www.alpha-sports.com/spart.php?part_number=13553-19F00)
item 19 in the list associated with the carburretor fittings.
approx £31. But you will need to check that.
yorkie_chris
29-01-08, 11:01 AM
And the linkage arm i what controls the flow of juice in to the carbs ? is that correct ?
If so, then i could just replace it i guess, but i was told that there was what seemed to be sand around some of the carbs also, I guess untill i take as look my self i wont know.
Would have body have a part number handy for the linkage arm ?
The linkage arm doesn't control the flow of juice per se, it controls the restriction to air flow through the rear carb, the front carb being controlled by you. The carbs then meter an amount of fuel into the air.
Keith1983
29-01-08, 11:11 AM
the easiest solution would be to buy my injected k6! carb problems eliminated!
yorkie_chris
29-01-08, 11:14 AM
the easiest solution would be to buy my injected k6! carb problems eliminated!
Because throttle bodies never need balancing! :rolleyes:
Keith1983
29-01-08, 11:19 AM
i simply said carb problems eliminated, I never claimed that others wouldnt take their place!
I think it's called the lever assembly, part
13553-19F00 (http://www.alpha-sports.com/spart.php?part_number=13553-19F00)
item 19 in the list associated with the carburretor fittings.
approx £31. But you will need to check that.
I'll have a snoop about here for that part so, altho im thinking i'd be safer off replacing the entire carbs and housing if i can get a better set.
The linkage arm doesn't control the flow of juice per se, it controls the restriction to air flow through the rear carb, the front carb being controlled by you. The carbs then meter an amount of fuel into the air.
So the throttle cables dont control the linkage arm, i was under the impression what ever the throttle cables connected to, that was the loose part, of course in saying that, i've yet to take off the air box and investigate my self.
What a decent price for a set of carbs would ye say ? ball park figure
yorkie_chris
29-01-08, 11:33 AM
Throttle cables go to the RHS of front carb, then theres a shaft out of the LHS of front carb, this connects to linkage arm, linkage arm connects to rear carb.
Evening all.
Good show Yorkie! I'm glad it's sorted at last:D
That explosion of fuel in the exhaust made you jump I'll bet! At least the neighbours didn't ring the bomb squad eh!
Cheers.
Not much point in ringing the bomb quad after the bang! har har
Okay... I'll get me coat.
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