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View Full Version : Adjusting the idle circuit on carby TB42



melts
10th April 2011, 03:05 PM
hi everyone
I'm looking for a bit of help adjusting the idle circuit on the nikki carby on the tb42. I don't have that much experience with carbies, but what I know is that the carby is running on idle cold and hot. on top of that, i'm getting pretty poor fuel economy to boot.

now i want to also adjust the tappets, dialing them back in, which might be a good idea before i start with the carby, but while i'm doing that, I thought i'd put this post up and see if i can collect some comments while I'm out doing the tappets

timbar
10th April 2011, 03:28 PM
what sort of economy are u getting cause the tb42 isnt an economy engine it can be quite thirsty !!

Ted
10th April 2011, 04:40 PM
Amen to that,
I've got my carby and tappets sorted and have noticed some more km's but I could be imagining it... I noticed a big diff putting more air in the tyres though...

melts
10th April 2011, 05:46 PM
ah, at the moment it seems like its around 24l/100km - just seems to be going through the juice more than before, though the fourbie now does a lot more low speed, stop-start trips than it did a while ago. its more the smell that bothers me, as my mate put it - you can smell the money coming out of that exhaust.

what i would like to know is what the 2 screws are on the carby, accessible from the drivers side. the one on an angle up, thats more toward the firewall - seems to be idle air control. the one coming out perpendicular at the bottom of the carby body seems to be fuel regulation of some sort. it would be good to have that confirmed and a description of how to adjust them to get the idle nice.
i also think some sort of electrical problem is in play with the idle control since the idle will sometimes sit at 1500-1600, usually drops when you give it some revs, and most of the time it'll sit at 1100, which is a bit fast. and a few times i've seen it stutter along at 400-500 for no reason.

anyway, any info on adjustments and the like would be great

timbar
10th April 2011, 05:50 PM
yeah well im getting around 26L / 100km but thats around the city with a tandem traler which is quite heavy