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Post by joriff on Jul 8, 2008 21:23:47 GMT
I've read that moving the clip on the main needle is a better way of making it run more or less rich without touching the mixture screws. Can anyone support this and give a quick guide?
All my plugs are sooted. Thanks.
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Post by CD on Jul 8, 2008 21:31:00 GMT
The needle jet only has any real effect above 1/2 throttle. The easiest method (usually) is to lower the float level.
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Post by General Gman on Jul 9, 2008 8:23:49 GMT
Th needle jet works all the way from 1/4 throttle-ish to full bore, so can be worthwile moving the needle up or down to adjust the fuelling.If your plugs are sooted, I would first of all check the float heights - if the fuel level is too highg then it will run rich.Also check the air filter isn't clogged up...
I spent a lot of time fiddling with the needle positions on my old 750 slingshot, and it is mainly a matter of trial and error to get your settings right.
Another thing to check if your bike is rinning rich is the emulsion tubes (the bits the needles lower into) - if they are worn or oval, you'll get nasty fuelling and need to replace them.IIRC, they're about £15 each.
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Post by joriff on Jul 10, 2008 8:29:46 GMT
Thank you Gman, thats some good information, i've read about float height adjustment but cant get my head around it. Something about tipping the carburettor upside down untill the little needle things go in, then bending the wires accordingly? Could you explain this in detail?
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Post by General Gman on Jul 10, 2008 11:33:56 GMT
Joriff.. (takes a deep breath) OK - remove carbs from the bike, and drain the float bowls (there is a drain screw on the side of each float bowl). Remove the float bowls (at this point you'll find that the screws that hold them on are made of cheese, and may have to cut a slot in the screw heads to be able to undo them). Now then..... holding the carbs upright with the floats hanging down like 4 sets of dog's danglies, slowlt start to invert the carbs until the floats *just* flop over.This is the point where you need to measure the float height - before there is any pressure on the valve.Measure from the gasket face on the carb to the highest point of the float.Easiest to use a vernier caliper. IF they need adjusting, you'll see a metal tab near the needle valve - you have to bend this to adjust.Do it very carefully - a tiny bend goes a long way. Once you have the correct float height, put it all back together again and you're done ! Once you are sure that float heights are correct and the emulsion tubes are not worn, then it can be worth trying different needle positions. BTW - pictorial guide to float heights as used by me a few years back when I did mine for the first time of many : www.factorypro.com/tech_tuning_procedures/tuning_float_height_adj_procedure.htmlHTH, if you need any more help, I'm only in slough - we could mebbe meet up. |
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Post by joriff on Jul 10, 2008 14:05:45 GMT
Brilliant, i'm gonna copy that text and print it out!  Should be able to give that a go tonight, i'll let you know how it goes. This would probably be helpful to lots of our members, i often see threads relating to float heights but no-one ever explains it in detail. Thanks again Gman!  |
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Post by joriff on Jul 15, 2008 19:38:36 GMT
Just to update i adjusted and bent the tabs on the float bowls to give a leaner mixture, it does still coat the plugs in a thin layer of soot though.
Next step move clip on needles?
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Post by General Gman on Jul 15, 2008 22:19:11 GMT
If everything else is ok, then yes, worth a try.
Did you the check the emulsion tubes ?
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Post by joriff on Jul 16, 2008 9:11:05 GMT
oops, no i didnt. I'd better check those before moving needles |
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Post by joriff on Jul 23, 2008 14:00:48 GMT
Still haven't got round to checking emulsion tubes etc, but....
Passed my bike test yesterday (woohoo!) so have had the divvy out and put 100 miles on it, checked the plugs and they are BLACK, i mean proper black! cleaned them off this morning and tried to start and it only started on three cylinders, another quick clean and it started, sounded a little lumpy though (cold) and settled nicely after half a mile. I must add i didn't use choke to start it.
This might shed more light on what to check, it was quite smoky...:/
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Post by joriff on Jul 23, 2008 22:35:17 GMT
Ok update:
Got the carbs in bits again, emulsion tube is fine, so i've moved the clip one space in the direction of the diaphram, was this the right way to go? I cleaned off the choke plungers too as they were a bit carpy.
Oh yeah, and a question for Gman (or anyone:) )
What is the correct height?
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Post by General Gman on Jul 23, 2008 23:00:19 GMT
Firstly - yes, you've moved the needle the right way.
Float heights are:
1992 to 1995 bikes - 11 to 13mm
1996-on bikes - 8.8 to 10.8mm
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Post by joriff on Jul 23, 2008 23:05:49 GMT
Thanks, you're like the fountain of all knowledge for these bikes!
Its a 95 so i'll set it at 12 and take it from there.
Thanks again.
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Post by General Gman on Jul 24, 2008 0:43:01 GMT
I looked it up in the manual I had one a few years back, and Jools has a 94 model which I'll shortly be doing a few bits on. funnily enough, one of the problems is dodgy carbs - it hesitates quite badly on full throttle under load, so need to have a good look to see what state they are in. Got to do the shims, too  |
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Post by joriff on Jul 24, 2008 10:43:29 GMT
ah i see, thought it was all stored up in your head! I changed the float heights to 12mm, adjusted the needles put it all back together and forgot to tighten the nut on the throttle cable! hahaha! aaahh! lol! Back to bits it goes! I'd be interested in how you get on doing the shims, is that the valves? Maybe when you eventually do it you could take some pics! |
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Post by CD on Jul 24, 2008 12:17:00 GMT
Sticking/leaking choke plungers are common for causing rich running. A proper clean out and new rubber tips on the plungers is well worth while.
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Post by General Gman on Jul 24, 2008 13:25:38 GMT
ah i see, thought it was all stored up in your head! I changed the float heights to 12mm, adjusted the needles put it all back together and forgot to tighten the nut on the throttle cable! hahaha! aaahh! lol! Back to bits it goes! I'd be interested in how you get on doing the shims, is that the valves? Maybe when you eventually do it you could take some pics! Yes, it's the valve shims.I can take pics if you like, it'll be easier than doing the ones on the ZX9 - have to take the cams out for that... |
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Post by taint on Jul 24, 2008 15:03:41 GMT
Of course Reaper covers the Shims quite nicely on his DVD ;D Highly recommended for the common maintenance tasks. T. |
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Post by joriff on Jul 24, 2008 16:50:04 GMT
They were a little worn actually, more obvious on choke number 1, choke plunger 3 was unaccessible unless i take the carbs apart from each other; not what i plan to do. Expecting these to be very expensive though. I also noticed the idle speed when warm was well under 1k, i adjusted it as per manual to 1200 rpm. After all the work I've done to it, its starting to sound less like a bag of bolts now and more like a motorbike. Going for a road test later to see if the smoke/plug soot situation has improved. |
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Post by CD on Jul 24, 2008 17:29:03 GMT
The choke plungers should not be costly. Try www.allensperformance.co.uk,. But no point not looking at all four. Take off the actuating spindle and the hex choke covers should come out with a suitable socket spanner. |
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Post by joriff on Jul 24, 2008 20:01:24 GMT
checked the plugs after a long run and found them to be grey and not black, must be a good sign! I seem to have lost a bit of power somewhere too, but i dont care as at least it starts and runs now! Still a bit smoky when cold but i don't know if this is normal or not. I'll leave it alone now unless it becomes a nuisance |
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