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SSI29d on 250 M3 NC
Posted: Sun Jul 30, 2017 1:12 pm
by Bevel bob
I have for a long time suffered with jerky running on very small throttle openings, I have tried adjusting the pilot screw while riding in this condition, weaker or richer just makes it either die or worse. A little more throttle and its fine. I have tried a bigger cutaway slide but did not help. I think the problem may be float sealing or level. Anyone sorted someting similar.
Re: SSI29d on 250 M3 NC
Posted: Sun Jul 30, 2017 3:46 pm
by Jordan
Running an SSI carburettor can be a nice hobby.
For a change, I put on a VHB square slide type.
I can report that starting and idling is vastly better, and it progresses more smoothly as the throttle is opened.
I wish it looked racy like the SSI though.
Re: SSI29d on 250 M3 NC
Posted: Mon Jul 31, 2017 12:59 am
by CaptonZap
Bevel bob wrote:I have for a long time suffered with jerky running on very small throttle openings,.
Is the slide worn, and a loose fit in the bore?
Since most of the time, on road bikes, the slide is down, the constant pulses of the induction force causes wear on the lower portion of the slide and bore, which changes the suction on the jet as the slide slops around, and air leaks around it, changing the mixture, thus the power produced. Which equals jerking.
CZ
Re: SSI29d on 250 M3 NC
Posted: Mon Jul 31, 2017 8:47 am
by Jordan
CaptonZap wrote:Bevel bob wrote:I have for a long time suffered with jerky running on very small throttle openings,.
Is the slide worn, and a loose fit in the bore?
That sounds reasonable, but my own SSI had a brand new slide in a body that is not too worn.
I'm not saying I'm a carby master, but I tried several different combinations of jets and adjustments with only passable results.
It could be that it is a racing carburettor, not optimised for perfect running at low revs.
Has anyone obtained really good all-round results with an SSI ?
Re: SSI29d on 250 M3 NC
Posted: Mon Jul 31, 2017 9:18 am
by Bevel bob
The slide and carb are a good fit and if weakness were the problem then I would be getting spitting and popping, No its too rich, but only just off tickover. I will be working on the float seating first and if this has no result then will try to lower the fuel level a fraction ,still on the lookout for a sensible cam (grey prefered) as this could also be the dreaded reversion rearing its head.
Re: SSI29d on 250 M3 NC
Posted: Fri Aug 04, 2017 1:12 am
by Vintmoto
I must say I was expecting more issues based on what I had heard when setting up my 29D. I used stock settings with a new 60 slide, needles, and jets and the thing runs amazingly well. From idle too red line. It won't idle real low which is fine considering there is not much oil pressure at very low revs.