Ignitech programable ignition system maps. Spit back through carbs.

[alfiestorm]

Anyone have experience of these systems.

I have one on my GSXR1100L that has a 1216 Wiseco big bore, Upperton flowed head and a set of Kent cams to suite the flowed head and big bore. The carbs are Mikuni RS38's which I have just ultra sonic cleaned and fitted a genuine Mikuni overhaul kit and exhaust is ss original cobra system from the early 90's.

The problem I have is quite bad spit back through the carbs all four of them at low revs up to 3.5k which makes for a rubbish ride around town. Seems to have become a problem since fitting the ignitech and I am guessing the map that it came pre programmed with is not suitable maybe. I have tried adjusting the advance up and down and only moves the issue to lower down the rev range. Is there a correct map to use for the oil cooled engine. The map that came pre programmed just says GSX. When I had the standard ignition box with one of them advance rotors all was ok however I did used to get the odd spit back now and again.

I am going to check valves clearance's again and cam timing again and dial them in this time. 

Is it possible I may have too much valve overlap?

Has anyone got any settings for the ignitech they could share with me for the oil cooled motors.

Any info will be much appreciated.

[dupersunc]

Sounds like the mixture is too lean at low rpm. 

[alfiestorm]

1 minute ago, dupersunc said:

Sounds like the mixture is too lean at low rpm. 

Thanks for the reply, It currently has 17.5 pilots fitted do you think they should be bigger.

 

[dupersunc]

3 minutes ago, alfiestorm said:

Thanks for the reply, It currently has 17.5 pilots fitted do you think they should be bigger.

 

Thats where I would start. 

The ignitechs are pretty good, and these engines arent that sensitive to a few degrees of ignition at low rpm.

Edited January 3 by dupersunc

[wobblegob]

I get some through the carbs on my gsxr7/12 (with ignitech system) but presumed it was my set up / valve clearances maybe (this is just on the bench)

[clivegto]

I'm running a ignitech on the the 1216cc turbo Harris just on the standard map with no issues. Been wondering if it's waisted on my setup to be honest. 

[alfiestorm]

What dupersunc said about weak low rpm mixture got me thinking. 

When I fitted the overhaul kit to the carbs it came with new fuel mixture screws with all the needle like ends the same length and the ones I took out were all different lengths due to wear over the years. I set the new ones to what the old ones were set to. Will put the colour tune on later today to see what the burn is and set it with that and see what happens.

[rodneya]

I had to go up a size on pilots on the RS36's on my 1170 Kat. Tried to get the bike into local shops to get setup on a dyno, but the few guys that actually knew what a carb was kept giving me the run around. Tried the color tune but its a pain to use. Ended up getting a Koso AF meter and welding a bung into the pipe. At first I was just going to use it stuck into the tailpipe, but this way I can see whats going on while riding.

There is also a lot of bad info around the web regarding tuning RS carbs, especially syncing and fuel screw settings that really made it hard for me to figure out what I needed to do

[alfiestorm]

I have sorted it out it was indeed what dupersunc said weak mixture at low rpm's, I used a colour tune set to get it right. 

Relieved it was just that and didn't have to go further into the engine. The screws are less than a quarter turn out and they were half turn out so these carbs are quite sensitive to adjustments on this fuel mixture screw. 

Thanks for all you advice chaps much appreciated.

Edited January 4 by alfiestorm
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