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01 790 hard cold start /cold misfire

3K views 6 replies 3 participants last post by  kiwiraca 
#1 ·
01 790 bonnie:norman hyde peashooter (commando style)
unifilter ,snorkle and baffle removed ,42 pilots ,1mm shim on stock needle ,145 mains .
valve adj right on, carbs in sync

i live at sea level in santa barbara ,calif so it never gets below 50 f in my garage .

trying to start the bike with the choke out most of the time it won`t start .push the choke back in, block the air intake (where snorkle used to be )it will fire up straight away ,pull the choke out now it`s running and it goes to fast idle like it should .if i push the choke in too soon it will misfire a bit on first part of throttle.once the engine is up to temp it pulls strong everywhere.

does anyone know whats going on here, thanks tony
 
#2 ·
no reply ,does this mean nobody know or has it been addressed somewhere here already .i`ll admit as i have a few different bikes i`m not on here all the time ,but i like my bonnie and could use your help ,if it helps as far as the jetting specs i have this is the style straight through mufflers i`m using thanks tony
 

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#3 ·
I don't have the knowledge to help you with your issue too much but i just want to point out that your carb jetting seems high for an airbox, no matter what you have done to it.


I have pod filters and run 140 mains 42 pilots. this was reccommended by british customs.

145, 42 seems high for your setup and is not recommended by most of the jetting guides on this site or elsewhere

I'm not sure if this is related to your issues or not but it's just an observation
 
#4 ·
+1 on what BBNYC says.

Your running way too rich with 145/42's with the mods you have.
Really you should be looking nearer 120's or 125's max.
IMHO no need to change the stock 40 pilots.

May be an idea to get that sorted and see how it goes from there.






V.
 
#5 ·
yes i agree i seem to be to rich .i was going by the jetting guide lines on TJP site but i guess i missed the boat ,but looking back at it, it would appear that they are suggesting richer for the 790 than the 865 .going by there guidelines 790 135 42 1 shim 3turns out
865 125 40 1 shim 3turns out .should i stick with 865 spec ,is there stock needle the same as 790`s ,thanks guys
tony
 
#7 ·
jetting ?what about nology profire ?

ok , due to popular opinion i went leaner on my jetting 125 ,1 .5 shim on needle left 42 pilots in .bike does not pull as strong in the middle ,i pretty much had to rev the piss out of it to make it jump where as before it pulled strong (considering what it is)through the middle and to the rev limiter if i did`nt shift in time .i`m going back to 2 .5 shims under the needle for now and leave the mains at 125 to see how it pulls.cold starts with choke still very inconsistant maybe even longer warm up time till it stops sputtering .from you 790 owner any tips .on another note i was told by a guy that the nology profire coil make a big difference everywhere,what is your experience? thanks tony
 
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