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-   -   Question on re-jetting cv carb with thunderheader ???? New bike seems fine (http://www.hdforums.com/forum/softail-models/300077-question-on-re-jetting-cv-carb-with-thunderheader-new-bike-seems-fine.html)

ericdiver 12-12-2008 11:56 PM

Question on re-jetting cv carb with thunderheader ???? New bike seems fine
 
Ok got this fatboy from someone, he got it from a "used bike lot" now the other owner could have had a aftermarket exhaust and put the stock to sell it or not, who knows, he said he took off whatever was on the bike (which was a dual exhaust) and put a thunderheader on.... he said he never rejetted the bike.... i just got it.. it runs perfect in my eyes, no popping, no backfires, no decel noises, plugs look tan.... so should I be concerned? I want to rejet it for some reason, because i dont want to screw up the bike, it does not ping or knock, and seems to run strong.... my fear is i rejet it bigger (right bigger for a thunderheader?) and it runs worse..... should i leave well enough alone, I will be adding a high flow air intake will this make a difference??? and does anyone have a jet size i should try..... and i know the picture is not a fatboy that is my old bike.... If the plugs look good and no ping am i good to go???

ericdiver 12-13-2008 11:11 AM

anyone??

krusr 12-13-2008 02:21 PM

1 Attachment(s)
you can reduce the torque dip some by bending in 2 or t 3 edges of the cones like this. Other than that, if it's runnig fine, leave it alone but keep an eye on it.

Attachment 16120

Lundee 12-13-2008 05:43 PM

These bikes are ment to be run rich I'f you need to just raise the needle up . Radius the slide on the front edge, and drill out the hole in the top of the slide. Jets depend on elevation above sea level. So depends on where your at. Raising the needles free.

ericdiver 12-13-2008 08:59 PM

Quote:

Originally Posted by Lundee (Post 4230163)
These bikes are ment to be run rich I'f you need to just raise the needle up . Radius the slide on the front edge, and drill out the hole in the top of the slide. Jets depend on elevation above sea level. So depends on where your at. Raising the needles free.

sorry but.. WUT.....slide on front edge of what... my last harley had a S&S carb so it was super easy to adjust..... so there is not a screw i can just turn, i will have to study some pics of the cv carb.... but if someone has some suggestions or easy quick ideas they are welcomed

tmitchellof PG 12-13-2008 09:02 PM

I would say you are good to go.
Tom

ericdiver 12-13-2008 10:00 PM

Quote:

Originally Posted by tmitchellof PG (Post 4230675)
I would say you are good to go.
Tom

Thanks, the bike in the sig, had more whiteish plugs and pinged, i sloved it by not messing with the jets, but going to autolight 64, one step colder.... and pulled the plugs one week later and they where perfect tan and no more ping (after weeks of messing with the screws)... i am going to put new plugs in this new bike (to me) and run it and do the turn off at 3k trick and read the plugs, but my gut says its running pretty sweet, but i do have some blueing at the port of the exhaust just alittle which concerns me, but thunder headers are kinda cheap chrome and i heard this is normal, i also have the chrome heat cover over the thunderheader probally keepin in the heat.....the 96 fatboy i just got only has 17k miles and i would hate to melt a pistion or something.....

Citoriplus 12-14-2008 01:26 AM

If your plugs are tan, I don't think your going to have to worry about melting anything in there. Tan usually means things are nearly perfect.
If you plan on drag racing the thing then I would try to richen it up just a tad, but for a street bike with only an occasional hard stop light take off, your fine.

Buddy7394 12-14-2008 01:44 AM

"I will be adding a high flow air intake will this make a difference???"

Sounds like now you are set ok (now),

but adding the Hi-flow ac will lean it out some. generally when the motor can inhale more, it runs a leaner AFR..

you should check yer plugs after 50 miles after the Hi-flow mod.

If you have a stock jet needle, you can put a .030 shim under the head of it, to richen mid-range..

But hard to say what the bike has already been done, cam ? carb-kit ?
So naming jet sizes is (at the moment) futile..

ericdiver 12-14-2008 07:44 PM

Quote:

Originally Posted by Buddy7394 (Post 4231462)
"I will be adding a high flow air intake will this make a difference???"

Sounds like now you are set ok (now),

but adding the Hi-flow ac will lean it out some. generally when the motor can inhale more, it runs a leaner AFR..

you should check yer plugs after 50 miles after the Hi-flow mod.

If you have a stock jet needle, you can put a .030 shim under the head of it, to richen mid-range..

But hard to say what the bike has already been done, cam ? carb-kit ?
So naming jet sizes is (at the moment) futile..

thanks, could u suggest the best needles sizes if i where to change them.... or which jet to change.... if i pull the jet needle out is it written on it what size it is.... and also i doubt i will mess with the intake, i like the harley one that says FATBOY


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