CV Jets ? Topic is solved

Do I have wrong jets in my carb?

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neilw
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CV Jets ?

#1

Post by neilw »

I have a problem with my wide open throttle response . When I'm in 4th ,or 5th gear, and twist the throttle all the way open at higher rpm's, the bike picks up speed, but when I back off 1/8 of a turn I notice a strong increase in acceleration.
My bike runs and starts good, no back firing or hesitation .

It wasn't until I was changing spark plugs this spring ,and noticed they were white that I thought I'd better do something about it .

I started tinkering around , switching jets, emulsion tube, needle jet. pilot jet ,and while I was at it ,I got the aftermarket air adjustment screw that you can turn with you thumb and fore finger that replaces the one under the little plug the factory hides. Oh, I also got a different jet needle . My old one was adjustable, and when I raised it all the way up ( with the little E clip, and washer) it cut out as soon as I gave it half throttle or so
.
Anyway The carb had 45 and 165 jets . I got a few different sizes and started experimenting .
Some combinations made it back fire, others made it hard to start, some had the bike hesitating . when starting off .
I was reading on CV Perfomance's site, where they said the reason my bike picked up speed at 1/8 when backed off from WOT was from running to lean. My white spark plugs confirmed that.

I still have the same increase when backing off 1/8 of a turn on WOT. And I am now using a 52 pilot jet and 195 main jet. That's a lot richer than my original 165. I'm wondering if I put my old adjustable jet needle in at a different height if it might help.
I've had my carb on, and off the bike ,and switched so many things ,I really don't want to keep at it. I also don't want to be running lean again, even though a 195 jet up from 165 should be somewhat richer. I'd be content the way the bike performs, as I said I rarely use full throttle, except I don't like it running lean.

I'm attaching a photo of the air cleaner with K&N filter , and I don't know what those pipes are called but the baffels are drilled out a little. I think 25 years ago I took a 3/8 drill bit ( a bout a 14 inch long one) ,and drilled through the center of the baffels. It isn't real loud ,but louder than any thing from the factory. It also has a 27 Anrdews cam .
The only other thing I can mention besides the slide hole being drilled out to 1/8" is that the bottom front of the slide has been rounded off a little . ( hot bike tips from by gone years) . I mixed and matched 2 CV carbs, and bought a few different jets I've been playing with.
The things that come to my non expert mind is that the pilot jet shouldn't matter here , and maybe by raising the jet needle has to allow more gas into the engine. That's about it . I'll wait and see what replies I get before doing anything farther .
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RooDog
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Re: CV Jets ?

#2

Post by RooDog »

Your very first sentence tells me you need a larger main jet....
....RooDog....
neilw
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Re: CV Jets ?

#3

Post by neilw »

Thanks , that sounds like an easy cure .
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Re: CV Jets ?

#4

Post by flat38 »

The first thing that needs to be done is to do a vacuum leak down test of the hypercharger. The diaphragms tend to leak. I had one with that problem and it made tuning impossible. No matter what I did, it was always lean. After I got rid of it, tuning became much easier.
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Re: CV Jets ?

#5

Post by Panacea »

Does it go POP POP POP upon deceleration?
RooDog
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Re: CV Jets ?

#6

Post by RooDog »

Good point.
neilw
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Re: CV Jets ?

#7

Post by neilw »

Thanks for all the help. No pop,pop when decelerating. and by way of saving removing the air cleaner each time I readjusted something on my cab, I just left it off ,and put a bolt in the vacum line that goes to the air cleaner .
Another thing I notice is the new knock off carb came with the emulsion tube with only 2 holes down near the bottom. they are opposite each other .The emulsion tube that was in the old carb has 8 holes going up the sides of the tube . Did HD change things since 1991 ? ( my bike's a 1991)
I bought this bike in 1995 ,after it had been in a shop fire . I really don't remember all I replaced back then ,but I may have put one of the hop-up carb kits in. Yost power tube, or was one called thunder something or other .
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Re: CV Jets ?

#8

Post by RooDog »

Do you have a trash can, or a recycling bin handy? A good place for that butterfly air scooper while you are sorting out the carb....
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