ok, 91 heritage. when i got the bike it had some short pipes with no baffles and the bike ran good. the pipes just didn't fit the look of the bike and were way to loud on the highway, so i swapped pipes to a set of V&H longshots.

my question is this, with my new pipes (longshots) with the stock v&h baffles, and i have a K&N air filter with the stock cover, is there anything i need to be careful of or look out for when i rejet this bike?

it seems that the PO did drill out the plug over the mixture screw, so that's cool. but from what i can tell, the bike was never rejetted. i ordered the cv performance deluxe tuning kit so hopefully that has everything i need.

i'm pretty good at rebuilding carbs, done it for years on my old vw's, but was wondering if there was anything that i need to be on the lookout for. also, i have a jet gauge so i will check the jets that are in the carb and see what size are in it already, not really sure how much to go up on the jetting. right now at about half throttle the bike just falls on it's face (around 2500ish rpm) at a little over 3/4 throttle the bike comes back alive and runs good up to around 5000 rpm. i did try 4th gear 45mph and hammered the throttle. bike falls flat, after a second it'll catch and run pretty good up to around 60mph, there it falls again. at 60mph (still in 4th gear) if i let off the throttle a little the bike will accelerate again.

also tried pulling the enrichment out a little. at about 1/4 out the bike doesn't fall on it's face at all and runs great thru all the gears.

 

Sounds lean to me. All bikes are a little different, but there are some settings to get you started. Because the idle mixture plug has been drilled it is a good idea to see what you have inside. There are varying opinions and you will read 45 or 46 as a staring point for the idle jet. You will also see people running 48-50 on the idle jet. A Sportster needle is common and a main jet can be anywhere from a 165 to a 180. There is a company that makes a needle to replicate the Sporty needle, but I cannot recall the name at the moment, others will likely chime in. The fact that it runs good with a slight tug on the chock tells me it is lean. Other things to check are the accelerator diaphragm and the rubber boot under the cap. I would also pull the carb and check or replace the rubber grommets where the intake mounts to the heads. One other item, if it still has the plastic fuel inlet replace this with a brass fitting, the plastic will crack. I would bet you are close and with a little tweaking you will be set. The CV is a great carb.

 

well as long as the po didn't drill out the slide you wont need the sporty needle , as for the CV P kit it should have all you need , do you know if anything was done to the engine besides pipes & AC ? from the way you saying it's falling flat I would start with the 46 slow jet & 175- 180 on top end jet , & like said above double check the rubber boots the carb mounts in & the diaphragm in top of carb

 

These are classic symptoms of a lean mid range. You are going to have to shim or replace the needle. The needle controls throttle in the 1/4-3/4 range. Main Jet is 3/4 to full throttle and it's recovering in this range.

The slow jet controls idle to 1/4 throttle.

The CV kit should have a new needle and larger main and slow jets. I suggest you replace the needle and go up a size on the two jets. You shouldn't need a jet gauge as the jets are numbered and very few poeople drill jets.

From memory, I think your stock jetting should be 42 slow and 165 main. I'd replace with 45 slow and 170 main and replace the needle. If there's no needle in the kit, you can shim the stock needle with one or two small washers to richen the midrange.

Verify there are no tears or pinholes in the diaphragm and also verify that the accelerator pump is working and aimed at the center of the carb bore.

 

I have a 48 idle jet. For open pipes with next to nothing baffles I can't imagine going any smaller than that. I still have my idle mixture adjustment out three full turns. It feels right now with that.

I have read that EVOs like it a little lean. I don't know exactly what that means. Lean can be a destructive thing so, I'm sure there's a sweet spot.

Once you get a new idle jet in there back the mixture screw out like 2.5 turns. Then take it for a ride. If it occasionally coughs out on the highway give the screw another 1/2 turn. Then try it again. If it still coughs start trying 1/8 turns out till it goes away.

Then, ride for a bit, cut the bike off and check the plugs to see how they look.

 

thanks guys. the jet kit will be here tomorrow, i'll tear into it in the evening. it comes with a new needle also.

i've dealt with alot of carbs on cars, and looking at the one on this bike i don't think it's ever been apart. the bowl screw heads are new looking (don't think a screwdriver has been in them), all the clamps are factory style. i believe that the PO swapped pipes and air cleaner and just turned out the mixture screw! the bike did run fine before i swapped the pipes out, the plugs were good, it did take it a while to warm up tho.

on the jets i didn't know if the stock jets were marked or not. i know with our weber carbs (for our vw's) some jets are marked some are not. also alot of people tend to drill out jets. i always have to check them to make sure.

the local older harley guru (also works at the local HD dealer) told me that they (dealership) would rejet my bike for $275, BUT he recommended that i do it myself. he recommended the cv performance kit, and said that he would start with a 46 slow, and a 175 or 180 main. sounds as good a place to start as any, depending on what size jets are actually in the carb to start with.

 

ok. here is the update, sorry but it may be long winded.

pulled carb mostly off bike. couldn't fully remove due to enricher. i took the enricher out of it's bracket (btw, the plastic threads were broke in two!) but the enricher would not slide thru between the bracket, head, rocker box, small chicken, and everything else so the carb was left sorta hanging!

what was in the carb to start with: slow jet was a 40 (had been drilled to a 42), main jet was a 170. needle had a circlip on it and was set to the 4th groove. slide hole i believe has been drilled out, the bit that came with the cv performance kit was a tad small , the next size up drill bit was a tad to big. the diaphram was in good shape. the boot between carb and manifold was decent, but could be replaced (will do that when i change the enricher out).

what i did to carb: cleaned out carb as best as i could, replaced slow jet with a 46, main jet with 185 and put in new needle all from cv performance kit (jetting by their guide).

results: wow what a difference. throttle response is immediate. off idle and low throttle settings are very precise, smooth. low speed testing was great, 30mph 4th gear roll on throttle was smooth and progressive pull. 30mph 4th gear snap to full throttle there is a slight (very slight) hesitation and then slide you back in the seat acceleration.

since i don't have a tach and really am not sure of higher rpm's of these motors i did a 45mph 4th gear full throttle run. a snap to full throttle i got the same slight hesitation and then hard acceleration up to 65mph (where i let off). i let off fully on the throttle, no popping/backfiring, just straight decel.

i also did a 55mph 5th gear full throttle and at 85mph i let off. strong acceleration without any hint of slowing.

as far as jetting goes, i think i'm good for now, BUT there are a few problems.

first problem is enricher, i have to change not the cable, but the whole assembly. not sure how to do that or where to get one.

second problem is the mixture screw. installed the ez-adjust screw with washer and oring. it has NO effect at all. all the way in, half way out, almost falling out, there is no change. i idled the bike down to maybe 300-400rpm and still no affect. the butterfly is fully closed at idle, so i just left the mixture at 2 1/2 turns out for now.

 

changed the enricher cable today, pretty easy job. also while i was there i put a new boot inbetween the carb and the intake.

still tho, the mixture screw has little to no affect on the bike. going for a ride tomorrow and if all is well i'll just leave it alone. if not, i'll most likely pull everything back apart and throw a 45 slow jet in and see what that does.

 

Sounds like your getting things dialed in. Your original jetting was way lean.

Make sure there is no dirt, debris or a left over O-ring in the mixture screw housing and port. Make sure that circuit is really clean. I have the CV ez adjust and I don't get much of a change either. You have to have the bike level, warm, idle around 1200 to 1500 and move the idle mix screw slowly while listening for changes. This is where a tach is helpful. Adjust a 1/4 turn, wait, listen (or watch tach), then adjust another 1/4 turn, etc.

Switching the slow jet won't hurt. It's a good idea to see if how it's running now can be improved even more.

I would leave the hole in the piston slide alone. It could be filled with JB weld and redrilled (or filled and a new hole redrilled with the bit from CV performance), but again, I would leave it well enough alone.

Sounds like your new jetting is really close...might consider a 180 main to try instead of the 185, but I would see how things go with the smaller slow jet and watch the pipes and plugs for awhile first. Plug reading is different nowadays from the days of old, but it can still be used as a guide.

A garbage bag wire twisty tie works great for cleaning small holes and ports in the carb. I use a bic lighter to burn the paper off the twisty tie. This does two things: gets rid of the paper cover and softens the metal wire a little.

After burning the paper off, wipe it off, and gently go fishing. Just don't stuff it up something so hard that you break the wire off inside a port. That would be bad....sorry, had to say it. You never know who reads these posts.

Again, it sounds like you are close. The CV performance parts are good stuff. As far as idle, remember evos like 950 to 1050 rpms at idle to keep the oil moving to all the critical parts...beg, borrow, or steal a tach to get the idle at that range.

For now, set the idle by ear, then adjust a touch higher than what you think sounds right. At least you will be covered from an oil flow standpoint (till you get your hands on a tach). YD

 

Couple things:

That needle with the clip is aftermarket and possibly came with its own emulsion tube. If so your new needle may not fit correctly in the tube and be letting a little too much fuel by even at low RPMs, this would also explain why your needle has no obvious effect.

You can also just put the old needle in, those easy adjust ones are handy but unless you are going up and down large mountains every day they are unneeded. Once you have the needle set it does not need to be touched in most cases.

Ds