Author Topic: 29mm cr carb jetting???? (Read 16918 times)

MRieck · « **Reply #25 on:** March 01, 2007, 05:34:55 PM »

Jesse
Here are the offical Keihin CR Special jetting spec for the 29's;
Main Jet 120
Air Jet 250
Throttle Valve 2.5
Needle YY-8
Clip 4
Slow Jet 60
Valve Seat 3.2
Starter Jet 45

I guess I was off on the slow jet....I think I have 60's. Start on the 2nd clip.
Mike

Hockers Choppers · « **Reply #26 on:** March 01, 2007, 07:13:06 PM »

THANK YOU MIKE!! I have 230 main air, #45 slow jets, #35 start jets, I haven,t checked the valve seats, but everything else is right. I really appreciate the help. I don't think the sudco guy will sell me any jets, but I think I can get them at the Honda shop!
Jesse

MRieck · « **Reply #27 on:** March 02, 2007, 05:12:49 AM »

Quote from: Hockers Choppers on March 01, 2007, 07:13:06 PM

THANK YOU MIKE!! I have 230 main air, #45 slow jets, #35 start jets, I haven,t checked the valve seats, but everything else is right. I really appreciate the help. I don't think the sudco guy will sell me any jets, but I think I can get them at the Honda shop!
Jesse

Jesse
The starter jet is fine at #35. That 230 air jet is rich. I have a good assortment of CR jets...I'm at work now but I'll check when I get home.

MRieck · « **Reply #28 on:** March 02, 2007, 02:26:51 PM »

Quote from: MRieck on March 02, 2007, 05:12:49 AM

Quote from: Hockers Choppers on March 01, 2007, 07:13:06 PM
THANK YOU MIKE!! I have 230 main air, #45 slow jets, #35 start jets, I haven,t checked the valve seats, but everything else is right. I really appreciate the help. I don't think the sudco guy will sell me any jets, but I think I can get them at the Honda shop!
Jesse
Jesse
The starter jet is fine at #35. That 230 air jet is rich. I have a good assortment of CR jets...I'm at work now but I'll check when I get home.

I have a set of 240 air jets and #60 slow jets.

Hockers Choppers · « **Reply #29 on:** March 02, 2007, 03:04:58 PM »

Are the 240 air jets what you'd use? Or do I need the 250's? I'll take them, let me know where to send the $.
Thanks a million Mike!!!!!

MRieck · « **Reply #30 on:** March 02, 2007, 05:24:15 PM »

Quote from: Hockers Choppers on March 02, 2007, 03:04:58 PM

Are the 240 air jets what you'd use? Or do I need the 250's? I'll take them, let me know where to send the $.
Thanks a million Mike!!!!!

I'd start with those and the slow jets to establish your baseline Jesse. PM me your address.

Hockers Choppers · « **Reply #31 on:** March 02, 2007, 05:30:15 PM »

Sent!

Hockers Choppers · « **Reply #32 on:** March 07, 2007, 02:48:49 PM »

What exactly do the air jets do anyway? Control the air to the needle jet? So do I need to go down with the needle with the richer air jet? I'm not new to carbs, but new to CR's. How many of you are running these carbs?

Hockers Choppers · « **Reply #33 on:** March 18, 2007, 12:55:39 PM »

OK, I'm ready to put my stock carbs back one! I have the 29's set at

Main Jet 120
Air Jet 240
Throttle Valve 2.5
Needle YY-8
Clip 2 from top
Slow Jet 60
3/4 turns out on the idle screws
Valve Seat 3.2
Starter Jet 35
14mm float height set like the stock carbs, just as the float makes contact with the needle.

Throttle response is not good. won't rev over 6000rpms. get a lean popping. if you down shift and rev it up it will run up to red line but with little power. plugs are looking lean. I'll try bigger mains. sitting on the stand if revs nice if you hold it at 3000rpm. Lots of black smoke? but responds better with the needles at the #3 notch from the top? I guess I'll just take it to the dyno with the exhaust gas analyzer and go from there. I don't understand why it has all the lean conditions, but blows black smoke when I rev it?

MRieck · « **Reply #34 on:** March 18, 2007, 04:28:02 PM »

Jesse
Does the bike idle? If so...do the plugs load up?

Hockers Choppers · « **Reply #35 on:** March 18, 2007, 04:51:08 PM »

starts and idles nice. loads up a little but not bad. Starts alot easier than with the stock carbs. Can't even touch the enrichener, it will flood it. I'm almost guessing that I'm rich on idle and lean on the needles and mains? How could I be this far off?

Hockers Choppers · « **Reply #36 on:** March 19, 2007, 06:02:34 PM »

Hey Mike I think I finally figured out my problem! My adaptor spigots are about a 1/2 " longer than they are supposed to be!! The ones I have are around 40mm and the sudco website says they are to be 28mm. Do you think this would affect the carb performance??
Thanks,
Jesse

Hockers Choppers · « **Reply #37 on:** March 19, 2007, 07:04:32 PM »

Do you set the floats the same as the stock carbs, hold on an angle till they just touch the needle? 14mm?

MRieck · « **Reply #38 on:** March 19, 2007, 07:05:45 PM »

Quote from: Hockers Choppers on March 19, 2007, 06:02:34 PM

Hey Mike I think I finally figured out my problem! My adaptor spigots are about a 1/2 " longer than they are supposed to be!! The ones I have are around 40mm and the sudco website says they are to be 28mm. Do you think this would affect the carb performance??
Thanks,
Jesse

Possibly but I don't think it would ahve a huge effect. I would cut down the adaptors on a lathe to the size Sudco recommends. The early adaptors were much longer than the recent ones which leads me to believe the effect wouldn't be that great. I have cut down older several sets in the past and was surprised to see the latest pieces the same length as my cut down ones. The early adaptors also had a receiving groove( for the lips on the the boots) which were to narrow and too shallow. You can make a bit to cut a better groove in the adaptor. Turn your air screws out another 1/2 turn to lean out the idle. See if it cruises smooth at around 4,500 or 5,000 . The throttle is just open and it test the idle circuit. Once you get a smooth cruise by adjusting the air screws than you can jet for power. At this point I'd throw in the 230 main air jet and see if it get better. If it does your are lean and will need a larger main jet. You will need get a proper main jet,main air jet combo than adjust your needle height. I should have thrown in some 122's for you try too

MRieck · « **Reply #39 on:** March 19, 2007, 07:06:13 PM »

Quote from: Hockers Choppers on March 19, 2007, 07:04:32 PM

Do you set the floats the same as the stock carbs, hold on an angle till they just touch the needle? 14mm?

Yes

Hockers Choppers · « **Reply #40 on:** March 19, 2007, 07:40:52 PM »

Another potential problem I just found, I'm using the F3 carb boots on the K head. When I clamp down the rubbers it makes the rubber smaller on the i/d and actually chocks down the opening. I'm ordering the late K boots tomorrow. One of these days..I'll get it all together!!?

Hockers Choppers · « **Reply #41 on:** March 20, 2007, 07:03:53 PM »

what works good to seal carbs to boots? I cut my grooves a little deep on the adaptors. I quess it would seal on the rest of the adaptor but I'd rather be sure.

Hockers Choppers · « **Reply #42 on:** March 21, 2007, 06:43:10 PM »

OK, cut down the spigots, ran the bike. No change. Tried 125 mains, worse!. I had a set of 105's that came with the carbs. Ran much better, could actually get it up to 120mph! plugs looked clean with all the jets? Still smokes in the shop when you rev it up! But I think its close enouph to ride it 15miles to the dyno! What kind of oil do you guys run in your hot rods? I'm running rotella t 15-40 and it seems to be burning it after a 100 miles?

Hockers Choppers · « **Reply #43 on:** April 04, 2007, 05:16:02 PM »

OK, I just found that the carbs have the screened nozzles for alcohol?!?!?!!!!

No wonder it was running rich!!! I'm ordering them tomorrow. AAARRRRRRRRR, I wish I would have just got new carbs instead of getting a "good deal" on ebay! I've wasted more time on these damn things! But I've really gotten to know my carbs! $:-\$

Kamal · « **Reply #44 on:** May 01, 2007, 09:56:38 AM »

I may be in the same boat.

The 29mm CRs I have for my drag motor I am building originated from a Yamaha FZ600....I paid $100 for them new, with the velocity stacks. WOW!

I figure the rest of the hundreds I saved will be "spent" screwing around to get them to work right...but this has been a great thread to give me a head start.

Kamal

Hockers Choppers · « **Reply #45 on:** May 01, 2007, 06:06:29 PM »

I also found that the machine shop used a .2610 reamer on my valve guides!!!FFFFFUUUUUTTTTTT!!!!! Now I have to redo the topend again. The 120mains and #2 notch from the top will be about right once it stops sucking oil. Nice buy on the carbs!! I hate you

Old Scrambler · « **Reply #46 on:** April 26, 2011, 01:11:50 PM »

Great Thread......................Do it yourself is proven correct if you get some expert advice from a few Good Friends!

News:

Author Topic: 29mm cr carb jetting???? (Read 16918 times)