Motorcycle carb tuning
Motorcycle carb tuning
(OP)
I have a bone stock (had) 1988 Honda Hurricane 600. I bought a new exhuast and canister along with K & N air filter. Naturally it ran lean. So I ordered the DynoJet kit #1122. I installed the stage 2 of the kit, but dont have on hand the actual jet sizes right now. The kit replaces the main jets in the float bowls and the needle jet the slides move.
My problem is fine tuning the carbs. The bike picked up a little on the bottom, and I mean just a little. But up around 6 grand and above the bike falls on its face bad. It sounds more like a old Quadrajet on a chevy, and it sputters and pops on decel. I have talked to others with the same bike and mods and they said the kit was night and day for them and something wasnt "right". The weak information packet that came with the kit says such symptoms are from being too rich. Since it is a major pain to get the carbs on and off, does anyone have any more detailed information to diagnose the situation futher? What exact components should I be tweaking. I know each component plays a part in a certian rpm range, but I dont know how much. Any help would be greatly appreciated.
My problem is fine tuning the carbs. The bike picked up a little on the bottom, and I mean just a little. But up around 6 grand and above the bike falls on its face bad. It sounds more like a old Quadrajet on a chevy, and it sputters and pops on decel. I have talked to others with the same bike and mods and they said the kit was night and day for them and something wasnt "right". The weak information packet that came with the kit says such symptoms are from being too rich. Since it is a major pain to get the carbs on and off, does anyone have any more detailed information to diagnose the situation futher? What exact components should I be tweaking. I know each component plays a part in a certian rpm range, but I dont know how much. Any help would be greatly appreciated.





RE: Motorcycle carb tuning
How does it run at idle?
If you get past your 6000 RPM problem zone does it clear up?
This sounds like a lot of questions, but there are multiple circuits in the carb that must work together to give you best perfomance.
Here is the run down of which circuits affect which throttle settings:
Air (or fuel) screw 0 to 1/8 throttle
Pilot jet (small one next to the main jet) 0 to 1/4 throttle
Needle Position 1/4 to 3/4 throttle
Main Jet 2/3 to Full throttle
The length, diameter, and taper of the needle affect mostly the transitions between these circuits. Dynojet generally changes these parameters in order to avoid having to supply pilot jets with the kit.
If these are vacuum slide carbs (which I suspect they are) Dynojet also gives you new (lighter) springs to make the slides more responsive.
Based on the info you gave. It might be the main jet if the thing runs like garbage all the way through the throttle. If it runs ok at low throttle and ok at high throttle, you should look at you clip position (which is easier than changing main jets).
Post more info, and I will try to help out more.
Good Luck,
Ed
RE: Motorcycle carb tuning
It runs fine at idle, starts right up with little or no choke, then again this is summer time.
Above six grand it seems to non responsive. Below six it feels a bit more torqey, but not much. It could be dealt with, but the range up top is bad, I have a real hard time even getting into the flow of traffic on I-5 off a on ramp.
No new springs were given in my kit. I should check into that. Here is a link to the pdf of the illustrations for the kit. http://www.dynojet.com/pdf/1122.pdf
I stuck in the 120s for the main jet. I might to verify that I stuck in the correct jets and I was loopy that night. According to your breakdown it most likely has to be the clip position or the main jets. I should check both.
RE: Motorcycle carb tuning
Check needle and seat size, check fuel pump performance, check fuel filters etc.
Regards
pat
RE: Motorcycle carb tuning
RE: Motorcycle carb tuning
Doesn't dynojet offer tech support- they certainly should for the prices they sell at!
RE: Motorcycle carb tuning
RE: Motorcycle carb tuning
They do, but I was afraid of the advise from judging the poor instructions that came with the manual. Plus in the kit you have to fill out a lenthy questionaire about the condition and symptoms of the problem. I remember some of the requirments I couldnt do from the lack of tools or equipment such as mercury gages.
Metalguy-
I will check that this weekend for your suggestions. Its always a possibility, I too after a lengthy session of cussing, beating my head on the wall, the dogs and cats take off and I might of just missed it from blindness of frustration. Thanks for the tip.
RE: Motorcycle carb tuning
Have you checked the condition of your plugs? I understand the best way is to put new ones in, ride the bike at or near where you experience the problem (6000 RPM?), shut it down and coast/brake to a stop. Then pull the plugs and look at 'em. It's a pain, but it is a way to tell if you're rich or lean (sometimes).
Good luck!
. . . Steve
RE: Motorcycle carb tuning
RE: Motorcycle carb tuning