Carb jetting

[3wheel_life]

Been having issues on my project 200x, hard starting, backfiring on deceleration, and seems to have a flat spot at certain Rpms. I'm 99 percent sure it is carb related. The trike has a supertrapp exhaust, uni filter and airbox lid removed. I pulled the carb to check the jetting because I know with those mods it definitely needed to be jetted up some. From what I can gather, the stock main jet is 108 (for a 1985 200x) and slow jet is 40. In my carb, the main jet is a 118 and the slow jet is still at 40. The needle clip was leaned out all the way (clip was at highest setting). Took the plug out and it definitely showed a lean condition. I moved the clip to the 3rd slot, turned the pilot screw to 2 and 1/4 turns out. Haven't started the trike yet to adjust idle. My question is, does a 118 main jet seem high? I'm not very knowledgable on jetting and have never really done it since I've never had a trike with any performance stuff on it.

[barnett468]

post a photo of your plug . if it is pure white or close to it, it is screamin lean and i would then try a 122 in your case.

the pilot may or may not be too small . you can tell to some degree by the way it starts . if it easily starts with no choke, it is likely not too small.



PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR

[yaegerb]

Been having issues on my project 200x, hard starting, backfiring on deceleration, and seems to have a flat spot at certain Rpms. I'm 99 percent sure it is carb related. The trike has a supertrapp exhaust, uni filter and airbox lid removed. I pulled the carb to check the jetting because I know with those mods it definitely needed to be jetted up some. From what I can gather, the stock main jet is 108 (for a 1985 200x) and slow jet is 40. In my carb, the main jet is a 118 and the slow jet is still at 40. The needle clip was leaned out all the way (clip was at highest setting). Took the plug out and it definitely showed a lean condition. I moved the clip to the 3rd slot, turned the pilot screw to 2 and 1/4 turns out. Haven't started the trike yet to adjust idle. My question is, does a 118 main jet seem high? I'm not very knowledgable on jetting and have never really done it since I've never had a trike with any performance stuff on it.

only adjust 1 circuit/setting at a time when adjusting a carb....otherwise if you see improvements you don't know which change you benefited from.

With your mods, I would think you would need no more than a 112. Turn your pilot screw back to stock specifications, put your airbox lid back on and put your needle clip on the richest setting (bottom) and see how it responds.

also, have you thoroughly cleaned the carburetor and checked for intake leaks?

[3wheel_life]

post a photo of your plug . if it is pure white or close to it, it is screamin lean and i would then try a 122 in your case.

the pilot may or may not be too small . you can tell to some degree by the way it starts . if it easily starts with no choke, it is likely not too small.



PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR

It does not start easily or stay running without feathering the throttle until it's warm. The plug is a brownish color, I'll post a pic when I pull it back out.

[3wheel_life]

only adjust 1 circuit/setting at a time when adjusting a carb....otherwise if you see improvements you don't know which change you benefited from.

With your mods, I would think you would need no more than a 112. Turn your pilot screw back to stock specifications, put your airbox lid back on and put your needle clip on the richest setting (bottom) and see how it responds.

also, have you thoroughly cleaned the carburetor and checked for intake leaks?

The only thing I've done so far is move the needle clip to the 3rd position and moved the pilot screw back to stock. I soaked the carb and cleaned and blew it out. Still will only start if I'm giving it a little throttle. I will put the airbox lid back on, see what happens. If no change, I will move needle to richest setting and report back.

[El Camexican]

As posted above your symptoms likely have nothing to do with your main jet, so put the stock one back in until the rest of the issues are solved.

Popping on deceleration and hard starting usually can be traced to a faulty choke circuit, lean fuel screw setting, a pilot (slow) jet that is too small or dirty, or a needle that is too lean.

I'd start by making sure your float height is property set and that your pilot jet has no obstructions before changing any jet sizes.

[El Camexican]

Might want to check valve lash and compression as well, a bad valve can cause hard starting and popping as well.

[3wheel_life]

As posted above your symptoms likely have nothing to do with your main jet, so put the stock one back in until the rest of the issues are solved.

Popping on deceleration and hard starting usually can be traced to a faulty choke circuit, lean fuel screw setting, a pilot (slow) jet that is too small or dirty, or a needle that is too lean.

I'd start by making sure your float height is property set and that your pilot jet has no obstructions before changing any jet sizes.

I didn't change the jets. The PO did and I do not have the stock jet.

[barnett468]

It does not start easily or stay running without feathering the throttle until it's warm. The plug is a brownish color, I'll post a pic when I pull it back out.

Is this with full choke?

Exactly what is your starting procedure?



PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR

[El Camexican]

I didn't change the jets. The PO did and I do not have the stock jet.

Google Jetsrus.com and get what you need. If you're hesitant to mess with your carb there is a guy on here that goes by Flyingw. From what I've read he can make your carb like new again.

[3wheel_life]

Thanks for the site info. Not hesitant to mess with it at all, have rebuilt a lot of them but have never messed with jetting. I'm going to bring the carb back to stock jetting, replace the float, float needle and seat, and go from there.

[3wheel_life]

Is this with full choke?

Exactly what is your starting procedure

PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR

I don't really have a starting procedure. I just keep kicking and trying different choke settings until it starts. But I usually always have to hold the throttle open some to get it to start

[barnett468]

I don't really have a starting procedure. I just keep kicking and trying different choke settings until it starts. But I usually always have to hold the throttle open some to get it to start

Waste of time time running a stock main jet with a Supertrapp unless it only has 1 disc in it . I would check the float level and try a 45 pilot before changing anything else . Also, if the carb is a Honda carb instead of a Chinese one, I would only use Honda jets because there can be a difference in flow between the same number size from different mfg's.

Also, make sure the plug is the correct heat range and gap.



PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR
AND OWNER OF A TRI Z THAT ACTUALLY HAS A REAR SHOCK ON IT

[3wheel_life]

Waste of time time running a stock main jet with a Supertrapp unless it only has 1 disc in it . I would check the float level and try a 45 pilot before changing anything else . Also, if the carb is a Honda carb instead of a Chinese one, I would only use Honda jets because there can be a difference in flow between the same number size from different mfg's.

Also, make sure the plug is the correct heat range and gap.



PREVIOUS KAWASAKI INTERNATIONAL R & D PROJECT ENGINEER AND ATV DEPARTMENT SUPERVISOR
AND OWNER OF A TRI Z THAT ACTUALLY HAS A REAR SHOCK ON IT

I don't think there are any discs in it actually. Completely open at the end.

[El Camexican]

Someone please correct me if I'm wrong, but I believe that Keihin is, or was owned by the Honda corporation. If that is the case I would be very surprised if a genuine Keihin jet like the ones sold by Jetsrus werent a perfect match for your carburetor.

I recently had a guy bring me a "Honda" float needle to install in his XR. He paid $26 bucks for it!