Stock or raptor carb

[Blackout]

I have a 98 warrior, engine has new top end(stock compression) timing chain valves and seals. The stock carb has been rebuilt. It idles great but sometimes will backfire through the carb while idling, more of a hiccup than a backfire. When i hit the throttle from idle, half the time it hesitates other times it works great. A few times it will bog and but start right up again. I'm running 42.5, 145 jets 3rd groove on the needle and 1.75 turns on the air/fuel. If has the pen spring mod as well. The accelerator pump boot is bad and has some wear on the slide. Anybody have ideas. Also wondering if i would be better off with just replacing it with a raptor carb or maybe a keihin pe. Thanks

 

[alex456123]

Pump boot should be done.

 

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Yeah i know the pump boot needs to be replaced. Guess i should be more specific with my questions. I'm wondering if the pump boot could be part of the problem or wear on the slide maybe jet combinations. Adjusting the air/fuel screw has no effect on the backfiring. If it could be a cheap fix i will fix the stock carb if I'm gonna have to buy a rod kit and jets I think I would be better off replacing it with an aftermarket carb and possibly jetting it. I dont want to spend money on trying to fix a junk carb.

 

[alex456123]

id just start with replacing the boot. i dont think the rappy carb would be worth it.

 

[YAMAHAULER]

mine was doing the same thing a couple days ago I adjusted the air/fuel screw to 2 turns out and it stopped

 

[Blackout]

Thanks I've adjusted the air/fuel and it does it regardless of the position. It will idle great for a few minutes then backfire a couple times then idle great again, hopefully the accel pump boot will help.

 

[duneracerweston]

May be a possible intake manifold with a tear in it or pilot getting is off.

 

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Thought it could've been the intake so i pulled it to getter a better look, even made blockoff plates and pulled a vacuum on it. It checks out good.

 

[duneracerweston]

Hmm, crank it, let it idle and warm up, kill it, and pull the spark plug and post a picture that will help us diagnose it.

 

[Blackout]

I'll do that tomorrow before work. Thanks

 

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Here's a pic of the plug after warming up, today is the first time it has idled without the hiccup. No changes have been made so hopefully there was some trash in the idle circuit.

 

[Blackout]

Ok, can't get pics to load. The plug is a light brown, no signs of running rich or lean.to me the idle mixture looks correct.