Hawk 250 won’t start after Nibbi install

[Desuboi941]

Hi guys, so I installed the nibbi pe28fl carb on my hawk, had some interference issues. Put my air box tube deeper and it fits better and now the hawk won’t start, a/f ratio and idle are stock from nibbi, it has a 112 main and I think a 35 or 38 pilot in it. I haven’t been able to even ride the bike yet. Any ideas?

[Bill Hilly]

Did you open the petcock?
I don't know what you mean by the airbox tube deeper?

[JerryHawk250]

Does it have spark? Check to make sure you didn't accidentally turn on the kill switch. Did you try choking it?

[CheapThrills]

So vague just saying it won't start.


- Check the carb has fuel, open drain and verify gas is coming out.


- Pull spark plug and verify there is spark.


Then post the results, good luck!!!

[Desuboi941]

Originally Posted by CheapThrills

So vague just saying it won't start.


- Check the carb has fuel, open drain and verify gas is coming out.


- Pull spark plug and verify there is spark.


Then post the results, good luck!!!

Indeed to everyone, I always do my fine-c, I drained the bowl still wouldn’t start. I finally got it to start last night and was able to ride it last night. Now my problem is the clutch I think. I had the idle set a little high to start it but once it started to heat up, I turned the idle down, possibly not enough. But when I clutched in, it sounded like it wanted to run away, and I was not on the throttle. I’m going to try and reroute some cables I just don’t know the actual spots for them so I tried my best during assembly.
Edit: also made sure I had spark but am putting in ngk today

[Desuboi941]

Originally Posted by JerryHawk250

Does it have spark? Check to make sure you didn't accidentally turn on the kill switch. Did you try choking it?

Yes, I either think it’s something to do with my clutch or my air fuel screw to the left of my idle screw, I’m running stock jets that came in the nibbi either a 35 or 38 pilot I can’t remember and a 112 main, I have the air screw out about 1 1/2 or 2 turns out.

[buzz]

Hello carburetor should have nothing to do with the clutch,I just used stock carb on mine.Maybe try the old one again ,and see what happens.

[Thumper]

It is always a good idea to make original equipment work first. This includes the carb. It should at least be close, and usually a bit lean. Then you can open the carb and see what is in there AFTER you've got it running and tested to see what the carb needs.

Doing this has definitely given you some experience, and I always enjoy working on the bike, so you I don't feel like you have wasted your time

What jet sizes were in the original carburetor? How well did it run? Was the needle shimmed? Simplest thing to do at this point is to rejet and re-install the OEM carb. The new carburetor won't give it more power if that was the goal. If you replaced the exhaust with a more high flow exhaust system, ported the head, then the new carb could make a difference. But if the bike is otherwise stock, the OEM carb will be fine.

Also, is the throttle cable routed in a path with least possible bends, no kinks through the instrument cluster and as straight as possible by the frame under the tank and no sharp bend getting to the carburetor? Kinks can prevent the cable from slipping smoothly, and the slide may not be dropping all the way down.

[BakedOregonian]

I had a similar issue after installing my Nibbi however once I took it apart I noticed the throttle cable was ever so slightly not completely in the hole at the bottom of the slide. Popped it in and no problem after that.

[WrenchMonkeyman]

Originally Posted by Desuboi941

Indeed to everyone, I always do my fine-c, I drained the bowl still wouldn’t start. I finally got it to start last night and was able to ride it last night. Now my problem is the clutch I think. I had the idle set a little high to start it but once it started to heat up, I turned the idle down, possibly not enough. But when I clutched in, it sounded like it wanted to run away, and I was not on the throttle. I’m going to try and reroute some cables I just don’t know the actual spots for them so I tried my best during assembly.
Edit: also made sure I had spark but am putting in ngk today

What did you do to get it to start? I am having the same problem, when I put the stock carb back on the bike started right up. I checked the jets weren’t clogged, I have fuel in the bowl and loosened my throttle free play to make sure the slide was sitting all the way down.

[Thumper]

Did it run before this "upgrade"? Spark plug was OK? It ran???

[WrenchMonkeyman]

Got it running! After trying to start it so many times the battery was drained so I bought a charger and once it was fully charged I adjusted the carb to run very rich. I figured the increased amount of air draw with the pe28 was causing the bike to run so lean to the point it wouldn’t start. I got it running and adjusted it down. Now my only problem is the bike is idling at almost 6000 rpm’s and the throttle is sticking. I’m pretty sure both issues have to do with the throttle cable coming out of the carb being bent at a 90° angle against the gas tank. I’m going to do what Dan said and put a dent in the bottom of the gas tank to give it more space.

[buzz]

Just get the right cable,thats all you need. Or just put stock carb back on.