Hawk 250 Engine is Bogging
 

Howdy Y'all,

Like most my first post will be a request for help. So about 900 miles into my new Hawk 250. She starts to lightly bog down in all gears while i'm cruising. Then starts to increase in severity over time. She would (and still is) completely bog down and give me noting after a 1/4 turn. Then with a FOT either die or take off like a rocket.

I pulled the plug and was covered in black soot. So I'm thinking its too rich. Change the spark plug and fiddle with the stock carb but no change. Order in the mikuni carb. She idles and revs good but no change after a 1/4 turn. I drop the jet needle down a few notches to lean it up. No change. :hmm: Tightened in the idle mixture screw. No change.:ohno: Only thing I haven't done is changed the jets. But what came on it is a 98 and everything I've read. It seems people go up to a 110 or 115 to make it richer.

Now this is my first time tuning a carb and it's driving me crazy!! I'm pretty sure my problem is its too rich and it's flooding the engine after a 1/4 turn. Or I'm might not be getting enough air. But now I'm starting to question everything. I go into it think "Ok I get it. I know what's going on". To " DEAR GOD I'M GOING TO SET THIS BIKE ON FIRE AND WATCH IT BURN!!" >:(

So any insight or thoughts on what else might be going on would be awesome!! :thanks:

If you light it on fire, please capture it on video.


It sounds like the CDI is failing; it happens. The symptom hasn't changed with all of the steps you've taken, so I'd look at the electrical side. The only way to troubleshoot a CDI is to buy another one.


Just for conversation, what have you done with the air filter to troubleshoot?

Could be that the main jet fell out and is laying in the float bowl.

I suspect an ignition issue or maybe tight valves.

On both carbs? Highly unlikely.

I'm throwing my bet at the choke is in the half-closed position? That would account for the sooty plug with the super lean jetting....and I'm with Weld, if you torch it, please post a vid. ;-)

A friend just suggested it might be the CDI. I think that's were I'll go next. Since it's acting like this with both carbs. I don't think it's the problem. Time to start working my way out. I haven't done any trouble shooting with the air filter yet. Also the main jets in place and the chokes not open.

If it comes to the torch and burn I'll make sure to record it. :tup:

What valves are you referring to?

I had real bad bogging such that I couldn't get past 40 mph. my issue ended up being I did the valve adjustment on the wrong stroke. If you didn't adjust the valves I would do it.

The valves are at the top of engine and come very tight from the factory.

I would disconnect the hose and remove it, that one that goes between the carburetor and the air cleaner. Then try riding it that way. Now it should be too lean, if it is the air cleaner or the air cleaner hose causing the problem.

Check the electrical connection / feed to the coil....

"the chokes not open"


Many people seem to be confused or get confused or not know open/close for their particular bike or just a wording/terminology thing.

Your choke should be fully open. No air restriction at all. Take the air cleaner intake tube off if you need to look inside the carb to verify how the choke plate opens and closes. Make sure your choke is full open. The internet says a cold start choke should never even be needed for a properly tuned bike in any air temperature over 50 degrees or so.

Fully open choke. (dont pay any attention to the red arrow)

http://i65.tinypic.com/2924mdx.jpg



Fully closed choke. Will make your bike run way rich and no power and flooded and dirty plug and no adjustment etc etc.

http://i65.tinypic.com/21uc6h.jpg


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I would start by adjusting the valves, with you asking "what valves" makes me wonder if they ever have been adjusted properly ;)

Check out "Motocheez" on youtube, he has some great videos out on the HAWK... make sure you "watch and read" anything that pops up in his videos, he has made a few mistakes here and there but he always corrects them... sometimes he corrects the problems with wording that pops up on his videos

Either way, watch this video, and set your valves (with an ICE COLD engine)... get back to us if it helps any or not :)

https://www.youtube.com/watch?v=RTpAcOuUf7w

I actually watched this video about twenty times and it was very helpful especially since I've never tuned a carb. But now I don't "think" the problems in the carbs.

I'll try everything suggested and will order the CDI and most likely the coil too since they're pretty cheap. I'll provide a link to what I order if they work. I appreciate everybody's input and If you have more thoughts let me know.