my mod plans(hawk 250cc) - Page 7

pcspecialist · 06-10-2016, 11:55 PM

how many miles do you have on it now? Mine struggled to do 50mph until I had over 70 on it.

w0ss · 06-10-2016, 11:59 PM

stock carb I shimmed the needle. I disconnected the line at the petcock, fuel flow looks good to me. I also got clear fuel lines and a fuel filter. When I plug in the fuel line after working on the carb and open the petcock it fills up quickly. I tried running with the petcock on reserve as well and no difference.

I am running 93 octane gas, Should be good quality.

w0ss · 06-11-2016, 12:02 AM

Quote:

Originally Posted by pcspecialist

how many miles do you have on it now? Mine struggled to do 50mph until I had over 70 on it.

I have used 3 gallons of gas. Some of it got spilled out of carbs but I am guessing at least 150. I don't know exactly because I broke the speedo cable and haven't ordered a new one.

pcspecialist · 06-11-2016, 12:27 AM

How many miles when you put the Mikuni in it? Better yet, don't answer and just try the stock one again.

Weldangrind · 06-11-2016, 11:32 AM

Quote:

Originally Posted by w0ss

Any other thoughts?

Yes. I'm with PC, in that you can't begin to properly troubleshoot the condition without the proper needle in place. Have you tried to find another needle online? I bet they're super cheap.

Once you have the needle sorted, you can hone in on the correct jetting for your combination, at which point CDI failure would be easier to diagnose. Since you're seeing changes as you swap the main jet, I think the problem is entirely fuel-related at this time.

Azhule · 06-11-2016, 01:26 PM

Where is the 'fuel filter' placed? Any chance you can check to see if there is an 'air bubble' trapped in the fuel line/filter? Wonder if that is (one of) the problems at higher RPMs

w0ss · 06-11-2016, 02:31 PM

Fuel filter is just after the petcock. I have clear line before and after it and when I open the petcock I made sure there was no air bubble in the filter.

I am going to go back to the stock carb, Might even try the stock plug. The NGK is gapped a bit more than the stock but I believe it is still in spec.

Some more info that I have that may or may not be relevent.

Once when bike cut out with the 115 jet it locked up the rear wheel. Can you hydrolock the engine with fuel? It restarted with the electric start fine.

When I did the valve adjustment with the spark plug out I still felt resistance when I was rotating the engine. It would be real easy then it would get hard to move. I assumed this is normal but figured I would mention it.

I have 93 octane fuel in it and I saw another post where someone said that can make it run worse. I believe 93 does have slightly less energy but I don't think it is a material difference. Is this true?

Also thanks to all who have helped me so far. If any of you are ever in RI let me know and I will buy you dinner

w0ss · 06-11-2016, 07:15 PM

I fixed it! I hit 50 going up a big hill and 65 going down the big hill.

It was valve lash. Not sure how I did it but I had the intake at like 1/4 inch or more. exhaust wasn't as bad but still way to much.

Thanks again to everyone who helped.

pcspecialist · 06-11-2016, 08:15 PM

You must have set them on the wrong (exhaust) stroke the last time around instead of compression.

Weldangrind · 06-13-2016, 10:48 AM

Glad to hear it's running well now.

w0ss · 06-13-2016, 11:45 AM

Quote:

Originally Posted by Weldangrind

Glad to hear it's running well now.

Thanks!

I am going to wait till my new mikuni needle and pilot jets come in.

I am running a 105 main and a 20 pilot and I assume it is running lean. I am at ~300 ft and have a pod filter and aftermarket exhaust with no cat.

w0ss · 06-14-2016, 09:54 AM

Wrapped the exhaust. I did a rather poor job so probably going to take it off and do it again. 50' of the 2" stuff can probably do the exhaust 3 or 4 times.

Weldangrind · 06-14-2016, 01:04 PM

Quote:

Originally Posted by w0ss

Thanks!

I am going to wait till my new mikuni needle and pilot jets come in.

I am running a 105 main and a 20 pilot and I assume it is running lean. I am at ~300 ft and have a pod filter and aftermarket exhaust with no cat.

I'm surprised your bike will even start with a 20.

zingshoen · 06-14-2016, 08:36 PM

Quote:

I have it running a 115 and 20 right now. It pops coming off the throttle. I think that means it is running lean?

Yes. I think 25 is the minimum. Slight popping on decel, I also tried 30 which was a tad rich. I have a nitrohead header/exhaust, almost no restriction there, and a unifilter.

Quote:

It was valve lash. Not sure how I did it but I had the intake at like 1/4 inch or more. exhaust wasn't as bad but still way to much.

That makes perfect sense, these engines can be all over the place from factory. It s easy to get the valve adjustment wrong due to inexperience or lack of attention, so doing it several times often helps.

pistolclass · 06-14-2016, 10:15 PM

I run a 20 pilot and it runs nicely. It is a mikuni that I set the needle on the lowest grove and turned out the screw 2 revolutions. I have a ngk iridium, not sure if that matters. I might try a 25 but for know it is running good. The main is a 110, that made a huge difference over the stock carb, which was a 98.

06-11-2016, 01:26 PM	#96
Azhule Join Date: Dec 2015 Location: CO Posts: 1,525	Where is the 'fuel filter' placed? Any chance you can check to see if there is an 'air bubble' trapped in the fuel line/filter? Wonder if that is (one of) the problems at higher RPMs __________________ "Think as you like... but this self proclaimed Professor is always right" - Buckshot "You never know what someone is hiding beneath their smile..." - NinjaTom - R.I.P.
	0

06-13-2016, 10:48 AM	#100
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Glad to hear it's running well now. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

06-10-2016, 11:55 PM	#91
pcspecialist Join Date: May 2016 Posts: 583	how many miles do you have on it now? Mine struggled to do 50mph until I had over 70 on it.
	0

06-10-2016, 11:59 PM	#92
w0ss Join Date: May 2016 Posts: 231	stock carb I shimmed the needle. I disconnected the line at the petcock, fuel flow looks good to me. I also got clear fuel lines and a fuel filter. When I plug in the fuel line after working on the carb and open the petcock it fills up quickly. I tried running with the petcock on reserve as well and no difference. I am running 93 octane gas, Should be good quality.
	0

06-11-2016, 12:27 AM	#94
pcspecialist Join Date: May 2016 Posts: 583	How many miles when you put the Mikuni in it? Better yet, don't answer and just try the stock one again.
	0

06-11-2016, 02:31 PM	#97
w0ss Join Date: May 2016 Posts: 231	Fuel filter is just after the petcock. I have clear line before and after it and when I open the petcock I made sure there was no air bubble in the filter. I am going to go back to the stock carb, Might even try the stock plug. The NGK is gapped a bit more than the stock but I believe it is still in spec. Some more info that I have that may or may not be relevent. Once when bike cut out with the 115 jet it locked up the rear wheel. Can you hydrolock the engine with fuel? It restarted with the electric start fine. When I did the valve adjustment with the spark plug out I still felt resistance when I was rotating the engine. It would be real easy then it would get hard to move. I assumed this is normal but figured I would mention it. I have 93 octane fuel in it and I saw another post where someone said that can make it run worse. I believe 93 does have slightly less energy but I don't think it is a material difference. Is this true? Also thanks to all who have helped me so far. If any of you are ever in RI let me know and I will buy you dinner
	1

06-11-2016, 07:15 PM	#98
w0ss Join Date: May 2016 Posts: 231	I fixed it! I hit 50 going up a big hill and 65 going down the big hill. It was valve lash. Not sure how I did it but I had the intake at like 1/4 inch or more. exhaust wasn't as bad but still way to much. Thanks again to everyone who helped.
	3

06-11-2016, 08:15 PM	#99
pcspecialist Join Date: May 2016 Posts: 583	You must have set them on the wrong (exhaust) stroke the last time around instead of compression.
	0

06-14-2016, 09:54 AM	#102
w0ss Join Date: May 2016 Posts: 231	Wrapped the exhaust. I did a rather poor job so probably going to take it off and do it again. 50' of the 2" stuff can probably do the exhaust 3 or 4 times.
	0

06-14-2016, 10:15 PM	#105
pistolclass Join Date: Oct 2015 Location: connecticut Posts: 980	I run a 20 pilot and it runs nicely. It is a mikuni that I set the needle on the lowest grove and turned out the screw 2 revolutions. I have a ngk iridium, not sure if that matters. I might try a 25 but for know it is running good. The main is a 110, that made a huge difference over the stock carb, which was a 98.
	0