Mikuni Carb help

SithLord · 06-28-2018, 03:35 PM

Greetings Community.
In the process of upgrading my Hawk 250 while I'm putting it together (2017 model). Since it may be relevant in answering my questions, here are the mods and upgrades I have done:

1. Airbox mod
2. K&N filter
3. NGK spark plug
4. EK O-ring chain
5. Mikuni carb (with 110 jet)

6. LED headlight and tail light
7. Sealed battery
8. Exhaust wrap
9. Mobil 1 synthetic engine oil 10w40
10.Burrito case
11.91 octane gas

Everything else is stock/unaltered

After completing all this, and while the crankshaft case, chain, sprockets, side covers, and rear wheel were removed, I couldnt resist the urge to crank her up with her sitting on the motorcycle lift. Granted, I was in the garage, and like I mentioned the crankcase cover was removed...but this thing is LOUD!
I've heard/seen videos of a nice mellow "PURRR", but this is like a lawn mower on steroids running up a hill.

Now to the question:
How do I "mellow" it out? Engine has 3 miles on it. I initially had the spar suppressor on the stock exhaust off, but same result putting it back on.

Same result, even louder, when I give it throttle

There is a small gap between engine body and gasket connecting the exhaust to the head. But there is no gas/air getting out.
Does it mellow out on its own after being broken in?

Any advice is welcome.

Kivi · 06-28-2018, 05:02 PM

Fit an air filter, it will be quieter.

SithLord · 06-28-2018, 08:20 PM

Thanks. I was looking for an option that goes with my setup, I already have the K&N filter on.
Not sure why it's that loud. My mistake was I have nothing to compare it to, as I resisted the urge to start it before I did the performance mods.

Sport Rider · 06-28-2018, 10:58 PM

adjust valves. there is a wide variety of how they set them at the factory. some good, some tight, some loose.

would suggest changing fork oil too. it's as crappy as the motor oil.

SithLord · 06-29-2018, 12:42 AM

Thanks.

Yes, my intent was to change fork oil, havent worked that far yet hehe.

The way I understood it, is that the valve job should be done after the engine is broken in. Could be wrong as this is all new to me. This bike has 3 miles on it.

Just cranked it up again, kinda feels like it wants to shake itself apart.

SithLord · 06-29-2018, 04:57 AM

Ok, I'm getting the hang of it and think I've solved it:
The Mikuni carb came with spring, ping and inner sleeve. I was lazy and didnt remove the stock spring, pin and sleeve.
Took Mikuni carb off, took stock sleeve pin and spring out and put the Mikuni ones in. Madee sure my sleeve was properly aligned to seat properly. Before I got too far with putting it together, I tightened idle screw all the way then backed it out two full turns.

Buttoned up the carb, reconnected hoses. Also noticed throttle cable was loose, so I tightened that.
Cranked her up, and I got a kitten in the garage! She PURRRED nicely.

Only issue is, I noticed the choke was at half. I'll play with idle adjustment screw to see what that does, because I noticed with the choke off, the lawnmower came back.

06-28-2018, 03:35 PM	#1
SithLord Join Date: Jun 2018 Posts: 17	Mikuni Carb help Greetings Community. In the process of upgrading my Hawk 250 while I'm putting it together (2017 model). Since it may be relevant in answering my questions, here are the mods and upgrades I have done: 1. Airbox mod 2. K&N filter 3. NGK spark plug 4. EK O-ring chain 5. Mikuni carb (with 110 jet) 6. LED headlight and tail light 7. Sealed battery 8. Exhaust wrap 9. Mobil 1 synthetic engine oil 10w40 10.Burrito case 11.91 octane gas Everything else is stock/unaltered After completing all this, and while the crankshaft case, chain, sprockets, side covers, and rear wheel were removed, I couldnt resist the urge to crank her up with her sitting on the motorcycle lift. Granted, I was in the garage, and like I mentioned the crankcase cover was removed...but this thing is LOUD! I've heard/seen videos of a nice mellow "PURRR", but this is like a lawn mower on steroids running up a hill. Now to the question: How do I "mellow" it out? Engine has 3 miles on it. I initially had the spar suppressor on the stock exhaust off, but same result putting it back on. Same result, even louder, when I give it throttle There is a small gap between engine body and gasket connecting the exhaust to the head. But there is no gas/air getting out. Does it mellow out on its own after being broken in? Any advice is welcome.
	0

06-28-2018, 05:02 PM	#2
Kivi Join Date: May 2017 Location: Serbia Posts: 217	Fit an air filter, it will be quieter.
	0

06-28-2018, 08:20 PM	#3
SithLord Join Date: Jun 2018 Posts: 17	Thanks. I was looking for an option that goes with my setup, I already have the K&N filter on. Not sure why it's that loud. My mistake was I have nothing to compare it to, as I resisted the urge to start it before I did the performance mods.
	0

06-28-2018, 10:58 PM	#4
Sport Rider Join Date: Jan 2016 Location: Mooresville NC Posts: 2,047	adjust valves. there is a wide variety of how they set them at the factory. some good, some tight, some loose. would suggest changing fork oil too. it's as crappy as the motor oil.
	0

06-29-2018, 12:42 AM	#5
SithLord Join Date: Jun 2018 Posts: 17	Thanks. Yes, my intent was to change fork oil, havent worked that far yet hehe. The way I understood it, is that the valve job should be done after the engine is broken in. Could be wrong as this is all new to me. This bike has 3 miles on it. Just cranked it up again, kinda feels like it wants to shake itself apart.
	0

06-29-2018, 04:57 AM	#6
SithLord Join Date: Jun 2018 Posts: 17	Ok, I'm getting the hang of it and think I've solved it: The Mikuni carb came with spring, ping and inner sleeve. I was lazy and didnt remove the stock spring, pin and sleeve. Took Mikuni carb off, took stock sleeve pin and spring out and put the Mikuni ones in. Madee sure my sleeve was properly aligned to seat properly. Before I got too far with putting it together, I tightened idle screw all the way then backed it out two full turns. Buttoned up the carb, reconnected hoses. Also noticed throttle cable was loose, so I tightened that. Cranked her up, and I got a kitten in the garage! She PURRRED nicely. Only issue is, I noticed the choke was at half. I'll play with idle adjustment screw to see what that does, because I noticed with the choke off, the lawnmower came back.
	0