jetting seems SO close, yet not quite

discochris · 06-01-2020, 08:07 PM

Got the Mikuni clone reinstalled on the Enforcer...

Running a 115 main and 25 pilot. Needle in the middle position. Ebay exhaust. Stock airbox.

At around 900' above sea level.
Have tested a few different settings with idle screw and fuel/air screw.
Bike starts and idles just fine. Runs decent below half throttle, as soon as it gets to mid-throttle, it sputters and bogs.

I don't have a tach, so I can't tell you exactly what RPM it stumbles at. It feels so close, but still off. I've read most of the threads here, but can't decide which way to go next.

wheelbender6 · 06-01-2020, 08:14 PM

Keep checking your spark plug. The electrode insulator should be tan in color when the jetting is right.

Wild Dog · 06-01-2020, 08:20 PM

Quote:

Originally Posted by discochris

Got the Mikuni clone reinstalled on the Enforcer...

Running a 115 main and 25 pilot. Needle in the middle position. Ebay exhaust. Stock airbox.

Did you check the spark plug? I bet it is crayon white.

discochris · 06-01-2020, 08:44 PM

here's the plug

discochris · 06-01-2020, 08:45 PM

I put in another plug and it ran much better, but this plug was brand new. I bought it last month when I bought the bike.

The stumble is still there.

Megadan · 06-01-2020, 09:36 PM

Make sure it isn't stuck at half choke. That fine til half theottle and then bog is exactly the issue you will run into if it is.

Also, that 115 may be a tad rich with a stock airbox. Have a 112.5 main jet?

discochris · 06-01-2020, 09:53 PM

Not at half choke. This is with choke off.
You think it's too rich with a 115? I was thinking it might be too lean, looking at the plug, and noticing the engine seeming pretty hot.

I don't have a 112.5, I have a 110...

Megadan · 06-01-2020, 10:10 PM

Quote:

Originally Posted by discochris

Not at half choke. This is with choke off.
You think it's too rich with a 115? I was thinking it might be too lean, looking at the plug, and noticing the engine seeming pretty hot.

I don't have a 112.5, I have a 110...

I live at 1100ft, a 27.5 pilot, needle 3rd slot, and a 115 main was what I ran with a pod filter and full exhaust in the warmer months. You might be fine with a 115, just a.thought since you have a stock airbox.

The only other thing I can think of is the float height might be off.

I only bring up the half.choke thing because it has bitten several members here, even me. Heck, I had the choke go to half on its own once when I hit a bump lol.

discochris · 06-02-2020, 09:38 PM

So I tried a 110 main. Bike ran EXTREMELY hot, and not well. Obviously lean.
Having already used the 115, I thought I would try a 120. No more stumble, bike pulls strong. Starts right up without needing choke.
(this was with the 25 pilot and the needle in the fourth position from the top.

However, idle was off - when I revved it in neutral, it wouldn't come back down, and it didn't idle well.

Turns out I appear to have lost the retaining clip that goes in the slide above the needle. Argh. I have no idea where it popped off to in the garage. I may end up having to order a whole new carb if I can't find it...

Megadan · 06-02-2020, 09:49 PM

Quote:

Originally Posted by discochris

So I tried a 110 main. Bike ran EXTREMELY hot, and not well. Obviously lean.
Having already used the 115, I thought I would try a 120. No more stumble, bike pulls strong. Starts right up without needing choke.
(this was with the 25 pilot and the needle in the fourth position from the top.

However, idle was off - when I revved it in neutral, it wouldn't come back down, and it didn't idle well.

Turns out I appear to have lost the retaining clip that goes in the slide above the needle. Argh. I have no idea where it popped off to in the garage. I may end up having to order a whole new carb if I can't find it...

The missing needle clip would definitely explain the part throttle weirdness. Glad to hear the 120 main worked out.

As far as needle cljps. https://www.amazon.com/MIKUNI-VM20-3.../dp/B003CJW4W8

Never hurts to have spares.

discochris · 06-02-2020, 11:31 PM

Not the C-clip. Isn't there another retaining spring thingy that goes above that?

Megadan · 06-03-2020, 02:02 AM

Quote:

Originally Posted by discochris

Not the C-clip. Isn't there another retaining spring thingy that goes above that?

Ahh, you are talking about the V shaped retainer. You should be able to just borrow one from the stock PZ30 carburetor. They may be called different names, but they share quite a few parts.

discochris · 06-03-2020, 02:58 AM

Quote:

Originally Posted by Megadan

Ahh, you are talking about the V shaped retainer. You should be able to just borrow one from the stock PZ30 carburetor. They may be called different names, but they share quite a few parts.

That's it! Thank you...

Megadan · 06-03-2020, 04:33 PM

Quote:

Originally Posted by discochris

That's it! Thank you...

Did that work out for you?

discochris · 06-05-2020, 06:10 PM

Still working on it. Didn't realize that I needed to plug off all the air box hose stuff with the new exhaust... It's getting closer.

06-01-2020, 08:07 PM	#1
discochris Join Date: Apr 2020 Location: Minnesota Posts: 35	jetting seems SO close, yet not quite Got the Mikuni clone reinstalled on the Enforcer... Running a 115 main and 25 pilot. Needle in the middle position. Ebay exhaust. Stock airbox. At around 900' above sea level. Have tested a few different settings with idle screw and fuel/air screw. Bike starts and idles just fine. Runs decent below half throttle, as soon as it gets to mid-throttle, it sputters and bogs. I don't have a tach, so I can't tell you exactly what RPM it stumbles at. It feels so close, but still off. I've read most of the threads here, but can't decide which way to go next.
	0

06-01-2020, 08:14 PM	#2
wheelbender6 Join Date: May 2015 Location: Houston area Posts: 1,902	Keep checking your spark plug. The electrode insulator should be tan in color when the jetting is right. __________________ "Its not WHAT you ride; its THAT you ride"
	0

06-01-2020, 09:36 PM	#6
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,151	Make sure it isn't stuck at half choke. That fine til half theottle and then bog is exactly the issue you will run into if it is. Also, that 115 may be a tad rich with a stock airbox. Have a 112.5 main jet? __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
	0

06-01-2020, 08:45 PM	#5
discochris Join Date: Apr 2020 Location: Minnesota Posts: 35	I put in another plug and it ran much better, but this plug was brand new. I bought it last month when I bought the bike. The stumble is still there.
	0

06-01-2020, 09:53 PM	#7
discochris Join Date: Apr 2020 Location: Minnesota Posts: 35	Not at half choke. This is with choke off. You think it's too rich with a 115? I was thinking it might be too lean, looking at the plug, and noticing the engine seeming pretty hot. I don't have a 112.5, I have a 110...
	0

06-02-2020, 09:38 PM	#9
discochris Join Date: Apr 2020 Location: Minnesota Posts: 35	So I tried a 110 main. Bike ran EXTREMELY hot, and not well. Obviously lean. Having already used the 115, I thought I would try a 120. No more stumble, bike pulls strong. Starts right up without needing choke. (this was with the 25 pilot and the needle in the fourth position from the top. However, idle was off - when I revved it in neutral, it wouldn't come back down, and it didn't idle well. Turns out I appear to have lost the retaining clip that goes in the slide above the needle. Argh. I have no idea where it popped off to in the garage. I may end up having to order a whole new carb if I can't find it...
	1

06-02-2020, 11:31 PM	#11
discochris Join Date: Apr 2020 Location: Minnesota Posts: 35	Not the C-clip. Isn't there another retaining spring thingy that goes above that?
	0

06-05-2020, 06:10 PM	#15
discochris Join Date: Apr 2020 Location: Minnesota Posts: 35	Still working on it. Didn't realize that I needed to plug off all the air box hose stuff with the new exhaust... It's getting closer.
	0