Pipes glowing red common on these bikes?

Pd1620 · 01-05-2020, 11:20 PM

Trying to get my Carb issues under control on the RFZ 125. I installed a VM22 style carb. Bike still idles high, I want to let it run and see if it drops after warming up, but the pipe gets glowing red hot after about 20 seconds. I read in a comment that that was normal, but I’ve never had that happen on any of my Jap bikes. So I’m assuming this is a lean condition. I contacted Apollo and they recommend I buy their VM24, wtf?

Red Hawk · 01-06-2020, 06:48 PM

Any chance you can post a picture of the spark plug tip, it does sound like a very lean condition. Lean enough for engine damage if you were to run it hard. Most likely you’ll need a rejetting of the carb. This isn’t hard to do.

pete · 01-07-2020, 04:04 PM

if the bike has a stainless exhaust and is sitting with the motor running the pipe can start to glow..thin stainless heats up very easly and with no air flow to help cool it...
but check to see if it is running lean..

..

Pd1620 · 01-09-2020, 09:27 PM

Quote:

Originally Posted by Red Hawk

Any chance you can post a picture of the spark plug tip, it does sound like a very lean condition. Lean enough for engine damage if you were to run it hard. Most likely you’ll need a rejetting of the carb. This isn’t hard to do.

Here is the plug, let me know what you think.
Just a heads up I went ahead and ordered the VM24 direct from Apollo motors. It idles better, but still has the glowing pipe issue, and is still running rough.

Pd1620 · 01-09-2020, 09:29 PM

Plug

Merlin · 01-09-2020, 10:30 PM

Could we see the plug straight on from the spark end?

Emerikol · 01-10-2020, 01:23 AM

Looking at the ground strap on the spark plug it does seem to be running a little lean. I would get the exhaust on my DR650 to glow red when I would fill up with 100LL AvGas out at my local airport. A picture of the spark plug head-on will help read the plug a little better. PD, what elevation are you at? If you're over about 2,500' ASL, you're likely going to have to go up a size on your pilot and main jets in the carb. If you determine that you are running lean, then a set of jet drills from Amazon might be a good investment for you. The only down side to drilling jets is that it's impossible to go back down in size. I think that VM24 uses Mikuni jets. Thanks to the marvel of internet capitalism, Amazon has jet kits for those, too. You can just buy the kit with an assortment of jets and spend an afternoon tuning. The collective wisdom of the forum should have you fixed up in no time.

**JerryHawk250** · 01-10-2020, 08:50 AM

I'm seeing the same thing as Emerikol. The high idle alone will make the pipe glow. What pilot jet is in the new carb? Is it the same as the stock carb or smaller. Have you adjusted the idle mixture yet? I would lower the idle to about 1500 rpms and adjust the idle mixture first.

Pd1620 · 01-11-2020, 07:43 PM

Here are more plug pics.

Emerikol · 01-11-2020, 08:57 PM

Yeah, that grey ash on the end of the ground strap (the bit that goes over the top of the electrode) indicates that you're running very lean. I would start by dialing in the idle timing and setting the valves, and then go up at least one jet size on the carb. When you take the jet out, there will be a number stamped into the face. That's your jet size. You can use that as a base point to start your tuning adventures. When you order new jets, you should probably order an adjustable needle, too. Here's a really good write-up on how to tune the carburetor:
https://www.sscycle.com/tech-info/in...rb-quick-guide

01-05-2020, 11:20 PM	#1
Pd1620 Join Date: Jan 2020 Posts: 6	Pipes glowing red common on these bikes? Trying to get my Carb issues under control on the RFZ 125. I installed a VM22 style carb. Bike still idles high, I want to let it run and see if it drops after warming up, but the pipe gets glowing red hot after about 20 seconds. I read in a comment that that was normal, but I’ve never had that happen on any of my Jap bikes. So I’m assuming this is a lean condition. I contacted Apollo and they recommend I buy their VM24, wtf?
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01-06-2020, 06:48 PM	#2
Red Hawk Join Date: Jul 2018 Location: NEPA Posts: 273	Any chance you can post a picture of the spark plug tip, it does sound like a very lean condition. Lean enough for engine damage if you were to run it hard. Most likely you’ll need a rejetting of the carb. This isn’t hard to do. __________________ 2018 Hawk P&P Decked .040 off the head. 17/43 D.I.D. 428, NGK Iridium plug, DeCat, Wrapped pipe, Custom S.S. Muffler core, Nibbi PE30 115/35, L.E.D. Lights, Digital Cluster, USB port, Cutting Bord skid plate, Oil cooler w/ custom CRF oil filter inline, 5Wt fork oil, Rear Shock, CNC Back Rack, 30mm FAT bars, Bark Busters, ProGrips, Adjustable levers, Shinko 700’s lots of Loctite!
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01-07-2020, 04:04 PM	#3
pete Join Date: Jan 2012 Location: ChCh , NZ Posts: 2,262	if the bike has a stainless exhaust and is sitting with the motor running the pipe can start to glow..thin stainless heats up very easly and with no air flow to help cool it... but check to see if it is running lean.. .. __________________ 09 XT660R ... 06 TTR250 ... 80 Montesa H6 125 Enduro... 77 Montesa Cota 348 MRR "Malcom Rathnell Replica"... Current resto projects.. 81 Honda CT110... 80 Kawasaki KL250A1... 11 Husaburg TE125 enduro... "sold" along with another 31... Lifan 125 Pitbike.. "stolen" ... KIWI BIKER FORUM...... http://www.kiwibiker.co.nz/forums/content.php All the best offroad rides in NZ... http://www.remotemoto.com/ E-mail... xtpete1@gmail.com
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01-09-2020, 10:30 PM	#6
Merlin Join Date: Jun 2016 Location: Colorado Posts: 1,107	Could we see the plug straight on from the spark end? __________________ Bashan Blaze Mods: Alloy Rim's, Muffler, Mukuni VM26 Carb, Foam Filter, Tachometer, Volt Meter,LED Headlight, LED Blinkers
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01-10-2020, 01:23 AM	#7
Emerikol Join Date: Oct 2016 Location: Carrollton, GA Posts: 1,465	Looking at the ground strap on the spark plug it does seem to be running a little lean. I would get the exhaust on my DR650 to glow red when I would fill up with 100LL AvGas out at my local airport. A picture of the spark plug head-on will help read the plug a little better. PD, what elevation are you at? If you're over about 2,500' ASL, you're likely going to have to go up a size on your pilot and main jets in the carb. If you determine that you are running lean, then a set of jet drills from Amazon might be a good investment for you. The only down side to drilling jets is that it's impossible to go back down in size. I think that VM24 uses Mikuni jets. Thanks to the marvel of internet capitalism, Amazon has jet kits for those, too. You can just buy the kit with an assortment of jets and spend an afternoon tuning. The collective wisdom of the forum should have you fixed up in no time. __________________ First Rule of Aviation: -Never Pass Up The Opportunity to Pee I was struggling to get my wife's attention; I sat down on the couch and looked comfortable. That did the trick! My wife says I only have two faults. I don't listen and something else... If at first you don't succeed, try doing it the way I told you to... The Stable: 2005 Yamaha V-Star 650 - SOLD 2015 Suzuki DR 650 2015 RPS Hawk 250 - SOLD 2016 Ural Gear Up
	1

01-10-2020, 08:50 AM	#8
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,585	I'm seeing the same thing as Emerikol. The high idle alone will make the pipe glow. What pilot jet is in the new carb? Is it the same as the stock carb or smaller. Have you adjusted the idle mixture yet? I would lower the idle to about 1500 rpms and adjust the idle mixture first. __________________ 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S (Sold) 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel
	1

01-11-2020, 08:57 PM	#10
Emerikol Join Date: Oct 2016 Location: Carrollton, GA Posts: 1,465	Yeah, that grey ash on the end of the ground strap (the bit that goes over the top of the electrode) indicates that you're running very lean. I would start by dialing in the idle timing and setting the valves, and then go up at least one jet size on the carb. When you take the jet out, there will be a number stamped into the face. That's your jet size. You can use that as a base point to start your tuning adventures. When you order new jets, you should probably order an adjustable needle, too. Here's a really good write-up on how to tune the carburetor: https://www.sscycle.com/tech-info/in...rb-quick-guide __________________ First Rule of Aviation: -Never Pass Up The Opportunity to Pee I was struggling to get my wife's attention; I sat down on the couch and looked comfortable. That did the trick! My wife says I only have two faults. I don't listen and something else... If at first you don't succeed, try doing it the way I told you to... The Stable: 2005 Yamaha V-Star 650 - SOLD 2015 Suzuki DR 650 2015 RPS Hawk 250 - SOLD 2016 Ural Gear Up
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