Strange Carb issue - Page 2

n4mwd · August 25th, 2013, 11:31 AM

About a week ago, I started out and the engine was dragging and it was so sluggish that about 5 miles from the house I decided to pull over and see if perhaps I was riding on a flat. Nope, tires good.

I accelerated hard (because I'm bad and I pulled in front of traffic) to get up to speed. About 45mph the engine started bogging down and convinced me that one my main jets was clogged up again because it bogged at exactly 5500 rpm but idled perfectly. I had just rebuilt it about a month earlier, but I figured I must have missed something.

So last week I rebuilt it again and paid special attention to all the passages and holes and things. The carb was still clean. This time it was also soaked in cleaner inside and out. When I put it back together and took it for a test drive, it was still missing in the wind, but otherwise running OK. That's what I call it when it a gust of wind hits it and the engine misfires.

So last night I think I may have found the problem. Right after I bought the bike, I stuck some foil insulation to the underside of the seat. This was to help keep the seat from getting too hot. I noticed that the foil paper in the front had delaminated from the sticky part and was free to flap around.

It occurred to me that this may be flapping down on the two intake holes and plugging them up. This would especially be true when there is a heavy vacuum like during acceleration.

So I ripped the insulation off. Today, I went out and there was no missing in the wind or bogging down.

Could I be right that this foil was the cause of the problem?

There is no way I would have noticed the foil on the intake because the seat comes up in the back and the foil comes off with the seat.

It makes a little sense as the cause of the missing in the wind problem as the foil could have been affected by a strong headwind gust that could cause it to momentarily plug up the intake holes.

choneofakind · August 25th, 2013, 08:02 PM

Seems like that would do it. If it stays fixed, you're good.

I thought it didn't sound like a carburetor issue.

jkv45 · August 26th, 2013, 06:05 AM

Sounds like that was your problem.

August 25th, 2013, 11:31 AM	#41
n4mwd ninjette.org certified postwhore Name: D Location: Palm Beach, FL Join Date: Oct 2010 Motorcycle(s): 2006 Ninja 250R, 2007 EFI Ninja 250R Posts: A lot. Blog Entries: 1	UPDATE - Missing In The Wind About a week ago, I started out and the engine was dragging and it was so sluggish that about 5 miles from the house I decided to pull over and see if perhaps I was riding on a flat. Nope, tires good. I accelerated hard (because I'm bad and I pulled in front of traffic) to get up to speed. About 45mph the engine started bogging down and convinced me that one my main jets was clogged up again because it bogged at exactly 5500 rpm but idled perfectly. I had just rebuilt it about a month earlier, but I figured I must have missed something. So last week I rebuilt it again and paid special attention to all the passages and holes and things. The carb was still clean. This time it was also soaked in cleaner inside and out. When I put it back together and took it for a test drive, it was still missing in the wind, but otherwise running OK. That's what I call it when it a gust of wind hits it and the engine misfires. So last night I think I may have found the problem. Right after I bought the bike, I stuck some foil insulation to the underside of the seat. This was to help keep the seat from getting too hot. I noticed that the foil paper in the front had delaminated from the sticky part and was free to flap around. It occurred to me that this may be flapping down on the two intake holes and plugging them up. This would especially be true when there is a heavy vacuum like during acceleration. So I ripped the insulation off. Today, I went out and there was no missing in the wind or bogging down. Could I be right that this foil was the cause of the problem? There is no way I would have noticed the foil on the intake because the seat comes up in the back and the foil comes off with the seat. It makes a little sense as the cause of the missing in the wind problem as the foil could have been affected by a strong headwind gust that could cause it to momentarily plug up the intake holes. __________________________________________________ My Ninja Blog Proud member of ABATE.My NYC Road Rage documentary - CENSORED!

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August 25th, 2013, 08:02 PM	#42
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Seems like that would do it. If it stays fixed, you're good. I thought it didn't sound like a carburetor issue.

August 26th, 2013, 06:05 AM	#43
jkv45 Rev Limiter Name: Jay Location: WI Join Date: Jul 2013 Motorcycle(s): '06 SV650n, '00 Derbi GPR, '64 CA77 Dream 305, '70 CL450 Scrambler, numerous dirt bikes Posts: A lot. MOTM - Jun '18, Oct '16	Sounds like that was your problem.