Normal or Not?

[Angelo]

After my bike ride today I decided to pull and check the air filters, no issues but living in the desert I've made it a habit to keep an eye on them. I also decided after reading threads on here to run Seafoam through it, again, no issues just maintenance. After I get all done with it, I put the filters back on and take it out for a ride. 1st gear fine, 2nd gear fine, shift into 3rd and the bike falls on its face. 4th gear and still nothing, really wind it up and it starts popping and backfiring, even worse when I let off the throttle.

 

I pull off the road and come to a stop and let it idle, snap the throttle a few times and she is all there, no hesitation or backfiring at all. I take off and again 1st and 2nd gear she's all there, hit 3rd and she's done again. I start thinking that I fouled a plug or something since it sounds like most of the noise is coming from the left side.

 

I head back home and go back over the filter housings and vacuum ports to make sure I didn't leave anything loose. Can't find anything so I figure I'll just pull a plug in the morning and deal with it then. So I go ahead and button up the lower fairing and while I'm doing that I look at the filter housing and start to think what are the chances that it's getting too much air without the fairing blocking the fronts of the filter housing. Crazy thought but I figured what the hell, one more quick ride to see. Sure as **** she runs like a raped ape again.

 

Now is that normal or could something else be going on? Seems strange to me but it runs fine so.........

[MikeWa]

Good to know.

 

Mike

[djh3]

Hmm so will it run at say 60mph? Does it accelerate up thru the bottom gears Ok. I have read of heavier doses of seafoam fouling plugs out. Migh be worth pulling the plugs and clean and setting them. I think I would start there. If cleaning plugs dont fix it look to fuel supply, filter first and then the pump.

[Angelo]

Hmm so will it run at say 60mph? Does it accelerate up thru the bottom gears Ok. I have read of heavier doses of seafoam fouling plugs out. Migh be worth pulling the plugs and clean and setting them. I think I would start there. If cleaning plugs dont fix it look to fuel supply, filter first and then the pump.

 

It runs just fine now, better than before I cleaned everything so I don't think it's a fouled plug now. If no one has seen this before I'm tempted to pull the plastic again to see if that is in fact the cause of it doing what it did. I kid you guys not, from 3rd gear on, ~30 mph, no power at all and a bunch of backfiring when I tried to force it.

[Marcarl]

Same thing happened on my 85. Put on a different air filter and it ran good, until I asked it to go to work,,,, no way, too much air, back to the original filter and all was well.

[M61A1MECH]

Had a similar thing happen on my 07 when i switched to K&Ns and opened up the air boxes, I shimmed out the slider needles and it was better, I eventually went back to a stock set of air boxes with the K&Ns, all was good after that.

[Ace]

Had a similar thing happen on my 07 when i switched to K&Ns and opened up the air boxes, I shimmed out the slider needles and it was better, I eventually went back to a stock set of air boxes with the K&Ns, all was good after that.

 

I went though this same thing with my 06, K&n's and opened up the air boxes. I had to go back to the original equipment to make that bike haul.

[Freebird]

Agree that too much air can cause issues. I had no problem with the K&N's alone but people who opened up the air boxes experienced those issues.

[Angelo]

At least now I know I'm not crazy but surprised they are that touchy.

[V7Goose]

If you are saying you tried to ride it with the lower fairings off, then your problem was normal. The issue is not too much air, but too much turbulence and air pressure change on the carb vent hoses that sit right in front of the air filter intakes. CV carbs cannot tolerate any pressure changes from turbulence on the vents, since then air pressure difference on each side of the diaphragm is what causes the slides to open.

 

Too much air flow CAN cause some performance problems by allowing the bike to run way too lean with stock jets, but that normally requires greater exhaust flow also, and the symptoms are different than what you described.

Goose