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who has removed the air box? how hard is it? Been running a K and N and recently found evidence that it is oil gumming up the Throttle body Assy. Possibly. anyway My throttle is really sticky when the bike is warm and others have had the problem. Its all fine when the bike is cold so kinda hard to figure out the exact cause. Need to take a look anyway. Help a guy out. Thanks.

If you are running a K&N, how did you get it in there? I would expect that you would reverse the process.

The air filter is no sweat to remove or install. Consult your service manual.

Edit: Stock air filter for me.

I removed the box from my 2003....not too much trouble if you take your time. I had to do it to get to my seat latch pull. Why in the world would you want to remove it?

Name Etc. wrote:who has removed the air box? how hard is it? Been running a K and N and recently found evidence that it is oil gumming up the Throttle body Assy. Possibly. anyway My throttle is really sticky when the bike is warm and others have had the problem. Its all fine when the bike is cold so kinda hard to figure out the exact cause. Need to take a look anyway. Help a guy out. Thanks.

The throttle plates get gummed up even without a K&N contributing oil. The leading money is on back streaming through the reed valves into the air box plus normal back streaming through the intake tract. Almost always the lower third to half of the throttle plates will be coated. Any accumulation along the very edge of the throttle plate will cause TB sync and idle issues.

Pulling the air box is a bit of a PITA. A high level overview -- remove the following items: seat, tank, tool tray, all associated hoses, sensors, electrical connectors, and then the air box.

Ok Thanks. It is probably due cleaning. At 86,000 miles now so it won't be wasted Maintenance anyway. the reed valves have been blocked off for quite some time. I am going to tear into it just to see. and letting go of the throttle at 50 mph or what ever... It just stays there... so it is time to fix that problem anyway...

Anyone think it would do any good to use a straw and just spray carburetor cleaner up the intakes with the motor running? It would be a two person job as someone would have to keep the revs up but it may clean the plates well enough for gubment work!!

HotRodZilla wrote:Anyone think it would do any good to use a straw and just spray carburetor cleaner up the intakes with the motor running? It would be a two person job as someone would have to keep the revs up but it may clean the plates well enough for gubment work!!

Used to do it to my cars all the time... Was thinking about it. Do I wanna wash the accumulated oil dirt and gunk collected in the intake into the running motor? Never used to think about it, back in the day... I have a camera on a snake, and hose long enough to reach. Hmmmmmm.

I would think that if it's just gunk, oily buildup, or whatever it shouldn't hurt as long as its not sand. With the filter in place and doing what it's supposed to do there shouldn't be any sand or actual dirt in there.

Like you, I used to do the same thing to my carbureted cars back in the day. Rev it up and spray cleaner on the butterflies until they were clean.

I will look with my snake camera and see if this is doable. If it is what the hell. I will try it. then give my results. I am not sure if I can set up my snake camera to record the actual pictures but maybe a picture of the screen will work? Anyway I will give it a try.

Ok. My snake camera could only see two throttle bodies. I went ahead and pulled the air box, it isn't that hard, way easier than my old Connie! Here are some photos.
They are definitely sticky and very dirty.


Even the tubes in air box have shit in them.

I am going to go ahead and say I think the dry paper element is better? Oil in intake tubes before TBs. Dirty air etc. Granted this is 86,000 miles but my TB have been sticky since about 40k I will be happier when I get this done. I can watch the throttle butterflies slowly move with the slack in the cables. It is slow enough that it's obvious when you run the throttle. No wonder my hand is so damn sore!

Here is the end of the K and N filter. leaks? I am not sure if it is getting past that outer seal or not?

My first guess is that you've over oiled the filter?

Mobile Clocklaw

Apparently. Except others who think they know what they are doing also found the same thing or worse. What I did find was massive leaks at all four boots between the TB and the motor. So I am ordering new ones. And waiting. This is how I finished out the day. Massive leaks. Explains maybe the ping I've been having, maybe the bad gas mileage... We will see when I get back together. I figured ok! I will just tighten these clamps.... The clamps are tightened all the way so there is no tightening. Not like the old boots on my OLD bikes.

Also, I'll never admit where I found the thread about K and N and oil and dirt in the TB assembly.

K&N filters are good for keeping semi trucks and two ton hay bails out of your engine. Other than that, they're shit. Be better off with an oil bath filter from a 50's Chevy.

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silverback wrote:Be better off with an oil bath filter from a 50's Chevy.

Actually, those were extremely effective but not very practical....my '64 Ford pickup had one.

silverback wrote:K&N filters are good for keeping semi trucks and two ton hay bails out of your engine. Other than that, they're shit. Be better off with an oil bath filter from a 50's Chevy.

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yes I am replacing with paper. I am very careful with the oil bit also. I was afraid I was under oiling. I wash it. Dry it over night or more then oil it and let it sit inside a plastic bag while I do other shit and then put it back in. Now I am More worried I Lost #4 compression... but I am hoping the vacuum leak was just so bad that that one cylinder was just low.

Oops! How did I manage a double post? Deleting duplicate.

Name Etc. wrote:...I am More worried I Lost #4 compression... but I am hoping the vacuum leak was just so bad that that one cylinder was just low.

I sure understand your worry upon finding low compression after finding intake leak(s). An intake leak should have no bearing on a compression test, but a clogged air filter would. Since it is just one cylinder that lets out the air filter. Can't rule out operator error For the non-mechanical people, adding a tablespoon of oil to the low cylinder will help determine if the problem is valves or rings. Add oil and compression goes up = worn cylinder or stuck rings. Add oil and compression does NOT go up = leaking valves.

For some reason the FJR seems to be prone to sticking rings. If compression is low on only ONE cylinder you may want to try a few applications of Yamaha Ring Free in you gas, then check again. At just 40k miles all 4 of my Gen I cylinders had stuck rings. Ring Free is intended for boat use and is bottled to treat a standard inboard/outboard gas tank so parse out the bottle accordingly -- 1 oz Ring Free to every 10 gallons of gas. It is really expensive but 6 oz treats 60 gallons of gas. This is the real deal and does its job very good.

I have been running a K&N filter in a performance enhanced engine where at the drag strip the engine runs 100% WOT after the launch and the extra intake air flow helps. I found the aerosol can of filter oil was much easier to use and get a better dosing. I had more problems with normal intake back streaming than oil from the filter.

ionbeam wrote:

Name Etc. wrote:...I am More worried I Lost #4 compression... but I am hoping the vacuum leak was just so bad that that one cylinder was just low.

I sure understand your worry upon finding low compression after finding intake leak(s). An intake leak should have no bearing on a compression test, but a clogged air filter would. Since it is just one cylinder that lets out the air filter. Can't rule out operator error For the non-mechanical people, adding a tablespoon of oil to the low cylinder will help determine if the problem is valves or rings. Add oil and compression goes up = worn cylinder or stuck rings. Add oil and compression does NOT go up = leaking valves.

For some reason the FJR seems to be prone to sticking rings. If compression is low on only ONE cylinder you may want to try a few applications of Yamaha Ring Free in you gas, then check again. At just 40k miles all 4 of my Gen I cylinders had stuck rings. Ring Free is intended for boat use and is bottled to treat a standard inboard/outboard gas tank so parse out the bottle accordingly -- 1 oz Ring Free to every 10 gallons of gas. It is really expensive but 6 oz treats 60 gallons of gas. This is the real deal and does its job very good.

I have been running a K&N filter in a performance enhanced engine where at the drag strip the engine runs 100% WOT after the launch and the extra intake air flow helps. I found the aerosol can of filter oil was much easier to use and get a better dosing. I had more problems with normal intake back streaming than oil from the filter.

I maybe wasn't clear. I was doing carb sync. 1 2 3 all normal. 4 like 12 cm