UPDATE !! Foam in AIRBOX-cover on export-valk's !!

[FLATSIX]

I FINALLY GOT THE NEW AIRBOX-COVER FROM HONDA - partnumber 17221-MZO-710 (cover, air cleaner)

The foam IS INSIDE THE AIRINTAKE OF THE AIRCLEANER-COVER  and I measured 10mm. thickness exactly.

I had put in only 8mm. and believe me : the Lady got still too much air! She pulled good , but at certain openings of the throttle I  felt hesitations. So the amount of air and I think also the speed of that air must be exactly the same like in the OEM-cover or your exportbike will do things that you don't like.

QUESTION NOW:  I have an K&N-air filter with pre-filter mounted. Do I use the O-ring for the airbox - then put the K&N-filter and then put the airboxcover with another O-ring in it??? or do I only place 1 O-ring + K&N filter + the cover without a second O-ring in it.

I am a little bit confused about the sealing O-rings.

The new cover came with 1 sealing O-ring, I ordered a spare one, but the Hondaman thought there were 2 O-rings necessary to seal or make the airbox tigt for false air.

Can you give advise on this, please ??

Many thanks,
 

[Robert]

If I understand you are talking about the air filter housing or air box cover that has I think 6 screws to hold it together then the KN filter has its own seal and you really dont need to have another. Just a side note if your bike is running lean then you really should either rejet or maybe if the jets are clogged clean them.

[FLATSIX]

Robert, I have put the 2 OEM o-rings that are in the airbox-cover + the K&N-filter and thightened the screws : the whole airbox closed - so no airleak possible there. This was the advice from the Hondadealer, there should be a couple of mm. that it keeps open , then tighten screws and the whole thing is tight.

About my bike now: with the OEM new airboxcover with the new foam in it everything is back to normal : she pulls good and climbs in high rpm's like it should. No more hesitations - so I leanred my lesson : never touch the foam at the inside as this is very important for the exact amount of air, with no foam it does not work, when foam to thin or not the same there is hesitation.

Lucky for you guys in the states that you don't have to bother about this, because it ain't there in your bikes......  on the otherside, we don't have to desmog, as that installation is not on ours 

[Udo]

Desmog seems to be different from country to country. My German model had this stuff. Rememberer doesn´t work, in the moment. I have no idea about the foam....will see, when i have to change the filter next time.

[John Schmidt]

When changing to a K&N the shape of the filter takes the place of that ring type seal that sits in the air box. If you do use it, most likely you'll mess up the shape of the edge of the filter. But in any case, the filter itself takes the place of that ring.

[Robert]

I wasn't going to post this but I cannot stand it any longer it really urks me when something is not right. Look Flatsix your fuel mixture is not right its to lean, and yes you can rely on vacuum to get it into the range that it will run but its not the right way to do things. Our Valks do rely on the airbox to keep the fuel mixture in check thats why if you modify it there are sometimes not good results. The foam does help as you already know but it relys on the vacuum in the airbox to draw more fuel out of the carbs in certain situations. This doesn't provide for consistent nor the best performance. The fact that you have to double seal the thing means that its really lean, in most cases the foam with a single seal is quite enough to make the bike run well or at least like OEM filter. With the stock air box the 2 cylinders under the baffle dont get the same airflow as the others and this limits there power. Now its enough to warrant a jet change in some of the jet kits for those two cylinders. This shows you part of the trade off that the intake system was designed with. If you put in a KN filter and did it for better performance then you just threw that out the window. If you did the KN to not service it for awhile then your good to go. But I would have left the stock filter in, they really do a good job and dont restrict that much. I have a jet kit in with the baffle out KN filter and of course no pre filter and she pulls really hard all the way to the top. At the very least you should shim your needles so that the mixture is a bit richer and I think that you would see some real changes in the performance of the bike.

[FLATSIX]

Robert, what did I wrong ?? I put a K&N filter + prefilter in the airbox a couple of years ago. Followed the instructions on the paper that came with the filter = NOT oil the prefilter for max. performance and there is no mention to take away the OEM seals when putting this K&N-filter. Further they say that when filter + prefilter installed it should be close to OEM-filter.

Now that I had my filter inspected and had to order a new cover for my airbox because the inside FOAM  was falling in parts from age (12 years) - I asked the dealer about the OEM O-rings if I should put new ones in or not. He said that the airbox should be tight (no false air) and that if the K&N filter is between cover and box there should be a couple of mm. that you should tighten - I have checked it and without any O-ring the 2 parts went on each other - so have put the 2 o-rins in it (1 in the cover and 1 in the underpice of the airbox - then I tightened the cover with the 9 screws till they were on each other. No problem as the OEM O-rings diam.3mm are made of very soft rubber that you can tighten easily.

So the airbox is tight like it should and inside it the combination of prefilter and filter from K&N is similar to the stockfilter.

My bike is bought new and full stock except the TW 6° - K&N-filter (but as said should give like stock) - interstate carb springs and tank 1,5 cm higher because of my stacks.

The mainjets on the '97 model export are #78 acc. to the manual taht I bought together with the bike + I do have that foam thickness 10mm to restrict the air - this is 100% OEM and now she is again 100% OEM as concerns the air because of the new airbox-cover that I mounted and is tight (no false air) as it should be.

I have no references with other Valks here, as I live in that small country called BELGIUM, with very few F6C's. If I would live in your neighboorhood then I would come to you and ask your opinion in the pulling of my bike compared to yours etc. etc.

No I am alone and no mechanic, but really want my bike to let perform at max. to my joy. A couple of weeks ago I looked at the color of my sparkplugs : they are darkbrown as coffee with very few milch in it. But I do only short distances, no long rides....

I don't know if the stockneedles can be shimmed or if you have to put special needles in it where you can put the needles 1 stop higher ???????
Is it safe to check the pilot screw - now everything is stock + 1/2 turn out, but I don't know at how much they are out in totall .

Should I simply turn them all 6 in and then 2.1/2" out ?? The manual says to connect an rpm-meter and then let drop the idle till 50 rpm - then 1 turn out etc. etc. BUT I HAVE NO RPM-METER AND THEY ARE HARD TO FIN + EXPENSIF !!

What I can say is that when the bike is completely warm (80°c) it performs the best - cold much much less.

Here a test on the testbank = 25 dollar - to let them change needles and test on testbank + again changing till everything O.K. would cost me about 1000 dollars. TOO MUCH FOR ME.....

Can I work things out by E-mail / technical board / etc. to get her at her maximum, or forget it all and ride like she does now?

Thanks for your help,

[Tundra]

When changing to a K&N the shape of the filter takes the place of that ring type seal that sits in the air box. If you do use it, most likely you'll mess up the shape of the edge of the filter. But in any case, the filter itself takes the place of that ring.

 John you are correct, took me a while to figure this out. If you look at the K&N Filter from the side, it is "T" shaped and one end of the "T" fits into the lower portion of the airbox and one fits into the upper portion or lid of the airbox. No stock gasket is required for proper installation of the K&N filter.
 
 Robert, right on! Ive had this discussion with several others. I run K&N, no pre-filter, gutted exhaust, de-smogged with 4" truck stacks and Dyna ignition. It has taken me a year to understand what you are saying. It took a lot of adjusting and cleaning of carbs. and chasing down vaccum leaks. My vaccuum leaks were causing popping which was amplified from the gutted exhaust. When I finally found and replaced the exhaust gaskets, intake gaskets, craked vaccuum caps and got my fuel and air correct, and then finally a Carb. synch.  (thanks to Thunderbolt) It's a new machine.
  Wow, guess what I'm trying to say is, it's a labor of love.

[John Schmidt]

I've been running the K&N without the foam prefilter for over six years. The instructions that came with it said to leave the o-ring seal out because the filter itself takes the place of it simply due to its shape as Tundra mentioned above. The first thing I did was to desmog due to some bad vacuum hoses, found when changing over to an I/S tank shortly after I got the bike. I've been running a 4 deg. TW for about five years, along with I/S carb springs and I/S ICM. About two years ago I installed #38 slo-jets, and for most of the six years I've been running an aftermarket exhaust...modified muffler and using stock headers. Result....overall about a 10% bump in HP, relatively good mileage if I behave(upper 30's mpg), and it doesn't run lean.

My feelings....if it's running lean you have other problems, judging from your posts/explanations. Maybe an air leak somewhere other than the airbox itself. If you've had the airbox off, did you make certain all the rubber intake tubes were down on the carbs when you reinstalled it? That's easy to overlook, they get curled under at the back of the carbs, thereby causing air to be sucked in unfiltered directly into the top of the carb rather than through the airbox. Get an inspection mirror and a flashlight to check the back side of the top of each carb. If any tubes are curled under, simply loosen the clamp, lift the tube up a bit and run a long skinny screwdriver around the top to install the tube correctly. I discovered that on myself a few years back, and that's the only time the bike ran lean and with poor performance.

[FLATSIX]

the airbox is neven been taken off !

I have changed the O-rings at the intakes + copper exhaust gaskets + tightened everything up to the max. for thightness.

I have changed the rubber plugs onto the carbs - only the #6 has a vacuumtube to the petcock, all others have plugs on the exportbikes.

So I really cannot imagine where I should have any leak???

 

[Robert]

Ok, I agree with John about the intake tubes there is a rubber oring in the connection with the head and like John said the rubber couplers sometimes leak. Because of being Loose taken off or just plain positioned wrong. I know the states have a pair valve this valve is located in the center of the engine below the carbs, I dont think you have this but check. The needles can be shimmed but its going to take small washers and thin too. They cannot be made to poorly because they have to be uniform in thickness. I found some from Radio Shack that worked before I put in a jet kit from Factory Pro. One shim under each needle will make a difference two is the same as one groove in a adjustable jet. Your plugs being brown is more than likely due to the air filter and air box. Start with the stock adjustment for the idle setting.  If you shim the needles then you may be able to get rid of the foam. There is a possibility that the carbs are dirty too maybe the jets are slightly clogged, I would do the easy stuff first see if this takes care of it and gives you the performance you are looking for. Like shimming the needles, then if that helps then go further knowing that your on the right idea. I read that you are in Belgium but our bikes are really a common design from Japan so you are not to different and if we can work on our own bikes and get good results you can too. It really depends on how much you want to. The tech pages will just about give you pics on everything that you would want to do and with a little mechanical ability you should do fine. Do a search in the Old tech archive and see how much info is available. It may not cost as much as you to do some mechanical things but I dont know any dealer that I would trust my bike to and not many personal techs either. It has always been better to work on your own bike as long as you do have some mechanical ability.