82 550- K&N issues.

[Kusuki]

I've just registered here, and have been using the search function to see if anyone has taken there air box out and replaced it with K&N air filters.I couldnt find a thread, but mabye one of you kat pro's might be able to help me out.

I bought a 82 550 katana awhile ago and have slowy been fixing it up for spring. Since i bought it I took the air box out because getting the carbs in and out was a serious pain in the ***, ordered and installed K&N air filters. So with the added air I added bigger main jets, went from stock to 117's. Figured that would be enough added gas to get it from running so lean. but nooooooo.

So heres the problem(s). Idles perfectly, has a very sexy purrr, but when under load it starts coughing and almost dies. Really have to work the throttle even in first gear.So I'm thinking its not getting enough gas even with the bigger mains?

Also after running for a few minutes it wont start again untill it's cooled down? anyone know a fix for this?

Any help on this would be great, I'm getting close to buying a dyno jet kit but wanted to see if anyone had a solution i was missing.

Thank you.

Tl;Dr- i put K&Ns in my 550 now it will barley run under load, even with bigger main jets, also wont start after hot. Help.

[DOCTORNITRO]

[KAT TOY]

every thread on this forum about K&N filters ends up with the stock airbox going back on. good luck.

[DClark]

Don't buy Dynojet, it is junk. As for K&N filters, they can work fine on these bikes. I say this because while in college, I drove a '80 GS 550e (from '82 to '87). I bought it used in '82 and it came with jetted with K&N seperates and a Kerker 4-1. Ran great, only problem was those filtes would pop off and were hard to reinstall. I replaced them with Uni foam filters, ran fine, good bike.

[Kusuki]

Well putting the air box back in is not an option, I did irreversable damage to it and also made a custom bracket for the electronics wich now sits in it's place.


I'll have to keep brain storming. Got to get it running soon. It's getting sooo nice out there.

[DClark]

Take the carbs out and see if there is a jet kit (look for notched needles) and note the size of the main jets.
Next, find the number of Factory Pro's tech department and ask for advice. Don't worry that they won't help as you don't have one of their kits; they are very helpful. Basically, tell them what you got, and that you want to run with seperates and if they don't have a kit for you, they might be able to rustle one up.

[jetmerritt]

Where are you? exciting to see another member in BC.

And for best results... Stock air box and filter, no dynojunk.

And I almost forgot, WELCOME!

[Kusuki]

Thanks jet, I'm on vancouver Island in nanaimo.

I'll give that a try Dclark, I do know that the carbs didn't have a kit in them. But I put in bigger main jets ( stock were 92's , put in 117s).

I'll see what I can do.

[Kreylyn]

From your problem description...

"work the throttle" and "won't restart when hot"....

I would say your probably running rich. Too large of a jump on the main jet.

The fix... Seriously... Put the bike on a dyno and get real numbers of your a/f ratio for all rpms, THEN you have the info to do exactly what you need to tune the carbs for the setup you want to run.

If you can't do that, then consider looking at putting a sensor on your bike.

If that just isn't going to be an option you persue, look at the tuning instructions for a factory pro jetkit. Even if you don't have one of their jetkits (I would recomend you get one, but... ) their instructions will work for your situation as well.

Start with the main jet size and make it right so that the bike runs best at top rpms, then tune/adjust down the rpm range from there.

Krey