Jetting problem?

[emjay]

So, I finally got my 82 550 Katana running better. Turns out a previous owner didn't bother to put the clamps on the inner two intake boots after some work they did. :shock: Too difficult to get at I figure.

Now it idles great, accelerates smoothly until it hits about 5000 RPMs. After there nothing changes, no more power increase. The bike is mostly stock except for a 4 into 1 header and a Vance & Hines megaphone exhaust. The pipe is very loud. I'm thinking the baffles need to be repacked but am not sure.

Anyway, I don't know that much about carbs, but I guess it's time I learned. I've searched around the tech section for ideas and think the main jet is either clogged or the incorrect size. Either that or a simple baffle repack would fix the problem. Am I correct in assuming it's the main jets that come into play after 5000 RMPs? Are they accessed via the float bowls?

Also, how do I remove the baffle to repack it? Do I remove the megaphone or is there some other way to get it out?

This is my first bike with the exhaust all on one side. It definitely has a different sound - all in my right ear. I know I prefer the look of a muffler on each side, now I think I prefer the balanced sound as well.

[Dave8338]

Yeah...it sounds like you're running out of petro at 5000RPMs. If the petcock screen is clean, move on to the fuel line. If there is not an inline filter, check for kinks in the fuel line. From there, I'd check the float the main jet size and the float height setting. Not sure on the spec for your particular bike, but someone here will know. If the float spec is correct, next check the screen on the back/bottom of the needle valve / seat set up. If all is clean there, you are headed for a carb teardown and sync.

[emjay]

Thanks for the idea. The bike does have an in-line fuel filter. The tank has been patched up a bit, so there's probably a history of fuels issues. That'd explain the filter. I'm pretty sure it has a stock petcock, so I'd think the filter in there would be adequate.

I wasn't thinking it was a fuel line, bowl, or float problem since it gets all the gas it needs below 5000 RPMs. But then again, it might be restricted but at lower RPMs it isn't an issue since it's not demanding as much.

I'll check all of that and even pull the in-line filter tonight. I'll post back with results.

I must say the 550 is much more "flickable" than my 850. I think I'm really going to enjoy this bike.

[emjay]

...Also, how do I remove the baffle to repack it? Do I remove the megaphone or is there some other way to get it out?

So. I looked at the exhaust today during my lunch break and discovered a bolt that holds the baffle in! :-D I removed it and pulled the baffle out. There is no packing at all, just the baffle. Should there be? I ordered some from these people http://www.cyclewareables.com/pages/...st_baffles.htm (thanks RJz1100E) so I'll find out how it sounds and if it makes a difference to how it runs.

[Dave8338]

My guess is that it will fix the problem or at least let you know that lean is the problem. PO may have removed it for that "cool" sound.