Dynojet kit

[FlyingSteve]

Ok, so I've been working on tuning my '80 550e engine in for better exhaust system (from an 82 gs550 katana) and pod filters. So far I got it pretty close, so where the mid-range and top end are pretty good... But after a period of low-speed/low throttle driving, the plugs get mucked up and then the bike wants to stall at idle... When I start moving again, if I rip on the throttle I can clean the plugs off and it'll be fine, but it's annoying and not right.

So I called up Dynojet and had a talk with a tech guy there and he told me what comes in the dynojet kit... One of the items are smaller main air jets. I came pretty close to getting the engine tuned in but unfortunately there are some things, like those air jets (expensive), that contribute to the drive-ability of the bike that are just not easily sourced or fabricated. I have spent 0 dollars on trying to tune my engine in and used old tricks like drilling my own main/pilot jets out... So I've really only spent time on this, but now it's just time to buy the fricken' dynojet kit and be done with it.

Now the closest kit I could find for my '80 GS550E, is the '82 GS550 Katana. According to carb information on BassCliff's site, both bikes use the same carburetors and I even looked at online parts fiche's to confirm this. DynoJet doesn't make a kit for my bike and so it would seem that the kit I need to get is the one for the '82 GS550 Katana. Is this right?

[gearhead13]

Not all kits come with main air jets, my 750 didnt but the 1100 kit did. There is no pdf about that kit on the dynojet site so unless someone has one you wont know until you get it.
The best thing is the adjustable needles and mains.
Drilled out jets are done by some people, IMO they just dont want to do it properly. I dont know of a kit that comes with pilot jets, so I think you will need to get new ones of those. Too big pilots will kill low speed and idle like you are describing. I would reccomend getting pilots one size bigger than stock. I have a set of 40's pilots here if those would help.

[FlyingSteve]

I drilled my pilots out 1 size over stock. Before I did that, my idle was really lean. Even after adjusting those mixture screws in the back. I was told by the tech at dynojet that the kit comes with the air jets. Like I said, I got the mid-range and top end good but the low end is ****e. I'm just tired of wasting my time on this. I have other things I could do in my life and on the bike.

From what the dynojet tech told me, I could probably tune this myself now by getting smaller air jets, but I wouldn't know exactly what size to get. I could go really small and drill it bigger step by step, but then I am spending money on the air jets... So it's just not really worth it. And drilling the jets out is a good way to go while tuning. It'll get you really close and then you can buy factory jets of the right size then if you want.

[chef1366]

If you're fouling at low speed than either your pilot jet is too big or the needle is shimmed too much.