Getting the Jetting (right)

I know there are plenty of jetting threads out there, just wanted to confirm something though.

I have a 1980 KZ440LTD with pod filters. My pilot jet is 35 (i understand finding larger than this is a problem), my Secondary main is 92.5 (went up from 88) and my primary main is 62 I believe.

At low throttle the engine bogs and sometimes dies, mid ranges seems great and i hit a brick wall generally at 7000 RPM when in top gear.

My question: Should I go up a size on my primary main jet? My guess is that the primary is the one that is limiting my top end?

The "main jet" augments the jet needle to provide off idle fuel... the secondary main jet is the one that provides fuel when the jet needle is completely out of its seat as when the throttle is wide open. Did you alter your airbox or exhaust?

WG, currently I have pod filters.

I've noticed that my problem isnt happening at a specific RPM range, just when i open the throttle more than half way when the engine is under load.

At half throttle, its fine, I accelerate. When I try to go past that, the engine tone changes and my RPMS just hover at one point no matter how far i continue to open the throttle.

So for my problems with off idle, I might be wise to increase my main jet a size? I have already increased my Secondary main jet two sizes so this trouble with half-full throttle is confusing me a wee bit.

Oh my needles also have a thin washer underneath them, I guess for the purpose of raising the needle. This was how they were when I bought the bike.

The washers under your jet needles (all called jet shims) are there because the person who tried to tune the carbs for your pods couldn't located the main jets needed. If you went up to #68 mains, that would work well; even #65s would help. The problem you are having at 5K rpm, is more likely the secondary main jets. Going from #88 to #92.5 was more or less a waste of time. The CV carbs need larger main jets... Since I have no bike to try different main jets and your bike is starting to run out of gas at 5K rpm on the main jet, I would try some #120s to begin with.

Once you get into checking main jets, there are several ways to do this. The plug chop will work but could take a LONG time to figure out unless you get into the ballpark to begin with. Get a set of #120 Keihin main jets and install them as your secondary main jets. See if the bike will pull redline CLEANLY. If it starts to bog/stumble, pull the choke up a bit and see if this HELPS or MAKES THE PROBLEM worse. If it helps, the mains I suggested are too small and if it makes the problem worse, they are too rich.

You may end up buying several sets of main jets. I would suggest #115, #120, #125 for the testing... its only six main jets. Start with the #120s and see if they work OK and then move up or down in size based on the choke test. Honestly, a bike running out of gas when the mains are too small feels almost identical (to me) to one that is too rich that falls flat because of richness.

The washers under your jet needles (all called jet shims) are there because the person who tried to tune the carbs for your pods couldn't located the main jets needed. If you went up to #68 mains, that would work well; even #65s would help. The problem you are having at 5K rpm, is more likely the secondary main jets. Going from #88 to #92.5 was more or less a waste of time. The CV carbs need larger main jets... Since I have no bike to try different main jets and your bike is starting to run out of gas at 5K rpm on the main jet, I would try some #120s to begin with.

Once you get into checking main jets, there are several ways to do this. The plug chop will work but could take a LONG time to figure out unless you get into the ballpark to begin with. Get a set of #120 Keihin main jets and install them as your secondary main jets. See if the bike will pull redline CLEANLY. If it starts to bog/stumble, pull the choke up a bit and see if this HELPS or MAKES THE PROBLEM worse. If it helps, the mains I suggested are too small and if it makes the problem worse, they are too rich.

You may end up buying several sets of main jets. I would suggest #115, #120, #125 for the testing... its only six main jets. Start with the #120s and see if they work OK and then move up or down in size based on the choke test. Honestly, a bike running out of gas when the mains are too small feels almost identical (to me) to one that is too rich that falls flat because of richness.

Once you get the main jet sorted, please contact me to let me know what you settled on for a main jet with pods. Thanks!