TOPIC:

Greetings all,
Ive been have quite the time with my GPZ550 H2. Rejetted with the Dynojet kit, 3rd clip and 86 main jet. Running stock airbox with UNI filter and Mac Headers with no baffle. When the bike heats up, I lose all power and the bike dies and I cannot start he back up until I let her cool down. I have new intake boots and airbox boots as well. I also did a mechanical sync to the carbs according to the specs. Am I just running too lean? Or did I mess something big Up? My spark plugs are quite black as I was running her very rich, thinking the bike was super lean from the new filter and no baffle.

Stalling when hot, if it's due to jetting, it's too rich.

It says to use the 80 main jets.
86 was stock main jet.

s3.amazonaws.com/gpzweb/TK26mainPage/TK2..._003instructions.pdf

I assume you followed the stage one directions and actually did install the 80 main jets.

So some possibilities are that the slides are not moving up properly due to cracked diaphragms or some other mechanical issue. Another is that the enricher system is not shutting off completely. Does the enricher (choke) push in with a very positive click? If not maybe the ball in carb #3 is missing and the enricher becomes active from vibration. I just went through that. The previous owner removed the choke rod and that causes the ball to pop out of carb #3.

See the end of this page on port routing.
s3.amazonaws.com/gpzweb/TK26mainPage/TK2...TK26portRouting.html

Hey LoudHVX, I think I may have misinterpreted the warmup symptoms for being lean and i put on the 86, Ill swap it back and do a PROPER warmup and see. Also I have a slight oil leak, and it does tend to get worse when the bike heats up..

Have the valves been checked for proper lash?

Hey Tex,
I won't pretend to know what lash is, but ill google it! I checked the valve clearance and its all per specs.

Hey Loud,
I put back the 80 jets, and the bike has a much better power delivery from idle to WOT, BUT after I warmed the bike up, drove about 1.5km and from a stop the bike just bogged down and died in the middle of an intersection!! I hopped off and checked out the choke-position (was off). I was not able to get the bike started until I let the bike cool down for 10 min or so.
Some observations when I had the bike warm:
half choke spiked rpms
full choked killed the engine
Bike was spiking rpms when blipping throttle and took a few seconds to lower back to Idle speeds
Slight backfire when letting off throttle
power loss at various throttle positions as the bike ran (after warmup)
I did a bench sync of the carbs earlier that day

Just a quick thought, Have you check your fuel tank cap vent, if its clogged you got a vacuum in the fuel tank that
reduce the fuel flow (lean mixture). Try to drive with an open tank cap if the bike runs better over a longer distance or warm up time.

Michael

Does the choke shutoff with a solid click when you push it in?
Scroll to the bottom of this link to see where the choke detent ball resides:
gpzweb.s3-website-us-east-1.amazonaws.co...TK26portRouting.html

Are you certain you are idling on the pilot circuit? The intermediate main circuit will kinda let it idle on that circuit when cold. But once it gets warm it won't idle anymore. Then if you open the throttle to get it to idle, it will end up racing or stalling.

Have you looked at the pilot jets to see that they are spotless internally?
gpzweb.s3-website-us-east-1.amazonaws.co...26jets/TK26jets.html

Are the pilot jet caps (aka plugs) in place with good orings?
gpzweb.s3-website-us-east-1.amazonaws.co.../TK26pilotPlugs.html

The choke click is very solid feeling and audible. I double checked the pilots and cleaned them last rebuild, but I will check again.. I think one of the plugs does not have an oring, Ill double check tonight. Also I didn't tighten down my intake boots from the carb to manifold well , so they might have heated up and I had a massive leak. Ill look into it and troubleshoot some more. Thanks
Edit->
Checked out the choke rod detent balls on each carb and they are there thankfully

Just pulled the carbs off, and yes carb #1 has a plug with no o ring

kosh3rhalal wrote: Edit->
Checked out the choke rod detent balls on each carb and they are there thankfully

There should only be one on carb #3. What exactly are you looking at? That link I gave shows the hole on carb #3 where the detent ball and spring should be. The other carbs don't have it.

You are using the rejetted H-Model TK26 Carbs, right?

Turn the petcock to PRI and ride it, to see if this issue goes away. Could be fuel starvation, or like mentioned, the cap is not venting?

How much fuel is in the tank, and how clean is the tank? Could be the screen inside is clogged al lower fuel levels,

When it does run good, can you take it to 7-8k? How long or how far can you ride before it starts to die out?

Between carbs 1-2 and 3-4 there are vents on the air box side. Are these open or capped off? They should have hoses routed to clean air. I have seen these connected together with the same hose, and the bike dies out.

There are clips on the carb choke rods at each carb, and I have seen one of the clips missing, not allowing the rod too move back in, but the other 3 will.