TOPIC:

Carbs totally gone through for the 4th time as everything was poked through, sprayed with brake cleaner then blown out with compressed air.  I have owned this Gpz550 since 1997 and was running perfectly/rejetted, then parked as it sat in my garage for about 25 years.  It is a 15k mile 1982 GPz-550 with a Bassani pipe and Uni pods (on TK 26 Carbs).  Tank cleaned/new gasoline, new fuel/vacuum lines and a fuel filter installed. (Runs the same without the fuel filter) 
All wiring/electrical is stock reseated/Deoxit connections.  All Ignition parts test in spec with new standard NGK spark plugs.  Air box was gone when I got it so the vacuum lines were replaced following is how they were routed:  Carb # 1 and 4 are tied together, carb 3 is blocked off and carb 2 vacuum line goes to the rebuilt fuel petcock.

At this point it will start fine on choke, idle but will take no throttle over 4-5k rpms in the garage.  Just bogs until I back off the gas and it will idle again.  Took off the air filters and the same but son says all the diaphragms move up smoothly with throttle then flutter up and down when it bogs. 

Been at this for months with no progress, ideas please?
 

Green do you have the pugs for the pilot jets?

here is a superb source for info on TK's

gpzweb.s3-website-us-east-1.amazonaws.co...ge/TK26mainPage.html

/A

Yes, original pilot plugs with new Orings throughout all 4 CV carburetors.  Some small cracks in the diaphragms where they fit in the carb groove seem to be fixed with 4 thin coats of Plastidip applied using a small paint brush and dried for a week (replacements not available in the USA). 

Bike is reluctant to take throttle then hits a brick wall at sometimes up to 5k rpm if I am lucky.

Well either it getting to much air or to little fuel.
did you check float heights?
have you checked for vacuum leaks?
Do you have a photo of the carbs installed?
/A

Different bike, but I once had same problem when I first got my 89' (Yes, 89. First model that came out) ZX-7. Back in the days, it took so long and limited sources to get aftermarket parts. Anyway, back in the days, normal things to do was take the air box off and put some pod filters (along with some usual modifications back then).

Long story short, when I tried to run the bike without the air box, it sucked so much air it never went above 4k on the tach. I went all over the island to find some jets, but at that time, no one had jets for Keihin carbs (most of the shop only carried Mikuni jets). 

Try block off the carb intake side with long piece of wood or plastic and see if the engine will rev up. If it does, you just found the problem. If it's the same, try look at the carb boots on the engine. 25 years is long time and i wouldn't be surprised to find some hairline crack(s) on the boots.

My guess is a stuck timing advancer. 

scubaanders wrote:

Well either it getting to much air or to little fuel.
did you check float heights?
have you checked for vacuum leaks?
Do you have a photo of the carbs installed?
/A

Yes, float height set to 27mm and double-checked last time they were gone through.
Has the Dynojet stage 3 kit.  Needles on groove #2 and DJ110 main jet.  I do now have the fuel air mixture screw at 3 turns out, Dynojet specifies 2.5 out. 
All these settings ran perfectly when the bike was parked 25 years ago including using the Unipods.
It really seems like this thing is just running too rich, gas smell out the pipe.

Is the fuel air mixture screw richer when turned out?

scubaanders wrote:

Well either it getting to much air or to little fuel.
did you check float heights?
have you checked for vacuum leaks?
Do you have a photo of the carbs installed?
/A

New vacuum lines are secure and the boots appear good, the carb boots need a bit of heat then the carbs go on with a pop..

 

Ojisan rider wrote:

Different bike, but I once had same problem when I first got my 89' (Yes, 89. First model that came out) ZX-7. Back in the days, it took so long and limited sources to get aftermarket parts. Anyway, back in the days, normal things to do was take the air box off and put some pod filters (along with some usual modifications back then).

Long story short, when I tried to run the bike without the air box, it sucked so much air it never went above 4k on the tach. I went all over the island to find some jets, but at that time, no one had jets for Keihin carbs (most of the shop only carried Mikuni jets). 

Try block off the carb intake side with long piece of wood or plastic and see if the engine will rev up. If it does, you just found the problem. If it's the same, try look at the carb boots on the engine. 25 years is long time and i wouldn't be surprised to find some hairline crack(s) on the boots.

We nearly blocked off the carbs with a thin piece of wood but it did not help, same issue.  Air filters were off for this...

ckahleer wrote:

My guess is a stuck timing advancer. 

We did remove the timing cover thingee and cleaned things up and lubed it where the manual specified.  
Seemed to spring like it should but do not think there is anything to adjust/test as there are no points.

Not great pictures but these spark plugs have 15 minutes on them, bought new today.  The old ones smell like gas when pulled out.

 

GpzGreen wrote:

ckahleer wrote:

My guess is a stuck timing advancer. 

We did remove the timing cover thingee and cleaned things up and lubed it where the manual specified.  
Seemed to spring like it should but do not think there is anything to adjust/test as there are no points.
 

I would still verify timing advance with a timing light. It"s an easy check. Just verify timing advances as rpm's increase. On a CX500 I recently worked on, 4.5k rpm is as high as it would rev with no advance.