TOPIC:

I am at my whits end. I am very close to saying screw it, and ordering the BS34 kit from WG. My VM26's have been cleaned and blown with compressed air several times. I have done the coil repowering mod in combination with installing new Dyna coils and wires. the spark plugs are new and gapped correctly. I have statically timed the bike (Dyna III ignition). It won't idle well/low enough to do it dynamically. I jetted the carbs per WG's recommendations (112.5 mains, 17.5 pilots) and set idle screw to 1.25 turns out per manual as well as trying 1.5 and 1.75 turns. The floats are all perfectly even (can't remember what height I set them to, but I got it from the mutual consenses here). I bench sync'ed them as best I could and as best as I can tell with the rough idle on my vaccuum tester, the vaccuum is pretty even. The compression checked out great. The cams are on the right teeth and I reset the chain tentioner per the manual. I have pods on it with stock exhaust, but they don't have the lip in them that would/could restrict airflow.

I can't come up with any more reasons why this damn bike ('77kz1000b1) won't run right. The idle is rough, but it will run w/o the choke on. However, when I try to ride it, it doesn't really want accelerate. It jerks and lerches, boggs down, then will try to take off, but poorly. I have been fighting with this bike for, what has now become, years. I don't know what else to do.

Post edited by: kzmason, at: 2006/10/28 20:19

I forgot to mention that my battery is new and well charged and that the bike starts right up and can be weened of the choke within about a minute or so.

hi,i dont really know alot about bike's but your bike sounds alot like mine it had all the same symptomes.i just got it going yesterday.have you checked the plug lead's one of mine was cracked,i allso put in a hotter plug that made a big difference.and with the pod's i had to change the main and pilot jets.i dont know how long it will last but the bike is flying now.hope you get it going.

i'm in the process of solving a problem similar to your's on my 750 twin, i've done everything you've done, except, leaks in carb boots, maybe??? the left hand cylinder is missing, it's bogging down the right hand, i'm thinking the intake boots haveto be really tight, it's alot easier for it to suck air through a crack than gas/air through the carb
and i still have some suspicions of the carbs although i've checked them out 34,567 times

Checking the carb holders for leaks is a worthy idea -
they get hard and inflexible over time, and cracking and air leaks can develop either that way or at the mating surface due to warpage or whathaveyou...

That could cause the conditons you're seeing.

A thin film of sillycone on the head/holder joint ain't a bad idea under any circumstances.

I had the same problem with a set of vm26's and found that the passage in the carb bowl was plugged not letting the small pilot tube pick up fuel.Causeing a low RPM problem once the RPMS wear up into the main needle circuit the bike ran better.Just a suggestion I myself over looked this (passage in the float bowl) the first time from being in a hurry.But learn from my mistakes I have.

kzmason wrote:

...The floats are all perfectly even (can't remember what height I set them to, but I got it from the mutual consenses here)....

Hmm. This does not sound correct. The floats should not all be "even" with each other necessarily, they should be set to the level that each individual carb required as determined by a "wet setting".

You can use the "dry" method to set them as a *starting point*, but you should use a float fuel-level gauge (home-made or otherwise) to verify them to be absolutely sure.

You say it only runs with choke on - a sure sign of an extreme lean condition. And since it looks like the floats are the only thing you did incorrectly (judging by your description), that's probably what's wrong... no guarantees...

I set floats with a caliper. They are (even both sides of each float) all set exactly the same (25mm if I recall correctly, but not sure).

I said it runs fine with out the choke on (knew I shouldn't have shortened that:) )

As for the bowl passages, all are clean and pass cleaner and air.

In the past, I have sprayed starting fluid in around the holders and noticed no change. I also tried it with propane from my turbo torch.

Post edited by: kzmason, at: 2006/10/29 11:29

Check your timing advance unit. Roy

The unit advances, I can see it with the timing light as I rev the engine.

kzmason wrote:

I set floats with a caliper. They are (even both sides of each float) all set exactly the same (25mm if I recall correctly, but not sure).

Still, that is a good place to start, but you still have no idea if they are set correctly as far the fuel level in the bowls at runtime, with gravity. You need to get/make a fuel-level gauge with plastic tubing and maybe a fitting.

kzmason wrote:

I said it runs fine with out the choke on (knew I shouldn't have shortened that:) )

My bad.

So how do your plugs look? Sooty? White? Tan? In-between?

I'll check them out. I haven't cleaned them and reinstalled them after warm up yet. I also have a colortune that I haven't encorperated yet either. Though I wasn't impressed with it when I tried it on my other bike (causes a lot of missfiring).