Hibernated XII wakes, revs and dies.

[Write2Paul90277]

Hi folks,

I recently picked up a beautiful 88 ZG1200 that had been sitting for 3 years. I drained the float bowls, added fresh gas, changed the fluids and it STARTED INSTANTLY. But... it revved to 3 or 4,000 RPM, then died. I restarted it and got the same thing.

Like all good shade tree mechanics, I read everything I could find in your forum, then rebuilt the carbs according to the book, using new parts, 17mm float height, set the pilot screws to the initial 2 turns out, etc.

Now the carbs are back on and the bike does the SAME THING: Instant start, high, high revs, then dies. I can (barely) keep the engine running at high speed using the choke, but any throttle and it goes dead.

Anyone have this experience?

Thanks in Advance,

Paul
Redondo Beach, CA

[voyager55]

Are you sure it's getting gas? Fuel pump working ok? Replace fuel filter?
Put some Sea Foam in the tank. 1 ounce per gallon.

[Mr Jensee]

You are obviously getting fuel and spark however it could be air starvation. Make sure there isn't some critter who didn't build a nest in the upper or lower air box. Put some power to the fuel pump while you are at it and make sure it is pumping. Change the fuel filter too since they are cheap and easy to find. I am working on my own issues with another Voyager that has been sitting in a shed for 2 years. Good luck.

[Write2Paul90277]

Thank you, voyager55 and Mr. Jensee, for your suggestions.

Here's where the bike stands:

The tank is clean, the fuel is fresh, the fuel filter is new, the carbs are newly rebuilt, and there are no creatures living (or dead) in the upper or lower airbox.

I have not yet tested the fuel pump. Can someone tell me the EXACT wires involved in activating the pump? The last time I tried a fuel pump test (on one of those "other" touring bikes from Honda) I shorted out the whole pump.

Also, I have a California bike that was partially de-smogged by the previous owner. If anyone suspects that the de-smogging may be part of the problem, let me know, and I'll tell you what has been removed, what remains and where the various tubes are hooked up.

Thanks for helping a newbie out!

Paul

[Mr Jensee]

Paul, give Carl Leo in Florida an email voyagerparts@bellsouth.net and see if he can give you some good suggestions.

[Write2Paul90277]

Good suggestion! I will get on that right away.

Paul

[scottolds]

When I had a suspicious fuel issue, I was instructed to just place a finger on the pump while cranking the motor. If it is working, you will feel it clicking.

Another thing you could try if you have an auxiliary gas tank (like the one from Motion Pro) https://www.amazon.com/Motion-Pro-Auxil ... B001DDNSKC

You can put gas in that, connect it to your carb inlet and let it gravity feed the fuel for testing instead of relying on the pump.

[Write2Paul90277]

Thanks, scottolds.

As it turns out, I didn't have to try the gravity-fed fuel tank as suggested, because I tested the fuel pump and it works like a champ.

Anyway, my original problem still exists: The bike starts (with full choke) then jumps up to 3 or 4,000 RPM. If I try to release the choke or twist the throttle, the engine dies.

One NEW piece of information is that if I pull the vacuum hose off the igniter, the RPMs go down slightly but the engine still won't run without full choke. When I put the vacuum hose back ONTO the ignitor, the revs go even higher.

Does anyone -- after reading this whole thread -- have any additional suggestions?

Also, I haven't heard back from my email to Carl. Is he out of town?

Thanks, guys.

Paul

[triton28]

Activating the start lever cable causes an over rich fuel condition separate and apart from the idle circuit to overcome the cold bloodness of a CV carburetor, which in turn usually results in the engine starting albeit at an rpm well above idle rpm.
In normal conditions, with NO internal idle passage blockages, one gradually reduces the pull on the starter cable thereby reducing the over rich fuel condition until one is at idle rpm and recommended fuel mixture through the idle circuit.
However; with any blockages of the internal idle passages the engine with NO choke applied will neither start nor run at idle rpm even if the engine is at optimum operating temperature, let alone at cold operating temperature.
No amount of adjustment will compensate for a blockage in one or more of the carb bodies.
OR, the carburetor/s when at "installed" position has/have the float level/s set too lean, meaning the floats are closing off the supply of fuel too early and causing too lean an idle condition.
I hate to say it but with the bike having sat for 3 years, my money is on blocked internal passages. The only way I have found to clear them is with an ultrasonic immersion using an aluminium friendly cleaning solution. For this the carbs can NOT have any rubber parts immersed.
With respect to Mr. Leo, I believe if you go to www.abbikeboard.com , under advertisements you may find a phone number.
I hope you discover something requiring less effort than my scenario,
regards,
Dave

[Write2Paul90277]

Thanks, triton28!

If you remember back to my first post, I already did the whole carb rebuild, including the ultrasonic cleaning and (what I considered to be) a pretty accurate float height adjustment. But one never knows if there's just that last little bit of debris in the carb(s) that can spoil the whole show.

Before I yank out the carbs again -- which you know is a beast of a job at best -- I'd like to eliminate every other possibility.

What haven't I tried??

Anybody?

Thanks,

Paul

[ekap1200]

assuming you didn't get crap back into the carbs on the install...where do you stand on the initial set up of the sync of all four. back off on the idle screw. get a set of vacuum gages and see if that makes a difference. try to get the cold choke rpm to about 2,000 for a minute or so and see if then you can get a vacuum reading and go from there.
Are all the carb boots on correctly ?
Also Carl recommended to all a while back not to use the aftermarket wire clips from the float to needle valve's.

[Write2Paul90277]

Thanks, ekap1200.

I wish I had seen Carl's recommendation on not using the aftermarket float valve wires! I assumed that newer was better. The float level seems correct (17mm), but I must admit that during the wet test, the carb bodies were not held at the 45-degree angle as suggested. They were simply level with the ground. Could that make such a radical difference? All four bowls are getting gas, and the fuel pump is strong.

In response to your questions...

When assembling the carbs, I made sure all four butterfly valves were opening simultaneously. As far as doing a sync procedure (with gauges), I'm not sure I can pull that off when the engine is so hard to keep running. I'm not sure how that would solve the problem of the engine only running on full choke, then dying when the choke is released even slightly. But I will give it a try.

Yes, All the carb boots are on correctly, but I will check again. Are you suggesting that an air leak could be the problem?

Final question -- could the removal of any of the emissions hoses be at fault? I capped off the four vacuum inlets to the carbs and kept the small hose that leads from the #1 carb to the igniter box.

Thanks everyone for your help!

Paul

[Write2Paul90277]

Hi guys,

Here's a quick update.

I just got a call from Leo and he suggested a number of things that could be causing this high-revving / quick-dying engine problem. There's a possibility that one or more of the needle jets in my carbs either fell out during the rebuild or were lost by the previous owner. He also suggested that I double check whether the needles themselves are loose.

But before I go yanking out the carbs again, Leo recommended looking at some of the emissions hoses that might be plugged (or in the wrong place) as well as making sure that the two tubes that connect the lower and upper airbox are airtight. But guess what -- both of those rubber tubes and clamps are missing from my bike. I will go online right now to find replacement tubes, then investigate all the options above.

More updates as they occur.

Thanks, guys. Thanks, Leo!

[triton28]

none of the 4 vacuum hose barbs located by the throttle plates are used on Canadian models as the Canadian models came equipped WITHOUT the fresh air system that utilized reed valves in the cylinder head cover, tubing and muffler from the upper airbox, and a vacuum valve operated by a joined line from 2 of the carbs.
Our 4 brass ports on the carbs are all blanked off with those black rubber caps.
The California model used all 4 ports as it had EGR/pollution equipment mounted to the 2 unused black rubber capped ports on the U.S.remainder model setup
The #1 carb side hose is used for the ignitor on all Canadian, California, and U.S. remaining states models as you have surmised.
Dave

[Write2Paul90277]

Thanks -- I have done away with the rat's nest of California emissions plumbing. I feel a bit more Canadian already! Cool, eh?

[Mr Jensee]

Paul you are saying the top and bottom air boxes were never attached? How much dirty air probably got into that engine as a result? That is scary.

[Write2Paul90277]

.

No, no, no -- that would be disastrous! The bike was always operated with both the top and bottom airboxes in place. At one point during my carb reassembly, I thought I had misplaced the rubber connectors that join the two boxes together. They were there all the time.

BTW, I was looking at some video tutorials on how to cure lean conditions that can cause the engine to only run with the choke on (the same condition that keeps it from idling). The videos suggest to not only check all the jets for blockage (which I did already during the carb clean) but to check for vacuum leaks that occur in the rubber intake manifolds, air boxes, hoses, etc.

All of that is on my list for my next visit to the garage.

Thanks,

Pau

[Write2Paul90277]

IT'S ALIVE!! IT'S ALIVE!!

Hi,

After weeks of carb rebuilding, re-rebuilding and re-re-building (and lots of great advice from you) my 88 XII is back together and running great!

To get all four float bowl fuel levels equal, I had to vary the float heights between 20mm and 21.8mm. The wet test is now well within the 0.5mm +/- 1.5mm as specified in the service manual.

I set the pilot screws to 2 3/4 turns out and was able to synchronize the carbs to a "T." I used the dial type vacuum gauges and was able to calibrate them in advance using a Miti-Vac to standardize the readings.

Now the engine fires up instantly, idles evenly and revs effortlessly.

After years of riding GoldWings, this is my first Voyager. I'm surprised how incredibly smooth, quick and responsive it is.

Thanks again for your help and patience!

Best regards,

Paul