Thanks to Murray (MUZ)

With Thanks to Muz, Without Whom This Would Not Be Here

Sunday, January 8, 2012

GT380 Carburettors

I have settled in at the new location and have finally got a bit of time to address the GT380. The last post was about the leaks in the fuel tank. I put a liner kit in it. I did take photos and documented the process however in the move I seem to have lost the photos. If I find them I will post them.

Anyway the kit worked well, the tank is fuel tight. The fuel tap has a leak and I must get a kit for it (if possible). When I cleaned the carbys there was a hole in the fuel bowl of the middle carb. I was unable to fix it properly, I made a temporary fix for it. It held fuel but did weep a bit, it was good enough to consider staring the bike.

My info was that the bike hadn't been started since the 1980's, I could be wrong about that. Anyway with the ignition off the engine turned over on the kickstart smoothly. I cleaned the points and sprayed a fairly heavy mix of fuel and oil into the intake ports and turned the engine over a few more times. These engines have roller bearings and as long as they haven't rusted they should be alright with a bit of oil. The engine felt smooth and the compression was ok. I put in a new battery, then put a little premix in the tank. I choked the carbs, turned the ignition on and gave it a kick.

Wonderful !!! It started first kick. It idled for about five seconds then stopped. I tried the kickstart it was locked solid. I didn't try any anything else. I'll pull the engine out and see whats happened. Could be anything. I doubt if it's a catastrophic failure. The engine was only idling at about 800 rpm when it stopped. We were getting ready to move at the time so I haven't touched the bike till now.

One thing I did do was to set up an ebay watch for a bowl for the carby. I also contacted Mikuni and many other retailers and specialists to get a bowl. No luck at all, seems the 28mm Mikunis on that are not even known to exist nowadays. Then I came across a set of three from the same model. They were being sold by a wrecker in Ireland. I only needed the bowl but he wouldn't break up the set, so I unwillingly bought all three for almost $150.00. They arrived a few weeks ago and so I began to pull them apart. I thought I would keep the bowl and restore the rest and on sell them again.

I don't know if that is possible. Externally they didn't look too bad, when I began to dismantle them.....yuck and double yuck. The slides were stuck, which I expected. When I removed the bowls, disaster. They were full of a white crystalline substance. I have seen similar stuff on the inside of carbys before but nothing like this. They are almost full of this crap. I don't know if it's a by product of the breakdown of the aluminium or something else, but it's extremely hard to remove. See Below.

It's amazing the entire bowl is just full of the stuff. It had formed around the float and was extremely difficult to remove without damaging the float. Nothing seems to dissolve it. I'll keep looking for a solvent but if I can't find one it's a matter of a lot of time and patience to remove it. I hope the bowl hasn't got a hole in it.

Here a a couple more photos of the stuff.

I'm going to pull the engine out in the next week or so to see what has stopped inside it. I'll post the process.

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