TOPIC:

it took me 10 (ten) years to have the babe starting properly. People even gave mne applause coz I had been able to start it on a rally. Now our relation is much better (thanks to the right battery) ...

Wish you all the best

Holger

Thanks fellas. I was pretty wound up last night. Just getting really frustrated.

So here are some more details.

There is no solenoid fuel valve. Gone off of this engine and both of the other bikes didn't have them either.

There is a fuel filter which is not visibly plugged. It is a very small filter but I don;t think its flow is the culprit because it HAS worked beautifully with it on and has worked like crap with it off. I put the filter on just prior to having my 79 tank cleaned.

Routing. With the 79 tank on the fuel leaves the petcock, 1 inch of line, tiny fuel filter, then angles straight into the rail.

With the 81 tank on the fuel leaves the tank, goes through 3 feet of line coiled up, meets an inline shut off valve, then joins to the line as described above for the 79 tank. Filter and all. The reason for the extra line and valve is because I've been putting this tank on a stand beside the bike to play with the carbs. When I take for the test run I throw the tank right on the bike. Cosmetically its not as nice as the 79 tank so I'm not as worried about moving it around.

Weird thing.... it consistently runs better with the 81 tank despite the mess of extra line and valve. On or off the bike.

I thought the 79 tank was dirty so I had it cleaned by someone who does such things. I wanted it lined but he advised against it. He said the tank has so many valleys that the solution will take forever to dry properly and said other than buildup and some rust on the edges it wasn't too bad inside.

The 81 tank is lined with red goop which I assume is red kote. As I said it works consistently better with the 81 tank. After swapping tanks it doesn't work better immediately.... which I would have thought it would if it were a flow problem alone. After switching the tanks it doesn't crap out or work better immediately. Hard to say what the interval actually is since I've been messing around with this for weeks. Hours? Overnight?

Edit to add: Other than the tine it acted like it ran out of fuel it always starts with just a touch of the button. Cold or hot as long as the lever is in the right position for the temperature. When cold it idles rough until it warms and idles well at 1000 rpm. When hot it idles higher at 1500 rpm regardless of how low I set the knob.

When you have ran the bike for a short time, does the petrol flap HISSSSS when you open it ?

Pete F
UK

No, the cap doesn't appear to hiss.

I swapped back to the 81 tank. No missing, runs well. I blew the vent and overflow out on both tanks and weirdly the 81 had a yellow cloud come out... that is the tank that works.

I'm swapping caps next. Then petcocks. I'm ordering a pingel anyways.

Hi, I'm a newcomer to this site, but my A1 does the same type of thing. Starts OK then after a few miles starts popping and missing just like fuel starvation. So I fitted a large glass bodied fuel filter about 3 inch's long, next to the left hand side carb. So this will also show you the fuel level inside the carb. This has been done with the fuel shut off valve by passed. Most of the time the glass bodied filter is only 3/4 full, when the bike is running well it drops showing you the fuel level inside the carb. When the bike starts popping and banging(running crap) you can see the filter is almost empty. I can't say why it does this, but NOT ELECTRICAL. So Vent in tank ? blockage between carbs ? Petcock swelling due to ethanol in the fuel, here in the UK we have had lot's of problems with Ethanol melting plastic filters and swelling the gauze in the filters. Oh and don't forget Sticking fuel valve inside the carbs. Well I think that covers everything ! Well almost, I've heard of low pressure fuel pumps fitted to 1300's has anyone done this ? does it work?

One thing that may be causing low fuel flow is if you use plastic the surface tension of the fuel against the plastic will slow the fuel considerably. A rubber tube will flow much more fuel. Another thing I have experienced is that of using the plastic car type of fuel filters with a paper element, they are not at all good when gravity is the only pressure. I had a R80 BMW which was fitted with these filters from when I bought it and while riding it home it would not keep going at 100kph and would after 2-3 km start to starve for fuel. I fitted small brass matrix filters and the flow was close to 3 times what it was and the bike never missed a beat for lack of fuel again. A full tank helped a bit.