Poxy bloody carbs

[sfcpiet]

They fit into rubber mounts via an aluminium spigot that fits into the body of the carb. It's a 37 year old bike that stood for several years before I bought it so there's no saying whether the bike was taken off the road because of a carburetion problem or the problem started because it was left standing for so long.

I've got a completely unrelated problem to sort out on the bike when this is done and it involves a Ducati reg/rec and a stray wire that I've dislodged and need to work out where it goes  :

Sounds like you have the Formula type carb mounting set-up.  The rubber intake is actually a modified 250 Chott item, unobtanium by now, and most certainly will show signs of perishing.  The rubber bit often seperates completey from the steel flange plate.  Do check that all is well here, leakages will no doubt cause rough running.  Easy to swap over to the stock 500 intake system (same parts as early triples), won't feel the difference, other that the engine might finally run as it should.

Charging system comprises of 4 wires, 2 yellows to the R/R, an earth and a connection to the battery, doesn't get much simpler than that!

piet

 

[AndyB_11]

Thanks Piet. Until now I'd just assumed they were the correct intake manifolds but by now I should have realised that nothing is as it first appears on this bike. The intake rubbers look ok and nothing happened when I gave them the obligatory 'sniff' while it was running but that's not to say they aren't part of the problem.

I'll be heading off to work soon and once I get myself settled in for the week I'll start looking at possibly buying different intake manifolds if only to eliminate any potential problems in the future. I've always expected the bike to run rough because of what it is but I also expect to be able to dial a lot of that out if I spend enough time (and money) on it but sorting these carbs out seems to be as easy as herding cats.

 

[sfcpiet]

They are sort of "correct" Andy.

Not quite sure why the factory took this option, don't think it has much to do with power gain, probably more as a measure to combat fuel frothing during races.  With this set-up, the carbs need to be supported by a hanger from the top frame tube if the air box is omitted (obviously was on the racers).

Haven't had any issues regarding the stock 500 carb mounts during the past 20-odd years on wifeys' 500.

piet