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A Close call

Submitted by peter_shand on Thu, 12/03/2020
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Commando

What is in todays Petrol?

Yesterday i had the unfortunate experience of one of the two fuel pipes that attach to the SU carburettor come adrift and dump the best part of three gallons of petrol from the left hand side carb spigot. Very lucky not to set fire, and after begging a length of lockwire from the nice people at Teesdale Motorcycles in Thirsk, wired the pipe back on and filled up again to get home.

What a smelly mess its made. Totally stripped the paint from one half of the starter motor, better than using Nitromors! Turned the powder coating on the gearbox cradle, swinging arm and frame a yucky grey colour as well as cracking said powder coat (to be fair the powder coating wasn't very good quality and was on the bike when i got it) The petrol spigots on the SU do not have any barbs on them. I have replaced the pipes twice before when they lose their flexibility and on reflection should have done so again this winter. To any other owners of SU equipped bikes, wire the pipe clips together to prevent pipe and thus fuel loss

regards Peter

Attachments
petrol pipe mess2.jpg
Petrol pipe mess.jpg

Submitted by sam_milner on Thu, 12/03/2020

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Seems to me Peter you had a lucky escape with the bike not going up in flames, I've seen it happen with much less encouragement. Did your starter motor get filled with fuel ?.

sam

Submitted by andrew_heathwood on Fri, 13/03/2020

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Peter

Lucky that it didn't catch fire.  As a matter of interest what type of tubing was in use for the fuel lines?

I've has various types of plastic tubing go very brittle after a just a few months use with modern petrol. When this occurs the joints to metal fittings, e.g. t-pieces and banjos, have become loose and occasionally leak.  I'm now using a Tygon-based clear tubing which is lasting well - 2+ years to date.

Andy

Submitted by robert_tuck on Fri, 13/03/2020

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The original (plastic?) black fuel line is still in use on my 99. It has gone very hard  and I carry a spare pipe on the bike . It has the original crimped brass ferules . I expect it to fracture ,the long life may be due to the very firm tank mountings and restricted movement. 

Tygon based tubes are the way to go. I've supplied four different bikes with years ago and no fails at any of them.

Fritz

Submitted by peter_shand on Sun, 15/03/2020

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The pipes were fitted with good quality clips. It looks like the pipes had shrunk in length as well as going hard which contributed to the pipe detaching itself from the carb. Now fitted with new pipes a bit longer than what came off and with the pipes and clips wired together across the back of the carb.

Petrol has always gradually removed the plastisier from PVC pipe and the like (even in the good old days) it seems the modern petrol takes this a stage further. I will probably end up using tygon fuel pipe (or something similar) next winter when i replace the petrol pipes again.

Peter    

 


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