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*Touring Ted* 5 May 2010 15:51

Vacuum fuel pumps
 
I'm having problems with fuel flow and airlocks with my Clark Tank/DRZ400 set up.

The tap is lower than the carb and the routing is very tight and impossible to put a decent filter on without kinking the fuel pipe etc etc.

Anyway, I want to experiment with a vacuum pump. I have an expensive Mikuni one on my Africa Twin and it works great..

You can buy small ones for Go-karts for about £30

Kart - Rotax Max Fuel Pump

http://base1.googlehosted.com/base_m...4e4d70d7&hl=en

Has anyone got experience of cheap vacuum pumps ??? Any recommended ones ? The one on my Africa twin is £100 and I don't want to spend that lol.

Where can I buy the fittings for the carb ????? Anyone ??

Thanks, Ed

backofbeyond 5 May 2010 16:45

I have a similar problem with the (factory) 23L tank on my CCM. The taps are lower than the float chamber and the engine stops with just under 3L left. I looked semi seriously at fuel pumps but while I was still thinking about what to do with one I came up with a workaround that I'm still using.

The cap is the usual plastic one with a vent pipe that goes down through the head bearings. Normally I'll just refuel before I get to the last 3L but when I do need them I replace the vent pipe with a short bit about 3" long that has a tyre valve fixed in the end. A few strokes with a bicycle pump and the pressure build up in the tank pushes the fuel into the carb.

You don't need much pressure, just enough to move the fuel. Too much pressure and you'll overfill the float chamber (or potentially split the tank but mine's survived substantial pumping). I've only had to do it a few times - usually on a long run when I can't find a garage but it does work.

*Touring Ted* 5 May 2010 16:54

Quote:

Originally Posted by backofbeyond (Post 287784)
I have a similar problem with the (factory) 23L tank on my CCM. The taps are lower than the float chamber and the engine stops with just under 3L left. I looked semi seriously at fuel pumps but while I was still thinking about what to do with one I came up with a workaround that I'm still using.

The cap is the usual plastic one with a vent pipe that goes down through the head bearings. Normally I'll just refuel before I get to the last 3L but when I do need them I replace the vent pipe with a short bit about 3" long that has a tyre valve fixed in the end. A few strokes with a bicycle pump and the pressure build up in the tank pushes the fuel into the carb.

You don't need much pressure, just enough to move the fuel. Too much pressure and you'll overfill the float chamber (or potentially split the tank but mine's survived substantial pumping). I've only had to do it a few times - usually on a long run when I can't find a garage but it does work.

Fatasic ingenuity !! :thumbup1:
Sadly, mine is a permanent issue, no matter how much fuel I have so it's not going to work for me, unless I keep pumping while im on the motorway LOL

It might not be the problem, but it would be way to be sure and better safe than sorry.

chris 6 May 2010 16:40

I used a second-hand vacuum pump off a mid 90s Yam xtz660 on my 87 Transalp that had a 90 AfTwin Tank on it. Never let me down.

Also had a drz400s with a Clarke tank and had same problem regarding trying to get a fuel filter in the line. In the end I had 2 longer pieces of hose and coiled it round and used racing wire to keep it as high as possible. Hence the filter and the lines were at the same level as the carb and I could use the whole tank. Never had problems with air locks either.

Bike in action: Iceland TBSdotCom

If I were you, I wouldn't bother with a pump. More cr*p to carry etc. Go light...

HTH
Chris


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