Fuel tap/supply problem

[bigbossmonty]

Hi Lads,
First I would like to say hello I have literally just picked up a 93 900 sprint for I believe silly money on ebay.
http://cgi.ebay.co.uk/ws/eBayISAPI.d...ame=Action:MPS
reason I was atracted to besides being triumph it was litterally 5min walk away and we pushed bike home to save any agro fron the boys in blue.
Bike starts runs but here are comments by PO
"The bad news is that at least one of the carbs is flooding so petrol flows out onto your left foot. Also, the petrol tap has gone from Prime/On/Reserve to Prime/Off and it'll only go to Off if you know just where to put it. (I've marked that position for you.) Upshot is you'll need to know one end of the fuel system from the other to get this running properly, or know a man who does. Get him to wire up the new horn properly while he's at it, electrics are a mystery to me!"
I have not looked under the tank yet as I am knackered but will do tomorrow any suggestions appreciated
thanks in advance
BBM

[ervdrvr1]

BBM,
Welcome aboard!!

1st: Run, don't walk, to your nearest dealer, bookstore, whatever and get a manual(Haynes, Factory). You'll thank yourself. I'm not saying these are bad bikes, just sounds like yours has been neglected and is in need of lots of TLC.
2nd: Pull the carbs, take 'em apart, clean 'em, inspect 'em(especially the float seals, you have one or more stuck open-hence the fuel on your foot). set the float height, re-assemble, re-install, clean/replace air filter, syncronize.
3rd: There is no "off" position on the fuel tap. Sounds like the black knob is broken and is just spinning on the fuel tap shaft. Buy a new knob and fill the voids on the back side with epoxy to prevent it from breaking again. While you have the knob off, try turning the valve with a pair of pliers to ensure it turns ok. If not, fuel tap may need replacing.
4th: Inspect/replace all fuel lines and the vacuum line that goes from the carb to the back of the fuel tap.

I could go on and on, but I think you get the gist of it.

Happy Wrenching, and Happy Trails!!

Erv
Deep in the Heart of Texas!!

[bigbossmonty]

ervdrvr1.
Thanks for the reply, got haynes manual with the bike, I must admit it is like new no oily fingerprints etc.
have had a read and will do as you suggest.
As you might have noticed I have a meridan T160 infact 2 what make the fuel on the food problem intresting is when having rebuilt the amals this sometimes happens - so the remedy is to tap the offending float bowl with the wooden handle of a hammer works everytime float becomes free no fuel pouring out
Then again access to carbs is easy compared to sprint
cheers
BBM

[cheapsk8]

Originally Posted by Bad Monkey

It needs to run from the top of the number three carb to the petcock. Watch that you're not setting the tank on top of it when you replace it.

I'm curious...my vacuum goes from carb number one to the petcock. Most of you guys seem to have it hooked up to carb number three. Does it make any difference???

Thanks for the info ervdrvr1. I'll be ordering a new tap knob pretty soon here.

[ervdrvr1]

cheapsk8,
Nope, doesn't matter. It just makes less sharper bends from the #3 carb.

Erv
Deep in the Heart of Texas!!

[thus49]

Had time to take a look at the problem today and found that the vacuum line from the carb to tap had obviously split at the carb take off and come adrift. The previous owner had simply sealed off the vacuum feed from the carb by using a piece of fuel pipe with a bolt screwed into the top. I don't know why.

Anyway I snipped the split end off and reconnected the vacuum line to the 3 carb (it was on 1 carb) and the tap now works fine. Simple job, cheap fix (i.e. zero £). Happy bunny.

[SpeedFreak]

All vacuum takeoffs from the carbs need to be blanked off, except the one which is connected to the petcock. Unless the petcock is always run on prime, in which case all 3 vaccuum takeoffs would definitely need blanking. If previous owner didnt have a proper vacuum blank then sound like he bodged one. Found on mine that one of the blanks had come off without me realising and bike wouldnt idle. Other problem area is getting the vacuum line hooked onto the petcock and then repositioning the fuel tank. Is it me or is it impossible to get the tank back on without kinking the line?

[thus49]

I understand the need for blanking the vacuum feeds off, but not the decision to just run on prime. Seems odd. It did not take much effort to reconnect the vacuum line. The main problem was that the diameter of vacuum line fitted made it impossible to fit over the carb feed stud and believe me, I tried.. in the end I used the piece of pipe the previous owner had used as a blank, removed the bolt from the end and used this as an adaptor. It works fine. It is very tight under the tank when it is secured in position but it is just about possible, using carb 3 as the feed to route the line around the rear of the tank and forward to the carb without kinking. But I guess you guys know that already. I am a beginner with this machine.

BTW, I am absolutely loving it.

[ervdrvr1]

thus,
You can run it on "prime" without any probs, just don't leave it on prime with the engine off. If you get a float valve stuck open, it will flood the engine and air box with fuel. You can replace the stock vacuum line with 1/8" ID automotive vacuum line that helps alot with the kinking probs(auto vac line is thicker walled than stock line).

Erv
Deep in the Heart of Texas!!

[roadrunsl]

I have the same problem last year. I find that the vacuum line is pressed to the frame and is not operate. I fix the promblem quick by reroute the vacuum line.
Last week I have similar problem again. When the engine get starving I went on prime. After a few kilometers I go on "ON" pozition and the bike run just fine? This time the problem is not vith the vacuum line. I check fuel cap (for ventilation valve obstruction)- all is OK. What could it be?