starting problem

[alantf]

Has anyone out there experienced this problem, or can suggest anything ?

My bike (gz) is just under 2 years old, (bought new) with around 6,500 miles on the clock. The starting problem has happened twice - both times when it has not been started for 1 or 2 days. First, let me say that, previously, there have been no starting problems whatsoever. Last week I tried to start up, but the starter whirred round perfectly, but the bike would not start. From experience, it sounded to me like a fuel problem, so I switched to "prime", waited a couple of minutes, then hit the starter again. It started immediately, with no hesitation, & from then on ran just as perfectly as it had always done. Everyday since then it has started perfectly, until this morning (the bike wasn't started yesterday). Again the starter whirred but the bike wouldn't start. Switched to "prime", left it a couple of minutes, and it started up immediately. I rode about 3 miles to the supermarket, parked up, & when I came out I could smell petrol faintly. Started up immediately (no problems) & rode to the next supermarket (shopping for my wife! It gets me out when she's cleaning). Had a good smell, but nothing. Came out of the supermarket & FAINTLY smelled petrol again. Started up perfectly, engine fine!

It seems to me that something is leaking somewhere, VERY slowly (like 24 - 48 hours to drain the carb) I've checked for signs of fuel where I park in the garage, & I've checked all the obvious nuts, bolts, pipes etc round the carb, but I can't find anything loose or missing.


Any help or advice would be greatly appreciated.

[Easy Rider]

Originally Posted by alantf

It seems to me that something is leaking somewhere, VERY slowly

First get a book of matches...........NO, just kidding..... :biggrin:

I think your leak is so slow that it is evaporating before it drips so you can't see a puddle.
The easy and obvious thing to check is the drain screw on the bottom of the carb where it connects to the drain hose. That screw should be tightly closed.

The next thing to check for is a cracked bowl or leaking gasket above the bowl.

I think there is an overflow tube inside the bowl that connects to the same point as the drain hose (but is NOT controlled by the drain screw). If that is leaking, it would appear in the drain hose too. (That is from memory and may NOT be present; might be another engine I say that on).

Good luck. Definitely something you should fix before you find it the HARD way !!! :skull:

P.S. Leaving it on PRIme for a few hours when it is cold and out of the wind might develop a few drops and point you right to the leak. Do NOT do this overnight in a closed garage as the fumes might go BOOM !!! :shocked:

[Sarris]

Check the vacuum hose on the back of the petcock for leakage.

[JWR]

If mine does not start on the first try, I use the red kill switch one time, then it always starts right up.

It has always done this.

Jerry

[alantf]

Originally Posted by JWR

If mine does not start on the first try, I use the red kill switch one time,

Yes, but that points to an electrical problem. This seems to be fuel related. Thanks anyway.

[alantf]

re :- drain screw, cracked bowl, leaking gasket. Checked these again, & they seem o.k.
can't find the extra overflow - think it must be on another bike.

The vacuum hose on the back of the petcock also seems o.k. If this was the problem, wouldn't it also interfere with the efficient/smooth running of the bike while riding, & not just on start up?

As soon as I get a chance to "babysit" the bike, in the garage, I'll try letting it sit for a few hours in "prime"

Thanks, & if anyone can think of anything else please feel free. Once I try all the logical searches, it'll soon be time for "clutching at straws"

[Easy Rider]

Originally Posted by alantf

Thanks, & if anyone can think of anything else please feel free. Once I try all the logical searches, it'll soon be time for "clutching at straws"

I guess at some point you need to "prove" your theory.

If you can't locate a leak, then you need to let it sit a few days and open the drain screw. If you only get a little dab of gas, then there just aren't that many places the gas in the bowl can go (think down).

Might want to plug the drain hose (golf tee?) while the bike sits overnight.....just for grins....and then see if anything accumulates in there.

[alantf]

Six days later, & it's done it again. The bike had been standing overnight, in the garage, for 22 hours. Temperature - tee shirt comfortable. Tried to start it, starter whirred perfectly, but it wouldn't fire. First thing I did was to get a flashlamp & inspect everything VERY carefully. The end of the overflow pipe hadn't the slightest trace of moisture, nor did it smell at all of petrol. There was no sight nor smell of petrol ANYWHERE. Can anyone explain the vacuum system to me? From the petcock, the vacuum pipe seems to go for a couple of inches to a tee. One side of the tee goes to the front of the carb, where it joins to the engine, & the other side of the tee goes to a gadget on the frame (in front of the engine, & next to the horn) It fits onto a curved pipe on this gadget, & while not really loose, I was able to push it on about 3/8" to the end. Should this be dead tight i.e. clamped? Incidentally, what is this gadget for? I've never seen anything like it before. It seems to have two large diameter pipes on it - one goes to the bottom/front of the engine, & the other vanishes up under the tank somewhere.
Anyway, after the inspection, tried to start again, with the same zero results. Switched to prime, waited around 15 seconds, switched to run, & it started up immediately. No further problems, bike running perfectly, & this time no smell of petrol when I came back to the bike after I came out of the supermarket. Incidentally, before I parked up yesterday, I'd just come back from a 25 mile run.

[Easy Rider]

Originally Posted by alantf

Six days later, & it's done it again.

Can anyone explain the vacuum system to me?

Back to square one, looking for a leak.........or maybe the bowl isn't filling properly....but I'd think that would show up at other times too.

It sounds like you have the "California" evaporative emissions system because most of the bikes over here don't have that T; the hose goes directly from engine to petcock and just keeps the little valve open in the petcock while the engine is running. Sorry I don't know the details of the extra plumbing.

I'm gonna be on the road for 2 weeks, alas on 4 wheels not 2. You are on your own!! :biggrin:

[alantf]

The gadget I'm referring to is the silver/grey thing that is just above the engine guard, on the side nearest the camera. You can just see the pipe from the petcock tee, on the front of the gadget. There are also two large(er) diameter pipes on the gadget. One goes to a vertical steel pipe that is fastened to the front, bottom, of the engine by a flange. The other pipe vanishes up under the tank. Anyone know what the gadget is, or what it does?