Hi there guys .

Out for a nice little spin today , and pulling away from a set of lights , she bogged right down and wouldn't pull faster than a crawl , once the revs picked up she shot off like she normally does so I figured I must have had her in second gear without realising .

Later as I was almost home , slowed for a roundabout and she just died on me . Managed to coast her to the side of the road and without thinking turned the reserve tap on and she started right up . It was only as I rode the rest of the way home I thought , I only filled her up yesterday , she must have at least half a tank .

Got home and thought , I'll try running her with the tap in the normal position and she ran fine . Then I thought I'll run her with the tap turned off and she just kept on going and going.

So questions , why would she just die on me like that and is my fuel tap knackered? Also what should the tick-over RPM be?

P.S. Don't know if it's relevant but the road goes up a very steep hill on the way to where she stalled followed by a sharp left hand bend.
Also I'm still having cold start difficulties , lubed the choke mechanism but it makes no difference and I'm sure the choke is on full when the lever is all the way over.

Sorry about the garbled and rambling nature of the thread

 

Hawk, I had the exact same problem a couple years ago with mine. It did it to me like 3 times in one day and then never did it again. One of the times it took like 30secs to get it started, but the other times it fired right up.
I was convinced it was a moto demon possession, so I've since exorcised the bike and she's as good as new..

Seriously, I have no idea why the hell it did it. I planned on tearing her apart alongside the road next time it happened (even had tools in my backpack) and it never happened again. Weirdest thing ever. I chalked it up to bad venting of the tank.... some kind of vapor lock or something.
I think it happened to shadow once or twice, too??

 

Maybe a venting problem Dyan , never thought of that , though with the cold starting problems I was thinking about the carbs again. The revs were pretty high going up that hill so she would have been sucking pretty hard on the tank

 

Come on Hawk..everybody's stalled a bike before, just handle it mate. For a start though, your tap must rooted for your bike to keep running with the fuel off. Pull that sucker apart and see what's going on in there. My money's (if I had any left) on a 'floater' in the tank, or main fuel line or the tank vent. If it does it again open the tank as quick as you can with your melon real close to it and see if you hear it hiss.

Funny how the revs creep up sometimes. Mine does it too...must be a fault with this model .

 

Going up a hill, the carbs can be sucking hard, but the engine vacuum (sucking) can go so low it can't open the petcock. Maybe no fuel was getting to the carbs. It would be interesting to see what the minimum vacuum the petcock needs to open.

 

Sounds like an airlock mate, or crap in the tank ? It may be worth draining everything out and having a look , i think Davethepoms right with his vent idea....

 

I sad it before and I will say it again, ethanol. Pop the tank open and see if you can smell alcohol with the gas. Sometimes you can smell it from the exhaust. At lower RPM's you don't compress it fast enough to get good ignition.

Seafoam helps to keep the gas and alcohol from separating. try some and see if it runs better.

Your idle speed should be 1,000 to 1,200 RPM.

 

1 Run the bike up the same road with the tank lid slightly open.
If it runs fine, then you have a clogged vent pipe. Easy to fix just takes a bit of time and a hypodermic needle from your local vet...........
2 Could your needles in the carbs be dirty - only giving you limited fuel..........
3 the air correction jets will do it too (if you have one nearly fall out like I did due to shoddy work by a mechanic when I just had the bike and hadn't started tinkering with it....)
4 Is the petcock valve working correctly ?- may have an intermittent fault due to muck in it or something.
5 a bit off the wall, but I have heard of sidestand switches and kill switches with dirt in them giving similar results.

 

&
6 Leave the training wheels on

 

Yeah , thanks for that Mark! This from the only guy that has the only CBR tricycle in existence!!

As for the rest of the suggestions , I can't help thinking that the cold start probs are linked to this . I've ran this hill many times before with no problems

The urge to ride will always over-ride the urge to rip her apart , especially when it involves the carbs , which I've never touched before , so I find them a bit scary

But the urge to be stranded at the side of the road is not great

As for the petcock valve working correctly? I don't think so , as previously stated the bike runs with the valve tuned to the off position!

I'm in Shanghai right now so I'll have a look when I get back on Sunday , any more thoughts , or diagnostics I can run , will be much appreciated