Carburettor Float drain screw.(solved)

[funguy86]

Hi fellas,

I've been looking for a picture the clearly shows the drain screw but the diagrams I have found are confusing. Has anyone got a photo of it that they could mark the location on for me?

Thanks

[darrsi]

Here you go...

[darrsi]

Make sure you use a good fitting screwdriver as the screws are rather soft and could be quite easily damaged.

[funguy86]

Thanks!

That picture is perfect. Now I can drain these and hopefully fix this misfire. 

[darrsi]

Think that was courtesy of 'unfazed' from ages ago, it was such an simple but very descriptive picture i kept hold of it. 

[funguy86]

Well,

I've drained the carbs with great success, took the old girl out for a test ride of about 20 miles and not a single hiccup. Result.
Or so I thought.
 Today on my way to work the problem has returned. Several times the engine RPM would just drop down slowly, regardless of the throttle position. Strangely though if I pull the clutch in, let the engine stall and blip the start button again it will fire up again. I could always change the plugs but I'm thinking this is possibly water/particles getting into the carbs.

Any thoughts?

[darrsi]

Well,

I've drained the carbs with great success, took the old girl out for a test ride of about 20 miles and not a single hiccup. Result.
Or so I thought.
 Today on my way to work the problem has returned. Several times the engine RPM would just drop down slowly, regardless of the throttle position. Strangely though if I pull the clutch in, let the engine stall and blip the start button again it will fire up again. I could always change the plugs but I'm thinking this is possibly water/particles getting into the carbs.

Any thoughts?

Before changing the plugs, chop about 10mm off the ends of the HT leads, and rescrew them back in.
Better still, if you still have OEM spark plug caps on, replace them with NGK ones, a lot of us use them and they're dirt cheap in comparison to £200+ for OEM ones.

 https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR0.TRC0.H0.TRS0&_nkw=SD05F&_sacat=0

[darrsi]

Is your air filter clean?
Blocked air filter can stuff things up.

And make sure you haven't got a kinked breather pipe under the fuel tank, starving the tank of air.

[BBROWN1664]

And make sure you haven't got a kinked breather pipe under the fuel tank, starving the tank of air.

- This seems the most likely culprit from description

[funguy86]

I have had a look at the breather pipes and one of them did seem to have a kink in it.
I will have to check the air filter tommorow afternoon as I don't have a socket for the tank hinge bit that holds the airbox sheath thingy.
I'll report back if it is better once I have ridden home later

[darrsi]

Do one thing at a time, ride the bike first as it could well just be that the fuel tank wasn't breathing properly.

[funguy86]

Well I just got home....it was going so well up until about 20 minutes into the ride. That's when the problem came back. Had to restart the engine 3 times in the space of 5 mins. Is there a chance the pipe could be blocked?

[darrsi]

Easiest test is open the fuel cap.
See if it gasps for air, or if it starts straight after it's a good guide.

[darrsi]

Well I just got home....it was going so well up until about 20 minutes into the ride. That's when the problem came back. Had to restart the engine 3 times in the space of 5 mins. Is there a chance the pipe could be blocked?

There's 2 pipes that run through the tank, one's a breather that gives air to the cap, the other's an over spill pipe which will aim excess fuel, or any rain water, safely to the ground via the pipe.
An air line, or can of air, will be your friend here.


There's also a small chance the breather hole in your fuel cap could be clogged up. These bikes are old now so anything's a possibility.
I just bought a new one, it meant a new key but that didn't bother me and it looks better anyway.


Have a look through this thread, but bear in mind your cap is very slightly different to look at, being an older model, plus you have pipes coming off the underbelly of the tank, later models from 2000 aim the outer metal tubes on the tank into a rubber cup, to avoid the kinking issues when moving the tank.


(FYI, my thumb's still fooked now, and being operated on in 2 days   

[funguy86]

It does start straight away after, however I cannot detect any gasping sound when I open the tank.

[funguy86]

Can of air it is then 😎. I do quite often find rainwater around the rim on the inside of my filler cap.

I'm guessing halfords is the place to go

[darrsi]

Bicycle pump would also do the job, use it to blow upwards from the lower pipes.
Where there's a will there's a way.

[BBROWN1664]

You will find water around the filler neck occasionally and its worth blowing that pipe out to make sure its clear but that's not the one likely to be causing you problems.

IF the problem happens again, take off your helmet and take out your earplugs then open the fuel cap. If you hear a little hiss as you do it, its because there is a vacuum inside the tank. This is caused by the breather pipe being kinked. To fix that, lift the front of the tank and locate the breather pipes (back right). Find the bottom of the pipe and gently pull on that as you lower the tank. Problem solved.
At the very least, once you release the vacuum in the tank, the bike will start again and run for another 20 mins before it builds up again.

[darrsi]

Sorry, i forgot the link.....


http://foc-u.co.uk/index.php/topic,21819.msg252270.html#msg252270

[funguy86]

Well I can confirm that it is definitely the breather pipe. Did the hiss test after my ride home yesterday. I also checked the pipes for blockage and they seem fine.

At the moment these pipes go between the carbs and down the back of the gearbox and like this there is little I can do it seems to stop them from being caught on something. I'm going to remove them tommorow, clean them up, flip them upside down(top end seems to have been permanently squished)  and try to route them differently.
I don't really know how they got this way in the first place. I've never had the tank off before.
Thanks for all the advice so far, I would not have been able to figure out what the problem was without it 😎

[BBROWN1664]

The problem is most likely to be right below the tank.
When you lift the tank it pulls them up slightly from behind the carbs/gearbox. When you lower the tank again, they don't fall back via gravity and the excess gets kinked under the tank.
Simply grab the pipe where its behind the tank and pull down on it gently as you lower the tank. Job done.

[funguy86]

Ive done this yesterday and no change. I also noticed that blowing down the pipe that goes to the cap drain plug results in air coming out the other side. Can't say the same for the tank breather. Could it be possible that it is blocked inside the tank?

[darrsi]

Ive done this yesterday and no change. I also noticed that blowing down the pipe that goes to the cap drain plug results in air coming out the other side. Can't say the same for the tank breather. Could it be possible that it is blocked inside the tank?

Can't you just blow air upwards instead from the pipes?
If it was blocked the likely culprit would be rust.

[funguy86]

That is exactly what I tried. It seems it would take quite some pressure to force the air through.

[darrsi]

That is exactly what I tried. It seems it would take quite some pressure to force the air through.

The air should flow freely, i did exactly the same trick with mine and there was no resistance at all.