fuelling problem??

[boze]

the saga continues.....ive replaced the accelerator pump diaphragm etc and took the bike out today, after about 45mins (long enough to get bloody miles away from home) the useless piece of shit broke down again!! thats twice in two weeks!!

it just cut in and out a couple times then died, i stopped and kicked her again and she started but when i tried to rev her she just died again. this happene a few times.

im at my wits end and considering scrapping her as i need something reliable to get me to work!!

i dunno what to do, i spose ill strip the carb again tomorrow and see whats happening..

any ideas?

damo

[guest27]

Was running well and then died, would start but not run cleanly - sounds to me like you are getting dirt into the main or needle jet area.  When you take the carb off - keep it upright and carefully remove the float bowl, see if there is any dust, grit etc in the bottom.  Yoou may even see what looks like a small or some small transparet ball bearings - if you do there is a small amount of water in the carb.  What would happen is the water would eventually get drawn up into the jet where it blocks the flow, engine dies, bike will start - on pilot, but not pull on to the main.  After a bit the water falls out and the bike runs well then it all happens again.  Have a look in the fuel tank - is there any evidence of rust?  If so get a cheap in line fuel filter and chop this into the fuel line or lines.

If the accelerator pump rubber had corroded some of this may be floating about in there too, it only take a tinly little bit of crud to block the jet.  Cleaning it all out, try and pick up a can of squirty air - like an aerosol with no charge of chemical etc - often found in electonics shops, this will allow you to direct a good blast the wrong way down the jets - if something is stuck it has gone in from the 'bottom' and you want to blow it out if possible from the top so as to not jam it in more.

I have had carbs that have given me no end of grief, and in the end I have gotten out a bit of dust or grit so small it is barly there and - mmmm bike ran nice.

Mind could be wrong


Oh - and when yo have the carb apart you are a surgeon - so get your tools spotless claen before you start, ger the outside fo the carb spotless before it comes off and work in a good light on a clean surface

R

[Ken]

Is this a multi cylinder bike?  It a bit strange that all carbs would be so far out as to stop it. Are you sure you getting fuel down from the tap.?

Ken

[themoudie]

Aye damo,

I'd go along with Rog and also take the tank off, give it a good sluice around and throw the contents away and start with some fresh petrol.

Check that your tank breather is working.

If the inside of the tank is corroding, consider using tank sealer to stop further rusting and general nastiness getting in the 'petrol' or whatever the distillate is these days! At least a malt is still a malt!! ;-)

Frost's : www.frost.co.uk

They are as good a place as any to get a tank sealer kit from, although it may not be the cheapest and others may chip in here with alternative suppliers and prices.

If after all this, you still think you need to punt it, let us know. Somebody may have a home for the old war horse!

Regards, Bill

[guest27]

Having spent a couple of hours cleaning the gunge out of the fuel tap on the K4 - I would suggest taking the fuel tap off the tank and soaking it over night.  Seems modern petrol is not like the stuff of old.

On which pint I have an old petrol can of Jen's grandad's.  Now he died ummm 15 years ago, I picked the can up after her gran died 5 years ago.  Gave it a shake today - meaning to put some parrafin or the like in it to see if it leaked, and it sloshed.  Opened it and lovely petrol smell.  K4 even ran on it.  So there we have some 15 plus vintage petrol....  Whereas the modern stuff that had been in there about 2 years had turned to gunge - must be more volatile or some like

R

[boze]

right im off today and am gonna get battered into it...

ken: its an sr500 thumper

rog and bill: im gonna strip the carb today, plus ill drain the fuel, check the fuel tap and clean ou the tank, ill let ya know how i get on.

cheers

damo

[guest7]

 If you're not going to coat the tank (petseal, etc. ) then you can't guarantee that you have got all the nasty little bits of rust out.

An in-line filter is a cheap and easy way to ensure that any crud doesn't get into the carb.

Cheers and good luck
GC

[GB500nz]

In regard to water in the fuel: it's extremely common, and easily cured by adding alcohol or a marine additive like Fuel Set to every tankfull. Do this and you'll have no more rust. Pure methanol or ethanol seem to work best.

[guest27]

Adding methanol or ethanol - yup will absorb the water pretty well down to about 70% alcohol equ.  However, despite the addition of ethanol and methanol to petrol for sale, doing it your self is technically strictly illegal... ho humm whyat they  dont know wont hurt them

R

[boze]

im gunna cry.


how much would i get for a 1980 sr500 in need of a new carb?

damo

[MrFluffy]

I could send this onto the uk for postage cost if its of any use and the vendor wont send it to the uk.
http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=300097082785

[guest27]

What is the problem with the carb Damo?

I must learn to look on other eBay sites - or at least the French / German etc names for things

R

[peterj]

Just a thought, but aging Yam's are notorious for developing intermittant shorts in the kill switch. This can also cause the symptoms you describe. Check by disconnecting the single wire going to the kill switch. I don't think my SR (or any) had a clutch or a sidestand cutout, but if yours does, same goes for them.

[themoudie]

Aye damo,

Whats up wi the carb?

Bill

[boze]

ive stripped the carb 4 times in the last 2 weeks, twice today, the bike starts then after a wee minute it judders like it cuts in and out makin the bike jerk then it stops. if i kick it, it will start again but dies after a few seconds.

it has a new air filter (but its not a performance filter, just stock) new spark plug (once again its definately the right one) and today i drained all the petrol out, cleaned the filter in the tank, flushed the tank with clean petrol then dried it totally with a hairdryer to make sure there wasnt any water in it, it still does the same thing. i also stripped the carb again and cleaned it thoroughly. no dirt etc in it. ive also tried adjusting the air/fuel mixture but to no avail.

its as if it starts to fuel properly then something happens and the fuel supply is cut short. ive checked all the diaphragms in the carb and theyre sorted, the accelerator pump is also functioning correctly.

im really at my wits end here, i need it to get to work on, its sooooo important.

it sounds to me like a fuelling problem but i dont know what else i can do, ive had a few bikes before which ive stripped etc but im by no means a pro, im only 24 and you guys have a much greater understanding of these problems, does anyone have any ideas as to what i should do? should i get a new carb? should i take it to a garage (with all the cash i dont have)? should i sell it and buy a plastic rocket with wheels? should i sell it and buy a skateboard?

damo