anyone in Surrey and would take a look update . Its FIXED :

hi all
still having problems with the roadster and was wondering if anyone is nearby and knows a bit more than me as im itching to get out for a ride and cant get it to run properly
basically i think its carb problems
it will run pretty well on full choke and cuts out when choke is turned off
i thought air leak so sprayed carb cleaner on the inlet manifolds and sure enough the revs rose
fitted new O rings and Rv siliconed the black heat spacers
made no real difference , now if you spray the joints the revs will rise ever so slighty,not as bad as before suggesting theres still a leak but ive checked the faces of the manifold and carb and they all seem straight
cant really think of what else to do

also the carbs were cleaned out and a new gasket set fitted,sprayed cleaner through the pilot jets and saw it coming up into the carb body whilst the carb was off so i dont think they are blocked either

thanks
matt

Re: anyone in Surrey UK pstcode KT and would take a look

Hi Matt, Sorry i wasn't much help on the phone and you're still having probs.
It's hard to beleive it will run quite well on full choke (loose cables) since it would need a massive airleak (IMO)to compensate that condition. The fact that spraying carb cleaner increases speed does indicate a leak of sorts that should not be there.
Are these new carbs? If so have they been machined on the flange (to adaptor) and area around throttle stop? Amals on Commandos won't sit down (parallel) on adaptors/intake manifolds without this, well not on 932's they won't.
What condition is the balance tube in? The balance tube stubs etc?
Do you know for sure the needles are in place? Probably wouldn't affect start and idle though. They can get pushed through the copper clips.
I'm sure someone will ask you to check the choke operation but you seem to have that right.
I'd volunteer but due to a serious small toe issue I can't drive at mo.
Hope you find something obvious, it has to be.

Re: anyone in Surrey UK pstcode KT and would take a look

Hi keith
you were helpful on the phone it was just i didnt want to keep bothering you hence this post and not another call !
and also i know you cant drive up so I thought id ask in case someone is nearer

the balance pipe looks fine although i will start it again and spray around it just to check
and the needles are both rising up ok

im tempted to take them off again but I cant think if a way to seal up the faces better than I already have

the carbs are as far as i know untouched,strange thing is , is that the bike was running fine until it was put into storage for a few years so i still keep thinking its got to be something daft im missing

Re: anyone in Surrey UK pstcode KT and would take a look

MATTT said:

...strange thing is , is that the bike was running fine until it was put into storage for a few years so i still keep thinking its got to be something daft im missing

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I saw a Honda with the airbox filled to the brim with sunflower seed husks, it seems a mouse had made its nest in there and over time filled the airbox with its discarded shells it was retreiving from a bird seed bag. Are you sure the ignition is OK? Are you running points?

Jean

Re: anyone in Surrey UK pstcode KT and would take a look

its running a boyer
and i had the airbox out and so sign of any sunflower seeds :lol:

trouble is ive been over it so many times a fresh opinion and someone who has one already and i bet its something daft

Re: anyone in Surrey UK pstcode KT and would take a look

Are you absolutely certain the pilot jet (pilot bush) behind each carb pilot air screw is not blocked?

Check that the two gallery holes in the carb float bowl gaskets have been punched out correctly?

Check that the float bowl gasket faces are flat.

Replace both pilot screw and throttle stop screw O-rings if you haven't already done so.

Re: anyone in Surrey UK pstcode KT and would take a look

ive taken the screw out 3 times on each and pushed a straw from the can of carb cleaner into it as far as it can go,when you press down on the can you get a squirt of fluid up into the throat area of the carb body
i think its ok ?

Re: anyone in Surrey UK pstcode KT and would take a look

Fresh petrol & good flow from pet cocks??

Re: anyone in Surrey UK pstcode KT and would take a look

MATTT said:

ive taken the screw out 3 times on each and pushed a straw from the can of carb cleaner into it as far as it can go,when you press down on the can you get a squirt of fluid up into the throat area of the carb body
i think its ok ?

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No it's not OK, because those holes into the throat are in the green area (see below) and the pilot bush is beyond them, so what you need to be seeing is carb cleaner spraying out of the hole marked GAS in the photo. The only way to make sure the pilot bush is completely clear is to gently poke it with a .016" wire or 0.4mm (#78 US) drill bit.

Re: anyone in Surrey UK pstcode KT and would take a look

I can't help myself but nobody has mentioned it and go ahead and slap me across the head if ya have to but, assuming that these are Amal MK1's, with the choke lever pulled tight. the choke is disabled, slacked engaged. Another thought would be to remove the choke assembly and blank the cable hole. This is not to say you should do with out it, that is your preference, just part of a troubleshooting methodology.

Re: anyone in Surrey UK pstcode KT and would take a look

Having not had my carbs apart for while or looking at the book, it seems that you have a blockage somewhere. The choke on most carbs restricts the airflow into the carb, but the engine will still need the same volume of air per cycle, so it pulls air faster through the carb - faster air flow = more suck on the fuel in the carb bowl so it will be richer. So if the choke is off - the same volume of air travels slower through the carb = less fuel is sucked, this is the reason you use more fuel with choke left on. Providing all joints are as good as you say and the balance pipe is fitted, then look at the carb, passage ways, jets and float level and operation. If left running with choke on will it eventually cut out? - fuel starvation, do the ticklers work? and will it run once tickled and with the choke off? Hope these ideas help. I'm just down the other end of the M3. and you're more than welcome to get in touch.

Re: anyone in Surrey UK pstcode KT and would take a look

Just to be clear, the brass bit between the green and red is the pressed in pilot jet. People have used piano wire to a wire broom bristle from the green side screw hole. Another thing that can be done if ambitious enough, is to carefully drill out the blank on the opposite side(as shown) to insure cleaning. You can then tap and plug with an extra air screw cut off insuring the oring is in place.

Re: anyone in Surrey UK pstcode KT and would take a look

Assuming everything is together and ready to go follow this:

• Remove the air screw completely

• Take a flashlight and shine it in the air screw adjustment orifice

• Tickle said carburettor

• Note fuel seeping into orifice

If this happens then the pilot jet is clear. If not you'll need to clean it out following instructions others have given above (i.e. piano wire, guitar wire, etc).

Re: anyone in Surrey UK pstcode KT and would take a look

you were helpful on the phone it was just i didnt want to keep bothering you hence this post and not another call !
and also i know you cant drive up so I thought id ask in case someone is nearer

Click to expand...

Not a problem to call, not doing anything!
Same as LAB I just thought about the feed to idle jet from float bowl and thru' float bowl passage. Its a big opening so would have to be a rock up there. Same goes for the idle air feed from air cleaner while you're in there but not a problem with your issue. Good point from LAB on the pos'n of those tiny holes, never noticed that before. Could be quite a bit of rubbish behind the jet which gets sucked back in when you start up. Block those, screw in needle gently, squirt more cleaner and see what comes out the back of the carb or v versa. That pic shows a modded carb with blank screw on other side of idle passage which is intended to solve any buildup behind the jet.
Are you testing with aircleaner attached or off? Have heard of sealing rubber (bellows) perishing and collapsing into air passage(s).
Worth checking the Boyer plate connections just in case its electrical :roll: Doesn't seem likely but elimination is good.
You said the float level was ok, float top level with bowl face or 2mm below? Will run ok within this range. Are your floats moving on their pins ok? Recently had my carbs apart and both were sticking. Worth a check on gaskets in case they are snagging the floats. Wouldn't run long on full choke though if stuck up.

Re: anyone in Surrey UK pstcode KT and would take a look

I would have thought the pilot jet isn't likely to be causing the problem. Once the engine is running much above tickover the pilot jet isn't doing much, if anything. It's the needle, needle jet & main jet that are the key, assuming the float bowl has petrol in it. Make sure the needle is fitted correctly & is sliding up & down the needle jet ok. With the carbs still on the bike you can remove the float bowls, & then remove the block that holds the main jet & needle jet. You should then see the bottem of the needle & will see it move when you operate the throttle.

There is an old saying though. If you have a fuel problem, it's probably the ignition.

Good luck

Ian

Re: anyone in Surrey UK pstcode KT and would take a look

There is an old saying though. If you have a fuel problem, it's probably the ignition.

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Ian has a good point here, a weak spark will often ignite an over rich mixture while fail to an otherwise correct mixture. If you are running twin carbs and both are effected equally the chances are the problem isn't the carbs. Could be, fuel supply, ballace pipe, or ingnition.

When you lift the choke slides does the motor pop and bag or just shut down with no response?

Cash

Re: anyone in Surrey UK pstcode KT and would take a look

If the bike wont run at all without choke on, then I would guess its an ignition problem of some sort, and the first thing to do is check how good your spark is. However if you are dealing with Amal carbs, then it has been known for people to fit brand new ones and find that their bikes then dont run, so if your spark is good and battery fully charged, it would be worth trying to borrow another set to try, and if that does the trick, then replace the carbs.

Re: anyone in Surrey UK pstcode KT and would take a look

Matt
Check your inbox, I think I have some spare 932 gasket kits and I could either come up or you can come down to my place with them and check them on my MKIII.

Re: anyone in Surrey UK pstcode KT and would take a look

Hi Matt
A bit late picking up on this thread but I work in Sunbury and could come over after work in the week.
I've quite got a lot of stuff that could be used to swap out to pin down the problem
Single amal concentric carb on manifold and I should have some other carb spares around, also got amongst a lot of other stuff, spare analogue boyer, twin output coil and a standard coil set......

Putting the single carb on is a bit of a lifesaver step when I'm really scratching my head where the problem but depends on airbox setup whether its an option.

Cheers
Rich

Re: anyone in Surrey UK pstcode KT and would take a look

thanks for all the helpful replies ill reply to your pm in a sec ,thanks

theres too many to reply to individually so i will just give an update on what ive looked at lately

checked the spark again and it looks blue and reasonably strong to me

removed the airscrews again and checked the ticklers and couldnt see any small weep of petrol
recleaned the pilot jets using some fine copper wire pressed the ticklers and theres a small weep of fuel now

this does seem to have helped as it will run slightly off full choke now
but still after running for 5 mins it cuts out if you pull the choke off

and finally to Rich , if you able to come over that would be great at least we could find out if it is carb or points

i will pm you my tel number