New FH is born - briefly

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Martin K
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New FH is born - briefly

Post by Martin K »

So the good news first. With thanks again for all the advice along the way, my Huntmaster has emerged blinking into the sunlight and fired up after two kicks. No rattles, oil returning nicely, all seems good….except it spluttered out after about 40-50 seconds.

It’s definitely fuelling - so I wonder what further advice anyone can offer about the basics to get the Amal feeding well.

It’s been totally stripped, blasted, blown, ultrasoniced and refitted with nice new gaskets, same jets (ultrasoniced too) and - maybe importantly? - a new float needle with a nitrile head (to defeat the dreaded 10% ethanol in unleaded). Don’t worry, the head has also had new valve seats for unleaded too, so that should all be fine, but I wonder if the float height is now ‘out’ - and does that matter?

So - back to the float needle. DH ran beautifully having done the tickle thing (and saw fuel flow through the pipe with each press). Tiny trickle from it (so I guess the bowl is full) and that’s when I kicked it - off it went, all good. Once that initial surge had gone, that - I think - is when it stopped, so would the float height have anything to do with that? Can it be set, and would the new float needle affect the float height? Is there a setting to get that right?

I unscrewed the float bowl screws to see if the needle had stuck (hadn’t) or the float was trapped (seemed good) and a LOT of petrol came out so seemed like it was flooded maybe?

If all the above is nonsense - any ideas please?
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chris.shearwood
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Re: New FH is born - briefly

Post by chris.shearwood »

Are you sure the fuel tank vent isn't clogged?
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Martin K
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Re: New FH is born - briefly

Post by Martin K »

Sadly, yea Chris. Filler cap off - still dies after that initial 30-40seconds.
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Re: New FH is born - briefly

Post by Mick D »

Hi Martin

Just sounds like it's a little cold / weak. Did you try to richen it using the choke once it was running? Were you using the throttle to sustain the revs? Was it responding to the throttle without spitting back before it shut down?

Carry out subsequent starts and see if things improve as the engine warms up, once it is possible to keep it running without choke use the throttle stop to set it to run as slow as it's comfortable with and the do the balancing act with the air screw and throttle stop.

Keep an eye on the exhaust pipes at the head, if they start to colour it's probably indicative of timing too far retarded.

Almost there :)

Regards Mick
Martin K
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Re: New FH is born - briefly

Post by Martin K »

Morning Mick

It revved quite nicely (obviously VERY gingerly on the throttle!), no spitting.

I still get in a muddle about choke on/off, so it’s possible in all the excitement that I pulled/pushed it precisely the wrong way.

After the initial vroom, it responds to the throttle for a few seconds revving up, but then c.10secs starts to falter, cough and dry up.

Once it stops, a bit more tickling etc it does restart but not as cleanly, and then fades out (quicker). After that doesn’t respond at all.

I suspect as it’s warming slightly, the choke/throttle/tickler configuration needed changes and I’ve not ‘got it’.

Header pipes still chrome and not discolouring (prob not run long enough to happen!).

Onward (if my right leg can cope!!!)
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adrie.degraaff
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Re: New FH is born - briefly

Post by adrie.degraaff »

This sound very familiar; your magneto slipring is leaking.
Martin K
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Re: New FH is born - briefly

Post by Martin K »

Thanks Adrie - it’s got electronic ignition, so no magneto.
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Re: New FH is born - briefly

Post by Mick D »

Hi Martin

The choke is closed by pushing the lever forwards, I start my FH with the choke fully open. If you start the bike with the choke open you should be able to sustain running with the throttle blipping. If not it could be a blocked pilot jet or pilot by pass gallery, easily blocked by a bit of crud from the tank, have a look there first ;)

If it will sustain on blipping the throttle, warm the engine up and adjust the throttle stop / air screw for a sustainable tickover.

My bike doesn't achieve a steady tickover with the choke open until the engine is warm, about two or three minutes - If you can initially get yours warm and ticking over without using the choke it removes on variable during set up, once set up you can learn the choke foibles.

Regards Mick
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Re: New FH is born - briefly

Post by adrie.degraaff »

The story is the same if the coil is leaking so I would try a new coil.
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