Won't start

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john.nash
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Won't start

Post by john.nash »

Recently assembled VH500
New mains, new big end, new rings, new carb (amal concentric) and mag rebuilt.
timing is good. spark plug will spark against the barrel (tried a couple now), valves have clearance at tdc, lifter disconnected. Compression isn't brilliant, but all the kicking and a drop more oil down the bore is sorting it.

just will not start. Occasional huff back through the carb. Even brake cleaner won't get it to fire.

I am still thinking the compression isn't all that good, but I've had bike with chunks out of the valve start and run.
John Nash
AOMCC No.4119
''78 t140 bonneville, '77 BMW R80, '67 CJ750, 196-ish Ural M62 outfit, '51 VH500, '49 project Ariel , '47 VH twinport, '44 Ariel WNG, '42 indian 741b, '41 Ariel WNG and piles of rusty scrap ....
tony.barnett
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Re: Won't start

Post by tony.barnett »

Where are you setting the ignition when you are trying to start it? Advance it fully and see if that helps. The spark is strongest at that point (but it might kick you back a bit). I'm assuming you have fuel to the carb? Air screw screwed out 1 1/2 turns? Using a choke slide or tickling the carb?
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Re: Won't start

Post by tony.barnett »

I am also assuming you have set the ignition to fire on the compression stroke? Its easy to get that one wrong....
KOBI
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Ariels - 1913 TT Model, 20 Roadster, 28 Model D, 30 Model B, 38 VH, 52 VH
Velocette MAC, KSS Mk1
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john.nash
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Re: Won't start

Post by john.nash »

I've tried a variety of ignition and carb settings - retard, advance, flooded, choked etc.
I am confident it's timed on the compression stroke and that the timing is thereabouts.

On a lighter note, I've found the compression issue - the head gasket on the push-rod side is leaking.
I'm a 52 model, so I assumed a head gasket was needed - obv not or it's not torqued down enough on that side.
I'l have to fix that, and I'll double check the valves and carb as it all comes off ..;.
John Nash
AOMCC No.4119
''78 t140 bonneville, '77 BMW R80, '67 CJ750, 196-ish Ural M62 outfit, '51 VH500, '49 project Ariel , '47 VH twinport, '44 Ariel WNG, '42 indian 741b, '41 Ariel WNG and piles of rusty scrap ....
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Re: Won't start

Post by Julian Murphy »

Like @tony barnett said.

I did the same.

Re-timed it on the compression stroke......starts first kick.
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paul.jameson
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Re: Won't start

Post by paul.jameson »

You haven't got a slack wire magneto instead of a tight wire one have you?
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Re: Won't start

Post by JohnnyBeckett »

hi i would redo the timing from the beginning you may have the timing 180 degrees out have you done a compression test :?: or tried to bump start it
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john.nash
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Re: Won't start

Post by john.nash »

Update

Spent a while last night removing head gasket and then lapping the head joint (took ages).
After all that lapping, I suspected that the push rod seals were too porky (now trimmed down somewhat), as the club push road tubes are slightly longer than the originals, and weren't letting me clamp the gasket fully.
Oh well, it's lapped now.

Compression is now what I'd expect and away she went second go.
Few tense minutes for the oil return.
Now to sort out the leak from rocker feed stud and exhaust.
It's now 6 months waiting for the seat to get covered .....
John Nash
AOMCC No.4119
''78 t140 bonneville, '77 BMW R80, '67 CJ750, 196-ish Ural M62 outfit, '51 VH500, '49 project Ariel , '47 VH twinport, '44 Ariel WNG, '42 indian 741b, '41 Ariel WNG and piles of rusty scrap ....
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Re: Won't start

Post by Julian Murphy »

Well done. Good result.
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john.nash
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Re: Won't start

Post by john.nash »

Bad news. Bad news. :roll:

My bike wont start again. I've spent hours and hours and nowt doing - apart from once when it fired, idled revved and sounded great. I stopped it to fix some leaks and then it wouldnt go again.

It's been doing a bit of garage mileage and I fitted the oil pipe end of last week and it started fine to test it.

It bangs back through the carb, but nowt else.

The plug sparks on the engine. I've changed it for one off a running bike. I've checked the timing three times, taken the pick up off, and cleaned a clean slip ring. Not changed the cap and lead- but it sparks?
Mag is a new rebuild ( took old iron engineers six months plus), but I checked the points and that the points block isnt loose.

New concentric amal 930.
I've taken it apart twice. Cleaned and checked the pilot circuit and other internal bits. Fliat level is within spec. Nothing obvious. No muck. t floods up fine.
I havent touched it since last week, when everything was going.

There is now good compression, but I've checked my clearances again. Everything is operating as it should, opening and closing
Hand over the carb inlet reveals alot of sucking going on.

Drained fuel and replaced with some from a running bike.
.
I'm at a complete loss and am searching for something esoteric...... brake cleaner wont fire her up and neither will neat fuel in the cylinder so I'm thinking sparky stuff and timing as its banging back BUT it ive checked and te rececked and it seems right AND inbetween the hours of kicking it fired once and ran fine.
John Nash
AOMCC No.4119
''78 t140 bonneville, '77 BMW R80, '67 CJ750, 196-ish Ural M62 outfit, '51 VH500, '49 project Ariel , '47 VH twinport, '44 Ariel WNG, '42 indian 741b, '41 Ariel WNG and piles of rusty scrap ....
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