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750T FUEL

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malllywoods View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote malllywoods Quote  Post ReplyReply Direct Link To This Post Posted: 05 Apr 2021 at 13:49
OK ta
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malllywoods View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote malllywoods Quote  Post ReplyReply Direct Link To This Post Posted: 06 Apr 2021 at 08:37
could you please explain about the needle notchesCry
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Dave P. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave P. Quote  Post ReplyReply Direct Link To This Post Posted: 06 Apr 2021 at 11:04
The tapered jet needle and the needle jet or emulsifier work together to metre the amount of fuel drawn into the engine from about quarter throttle to around three quarter throttle opening. You can't change the amount of air going in at any particular position but you can change the fuel air mixture strength by simply changing the position of the needle. The lower the clip sits in the grooves the higher the needle sits in the slide. So, clip in bottom groove,richest setting. Clip in top groove, leanest setting.
TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

1971 V7 Special. 1972 850GT.
1970 T120 Bonnie. 2009 500 Bullet.
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Dave P. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave P. Quote  Post ReplyReply Direct Link To This Post Posted: 06 Apr 2021 at 11:16
TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

1971 V7 Special. 1972 850GT.
1970 T120 Bonnie. 2009 500 Bullet.
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malllywoods View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote malllywoods Quote  Post ReplyReply Direct Link To This Post Posted: 06 Apr 2021 at 20:29
o mate  thanks I'm keeping that.
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Brian UK View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 06 Apr 2021 at 22:15
We have had that on this forum for years.
Brian.

Better 5 minutes late in this world than years early in the next.
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malllywoods View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote malllywoods Quote  Post ReplyReply Direct Link To This Post Posted: 12 Apr 2021 at 19:43
Well carried out all that's been suggested and we have a bit an improvement, tick over ok but on a run lacks power, I found that on tick over 1000rpm when I remove the R/H spark plug lead the engine carries on running, even rev up,,, but removing the L/H spark plug lead the engine immeadatly stops. Is this a clue?????


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Richard Hyatt View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Richard Hyatt Quote  Post ReplyReply Direct Link To This Post Posted: 12 Apr 2021 at 20:00
This is a classic test to prove if a cylinder is or is not functioning.
If you pull a plug lead off and the tivkover drops   then clearly that cylinder was working  .
Conversely,  if you pull a lead off and there is no change , then that cylinder clearly is making no difference to the tick over.

So you've proved that you have a malfunctioning cylinder.
There are 3 prime requirements for a cylinder to work, fuel , spark , compression. 
You need all 3 to work and then jointly with the good cylinder the tickover will rise as both pots pull together.

Now the diagnosis begins, 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote andrewhush Quote  Post ReplyReply Direct Link To This Post Posted: 12 Apr 2021 at 20:04
The right cylinder isn't firing. Try swapping the ignition control units over and take off the plug leads off one at a time as before. If the left cylinder becomes the non firing one and the right cylinder starts firing then the right ignition control unit is dead. If the right cylinder remains the non firing one then the fault is in the right side ignition system, I.e. pickup (or points), ignition coil, plug lead, cap or plug. Or the right side carb isn't supplying the right amount of fuel/air mixture.

Edited by andrewhush - 12 Apr 2021 at 20:07
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malllywoods View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote malllywoods Quote  Post ReplyReply Direct Link To This Post Posted: 12 Apr 2021 at 20:14
You guys are so good, I will be on it tomorrow.  MASSIVE THANKS will let you know what happens.
mallywoods
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Richard Hyatt View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Richard Hyatt Quote  Post ReplyReply Direct Link To This Post Posted: 12 Apr 2021 at 20:28
This is a good and effective way of exporting the problem side to side.
I have 4 ht neon testers from ebay, I've used these for years to check sparks in situ

AccuSpark Sparkplug HT Lead Spark tester / testing tool

1st thing is establish that you have sparks on both sides obviously - YES? (they can spark when no compression but under compression the spark has a tougher job of jumping the gap)

we know the RH cylinder is not happy

simplest place to start exporting is swop spark plugs left to right - check engine running - pull RH cap off - no change - not the plug

then swop plug cap(unscrew from lead)  swop left to right - check engine running - no change? - not the cap

have you got compression on the RH side? check with comp tester expect around 150 psi 'ish

if not- valve clearances(I think you checked these ?)

is the RH plug wet or dry ? - wet flooded and flooding the spark out - dry then no fuel issue on the RH side - carb float or needle valve stuck(can you see fuel flowing into that carb when you turn taps on(clear fuel pipe try that)

then under tank, swap wires to ht coils over left to right (dont forget to swap the actual leads to the plugs as well)

slowly but surely by logical steps , you will narrow it down

but the most important is tea and digestives ! in copious quantities.

establish


Edited by Richard Hyatt - 12 Apr 2021 at 20:50
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malllywoods View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote malllywoods Quote  Post ReplyReply Direct Link To This Post Posted: 12 Apr 2021 at 21:11
Thanks Richard report back tomorrow.
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Brian UK View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 12 Apr 2021 at 21:43
Those would make a very sensible acessory for the toolbox.
Brian.

Better 5 minutes late in this world than years early in the next.
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malllywoods View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote malllywoods Quote  Post ReplyReply Direct Link To This Post Posted: 13 Apr 2021 at 13:29
Well you all deserve a beer and I really wish I could buy one or two for you.
You have all saved the day and following instructions she is now running the best since ive owned her, carburettor choke pistons replace with new springs, a good clean and a bit of time adjusting one turn in I/2 turn out here and there, Im sure you know what I mean, I think maybe feeling the exhaust they could a minimal difference in pressure between them but one has a brand new old stock silencer and the other is thirty years old so that's properly the reason I think.
A spark plug was the end problem, silly but it was a brand new one which just wasn't working, I didn't expect that.
As for the HT neon testers Ive come to realise they are invaluable and ordered 4 from Ebay should turn up on Friday.
Massive thank you for all your help, Its well appreciated, you've saved my day and ive learned a lot.

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Dave P. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave P. Quote  Post ReplyReply Direct Link To This Post Posted: 13 Apr 2021 at 13:56
Can you tell if your new plug was one of the rouge NGK's that are about.


http://ngk.sr/technical-information/fake-spark-plug/

Edited by Dave P. - 13 Apr 2021 at 14:03
TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

1971 V7 Special. 1972 850GT.
1970 T120 Bonnie. 2009 500 Bullet.
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