Author Topic: Still Running like a dog!!!  (Read 6785 times)

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Re: Still Running like a dog!!!
« Reply #60 on: August 21, 2019, 04:57:21 PM »
Just an additional thought,  all the syncing blank screws are in place aren't they?  Non have fallen out?

Offline matthewmosse

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Re: Still Running like a dog!!!
« Reply #61 on: August 21, 2019, 10:07:26 PM »
I had one engine do similar- noticed after thrashing its useless carcass 20 miles each way to and from work that one of the valve stems became discoloured from heat. It only did this after a frustrating long lot of use - not investigated it further just dropped the motor and swapped it for another. It's an outside possibility but I suspect mine was down to a sticking valve. It came into play with a hot engine, fine in the garage, naff on the roads.
« Last Edit: August 21, 2019, 11:19:07 PM by matthewmosse »
Got a 500/4 with rust and a sidecar and loadsa bits. nice and original and been round the clock

Offline deltarider

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Re: Still Running like a dog!!!
« Reply #62 on: August 21, 2019, 10:11:21 PM »
Try synching the carb's with Bryan method of mechanical setup and run it like that.  Don't put the guages on it at all.

Then setup the idle air screws as per Honda manual routine. It's very specific as to how it should be carried out for initial setup after carb rebuild.
Where can we find that?

Offline deltarider

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Re: Still Running like a dog!!!
« Reply #63 on: August 21, 2019, 10:14:18 PM »
Oh... and how about the exhaust gaskets? Are they well fitted and seal well?

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Re: Still Running like a dog!!!
« Reply #64 on: August 21, 2019, 10:20:26 PM »
Try synching the carb's with Bryan method of mechanical setup and run it like that.  Don't put the guages on it at all.

Then setup the idle air screws as per Honda manual routine. It's very specific as to how it should be carried out for initial setup after carb rebuild.
Where can we find that?

I'll get a photo and post it of the page,  but wont get to manual until the morning.  That's of the idle setting method,  but it shoukd be in one of Ash's manual files too.

Bryan method here http://www.sohc.co.uk/index.php/topic,17769.0.html

Offline paulbaker1954

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Re: Still Running like a dog!!!
« Reply #65 on: August 21, 2019, 10:42:53 PM »
Just an additional thought,  all the syncing blank screws are in place aren't they?  Non have fallen out?

Or missing the sealing washer

Actually I have bike set up for testing with carb balancer connected. I nterestingly if I pull off one of the vac hoses from the brass connecting pipes there seems to be no change

Is this any clue

Will try and post a vid on u tube over next few days so folks can hear what is happening
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Re: Still Running like a dog!!!
« Reply #66 on: August 21, 2019, 10:50:52 PM »
Just one cylinder that does that?  Or any one you try?  Revs should rise if you pull one of the tubes,  check the brass tubes to see if one of them is obstructed, I'd start with that one you've just pulled off and compare it to another.

What I'm angling at is that the guages are causing you to put mechanical error onto carb setup.  Hence request to set them as Bryn does to take the guages etc out of the equation.

Offline deltarider

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Re: Still Running like a dog!!!
« Reply #67 on: August 22, 2019, 10:43:13 AM »
I'll get a photo and post it of the page,  but wont get to manual until the morning.  That's of the idle setting method,  but it shoukd be in one of Ash's manual files too.
Bryan method here http://www.sohc.co.uk/index.php/topic,17769.0.html
Thanks and looking forward to it. As far as bench syncing, I have my own method that worked well at three different occasions. As a matter of fact, I haven't touched my gauges for decades. BTW, it is particular the mixture setting by the airscrews for the oldstyle Keihins that I'm interested in.
Quote
I nterestingly if I pull off one of the vac hoses from the brass connecting pipes there seems to be no change
Paul, that indicates something is not right, it should make a difference. To me it seems, there's some airleak already/overlean situation where pulling of the pipe does not makes much difference anymore.

Offline Nurse Julie

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Re: Still Running like a dog!!!
« Reply #68 on: August 22, 2019, 11:00:41 AM »
This thread may help you Delta.....this is relating to Keihins which have air screws (where the screw is at the air box, or back side of the carb, not fuel screws which are at the engine side, or front of carbs) So this covers most, if not all of the carbs fitted to our bikes. I bench sync all carbs with Bryans method and then adjust air screws as per that thread and the carbs are spot on. No need to vacuum them at all.

http://www.sohc.co.uk/index.php/topic,19585.0.html
« Last Edit: August 22, 2019, 11:02:44 AM by Nurse Julie »
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Offline deltarider

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Re: Still Running like a dog!!!
« Reply #69 on: August 22, 2019, 11:11:22 AM »
Thanks Julie, I'll study it with interest. I have two socalled air/fuel testers (oldstyle) lying around that both suffer from bad connectors in the leads but that for the rest seem to work OK. I have to figure out how I can improve these connectors to be able to do some experiments (my bike has 4-4). But that may take a wile due to... laziness.

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Re: Still Running like a dog!!!
« Reply #70 on: August 22, 2019, 05:57:09 PM »
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Above is photo of 750 K0 official workshop manual covering this method.

See what you think as I'm looking at it with a perspective of other systems and picking through how I recognise various bits.

It is essentially repeated in following Honda manuals I have for later bikes,  it doesn't change apart from the direction of adjustment screw as it moves to engine side of carbs.  It's very concise and does pick up on the elements that shoukd be optimised.

Remember though that the vac guage method on here is for the first iteration of this bike with 4 throttle cables and no synchronised lifting bar as later carb sets have. It's the idle trim after getting slides into equal positions that is common across successive carbs.
« Last Edit: August 22, 2019, 06:01:11 PM by K2-K6 »

Offline paulbaker1954

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Re: Still Running like a dog!!!
« Reply #71 on: August 23, 2019, 05:58:04 PM »
Fingers crossed may have it cracked yet to road test but seems to be running well
Combination of a number of things
Fuel level too high on 1 and 2 (odd as I bench tested 2 times before refitting carbs)
Small air leaks at inlet rubbers (still there a bit - need some better clamps see separate post)
Dodgy rectifier connection (May have been causing voltage spike to Boyer system)
One plug cap was only 4.2k ohms which may have also been affecting Boyer kit

As I say yet to road test but running much much better and misfire all but gone 😀😀😀

Thanks to all who have been contributing to this post that’s what this forum is for!!!!
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Offline Erny

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Re: Still Running like a dog!!!
« Reply #72 on: August 25, 2019, 11:02:54 PM »
Paul, wish you found root cause and issue is fixed!
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Offline paulbaker1954

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Re: Still Running like a dog!!!
« Reply #73 on: August 25, 2019, 11:08:35 PM »
Paul, wish you found root cause and issue is fixed!

Sadly road test not good, now down to air leaks at inlet rubbers I think. The new clips I bought from DSS just don’t clamp up properly. Ordered some thin jubilee clips from INOX fasteners to hopefully fix.
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Offline hairygit

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Re: Still Running like a dog!!!
« Reply #74 on: August 25, 2019, 11:13:33 PM »
Paul, wish you found root cause and issue is fixed!

Sadly road test not good, now down to air leaks at inlet rubbers I think. The new clips I bought from DSS just don’t clamp up properly. Ordered some thin jubilee clips from INOX fasteners to hopefully fix.
Did mention issues with the clamps a few weeks back!

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