More help from the great and good

oldnfat · Nov 16, 2017

Flushed with success at not completely cocking up the pushrods oil seal replacement on the right hand pot of my g/s I decided to do the left as well on the basis they were done previously at the same time so reasoned they would go soon.

Anyway, took the head of the be presented with a head that is much more carbonised ( if there is such a word) than the other side. Is this normal...if not what is likely to be the culprit? Could it be too smaller valance clearance...they seemed a little tight to me?

Any advice greatly appreciated...

....almost forgot....I can't get the pot off. Before I make a strap to pull it off has anybody got one already lying around that I could borrow for the price of postage?

Thanks one and all.

scooter paul · Nov 17, 2017

Could this be the old oil collecting in the left hand side combustion chamber when left on the side stand syndrome?

oldnfat · Nov 17, 2017

Good point...hadn't thought of that.

Rugged Path · Nov 17, 2017

Get them twin plugged while heads are off.

Sent from Steve's fancy iPad using Tapatalk

Rob Farmer · Nov 17, 2017

Rugged Path said:
Get them twin plugged while heads are off.

Sent from Steve's fancy iPad using Tapatalk

Thats a daft idea. no faster waste of money than twin plugging. He just needs to get the mixture right, its running rich. A quick run on a dyno will reveal all.

ChasF · Nov 17, 2017

Looks well coked up, I would suspect a carb fault possibly exasapated by incorrect valve clearances. I've not tried twin plugging but the general concensus seems to be that the benefits are negligible.

oldnfat · Nov 17, 2017

Yes....a very good friend in the USA had his twin plugged and reckoned it made bugger all difference. I did think about mixture being too rich but didn’t think it would be that coked up....but that is the way I will go first.

Thanks Rob...again.

Beemerboff · Nov 17, 2017

Twin plugging can be some value on certain bikes, particularly those with 40 mm carbs and excessive squish clearance.
But it seems to need the correct ignition curve and only the Boyer Micro Power twin plug system seems to have that.
Setting the squish a bit tighter and fitting the correct size of carbs will work much better, but neither is a cheap exercise if you want the full benefit.
Race bikes which are running full bore can benefit from the twin plugs as the head heats up more evenly than with a single side mounted plug head, which could distort a little and affect the exhaust valve seal, but road bikes probably wont get there.
Looks like you left carb needs work - maybe check float levels and slide needle projection.
Or maybe fit a deeper sump and dont fill it to the top.

Rob Farmer · Nov 18, 2017

I wasted a huge amount of time and money on a twin plugged airhead. Tried all sorts to see any improvements at all and eventually just had to give up on it. It looked trick though and gave the impression I knew what I was doing so probably worth it for that alone

scooter paul · Nov 18, 2017

Rob Farmer said:
I wasted a huge amount of time and money on a twin plugged airhead. Tried all sorts to see any improvements at all and eventually just had to give up on it. It looked trick though and gave the impression I knew what I was doing so probably worth it for that alone

I agree. I took over a project once that had zillions spent on it, to a very high standard, including twin plugged heads. Having owned many airheads before and since from my experience I see no benefit at all in real world riding.

B Murr · Nov 18, 2017

RE possibility of oil seeping down when on side stand, I'd guess if that was happening that there would be some unburnt oil in-situ when dismantled, unless it was dismantled very quickly after last use?

oldnfat · Nov 19, 2017

B Murr said:
RE possibility of oil seeping down when on side stand, I'd guess if that was happening that there would be some unburnt oil in-situ when dismantled, unless it was dismantled very quickly after last use?

Well...yes there was oil residue on the cylinder liner so guessing this is a contributing factor....but will also get checked out on a dyno as Mr Farmer suggests.....just for peace of mind like.

Rob Farmer · Nov 19, 2017

oldnfat said:
Well...yes there was oil residue on the cylinder liner so guessing this is a contributing factor....but will also get checked out on a dyno as Mr Farmer suggests.....just for peace of mind like.

you will be shocked at how little power they produce

For what it costs to put it on the dyno I've always found it to be worth every penny. not from any performance gains but just to get them to run as well as they can.

Steptoe · Nov 21, 2017

Rob Farmer said:
I wasted a huge amount of time and money on a twin plugged airhead. Tried all sorts to see any improvements at all and eventually just had to give up on it. It looked trick though and gave the impression I knew what I was doing so probably worth it for that alone

I used to be regularly asked to do twin plugging on customers bikes... My advice was always "save your money".

I've had more than few bikes in the past where the secondary plug used was slightly too long.
Which resulted in the last few threads getting carboned up and ruining the plug thread in the head as you tried to remove them. Great fun.

Beemerboff · Nov 21, 2017

Problem might be finding a small short reach plug in the correct heat range - mine always look as if they are a grade too cool, and they are the hottest I can find.
My twin plugged 1000 cc G/S came cheap because it was a vibratory slug and the two full time BMW specialists who had either fitted the 1000cc twin plug conversion or tried to tune it couldn't make it work properly.
But they were trying to simply retard the ignition, which doesnt work, and I replaced it with a Boyer Micropower twin plug system which has the correct curve.
As I had neither a functioning timing light or rev counter timing was set by trial and error, pulling hard up my long steep test hill , and the result was more than satisfactory, up from 105 to 130kph as I crested the summit.
Cant even see the timing mark , it is so far down.
Starting smoothness and fuel consumption improved too, and the bike now pulls happily and strongly from 60 kph in top.
G/S gearing on a 1000cc bike helps here too, of course.
Some of the tuners who did twin plugging only did it as part of a general tune which included tightening the squish clearance, and I suspect correcting the squish clearance made vastly more difference than the twin plugging.

Sylvester · Dec 2, 2017

It’s a bugger the other head is back on. If your oil consumption is low I’d say you need to have the carbs off clean them set up carefully espesh the float heights, set them up and see what you get plug color wise. It looks like one side is burning oil or running rich. I never leave it on the side stand to avoid the oil collection issue. It was designed with a cruel sense of humor anyway.

oldnfat · Dec 3, 2017

Sylvester said:
It’s a bugger the other head is back on. If your oil consumption is low I’d say you need to have the carbs off clean them set up carefully espesh the float heights, set them up and see what you get plug color wise. It looks like one side is burning oil or running rich. I never leave it on the side stand to avoid the oil collection issue. It was designed with a cruel sense of humor anyway.

Thanks for this....oil consumption is low and I rarely leave the bike on the side stand for any length of time. Goes on the dyno tomorrow.....I suspect you are right so the carbs will be set up as part of this process.

Cheers

mikeyboy · Dec 4, 2017

You don’t say whether you have cleaned or serviced the carbs,
We normally find a lot of shit in the air bleeds into the main jet/ needle seat,immulsifier tube,( call it what you choose)
I wouldn’t waste money on a Dyno run unless the carbs have been serviced,
I suspect You will find it’s running rich though the mid range,due to insufficient air bleed.

Beemerboff · Dec 4, 2017

Yep, if they are really gummed up they stay in place and dont come out with the needle jet, and some carb service instructions dont mention removing them!
Quick check is to blast some carb cleaner down both the holes which run parallel to the intake - large hole on the right should exit cleanly from round about the needle, small one on the left from a pin prick further down.
Then if you remove the slow running screw and blast down there it should come out the pilot jet and another pin prick.
No need to even remove the carbs and you have checked everything but the choke circuit!

oldnfat · Dec 10, 2017

Well thanks guys....the dyno run didn’t go ahead as when I got there the guy who was an ex police bike mechanic from way back said the same thing. The bike was running rich with both air bleeds gummed up with the right side worse than left for some reason. Anyway, I stayed and went through the process with him as a learning exercise.

He mentioned that they would go through a full card rebuild as part of and annual process that saw the bikes being stripped and virtually rebuilt.

Anyway, the assembled wisdom has nailed it once again, thank you one and all.

More help from the great and good

Well-known member

Well-known member

Well-known member

The Honourable.

Well-known member

Well-known member

Well-known member

Registered user

Well-known member

Well-known member

Registered user

Well-known member

Well-known member

What a waste.

Registered user

Registered user

Well-known member

Well-known member

Registered user

Well-known member

Similar threads