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No Like HOT
#825817 10/06/20 8:17 pm
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My '68 A65 Lightening runs well, but when the outside temps get 88 to 100 degrees the carbs get very hot.

Hot enough to vaporize the gas in a few minutes and the ticklers get too hot to touch.

What say you guys?

Thank you,
Steve

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Re: No Like HOT
Ragmanx #825821 10/06/20 8:59 pm
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Longer ticklers help, you can buy them from AMAL.
You can also use this thick o ring trick Triumph used for their carbs during 70 ties.

Re: No Like HOT
Ragmanx #825826 10/06/20 9:17 pm
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Phenolic spacers. I use one on my 70 Thunderbolt


1978 Bonneville T140E
1974 Trident
1970 BSA Thunderbolt
1971 Norton Commando
1972 Norton Commando
1973 Norton Commando
1974 Norton Commando
2018 Kawasaki Z900RS


Everything will be alright in the end. If its not alright, its not the end.
1 member likes this: Allan G
Re: No Like HOT
htown #825837 10/06/20 9:46 pm
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Originally Posted by htown
Phenolic spacers. I use one on my 70 Thunderbolt


Plus 1.

I tried the triumph method but you will need stepped studs for it to work properly (I think triumph used UNF, BSA used BSF in the head and cycle nut all the way through) you could do it will longer studs and reduced head nuts but the shouldered stud would be better, this stops you from over tightening the nut and the nut is still locked down enough not to come loose.

Phenolic spacers of a reasonable thickness (you can easily get away with 1/4” spacers with filters which is what I’m using now. Not put the 1/4” spacers to the baking hot day test yet but the thicker spacers I had on previous (I was also running velocity stacks) never gave me an issue even on the hottest of days.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: No Like HOT
Ragmanx #825901 10/07/20 2:47 pm
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I had a similar incident with a Velocette I put together some years ago. At the time I used a phenolic spacer as has been suggested and it seemed to work fine. A friend rode the bike on a 5k mile excursion and the bike survived but seemed noisy after that. Pulled the rocker cover and found copious bronze dust and not much oil in the vicinity of the inlet valve. Investigation showed the factory had messed up and not properly cut an oil way which was suppose to feed oil to the inlet valve. Might want to take a peek under your rocker cover on the BSA and make sure all is good before you start applying band-aid solutions.


Laurence Luce
Re: No Like HOT
Ragmanx #825933 10/07/20 10:19 pm
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Thanx, I'll look in to the rocker lube.

Just recently finally got the cover to stop leaking. Might pull the rocker feed line first.

Any other ideas?

Thank you
Steve

Re: No Like HOT
Ragmanx #825934 10/07/20 10:30 pm
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Have to check if your bike has 30mm carbs but these spacers will help solve your problem. If not 30mm other sizes are available.
https://www.eBay.com/itm/AMAL-30MM-CARB-PHENOLIC-TUFNOL-SPACER-INSULATOR-ABF814-70-2968-30-70-4918-30/264079397939?hash=item3d7c5bd433:g:QkEAAOSwCWRcDAxG


1978 Bonneville T140E
1974 Trident
1970 BSA Thunderbolt
1971 Norton Commando
1972 Norton Commando
1973 Norton Commando
1974 Norton Commando
2018 Kawasaki Z900RS


Everything will be alright in the end. If its not alright, its not the end.
Re: No Like HOT
htown #825950 10/08/20 4:39 am
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Thanx for the heads up!

I already have a phenolic spacers on the bike, but they are very thin.

The spacers you suggest are almost 1/4" thick.

Since the carbs only overheat when running in 90-100 degree heat, these spacers may make a difference.

It is certainly worth a try and bought them.

I will post the results.

Thank you again

Re: No Like HOT
Allan G #825953 10/08/20 7:13 am
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Originally Posted by Allan G
Originally Posted by htown
Phenolic spacers. I use one on my 70 Thunderbolt


Plus 1.

I tried the triumph method but you will need stepped studs for it to work properly (I think triumph used UNF, BSA used BSF in the head and cycle nut all the way through) you could do it will longer studs and reduced head nuts but the shouldered stud would be better, this stops you from over tightening the nut and the nut is still locked down enough not to come loose.

Phenolic spacers of a reasonable thickness (you can easily get away with 1/4” spacers with filters which is what I’m using now. Not put the 1/4” spacers to the baking hot day test yet but the thicker spacers I had on previous (I was also running velocity stacks) never gave me an issue even on the hottest of days.


I like and use the triumph way, a couple of thin 5/16 bsc clevlocks and a thick o-ring, works for me. You can leave the thin tufnol piece in if you want.

Re: No Like HOT
slow learner #825965 10/08/20 12:24 pm
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Originally Posted by NickL
Originally Posted by Allan G
Originally Posted by htown
Phenolic spacers. I use one on my 70 Thunderbolt


Plus 1.

I tried the triumph method but you will need stepped studs for it to work properly (I think triumph used UNF, BSA used BSF in the head and cycle nut all the way through) you could do it will longer studs and reduced head nuts but the shouldered stud would be better, this stops you from over tightening the nut and the nut is still locked down enough not to come loose.

Phenolic spacers of a reasonable thickness (you can easily get away with 1/4” spacers with filters which is what I’m using now. Not put the 1/4” spacers to the baking hot day test yet but the thicker spacers I had on previous (I was also running velocity stacks) never gave me an issue even on the hottest of days.


I like and use the triumph way, a couple of thin 5/16 bsc clevlocks and a thick o-ring, works for me. You can leave the thin tufnol piece in if you want.


I have nothing against the method which is why I implimented it... Just wasn't going to then buy a set of studs 5mm longer so that the nuts would have something more to bite on to. One of them backed off a bit and the thick O'ring dropped (luckily didn't go far) I fixed it on side of the road, tighten the nuts tighter than I would have liked and carried on my way. If I did it again I would use the stepped stud method as per triumph design then I would feel happier that I wasn't going to distort the carb body.




Originally Posted by slow learner
I had a similar incident with a Velocette I put together some years ago. At the time I used a phenolic spacer as has been suggested and it seemed to work fine. A friend rode the bike on a 5k mile excursion and the bike survived but seemed noisy after that. Pulled the rocker cover and found copious bronze dust and not much oil in the vicinity of the inlet valve. Investigation showed the factory had messed up and not properly cut an oil way which was suppose to feed oil to the inlet valve. Might want to take a peek under your rocker cover on the BSA and make sure all is good before you start applying band-aid solutions.


Joke answer: theres no bronze within an A65 head....

Joke apart, it would be surprising if that was the problem, A65's get a lot of oil up to the head, they placed a split pin within the gallery in the head to limit this.

Also this isn't a Band-Aid solution (their's was to feed the world! - sorry I couldn't help it!) BSA implimented this on a service sheet. which I will try and remember to attach later when I get on my home PC.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

1 member likes this: Kevin E
Re: No Like HOT
Ragmanx #825998 10/08/20 6:57 pm
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i would try riching up the mixture a bit ......lean mix will definitely cause it to over heat .......try moving to needle up a notch (cant hurt to try) also have a look at what slides your have ..........even a 3.5 slide will cause lean mix ..they should be 3 .........the other thing to check is the fuel level in the carb bowl......to low can also cause lean......check also for air leaks at the manifold (or more like where it bolts on as there isnt a manifold as such) .......while its idling CAREFULLY tip a bit of gas around the join and see if the motor note changes ......if it does u have a leak........its unlikely to be jets but who knows what you have ?

I made asbestos fiber gaskets about 1.2mm (or was it 1.6mm cant recall) thick , used 2 per side ....made a huge difference in insulating the carbs from the heat

check timing as well obviously


"There's the way it ought to be and there's the way it is" (Sgt Barnes)
Re: No Like HOT
Ragmanx #826055 10/09/20 3:36 pm
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I believe the first question to be addressed should be is over heating carburetors a common problem on a A65? I ran a A65 for many years and had many problems but that was not one of them. I live in south Calif. and it does get hot here.As I mentioned above, inadequate oil flow might cause this (bronze dust comes from the guides) and as Ignoramous says mixture could also be a problem. Another thing to look at would be timing. Bandaid solutions are great if they are not covering up a more serious, fundamental problem.


Laurence Luce
Re: No Like HOT
Ragmanx #826066 10/09/20 6:42 pm
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Many years back I was really struggling with my 70 overheating ....it would get so hot you could hear it making sort of crackling type noises when you shut it off in summer

DANG i tried everything
1 all the stuff above
2 tried synthetic oil which was horrendously expensive back then
3 modified an oil cooler of some huge jap s hit box (Kawasaki 1000 or something)

nothing worked

then i had an epiphany .............MAYBEE if I don't cane it quite so hard .....strangely it didn't get so hot then...but i was stuck with an overheating bike till i got older

Just saying


"There's the way it ought to be and there's the way it is" (Sgt Barnes)
Re: No Like HOT
Ragmanx #826086 10/09/20 10:33 pm
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“Hot” is subjective.

I think all “sporting” models have always got pretty hot while running normally. I think it is part of the package.

Considering the ~ 1000degC combustion going on in the chamber, its not surprising that the head gets toward 200degC, the barrels 100, and the upper cases approaching 100, when giving some stick.

So what, I would say? They are intended to take that. They are intended to work that way.

Of course if your timing or carburation is way off, then that is a different matter, and that may overheat a piston (seizure) or melt a hole in it.

You can often get an indication of over-advanced timing by pinking with say half-throttle at 3000rpm pulling in top gear, though extreme over-heating is more likely to result from retarded timing.

All engines are hot when up to running temperature.

Re: No Like HOT
Ragmanx #826161 10/10/20 10:42 pm
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As previously mentioned

Attached Files A3C28004-B51C-457D-A670-58954B6C537F.jpeg
Last edited by Allan G; 10/10/20 10:43 pm.

Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: No Like HOT
Ragmanx #826251 10/11/20 10:39 pm
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If you have a standard set up with 930s and the round chrome air filters, you won't have room to add the phenolic
spacers without the air filters hitting the side panels. I had this problem in 1973.. My A65L would get very hot
in traffic (around south London) to the point that it wouldn't tick over, so you had to blip the throttle which just
made things worse.I agree the spacers would be the cure, if you can get them to fit.

Re: No Like HOT
Ragmanx #827059 Yesterday at 12:20 AM
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All kinds of great insights from all you all!

I'm going to use most of them, one at a time

!. will start with checking the timing on the EI. Should I use stock advance?

2. replace the wimpy spacer with a pair of thicker pressed paper or thicker phenolic ones. Space permitting.

The weather is really cooling down so a hot ride is doubtful 'till next summer.

Will post results as soon as I have some.

Thank you,
Steve

P.S. I replaced my chrome primary cover with an older stock one that has an inspection cover. Eliminates full removal just to adjust timing.
Never really liked the chrome one.


Moderated by  Allan G, Jon W. Whitley 

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