Recent Posts

91

Introductions, Stories, Meetings & Pictures / Re: What have you done with your bike/s today?

« Last post by Topdad on 03.09. 2024 10:40 »

Was able to put 30 mins on the bike last Sunday as not fuel getting threw and suggested clean out of the pilot jet etc . So carb off and ready to do the jet I noticed something missing ,the needle ! searched high and low not a trace picked up the carb body of the bench and theres the bloody thing sitting in the needle jet ! Being 15 yrs or so since last done and being much more flexible then I didn't relish this job especially after a couple of tries resulted in the air turning a deep shade of blue in the garage (not gas  just bad language ) I gave up got washed and did a Berger we went the pub.

92

A7 & A10 Engine / Re: T120 rings in a +80 A10

« Last post by groily on 03.09. 2024 10:19 »

Thanks for that mike.
Maybe a thou more would be good - think at 72.5mm I had 5.25 thou but honestly can't remember for sure. I did run them in very carefully because I also heard their expansion rate was a bit more than normal.
Like with you, there was nothing else available in the size and comp ratio I wanted - and I don't think it has got any easier.

I was really pleased when I read about the IMDs on here - and the proof of the pudding has been in the eating. The current owner of the bike has done loadsamiles with loadsasmiles on them with low oil consumption. Which given that I didn't rebore, just honed, because the cylinders measured OK at half-way to the next oversize, has made me, and him, happy.

93

A7 & A10 Engine / Re: T120 rings in a +80 A10

« Last post by mikeb on 03.09. 2024 09:38 »

Bill - i went against local wisdom and cautionary tales when installing the JPs (as they were the only +80s i could find). i can't exactly recall what the clearances were but i think 4 1/2?. but not enough: they seized on a hot day, up a hill, wide open trying a keep up a with a passing vincent. but that's how i ride.
i'm an office worker so really don't know, tho am told they have a higher expansion rate than standard and a higher failure rate to boot (eg a local story of one splitting in half). during their short lives they certianly let a lot of oil slip by to be burnt. the imds? none.
am i being unfair? possibly. i have since been told they shold be bored with a wider clearance. and noting the rings are more widely regarded as the inferior part.

for a final verdict, lets see if Musky fits JPs ...

94

A7 & A10 Engine / Re: T120 rings in a +80 A10

« Last post by groily on 03.09. 2024 07:49 »

(and never JPs again over my dead body)

What was it about them mike? Criticism of them crops up here and there, the rings in particular, but I have had a +20 8.5:1 pair for about 25K miles in an AMC and haven't had any problems. Weights were very close to originals in that case but I had the crank dynamically balanced anyway. Key thing seems to be to rebore with adequate skirt clearance. Have I just been lucky?
I went flat top IMDs on my A, and agree they're a very good bet. In other engines hereabouts it's Gandinis or AE / Hepolite - the hassle is limited choice nowadays unless we've stashed a few on a shelf over the years. Some engines are better served than others, that's for sure.

95

A7 & A10 Engine / Re: T120 rings in a +80 A10

« Last post by mikeb on 03.09. 2024 03:58 »

Musky your compatriots JP make a +80 A10 piston and rings.... no? I wouldn't either, but just saying

EDIT: i had similar thoughts re t120 rings when my JP's died, but with heavy heart and open wallet resleeved to IMD stds. too soft for your cafe, but no regrets here (and never JPs again over my dead body)

96

Amal, Carburation / Re: Air filter

« Last post by Joolstacho on 03.09. 2024 00:25 »

Or you could use an original air filter (look in For Sale!)

97

Other BSAs, Other Bikes, Cars, Machinery & Tools / Lucas MCR Regulator.

« Last post by trevinoz on 03.09. 2024 00:01 »

Just a bit of trivia for those who may be interested.
The first Lucas regulators were introduced in 1937 being the MCR, not to be confused with the 1938 onward MCR1.
This one is off a 1938 M24 Gold Star and I believe it to be the original fitment.
There are some differences from the later version, the armatures are screwed together, not riveted, and are very different.
The tension springs are coil in the adjusters on the rear, changed to leaf springs later.
This one works as it should and will be going back onto the bike.
I have overhauled the MO1 magneto and rebuilt the generator as per 1938.

98

A7 & A10 Engine / Re: T120 rings in a +80 A10

« Last post by Swarfcut on 02.09. 2024 20:58 »

 G'day Musky

    My 1989 AE Catalogue lists ring set R1150, to cover nominal bore of 70.998mm on the Triumph TR6 650cc engine from '54 to '71.

    Ring thickness is 0.0625" for both compression rings, 0.125" for oil ring, 1/16" and 1/8" respectively.

    Ring groove depth on the piston is indicated as 0.1000" (2.540mm) for all three grooves. Sadly there are no listings for BSA pistons in this publication. The ring groove depth and the radial thickness of the rings may or may not be the same thing, there is no clear guidance. 

 Cheers

 Swarfy.

99

Wanted & For Sale / Re: WANTED: TLS Front Brake

« Last post by JulianS on 02.09. 2024 20:48 »

The photo shows on the left the BSA/Triumph TLS brake and on the right the Eddie Dow Duetto brake TLS to fit the 8 inch full width A10 drum. The difference in the anchor lug is significant.

100

Wanted & For Sale / Re: WANTED: TLS Front Brake

« Last post by JulianS on 02.09. 2024 20:42 »

If you try for the 1968 type forks be aware that almost none of the A10 parts, other than the bushes, oil seals, endcap bolts and bottom nut washer, will fit.