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Triumph bulletin board Jump to new posts
Re: Fuel, hand grips, & mirror mounts DMadigan 1 hour ago
WD-40 for grips. Wet the inside, slide it on. When dry will not come off. To remove, stick the tube under the grip, spray, twist and it comes off.
7 156 Read More
Bsa bulletin board Jump to new posts
Re: Carb mount - new Wassell to B50mx DMadigan 1 hour ago
Also known as Micarta
3 72 Read More
Bsa gold star forum Jump to new posts
Re: Timing-side case differences Boomer 2 hours ago
There is a definite physical difference between the iron barrel timing side case and the alloy timing side case. the base of the cylinders were different and needed different support area. Here's the difference showing the iron barrel case first.

[Linked Image from]

[Linked Image from]

Bill B...
3 126 Read More
British motorcycles in general Jump to new posts
Re: oil BSA_WM20 2 hours ago
In one of the old books. Tuning for speed from memory was a break down on the heat dissipation inside a single cyinder engine
from memory so it might not be exact 80% passed out the exhaust port 10 % was transferred to the head 8% to the cylinder wall and 2% to the remainder of the engine.

To use oil cooling you would need to use large volumes of oil plus have a reasonable sized heat exchanger to cool the oil down before returning it to the engine
The oil runs between 60 & 80 C which will rise another 10 deg or so if left at idle in still air so reducing the cooling effect of the fins

If I can dig it up there was another break down of the heat transfer rates through each rings to the bore & through the piston into the con rod and thence the crank, plus another for the piston to crankcase gasses then out the breather.

None of them had valuse for friction generated heat

Now some of the head cooling would be done by the oil pooling on the floor before returning to the sump but the amoungt of heat relative to what is radiated from the massive area of the finning would be very small

If the oil was doing significant amounts of cooling then it would be running much closer to the 200 deg a head runs at than the 80 deg the oil runs at.

Now I know that some engines do use oil to cool and usually it is done to cool a specific hot spot .

The rate of heat transfre is a function of the difference between the two surfaces and the thermal transfer rate of the material, the R value we are familiar with when rating insulation
Inside the engine the piston the thermal gradient is fairly low when compared to the thermal geadient between the fins & the air.
Now the thermal gradient between the oil and the part is is flowing over will be substntially lower except for the tiny oil film layer around the piston rings & on the cylinder wall .

Considering just how little cooling is done by the oil a difference between the theramal rate of 2 different oils would be negligible .
Now if you were quenching yellow hot steel it might be a different matter but in an engine if one oil had 1/2 the heat transfer rte of another the only noticable difference would be the less efficient oil would take a bit longer for the engine to get to full working temperature.

That’s rather empty rhetoric. If BSA wanted to build better bikes, I suppose they would have!

Not so empty
When spending a small fortune to squeeze more horses out of the Gold Stars BSA vastly increased the finning
They did not do the same to the oil flow through the engine .
Not everything was cut to the bone like the C series.
81 1,114 Read More
The competition forum Jump to new posts
Re: pre 62 Sidecar Mark Parker 3 hours ago
I have a flywheel centre machined up. I don't think is has bolt holes. It was a spare. And I have the last crank I had cut together because I might put it in the Firebird. I don't know exactly how strong they are, other than they are extremely tough to cut. There are lots of nuts and bolts and locktite. I tell myself the flange is bigger diameter than a Norton with more bolts plus the big ones up the pins. I advanced the left cyl, SRM the right, so it needs doing their way to suit their cam.

I think Gary only just left. They port heads and use nice machines and have a flow bench, but have never used it? And he doubts anyone there will use it.

I have a map we gave the machinest to cut the crank and bolt it up, I'll see if I can find it.


[Linked Image from]

This may be interesting, This is fit the cylinders easily on your own. Advantages, the block sits on a piece of wood and gravity stops the followers falling out. The pistons are already fitted in the bores and hanging out the bottom with inner clips in, fit pins at your leisure and clips. Check about 7 times each. 90 degree doesn't matter, put sealer on the joint, check followers, slide it on.

This is the first cyl I made with thin liners. I flogged it for years. The pistons were cast and had low skirts that came out the bottom a bit, It cracked a liner. So I then used Nicasil and pistons that fitted properly. I regarded this cyl scrap. I practiced tapping the threads oversize. Drilling the old holes bigger using a very quarely set up press was no good. It was not accurate. Holding between feet and drilling straight down meant you could feel the hole and get them exact, It didn't matter, it was practice and just scrap. Have another set machined almost ready to Nikasil$$$ for Bens 750. But I had a liner and it could be replaced and bored pretty cheap. And we had Pauls old 79.5 pistons done a million miles but sort of ok.

There are reasons not to but it was cheap the holes had threads and were straight enough to get bolts in. What's not good is liners can turn, doesn't matter on a short stroke because there is no cut out for the rods.

A hot rod 750 would need 9mm bolts, 8mm would pull out, even in Iron they may be a problem. Though if you used an iron block you could wait and see. They are reduced. Std are just under 10mm in pommy thread and distort the bore. The 9mm is rare but used in some VWs I think.

[Linked Image from]

This graph is for reference, it's a hot XS650. Stock is around 43rwhp like A65s, this lists what it has with the 750 big bore kit. Fairly close to the A65 750 Gary was talking about. But the aim would be getting as near to 80rwhp as possible with a very strong midrange.

Did the second port on the std size valve head. Before putting filler in, I compared it to the stock one just running 3 vacs on full, stock pulls 9" more water in comparison. It's a fair bit of extra air but I think it's better hitting the valve from the back and being smaller and faster.

Goodness knows what a stock A65 would go like with this head. It shouldn't be much behind the heads with 42mm valves.

[Linked Image from]
99 2,917 Read More
Garage sale - The private buy & sell board Jump to new posts
Re: WTB DBD Rockers Stuart Kirk 3 hours ago
If you have worn rocker tips, they can be re-hard faced. I have had this done. But sorry, no spares. I looked for a good set for quite a while before having my old hammered ones re-faced.
1 39 Read More
Bsa bulletin board Jump to new posts
Re: 1970 Thunderbolt Electrical Issue BSA_WM20 3 hours ago
Fuse the DC feed from the regulator to the battery not the AC
And this is usually a smaller fuse on a BSA because you should never need the same 20 A unless you are running high power halogens as all are running is lights & the coils.
Seen too many bikes with the fuse blown but the alternator / generator still feeding the short till the wires melt or the engine slows down
A bit belts & braces if you fuse both sides of the battery but it is a case of never again
Had the B50 steel side cover short out against the battery , yes was my fault it should have been insalled with the terminals in not out and had a big melt down on the A65 caused by the front stop switch shorting out against the brake cable.
15 241 Read More
Bsa gold star forum Jump to new posts
Re: Pics of my Mongrel Stuart Kirk 3 hours ago
Very nice.

And you don't have to worry about it as much.
5 81 Read More
Ariel forum Jump to new posts
Re: 1928 Ariel Model C gunner 5 hours ago
I've updated the link to the Burman Manual in by previous post as it was wrong, See This link for the Manual.
2,994 1,082,106 Read More
Bsa bulletin board Jump to new posts
Re: A65 Forks Installation? Mark Z 5 hours ago
Originally Posted by semprini
Sorry, the axle nut on the brake plate (twin leading shoe).

Ok, I'm not familiar with TLS brakes; my axle threads into the right fork leg.
47 845 Read More
Triumph bulletin board Jump to new posts
Re: 1952 Trophy Carb settings tiger_cub 5 hours ago
Your thoughts seem sound. I would advise him to remove the float bowl and check the needle valve for cleanliness and that the float isn't holed (does it have liquid inside?)
1 36 Read More
Three state mountain ride forum Jump to new posts
Re: head count 2021 Semper Gumby 6 hours ago
your new friend
41 636 Read More
Monthly photo contest forum Jump to new posts
Re: Worst Starting Point Ken Abrams 6 hours ago
Hey Bill, I've been making space In my garage for any orphans. I'll be at Jack's later this week.
Ken Abrams
21 2,513 Read More
British modified/specials Jump to new posts
Re: BSA A10 special NickL 7 hours ago
Used 638 on it.
Lasted a while but needed checking regularly.
90 7,276 Read More
Norton bulletin board Jump to new posts
Re: Norton twin in manx frame Rohan 7 hours ago
Whereas this is what someone (UK) supplies as a racing wideline

[Linked Image from]
4 50 Read More
Members bike projects Jump to new posts
Re: A10 is coming alive Hillbilly bike 7 hours ago
Yes, it's explained here... Mean effective radius

It does make a difference....and it can make a 6 plate plate grip quite well...The pre unit has only 5 discs..
12 419 Read More
The triple forum Jump to new posts
Re: Oil pump orings Steven A Yesterday at 10:35 PM
It is easier on those o rings if the o rings and primary inner are installed, then the oil pump slid in to the big hole.
3 136 Read More
Triumph bulletin board Jump to new posts
Re: Improving T140 Forks--Any Ideas? linker48x Yesterday at 08:40 PM
Tried it again on a warmer day, low 50's, made quite a difference and the forks are much improved. Not so sure about oil level and ultimately what fork springs and oil weight I will end up with, or whether I will change the fork legs for some Made In UK legs, put some sort of cartridge inside these, or mess with the damping orifices, or I will leave well enough alone, but as they are, they work much better than they worked before simply by changing to the Leakprooof brand seals, small p progressive fork springs, and 5 weight oil. Thanks for the help, guys.
47 2,523 Read More
Norton bulletin board Jump to new posts
Re: 65 Atlas Correct Size Battery Dave Comeau Yesterday at 07:21 PM
Tried a buy of the atlas battery at the local NAPA. I find it interesting that national internet pix of this battery is of a GS brand just like in my pix above. Their internet text description of the battery manufacturer is Eastern Penn which happens to be a competetior of GS-Yuasa. There was a paste over label with 12N5-4B underneath.

Cheap low density LA battery for a 5L-B premium price? It looked very china.....I took my money back and left the battery there.
Came home an ordered 5 from Summit for all brand name Yuausa 3 AGM and 2 Yumacron for all the ducati and nortons,.better price too. Some american and some are Taiwan made.
7 157 Read More
Triumph bulletin board Jump to new posts
Re: Clutch hub wont move Stein Roger Yesterday at 06:55 PM
I had a similar experience a few years back. Broke two pullers but managed to rescue one of them and finally got the hub off. The key had sheared and the hub had friction welded itself to the shaft. Sounds like a Friday night in a Skudeneshavn pub story, but it's true.

8 341 Read More
Triumph bulletin board Jump to new posts
Triumph Speed Twin 5T from 1947 Michel H Yesterday at 04:11 PM
I have to replace the illuminating bulb in the control panel in the tank and I never did. I suppose you just have to unscrew the panel and lift it a bit to access it or do you have to disconnect everything: ammeter, oil gauge, switch etc ? Or even more complicated ?
Greeting from Belgium.
0 48 Read More
The triple forum Jump to new posts
Re: NGK plug Semper Gumby Yesterday at 02:41 PM
Originally Posted by quinten

3 89 Read More
Garage sale - The private buy & sell board Jump to new posts
'69 Triumph 250 edunham Yesterday at 01:57 PM
Friend of mine has a very nice little '69 Triumph 250 for sale. I don't know all the particulars, but it looks good, runs well and has a title. It is located in NJ. He is looking for $2500. The unit singles are rising in popularity and desirability. If anyone is interested, PM me and I will put you in touch with him.

Ed from NJ
0 65 Read More
Bsa bulletin board Jump to new posts
Re: A10 Lithium Ion Battery? edunham Yesterday at 01:44 PM
I got my first Lithium battery a bunch of years ago when I was looking for a 12 volt battery that would fit inside the case of my old tar top 6 volt battery on my Velocette. The only lead batteries were tiny and they wouldn't last long. I got a Shorai 11 amp hour and it was like a revelation. All of a sudden my headlight was bright. The battery would last all winter without a charge. The JG 12 volt converter and Lucas generator seemed to keep it charged up.. I was sold. I started buying them for my other bikes. Some issues began to arose. My B50 killed them in short order. Don't know if it was the vibration or the charging issue, but after the second one on warranty I gave up on them for the B50. The special charger was a problem. If the battery was low, the charger would tell you it was no good. Put it on a regular battery tender and it would charge right up. I was told by Shorai that the difference between the chargers is that the special charger charges each cell individually, while a battery tender charges all of them at the same time.
The killer for me was a Shorai in my '68 Suzuki TC 250. Had I read the manual, I would have known that it had a very primitive regulating system. I didn't, and I installed the Shorai. Took the bike out for a couple of 30-40 mile rides and it was fine. Used the bike in the East Coast Moto Giro. 80 miles out in the middle of nowhere, the battery blew up. Of course the fact that I didn't properly research the suitability of the battery for that bike and the fact that there were problems with the chase truck and I didn't get rescued for 9 hours isn't the battery's fault, but it kind of soured me on them.
On my bikes where they are still working, they are remaining, but I wont be buying any more (except for the Velo).

Ed from NJ
17 563 Read More
Triumph bulletin board Jump to new posts
Re: 650 Twin Into Trident frame tiger_cub Yesterday at 12:39 PM
Thats exactly how I set it up, I must have messed it up later
18 1,212 Read More
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