Huntmaster R&D

[Sid.burch]

I seem to remember reading an article about someone toying with a huntmaster and A10 parts to get the best out of it. The photos were black and white so may be from the 50s. Any information would be appreciated.

[Sid.burch]

A few years ago I remember reading an article about someone taking a Huntmaster and using A10 parts to improve the performance. I'm rebuilding my dad's old Huntmaster at the moment and would like to reread the article if possible. I think it was possibly done in the 50s as the photos were all black and white. Any information would be greatly appreciated.

[PeterW]

Never seen that article but the Huntmaster I had in the 80's had been tuned by the previous owner - apparently Road Rocket head, pistons & cams but I didn't have any details. Think he taught engineering. I had it for 9 years during which it was 100% reliable & certainly went well :¬)

[Sean.O'Brien]

Sid,

You can keep it simple. Just swap out the the standard 334 cam for a 356, are use a higher compression set of pistons. Much the same as the Cyclone. Cyclone pistons were about 8.5:1.

[david.anderson]

I think that you will find that the Ariel Cyclone used the BSA spitfire cam which is the 357 cam, however for road use the 356 is a much better cam and the bike accelerates faster with the 356 than with the 357. The 356 cam and 8 or 9 to 1 pistons work very well together.
But the problem with the Huntmaster is the exhaust pipes are too large, resulting in slow exhaust gas speed which gives poor scavenging and loss of power. http://beezagent.blogspot.com/2009/01/c ... p-and.html So fit the same size exhaust pipes as fitted to the A10.
David

[Steven.Carter]

I've fitted a 500cc alloy head on my Huntmaster with flat topped IMD pistons with the 356 cam, goes like a steam train

[Simon.Gardiner]

I've fitted a 500cc alloy head on my Huntmaster with flat topped IMD pistons with the 356 cam, goes like a steam train

I'm told those 500cc heads have small combustion chambers - gawd knows what Steve's compression ratio is, I'm waiting for the weedy Huntmaster barrels to crack!

The '58 parts books have the 8:1 pistons for the Cyclone listed but the only cam that's listed is the 356. Be interesting to know if Ariel did actually use the 357 (and without improving those barrels!)

SG

[david.anderson]

While I cannot find the details at the moment, an article that I have states that Ariel fitted the spitfire cam and big bearing crank, which became a sore point with BSA, when they realised what Ariel was doing. However that may have related to export models.
For even more performance the 1954-56 500 head is apparantly the one that is sought after as it was originally fitted with a detachable manifold, and straight rather than splay ports, so is readily converted to twin carbs. The super rocket head was also twin carb, although possibly not all of them.
David

[nevhunter]

BSA twins mounted the gearbox on 4 long studs direct to the crankcases and ran a 2 row chain and a hinged adjuster below the chain. This is a far better arrangement than the Ariel set up so use top quality chain and careful tightening of everything IF you are getting your Huntmaster to anywhere near BSA Rocket Gold Star specs. Nev

[Steven.Carter]

I've fitted a 500cc alloy head on my Huntmaster with flat topped IMD pistons with the 356 cam, goes like a steam train

I'm told those 500cc heads have small combustion chambers - gawd knows what Steve's compression ratio is, I'm waiting for the weedy Huntmaster barrels to crack!

The '58 parts books have the 8:1 pistons for the Cyclone listed but the only cam that's listed is the 356. Be interesting to know if Ariel did actually use the 357 (and without improving those barrels!)

SG

I've no idea either on compression ratio Simon,, certaily very high in the morning with stiff legs