1955 Huntmaster questions

[david weare]

Hi John

I believe the chain is new or newish.
The present owner hasn't ridden it much but didn't recognise the irregular rattle sound.
So I think it was the first time. It disapeared readily when riden and thereafter.

Mag kill switch. OK also good to know.
Perhaps people fit additional kill mechanisms?

Thanks
D

Sounds like the tension is pretty well OK ......be very careful to check when hot ,and check a full revolution or more ,because there may well be tight and loose spots ......if the primary chain has a number of links that are a multiple of the engine sprocket,there will be worn regions in the primary.I know Ariel chains are difficult to remove ,so no need to do that ,if its near new.....but check thru the hole for broken rollers and marked sideplates...........incidentally ,maggie cutout(earthing points) stop the motor at idle ,but wont normally stop it at speed ,for instance if the carby sticks wide open,so dont rely on it.

[david weare]

Also the Huntmaster seems to deposit a teaspoonful of oil just below the front / centre of the engine, on the ground.

Hard to pin point where this is from.

If its from the vertical split in the crankcase this would be a problem I imagine.
But may likely come from the sludge inspection plate or whatever it's called or either side casing.

Is this a standard place for leaks?

Thanks
D

Briefly:
1) That's normal - should have auto advance-retard fitted
2) No idea, unless it's happening under load in which case it's the engine shock-absorber cam slipping (unfortunately, my particular area of hard-won expertise for these)
3) Half-width is standard spec for '55 and often considered better than the later full-width variety, they are often not properly adjusted (same hub/brake as singles and 500 twin, see a couple of other recent posts).
4) Should have a magneto 'kill' button.

(Engine-wise, it's the same as a BSA A10)

HTH

SG

[Mick D]

Hi

The primary chain tension is recommended to 3/8" total up down measured at the middle of the top run and with the chain positioned to it's tightest point - this would suggest your chain is too slack.

The rectangular plate front centre bottom of the crank cases held on by four nuts, (possibly wire locked together), is the sump plate. It's easily removed and re-sealed. It is however the lowest point of the engine so the majority of oil leakage will gravitate there - give the engine a very good clean and then a short stationary run, you will see where the oil is coming from on shut down, check the two oil pipe connections at the rear of the timing cover, the oil pressure valve at the front of the timing cover, (the domed shape thing) and the sump plate itself.

Regards Mick

[david weare]

Hi Mick
Thanks for the advice.
OK yes 3/8" - I think it was touch more than that TBH

I suppose all joints can be re sealed relatively easily except the centre crankcase joint.
So hopefully lots of contenders for the leak source before I get to that.
I forgot to really investigate when I viewed the bike.

David

Hi

The primary chain tension is recommended to 3/8" total up down measured at the middle of the top run and with the chain positioned to it's tightest point - this would suggest your chain is too slack.

The rectangular plate front centre bottom of the crank cases held on by four nuts, (possibly wire locked together), is the sump plate. It's easily removed and re-sealed. It is however the lowest point of the engine so the majority of oil leakage will gravitate there - give the engine a very good clean and then a short stationary run, you will see where the oil is coming from on shut down, check the two oil pipe connections at the rear of the timing cover, the oil pressure valve at the front of the timing cover, (the domed shape thing) and the sump plate itself.

Regards Mick

[JohnnyBeckett]

hi david a lot the leak on the crankcase is the sump plate and the bolts that holds the plate on

[will_curry]

With regards to the oil, if the engine hadn't been run for a while there's a good chance
some oil has drained down through the pump and into the sump. Once started, the
pump will scavenge most of the oil but in my experience there is usually a bit of smoke
in the exhaust and a slight loss of oil through the crankcase breather.

[nevhunter]

Force tension on the rear chain and see how much the front chain changes. This indicates wear in the gearbox sleeve gear or the large ball bearing race (less likely) That bike requires the highest quality chain. Not split rollers. Chain stretch or wear will give irregular feel of up and down . Nev

[john.whiting]

Yes,never disregard the primary chain in an Ariel......there is a good reason Ariel primaries are twice the price of others on fleabay.

[david weare]

OK thanks. makes sense, bike hadn't been run for a while.

Do you recommend a non return valve?

With regards to the oil, if the engine hadn't been run for a while there's a good chance
some oil has drained down through the pump and into the sump. Once started, the
pump will scavenge most of the oil but in my experience there is usually a bit of smoke
in the exhaust and a slight loss of oil through the crankcase breather.

[will_curry]

There should be one already built-in but they're not always that effective.
However, it's been a long time and I can't remember how to get to it.

I'm not a great fan of add-on non-return valves. If anything goes wrong
it's a wrecked engine. A friend of mine had one fail on a Matchless
twin - not a pretty sight and extremely expensive.

The best way to keep the oil where it belongs is to use the bike frequently.

There are a number of Huntmaster users who regularly contribute to this
forum. Hopefully one or more will be along soon.