A10 - most irritating bike I've owned

[mikeb]

nice one flash, i love a happy ending!

[chaterlea25]

Hi All
Thanks for the "thanks" 
The other problem I found with the monobloc carb is one I have never come across before
(until I looked for another better one at home )
The bike was behaving badly and hard to start, all other reasons had been gone through several times over
The idle screw did not seem to make much difference in spite of checking all the tiny passages several times
I decided to remove the jet block as it was the only thing left to check ,
When I upturned the carb the jet block fell out
The conclusion I came to is that air was being drawn in and around the base of the jetblock causing a weak mixture
We borrowed a monobloc from another bike and stuck that on , and the A10 started first prod on the kickstart

I had several 376 mono carbs at home, and tried mix and match to find out the reason why the jetblock was loose
For some reason the carb body bore was to blame, I found two more with the same issue to a lesser degree
they are now in the bin 

John

[Greybeard]

So was it wear, or bad manufacture?

[Swarfcut]

    Yes, a couple of happy endings. Always a good feeling when an actual cause is found. The evidence was there all the time, but some problems just escape diagnosis and digging it out to the basic parts is the only answer.

    Even then you can be fooled if you have no experience of what is correct and within parameters, and what's not.

 Swarfy.

[chaterlea25]

Hi GB,
As there is no relative movement between the body and jet block, wear cannot be an issue,
I wonder if the mazac "grows" with age???

John

[RDfella]

I believe it does, John. I've had to ream the spindle bore of oil pumps because the body has shrunk and become a press fit on the shaft. Aluminium apparently did that during WW2 as well, when pistons put into storage were sometimes allegedly bigger when retrieved than when made.

[Rex]

Mazak does grow with age, as any restorer of a long-unused BSA will attest when he starts reconditioning the oil pump.
Apparently made worse if old oil is left in the engine for a period of time.

[chaterlea25]

Hi All,
Usually you can see "blisters" on old mazac that has swollen,
The carb parts look fine in that respect,
Usually the carbs needs a dose of heat to remove the jet block

It was a first for me, after nearly half a century of playing around with old Amals and BSA's
(I did start at an early age though )

As for old piston growing with age??
Recently I got some NOS J.A.P pistons
If bored to the std plus oversize marked on them, they  would have 12 thou clearance

John

[Swarfcut]

 Found this thread while searching "Wales" Dunno how I ended up here but it makes interesting reading for those inclined to see how some simple statements wander. I'm as guilty as the rest of the contributors, and apologies in advance to all participants......

 Laugh and learn, count your blessings.

 Swarfy.

[Rex]

The bike was behaving badly and hard to start, all other reasons had been gone through several times over
The idle screw did not seem to make much difference in spite of checking all the tiny passages several times
I decided to remove the jet block as it was the only thing left to check ,
When I upturned the carb the jet block fell out
The conclusion I came to is that air was being drawn in and around the base of the jetblock causing a weak mixture

Interesting. I'm currently going through a similar scenario with a 389 on a Venom, and although the jet block isn't so loose as to fall out it can be pushed up and out with a screwdriver through the bottom. Something else to consider.

[muskrat]

G'day Fellas.
The most irritating bike I owned was my first NEW bike. At the age of 10 or 11 I bought a Tas Tora 60cc for $160. It was fully road registerable with lights and blinkers. Very similar to the Bridgestone. It had a rotary gearbox  meaning from neutral it was down to 1st, down to 2nd, down to 3rd, down to 4th, down to neutral, down to 1st and so on. A few times I thought I had another gear so went down only to find what I thought was a false neutral and went down again only to go over the handlebars 
Cheers