Author Topic: A10 - most irritating bike I've owned  (Read 2424 times)

Offline mikeb

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Re: A10 - most irritating bike I've owned
« Reply #60 on: 23.07. 2020 22:08 »
nice one flash, i love a happy ending!
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'61 Super Rocket  - '47 B33 -  '18 Triumph Street Triple RS

Online chaterlea25

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Re: A10 - most irritating bike I've owned
« Reply #61 on: 24.07. 2020 00:35 »
Hi All
Thanks for the "thanks"  *smile*
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 *ex*)
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 *eek*
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  *razz*

John
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1963 RGS (ongoing)

Online Greybeard

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Re: A10 - most irritating bike I've owned
« Reply #62 on: 24.07. 2020 09:33 »
So was it wear, or bad manufacture?
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Offline Swarfcut

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Re: A10 - most irritating bike I've owned
« Reply #63 on: 24.07. 2020 09:43 »
    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.
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Online chaterlea25

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Re: A10 - most irritating bike I've owned
« Reply #64 on: 24.07. 2020 12:21 »
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
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Online RDfella

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Re: A10 - most irritating bike I've owned
« Reply #65 on: 24.07. 2020 12:32 »
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.
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'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Offline Rex

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Re: A10 - most irritating bike I've owned
« Reply #66 on: 24.07. 2020 17:39 »
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.
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Online chaterlea25

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Re: A10 - most irritating bike I've owned
« Reply #67 on: 24.07. 2020 20:54 »
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 *lol*)

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 *conf2*

John
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1961 Super Rocket
1963 RGS (ongoing)