ATD Springs

Martyn Goodwin

Martyn Goodwin

Well Known and Active Forum User
Non-VOC Member
delboy said:
My only observation is why have you got two insulators?
The rest of us seem to have managed okay with just a gasket for the last 70 years.
Regards,
Delboy.
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In Oz its not uncommon to get a high summer temp in excess of 35 C. for days on end. As a consequence one does all one can to prevent vapour locks
 
Martyn Goodwin

Martyn Goodwin

Well Known and Active Forum User
Non-VOC Member
Martyn Goodwin said:
Made some small changes today but winter is setting in as has the rain and wind. Plus COVID permitting. given there is a new outbreak here and government imposed movement restrictions are back on.

First chance I get I will be out road testing to see the effect. Then I will reveal all- if it works!

Bugger.

I cannot understand the logic of opening up our borders to foreign travellers from regions ravaged by the virus
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Stuff the cold - Went for a run today on my Comet after making a change to the ATD and I can report that the issue appears to be resolved. No more 'run-a-way' idle speed once the motor is really warmed up. Bliss!

All will be revealed in the next edition of OVR, but the photo is a teaser.

Martyn
20210525_124127.jpg
 
V

Vinthou

Active Forum User
VOC Member
Martyn, I can't wait !! I run a twin with magneto and Type 29 carbs, and have been battling this same problem for a while. Once the bike gets hot it will not go go back down to anything close to a sensible idle. I have a magneto cut-out button fitted and if I tease the revs down using that, then they stay down - until the next time! Of course this usually elicits a good backfire or two ! I have two ATDs - one original Lucas and one Roy Price version. Both act the same now, although neither used to. I have tried new springs from the club to no avail. I had assumed that spring tension (or lack thereof) was the issue.
 
Martyn Goodwin

Martyn Goodwin

Well Known and Active Forum User
Non-VOC Member
Vinthou said:
Martyn, I can't wait !! I run a twin with magneto and Type 29 carbs, and have been battling this same problem for a while. Once the bike gets hot it will not go go back down to anything close to a sensible idle. I have a magneto cut-out button fitted and if I tease the revs down using that, then they stay down - until the next time! Of course this usually elicits a good backfire or two ! I have two ATDs - one original Lucas and one Roy Price version. Both act the same now, although neither used to. I have tried new springs from the club to no avail. I had assumed that spring tension (or lack thereof) was the issue.
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I believe your assumption is correct. So how can you increase the spring tension WITHOUT making any changes to the springs? Take a close look at the photo in my last post - the ATD is in the fully retarded position. What do you notice that's different to yours when in that position?
 
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mercurycrest

mercurycrest

Well Known and Active Forum User
VOC Member
Pushrod Twin said:
Has anyone made up a Pespex or Lexan clear cover, to fit in place of the ATD access cover, ET136? I suspect there may be fish hooks with this, there will be oil mist in the timing cover, but, with the aid of a strobe as suggested on post #30, it could be a way to confirm whether the weights are actually hanging up, or not.
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I doubt a clear cover would work for that, as when the engine starts oil is flung everywhere and the cover, almost instantly would be, "covered" over with oil.
 
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