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#856422 08/18/21 6:02 pm
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PJ1971 Offline OP
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Hello Everyone,
I am looking to swap my unit A65 into the rolling chassis of an A10 Super Rocket. I have only seen a very limited number of builds with this engine/frame combination and I was curious if anyone in the Britbrike Community could share their experience and/or photos of this style build.

I look forward to hearing from you all,

PJ

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There is an article in "Classic Bike" Feb 2021 edition (Issue 493) of someone who did a similar conversion - A65L into Plunger Frame A10 chassis. It is on the cover. They had to cut small sections of the bottom loops out, turning engine into stressed member to get it to fit.
Looks very tidy


68TR6P rebuilt as a C
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Thank you for the response, Morrisey.
The plunger frame A10/A65 Special in Classic is one of the only examples I have been able to find as well (with good photos.)
I am just hoping to find away to fit the power-egg without having to cut the frame loops. I only want to fabricate mounts and not compromise the integrity of the frame.
A10 framed TriBSAs seem in ample number even when they incorporate unit T120 engines. Seeing as the T120 and A65 share similar dimension (having also shared the same frame with different mounts in 1971-onward) I wonder if this "backdated" build with a Tbolt in a Super Rocket could work.

PJ

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The rockerbox holddown bolts had to be modified on the Triumphs to get them in the P39 frame, but I think this is mainly because the top tube was too wide to get the bolts out. However, in one of the other bike magazines I have, someone got a T120 in a pre OIF A65 frame but they had to shorten the motor front bosses.
The problem you may well have is how much mtce you are able to do with the motor in the frame.


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I see.
That is definitely something I will keep in mind.
So far, however, the A10 frame seems a fair bit more roomy than either the OIF and pre-OIF BSA frames that I have. Fingers crossed.

Best,

PJ

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I have seen one done but it was over ten years ago. There is a lot of room in an A10 frame so you might want to look at it’s position and if that effects the bikes handling, too far forward/back improve/worsen handling?? I don’t know as I have never done it.

The other thing to think of is the possibility of rubber mounting the engine whilst your at it. You’ll likely need engine plates made up for the front and rear mounts made. Depending on the lower frame space you might be able to use some T140 style mounts on there too.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (now rebuilt)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

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That makes sense.
I will think about engine position within the frame.
Rubber mounting may be worthwhile...

Thank you for your insights, Allan G.

Sincerely,

PJ

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The late small heath frame was much better than the A10SR frame, why would you do it?
I looked at putting an a65 into a slimline featherbed and canned that idea as the frame in
standard form made the engine look miles too small. It would be similar with an a10 frame.
Plus the fact that the SR forks are pretty crap without all the Dow mods etc.
A65 frame was better handling than the a10 frame ever was.

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Originally Posted by Morrisey
There is an article in "Classic Bike" Feb 2021 edition (Issue 493) of someone who did a similar conversion - A65L into Plunger Frame A10 chassis. It is on the cover. They had to cut small sections of the bottom loops out, turning engine into stressed member to get it to fit.
Looks very tidy
That's probably a simpler conversion than fitting an A65 engine/gearbox power unit to a later swing-arm A10 frame.

The plunger A10 had a "bolt-up unit" engine and gearbox, which would be dimensionally similar to an A50/A65.
Swing-arm A10 frames have a cross-member which doubles up as the gearbox lower mount/pivot, and is likely to be well and truly in the road.

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Originally Posted by NickL
The late small heath frame was much better than the A10SR frame, why would you do it?
I looked at putting an a65 into a slimline featherbed and canned that idea as the frame in
standard form made the engine look miles too small. It would be similar with an a10 frame.
Plus the fact that the SR forks are pretty crap without all the Dow mods etc.
A65 frame was better handling than the a10 frame ever was.

If you are making a special you can put in what ever forks you like, the late “BSA” A65 forks and the A10 forks are almost identical in appearance and fit. Or you could just go out and fit a disc front end.

Though I haven’t ridden an A10 for a while I always liked the handling over the A65.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (now rebuilt)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)


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