atlas engine compatible parts with 750 commando

Gilesy · Apr 1, 2018

84ok said:
year atlas? part # for Commando decompression baseplate maybe? or more info?

My Atlas is 1962. I'll have to check with Ashley at Andover Norton when they open after the holiday. He had a batch of these base plates specially made, of which I had the first one, to overcome the semi obscuring of the oil return hole.

jan nelder · Jul 30, 2019

84ok said:
from the very first link & a search of - atlas barrels

on the 15th result of the search titled - sleeving down a squish band
https://www.accessnorton.com/NortonCommando/sleeving-down-a-squish-band.23596/

a confirmation of a commando head on (non?) spigot (removed?) atlas barrel
(i thought the ring was for atlas heads that are made to fit a spigot barrel, but that can be modified to fit a flat surface, dunno why a commando head would need a ring)

https://www.accessnorton.com/NortonCommando/sleeving-down-a-squish-band.23596/#post-348093

this link lndicates
http://atlanticgreen.com/nhth.htm

https://www.accessnorton.com/NortonCommando/cylinder-head-for-spigotted-barrells.22319/#post-332745

then

flat barrel head

THIS 25319 head is a late Atlas type.

acotrel · Jul 31, 2019

If I was fitting an Atlas engine into a Commando, I would not bother to change the balance factor. A Commando was never going to be as smooth as a CB750 Honda, regardless of what was done to it. With the higher factor you would simply live with a bit of vibration, low down in the rev range. But at high revs, it would probably be better than with the low factor.

baz · Jul 31, 2019

Danno said:
I once transplanted an Atlas bottom end into a Commando for the rear ignition drive, which I converted to a K2F mag. Went right in.

I have considered doing this what did it start like with the magneto ?

baz · Jul 31, 2019

acotrel said:
If I was fitting an Atlas engine into a Commando, I would not bother to change the balance factor. A Commando was never going to be as smooth as a CB750 Honda, regardless of what was done to it. With the higher factor you would simply live with a bit of vibration, low down in the rev range. But at high revs, it would probably be better than with the low factor.

They tried an atlas engine with the standard balance Al it didn't work IE it moved the vibration forward and aft I believe
A commando is smoother than a CB 750 honda once it's above 2300 rpm

Danno · Jul 31, 2019

baz said:
I have considered doing this what did it start like with the magneto ?

I could never get it to run the same on both cylinders. Apparently the mag had a bent shaft. Starting was definitely not a problem. Plenty of hot spark.

swooshdave · Jun 2, 2020

comnoz said:
Pistons are interchangable but Atlas pistons are cupped for low compression.

Atlas con rods are not as strong near the small end as Commando rods are.

The timing gears would fit in a later Commando if the camshaft and sprocket, spindle and cover were changed also.

@comnoz Is the sump plug the same for the Atlas and 850 Commando?

atlas engine compatible parts with 750 commando

Gilesy

jan nelder

acotrel

baz

baz

Danno

swooshdave

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