18S engine overhaul
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18S engine overhaul
I'm just considering my options for overhauling my 18S engine, what are suggestions on things that can be done over and above, head skimming, honing, new rings, valve lapping, bearing replacement ? I saw comments about dynamic crank balancing and this got me thinkng, what else might be worth doing ? thx
1954 AJS 18S Cyprus export (frame decode says 1954 but many components match a 1955).
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Re: 18S engine overhaul
Hi
You can go as far as you can afford - porting, hotter cam, adjust the compression ratio, internal polishing, carb work or replacement, electronic ignition etc.
But is there much point? these engines are fairly agricultural and won't show much benefit from this work and expense - I'm more than happy with my bog standard G3.
Regards Mick
You can go as far as you can afford - porting, hotter cam, adjust the compression ratio, internal polishing, carb work or replacement, electronic ignition etc.
But is there much point? these engines are fairly agricultural and won't show much benefit from this work and expense - I'm more than happy with my bog standard G3.
Regards Mick
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- Location: florida
Re: 18S engine overhaul
yes thats a good point, the work should offer a tangible return. Got me thinking : what would I like from the rebuilt engine,
Easier to start !
Tolerant to sub-grade petrol (to be able to run on aviation fuel would be a big plus)
consistent tick over
smooth acceleration
Also would like to stick with stock carb and magneto
so from your list, porting and internal polishing might fit and possibly compression ratio (but I probably need it reduced to take the crappy petrol )
Easier to start !
Tolerant to sub-grade petrol (to be able to run on aviation fuel would be a big plus)
consistent tick over
smooth acceleration
Also would like to stick with stock carb and magneto
so from your list, porting and internal polishing might fit and possibly compression ratio (but I probably need it reduced to take the crappy petrol )
Mick D wrote:Hi
You can go as far as you can afford - porting, hotter cam, adjust the compression ratio, internal polishing, carb work or replacement, electronic ignition etc.
But is there much point? these engines are fairly agricultural and won't show much benefit from this work and expense - I'm more than happy with my bog standard G3.
Regards Mick
1954 AJS 18S Cyprus export (frame decode says 1954 but many components match a 1955).
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- Posts: 2884
- Joined: Mon Mar 24, 2014 5:44 pm
- Location: Aberdeenshire
Re: 18S engine overhaul
Hi
For your aims:
Easier to start - get the magneto professionally refurbished, new plug, lead and non supressed cap.
Fuel tolerance - no action required, these machines were designed when low grade fuel was the norm - if you're intending to use avgas ensure it's one of the lower grades.
Constant tick over - have the carb refurbished or replaced as necessary.
Smooth acceleration - will follow as a consequence of magneto and carb work
Porting, polishing and adjustment of the compression ration will have no appreciable benefit, (in my opinion).
Keep it simple - keep it cheap and enjoy the bike.
Regards Mick
For your aims:
Easier to start - get the magneto professionally refurbished, new plug, lead and non supressed cap.
Fuel tolerance - no action required, these machines were designed when low grade fuel was the norm - if you're intending to use avgas ensure it's one of the lower grades.
Constant tick over - have the carb refurbished or replaced as necessary.
Smooth acceleration - will follow as a consequence of magneto and carb work
Porting, polishing and adjustment of the compression ration will have no appreciable benefit, (in my opinion).
Keep it simple - keep it cheap and enjoy the bike.
Regards Mick
- spookefoote1956
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Re: 18S engine overhaul
You need a Honda mate!Easier to start !
Tolerant to sub-grade petrol (to be able to run on aviation fuel would be a big plus)
consistent tick over
smooth acceleration
Hail Joe Lucas ............ Prince of Darkness!
All my bikes are original........ to me!
"Creativity is your intelligence having fun" Albert Einstein
All my bikes are original........ to me!
"Creativity is your intelligence having fun" Albert Einstein
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- Posts: 135
- Joined: Tue Oct 22, 2019 3:42 pm
- Location: florida
Re: 18S engine overhaul
Funny you should say that , I have two Honda St1100's ! not sure about them running on avgas thoughspookefoote1956 wrote:You need a Honda mate!Easier to start !
Tolerant to sub-grade petrol (to be able to run on aviation fuel would be a big plus)
consistent tick over
smooth acceleration
1954 AJS 18S Cyprus export (frame decode says 1954 but many components match a 1955).