18S engine overhaul

[asterysk_usa]

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

[Mick D]

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

[asterysk_usa]

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 )

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

[Mick D]

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

[spookefoote1956]

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

You need a Honda mate!

[asterysk_usa]

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

You need a Honda mate!

Funny you should say that , I have two Honda St1100's ! not sure about them running on avgas though