Another Arrow engine oddity - Single cylinder 125cc

[Roger James]

Here's a photo of another Arrow engine oddity, a single cylinder 125cc. it is owned by a friend who is well on the way to completing the build with the intention of using it for sprinting. Jess

[bh.sprint]

Just noticed the size of the inlet port and no centre bridge ! + there appears to be a sixth boost port in the back of the cylinder as well as the extra transfer ports either side of the cylinder-- that should rev well. Brian H.

[bh.sprint]

Also noticed the final drive gearbox shaft has a sealed bearing, just wondered if this is to reduce friction by doing away with the oil seal which does produce some friction which is noticeable because it acts on a fairly large diameter. Brian H.

[JohnnyBeckett]

hi i think that is a new type of bearing that is sealed like the new type of wheel bearings you can get that i have fitted to my NH Ariel

[Roger Gwynn]

Sealed bearings are great at keeping dust out and grease in but will not cope with pressure, Great on wheel bearings and may well help on an output shaft as an additional measure. Adequate for short sprints no doubt.

[Paul_Linden]

I like the cylinder head as it is symmetrical, and must have been made for this project, instead of using a left or right handed one.
This cylinder head should also be used on the Arrow triple engine, pictures of which are on another post nearby on this forum.