GX and H89 are both 29cc stock

Dazza thats the H75 head more commen on the "econamy" a14's. most a15's came with the H89 witch has the same chambers but larger valves then the GX head. The advantage of a GX head is the aproach angle and lack of a water galery over the intake ports.

I think in a street going 1000 this motor will still move it along quite nicely!

and in a 700kg ute torque from 1800 is realy a wory.

I like carbs to! but youl be lucky to get carbs on a manifold for that money? if its not ya daily drive, try sell your old motor first maybe??

Will be a 60 series 4 speed though!

I tried drawing this to scale with what I think would advantages DeShrouding.




The black area is where deshrouding could perhaps be caried out, and for optimum flow into the chamber should be ground with a radius eaquil to the lift of your cam from the valve seat outward.

Gee I hope some of that makes sense??

Oh and it is based on a GX chamber with standard valves and 77mm bores.

Modifications are based on Modifications By 'Graham Bell' To a 'BMC mini' combustion chamber, witch is verry similler to our a series chambers. and I have re interprated them to suite.

I suggest anyone who wants to look into this further read '4 stroke Performance Tuning' by Graham Bell. Its a verry good bok

Nice, I looking forward to a similer motor!

I cant make it. I'll be raceing BMX, probly in the rain.... oh joy!

do you know anyone that owns another 100 or 1200? Id ask to borrow there wheels because yours are abviously bigger aswell. or see if some bigger datsun (i.e. 180/200b) hubcaps fit?

Could you passibly cc the chambers?