Shineray X2X review, Guandong

Cylinder + piston, piston shaft, rings, etc = 420RMB
Cylinder head = 800RMB (but now not available anymore for whatever reason)
valve set with all small parts = ca. 100RMB
Relevant gaskets are included.

For future 300cc cylinder heads we figured out a solution we want to try after CNY.
The plan is to take a 250cc head, center it on a lathe machine and lathe the combustion chamber from now 70mm to 76mm diameter. Position of valves and spark plug are identical to 300cc.
That is possible and easy to do. The head's cooling channels must be grind a little at the out edges to match the 300cc head gasket cooling liquid flow holes. But also this is a 10min job.
Once we did it we will publish the result. I sponsor volunteer my now available 250cc head :icon10:

At the end we might have a much cheaper solution for the community as a 250cc head is only 400RMB.

OK, that is a bit less than 180 euros. I would say - it is fair price.

You know, on small bore horizontal engines, their heads are almost the same, from 72cc (47m piston) to 107cc (52,4mm piston), except this, let me use two-stroker's vocabulary, squish band. :deal:

If you decide to mod standard 250cc head, IMO, you'll need milling machine with vertical spindle. Lathe for that job is a big headache.

The milling machine is for sure a good alternative. I will consider that advice too. (but I have only pure manual machines, no CNC)

Right now I have designed a center bolt with the same thread as the spark plug. (The spark plug is in the center of the combustion chamber)
With that I ensure the center position. The upper and lower head surfaces are milled parallel plane. So the top surface is a good alignment at the lathe.
I want use on of the cylinder bolt holes in the head to fix a stud there that is used as force transfer driver (english understandable???). In that way I make sure that the lathe forces are not going into the spark plug thread and ruin it.
It is anyway just a 1mm offset with diameter 76mm (no heavy duty)

OK... technical a bit complicated, but I trust you understand me (at least Zorge :lol8:)

Force transfer driver... yes, yes... I understand.

You'll will hire Frank Martin...

http://www.goodwp.com/large/201210/25428.jpg

...to do the job.

This English of mine is getting better daily. :naughty:


:lol8:


Jokes aside.

If the spark plug hole is in the center of the combustion chamber and the upper and lower surfaces are parallel, your task is much easier and simpler. You're right - this is job for the lathe.

BTW, after upgrade, did you felt... some other level of engine vibrations (because of increased reciprocating mass; bigger and heavier piston) comparing to standard engine?

Basically I don't feel a change. I have no idea how much heavier is that piston. IMO that can only few grams. Is that enough to get a significant change?

I'm asking you. Only you can feel any difference between "before" and "after".

I don't feel a change.

:thumbsup:

If someone else in the future ask same question - here's the answer.

For X2 Owners: here comes an interesting news regarding rear brake pads.

Seems Shineray has changed the rear caliper from X2 to X5. Therefore i had to realize that the ordered original read brake pads are to small.
I cross checked with Barry and we saw that his rear caliper fits for these pads, but not mine (Now the lucky bastards get some new pads for free)
I will order X5 pads and let you know whether they fit in.

Barry's X2 should be a 2013 model.
Mine is from 2014.

Update: the X5 pads fit in the 2014 X2 caliper.

I'm looking to upgrade my X2X to 300cc - how was the process and end result?


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