Author Topic: Tuning the GX200  (Read 337 times)

David F-R

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Re: Tuning the GX200
« Reply #15 on: 04 May 22, 05:48 pm »
I am personally keen to restrict CycleKarts to 10hp maximum. That's accepted as stage one tuning of the GX200. Anybody considering tuning their CK further for speed has not understood the ethos of CycleKarting. 

I'm very much with you on this Graham.

I shall probably start with a bog standard engine out of the box and enjoy driving a cyclekart that I've built. A bit more hp may be considered later for a spicier drive but strictly within the 10hp limit.
I'm not quite as green as I'm cabbage sounding.

Ian Fletcher

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Re: Tuning the GX200
« Reply #16 on: 04 May 22, 06:02 pm »
Hi David, I was thinking along the same lines but after a lot of thought it seemed to me that even using the standard engine you need to get inside it and remove all the governor gubbins otherwise your restricted to 3,600 rpm (at which case any warranty would be void).  You could start with a secondhand engine, but prices seem quite high for these compared to a new one. So to me the difference in cost between a standard engine and a ready built Stage 1 engine is not that great.  I would have loved to start with a standard engine and then fiddle with it, but the costs just didnt add up.

Adrian

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Re: Tuning the GX200
« Reply #17 on: 04 May 22, 08:08 pm »
I wholeheartedly agree that stage one, or 10hp should be the limit. I say that because there is no going back now.
The ready built ‘Stage One’ engine from the GX Tuning Store is actually 9+h.p. not 10 but I bet it’s close enough to make no perceptible difference. 
That engine costs £390 (including VAT) and comprises the following parts:
Loncin (Clone) GX200 Engine,
Size 75 Main Jet
140 Emulsion Tube
18Lb Valve Springs
4° Advanced Timing Key
A 010" Thin Cylinder-Head Gasket
In addition, they machine the valve seats to three angled ones one a very expensive machine, lap the valves in and remove the baffles from the exhaust.
You can get all the parts separately (all off the net) and they costs:
Clone engine       £160
75 Main jet      £5
140 Emulsion Tube   £5
18lb Valve Springs   £18 (includes £10postage!)
4° Adv. Timing Key   £10
Total for bits      £198
The three angle valve seats give the much the same benefit as radiusing the valve seats.
Opening-up and smoothing-out the ports is a couple of hours work with a ball cutter in your drill and some emery cloth. (You only need to do the inlet really).
So, you have £200 left in your pocket!
If you buy a GX200 clone they have 68mm diameter piston, the same as the Honda original but if you buy a 212cc version (Lifan I think) they are 7h.p. and have a 70mm diameter piston. Everything else is the same. We have a few of these in the club so I would go for one of these. (Actually I did, it’s in my Renault)
Torque is directly proportional to piston area so there is around a 2% benefit in torque. Not a lot I know. I don’t feel the difference anyway.
🚗