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How to make a 4 stroke more HP

Posted: September 17th, 2011, 12:47 am
by sweetchassis#15
G'day I have a Honda GX25 and I was just wondering what I can do to make it have for HP.
Could I do anything with the carby???
Cheers James

Re: How to make a 4 stroke more HP

Posted: September 17th, 2011, 4:13 pm
by bentley marshall
biger carb ,biger valves , cam timing , higher lift cam, roller rockers lol, up the compresion ,run av gas , ...

been looking for one of these for a project too will be intersting what ya can get out of it ..

Re: How to make a 4 stroke more HP

Posted: September 17th, 2011, 8:19 pm
by sweetchassis#15
Thanks mate, I was thinking about running it on methanol I have two of them, I have a brand new one that im gonna run in my late model and the older engine is gonna be the test engine

Re: How to make a 4 stroke more HP

Posted: September 17th, 2011, 9:59 pm
by bentley marshall
ok i would get a biger carb one off a chainsaw maybe do a bit of porting in the head inlet and exhaust ..to start with

Re: How to make a 4 stroke more HP

Posted: September 18th, 2011, 3:09 am
by sweetchassis#15
Thanks mate, pulled the old engine down in about 10mins lol. Tomorrow I am going to enlarge the inlet and outlet And get a larger carby. Is there any where I can get it dynoed?

Re: How to make a 4 stroke more HP

Posted: September 19th, 2011, 10:26 am
by jean phi
Bonjours,

We in Europe, we work for 2 years on the GX35, it has more torque!

Work ignition (CDI), the original is not good to use RC.

Jean Phi

Re: How to make a 4 stroke more HP

Posted: September 21st, 2011, 9:07 am
by jean phi
GX35 BigBlocRacing

Re: How to make a 4 stroke more HP

Posted: September 25th, 2011, 12:39 am
by bentley marshall
jean what ignition did you change to ??? and what spark plug are you using ??

i just bought a gx35 for a project (been looking for one for ages)

Re: How to make a 4 stroke more HP

Posted: September 25th, 2011, 7:35 am
by jean phi
Hello,.

I changed CDI Honda by a CDI Zenoah (2 time).

Then he must remove the PIN on the motor wheel and give advance ignition (+ 5 °).

Attention the best engine performance is achieved only after 50 hours of use (long running).

If you want, j have a Carbon/kevlar ventilation carter.

For info I work in collaboration with HONDA EUROPE!

Jean Phi

Re: How to make a 4 stroke more HP

Posted: September 25th, 2011, 7:28 pm
by bentley marshall
thanks for the info jean will see how i go with it

Re: How to make a 4 stroke more HP

Posted: September 30th, 2011, 3:36 am
by Alkismurf
Hi Bents, i've been reading up about these engines too.
Some of the mods people do are.
Replace the GX-35 cam with a GX-25 cam
Replace the GX-35 piston with GX31 piston


Here's a link. http://www.rcuniverse.com/forum/m_71680 ... tm#9462740

Re: How to make a 4 stroke more HP

Posted: September 30th, 2011, 11:07 pm
by bentley marshall
intersting stuff in that thanks smurf

what are you putin g one in ???

Re: How to make a 4 stroke more HP

Posted: October 1st, 2011, 9:07 pm
by Alkismurf
I'd like to put it in my drifter.....when i finish it lol, have you put one in a car yet?

Re: How to make a 4 stroke more HP

Posted: October 2nd, 2011, 10:47 am
by bentley marshall
no should be here today ....but i still have to build a chassis for it and finish the diff im building for it

Re: How to make a 4 stroke more HP

Posted: November 1st, 2011, 10:37 am
by jean phi
We modified the wheel of ignition, a Honda Gx 25 wheel mounting.

Much easier to use, because we can now use a 54 mm and standard Bell clutch.

Jean Phi