I'm getting sick of people thinking that a GPX 124 (or any stock chinese 124) should be on par with a full blown race 124 like the kitaco 124SE. Considering the parts, the GPX should be viewed more as "if TB made a 124 kit but left out the dome on the piston and the race cam" as far as the power goes. The had specs are a lot closer to a TB race head than they are to a Kitaco SE head. The GPX is also running about 9:1 compression stock with a mild cam. It is undercarbed with the 22mm mikuni as far as making it a race engine goes. The bore and stroke of a 124SE is 54x54. The bore and stroke of a GPX is 52.4x57. The 124SE is a "square" engine setup, where the GPX is a stroker. The stroke of the motor is going to make it more prone to being a torquey motor than a fairly balanced motor like the 124SE.
I think that a GPX 124 should be able to see 12-14 horsepower in theorywith the stock displacement. I am not a fan of increasing the displacement on a 124 to make more power. A TB117 makes roughly 12 horse, and a 124SE makes an average 16 out of the box with no trick tuning.
To upgrade a GPX to race status somewhere between a TB117 and a 124SE with stock displacement, these are the things you must consider.
-Compression. 9:1 is like a lawnmower. Get it up to at least 11:1 to match the 117. I believe the AHP piston will make it 12:1.
-Cam. Needs a more exciting bump stick than the stock unit. Try to match the TB race cam at least.
-Carb. A 22mm carb would barely feed a 108 to its potential. Try more like a 26mm or bigger.
-Exhaust. Keep the engine breathing with a good pipe.
There is no reason to punch a GPX 124 out to a 150 or anything to get it to at least hold its own against a 117. If you just increase displacement...you aren't helping everything else out. Remember that performance parts work in collaboration to make an engine more efficient. A carb is good. A pipe is good. A carb with a pipe is better yet!
I dont really know why i'm ranting on about this at 3:21 AM...but i just wanted to get some ideas off my chest. For the hardcore honda guys out there...its simple to say "well my 108 beats that motor and its a 124!" If you know nothing about motors other than reading the displacement on the cylinder...that makes sence. If your read this post and you still dont get it...you aren't gonna get it. The GPX is a gem with a lot of potential to uncork.... almost like another engine that everybody is familiar with. Thats right, the stock CRF50 motor. "My icon50x motor beats your honda 50 motor!" Hahaha. That is the same mentality with reversed roles.
I would like to give some props to Vince at TBolt, and Mark at AHP minis for providing mods to uncork this gem of a motor and sooner or later (if not already)it will be wiping the smirk off the faces of some honda riders.
I think that a GPX 124 should be able to see 12-14 horsepower in theorywith the stock displacement. I am not a fan of increasing the displacement on a 124 to make more power. A TB117 makes roughly 12 horse, and a 124SE makes an average 16 out of the box with no trick tuning.
To upgrade a GPX to race status somewhere between a TB117 and a 124SE with stock displacement, these are the things you must consider.
-Compression. 9:1 is like a lawnmower. Get it up to at least 11:1 to match the 117. I believe the AHP piston will make it 12:1.
-Cam. Needs a more exciting bump stick than the stock unit. Try to match the TB race cam at least.
-Carb. A 22mm carb would barely feed a 108 to its potential. Try more like a 26mm or bigger.
-Exhaust. Keep the engine breathing with a good pipe.
There is no reason to punch a GPX 124 out to a 150 or anything to get it to at least hold its own against a 117. If you just increase displacement...you aren't helping everything else out. Remember that performance parts work in collaboration to make an engine more efficient. A carb is good. A pipe is good. A carb with a pipe is better yet!
I dont really know why i'm ranting on about this at 3:21 AM...but i just wanted to get some ideas off my chest. For the hardcore honda guys out there...its simple to say "well my 108 beats that motor and its a 124!" If you know nothing about motors other than reading the displacement on the cylinder...that makes sence. If your read this post and you still dont get it...you aren't gonna get it. The GPX is a gem with a lot of potential to uncork.... almost like another engine that everybody is familiar with. Thats right, the stock CRF50 motor. "My icon50x motor beats your honda 50 motor!" Hahaha. That is the same mentality with reversed roles.
I would like to give some props to Vince at TBolt, and Mark at AHP minis for providing mods to uncork this gem of a motor and sooner or later (if not already)it will be wiping the smirk off the faces of some honda riders.
