Gx200

C

Christophr03

New member
Hello. Newby to these small engines. Starting my boy out in a dirt oval division. The rules call for a stock gx160 or 200. What can be done and where should I look for parts while remaining stock. He gets pulled off the start so it's apparent that we are wildly underpowered at out of box stock. I've removed the governor and plugged hole. I know I need to put a flat top Honda piston. Any advice or even pointing to an existing thread is appreciated. Thanks guys. Max lift is 230. Carb is 585 venturi and 751 rear bore max. And stock cast flywheel minimum five lbs.
 
Christophr03 said:
Hello. Newby to these small engines. Starting my boy out in a dirt oval division. The rules call for a stock gx160 or 200. What can be done and where should I look for parts while remaining stock. He gets pulled off the start so it's apparent that we are wildly underpowered at out of box stock. I've removed the governor and plugged hole. I know I need to put a flat top Honda piston. Any advice or even pointing to an existing thread is appreciated. Thanks guys. Max lift is 230. Carb is 585 venturi and 751 rear bore max. And stock cast flywheel minimum five lbs.
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Two things I can suggest; "compression is the Holy Grail". Confirm that your engine has close to the minimum CC's allowed for the class in the combustion chamber. To be safe, allow a little extra for any carbon buildup you might get in the combustion chamber.

Make sure your clutch is slipping (on the starts) at the peak torque RPM of your engine. If the clutch is holding the engine at peak torque on the starts, that torque is transferred, through the chain, to the axle. With maximum torque at the rear axle, you have maximum horsepower at the rear axle. While the clutch is slipping, the horsepower at the engine, and the horsepower at the axle, are different. (Torque X RPM / 5252.1 = Horsepower) Torque = work (force over distance), horsepower (a calculation) = how fast you are doing the work.

If you don't have a tachometer, you should get one, they are an essential for the newcomer.
 
Are you using a GX160 against GX200's What are specific rules, stock exhaust, airbox, are you allowed to adjust ign timing, what are you allowed to do. In Canada we raced Honda engines basically the rules were, no material removed Honda manufactured parts. We need to know more info it seems your competitors have the information.
 
Yes sorry. I am running a gx200. We are allowed any exhaust and air cleaner. Must use Honda oe parts. Does not say has to be engine specific though. We can shave the head and the block. No piston pop out allowed. Head work as far as machining not allowed other than head gasket surface. 25cc minimum. Stock valves with stock keepers. What else do I need to know. Someone at the track mentioned different Honda heads and such but did not want to let loose with the info. I can tell these other engines are "healthier" than ours just at an idle. Thanks for the help guys.
 
GX200 flywheel is at 20*BTDC get a GX160 they are 25*. You can file the key to gain more. Don't fall into the head # trap it is a vortex which you will find there is always a better one. measure your chamber cc you will be close to your 27cc as it is for a TK1 engine. The flat top piston will help here. It should already have the metal .009" head gasket. GX140 emulsion tube 16166-ZE1-005 . Jet start at about .033" Honda valve springs Part # 14751-883-000 ,. Pipe close to .900" .950" internal at least 12" long. Simple horn type air filter adapter basic paper cone type air filter adequate for dirt if you are on dirt.
 
Thanks Kart. What do you mean by file the key? Any idea if running a gx160 head will be too small or no advantage? I just feel like I am missing something for these guys to be spending a thousand dollars for those few simple changes. Perhaps I'm over thinking it. Thanks for the tips.
 
It depends on how far you want to go. You can de tension the rings, change the centerline on the cam, deck the block, mill the head, hone all kinds of different parts for reduced friction, go through lots and lots of parts looking for the most ideal ones, Then there's the carb, that's another matter entirely, and there's power to be had with a quality valve job. generally a hard running engine is the result of experience and attention to detail.
IMO the thing to do is to pick a reputable builder and let them have at it. It seems like a lot of money, but by the time you buy parts, tools, and ruin parts figuring out what you're doing it's cheaper in the long run just to have it done.
 
That is the reason we got away from Honda and would not adopt The Clone. Top shelf Honda engines were costing $2000 and up using stock parts. The head interchangeability was one of the cost factors, I have heads that would have bought two sets of tires, but we don't use Honda anymore. Work on the above suggestions get the chassis tuned have some fun. Your rule set has the class destined for failure. omeone always has deeper pockets.
 
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