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Offline Painlesstom

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GC190 Performance Ideas
« on: August 20, 2012, 12:37:09 PM »
For anyone who has, or would like to get the most from the GC190, this is the thread to explore the possibilities available.

I personally ran my GC190 without an air filter and put a stronger spring between the Mokai throttle linkage and governor arm. That helped override the governor a little and ensure I really was achieving full throttle. It did make a noticeable difference.

Anyone with other tricks and tips, please chime in!  :)
Tom

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Offline Hillbilly

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Re: GC190 Performance Ideas
« Reply #1 on: August 21, 2012, 02:10:33 PM »
Fresh air intake is very easy to achieve with the GC190.  The air cleaner housing sits just under the hood.  A few plastic plumbing pieces from Home Depot and a hole saw is all it takes. Solves any hot start problems.

If you want an air cleaner with better flow, K&N filter #33-2238 is a nice upgrade that also lets you Identify with hot rodders.

Improved exhaust is a major boost.  Better air flow, way better sound and elimination of exhaust CO and CO2 from the engine bay.  I have made adapters for the Robin EX21 and EX27 mufflers and even the Honda GX390.  The EX27 is a nice conversion with good sound and flow.  The GX390 is better flow and a sweet sound, but heavier and a tight squeeze.

Once you have improved air flow in and out, You can re-jet the carb.  The jets for the GX200 carb are interchangeable with the GC 190. Every size is available for the GX200.  I found that #72 jet with K&N filter, fresh air intake and EX27 or GX390 muffler was a great combination.  Real Honda jets are said to be better than the cheaper ones.  I wasn't into measuring performance when I did these changes but when I gave this motor to a buddy with many years of Mokai experience, he loved it.  "I can go up the river as fast as I used to go down it". The boat and motor were later stolen.

Locking out the governor at full throttle has been done by several of us.  I did mine by adding a small stiff spring attached to the governor rod with a long wire loop.  The spring only engages at about 7/8 throttle and is at full pull at wide open throttle.

I've also noticed that the EX21 carb appears to be a near bolt on replacement for the original GC190 carb.  Needs only 1mm widening of mounting holes on either side.  This is a larger carb with better flow.  Haven't tried this but looks promising.

Offline Hillbilly

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Re: GC190 Performance Ideas
« Reply #2 on: August 21, 2012, 04:21:29 PM »
Here is a picture of the GC190 with GX390 muffler and cold air intake


Offline Painlesstom

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Re: GC190 Performance Ideas
« Reply #3 on: August 21, 2012, 04:54:12 PM »
Good info George, thanks for the pic. First time I'd seen a GC with a different muffler too, nice work.  ;D I'll dig through my pictures later tonight and post up my cold air intake from my GC days, that definitely made a big difference.
Tom

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Offline Hillbilly

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Re: GC190 Performance Ideas
« Reply #4 on: August 22, 2012, 07:00:28 AM »
Here are a couple shots of the EX27 muffler on the GC190




Offline Hillbilly

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Re: GC190 Performance Ideas
« Reply #5 on: August 22, 2012, 07:06:26 AM »
This was my wildest GC190 exhaust.  Designed to be the proper length for extraction.  Worked well but sounds like a racing kart.




Offline Painlesstom

  • Painless Tom
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  • Engine: EX21 w/17 head - ES
  • Model Year: 2003 / 2011 / 2015
Re: GC190 Performance Ideas
« Reply #6 on: August 22, 2012, 09:10:53 AM »
Wow, nice work. That IS pretty wild looking!  :-\

Here are a couple shots of my cold air intake.

Tom

  >:D    

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