Honda Kid Kart Engine (GXH50) Lessons learned

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Matt Graybiel
Posts: 42
Joined: Thu Jul 25, 2013 9:39 pm

Honda Kid Kart Engine (GXH50) Lessons learned

Post by Matt Graybiel »

I wanted to get a thread going on lessons learned on the Honda Motor. There are two running in 2015 and a third will join us for the 2015 TX 4 Stroke challenge.

Lessons learned so far:
Cleaning the carb: The carb cleaning process is the same as the Comer, but it is a little more difficult to remove because of the gas tank and the throttle linkage. You can remove the two screws behind the air filter box and clean the carb without removing the throttle linkage. You just need three hands. Two screws on the bowl, you only need to remove the one in the center to disconnect the bowl. I found that using an ultrasonic cleaner with dish soap every once in a while really helps. Found one at harbor freight for under $30.

Fuel: 90+ octane, cheap gas can impact this engine. I have been using the non-ethanol stuff in a can from HD/Lowe's. It is a little more expensive than pump gas, but I don't like the ethanol in pump gas. HPD told me 90 pump gas or VPMS93.

Oil: I am very careful about changing the oil in this engine. HPD recommend every three race weekends. I change oil after 3 race weekends or after 150 practice laps. I also recommend getting a pump to help remove the oil, much easier than removing the engine or holding the kart upside down. Adding oil: Get a good funnel and measure your oil. Honda recommends Honda performance oil. We use a 30W Lucas Oil. A quart of oil will last you a while, as these engines don't have a large oil capacity.

Weight: These engines are 5-7 lbs heavier than the Comer's, but no where near the LO206. I put a 5lb weight on the left side of the kart for balance at one point it seemed to help. Recommend you check you weight distribution if you run one of these engines.

Clutch: There is one stock clutch available and it comes with a 15 or a 16 tooth driver. I have both, but have only run the 15 so far. The top end is really good on this kart but the bottom end suffers a little bit if the kid misses the entry on a corner. BUY EXTRA clutch keys. We had one sheer off, a somewhat common problem. I called the dealer we bought the engine from and he said they have a run on these over the last few months. I ordered 6.
I have had issues with the bolt that holds the clutch on coming loose. It is difficult to access because it is so close to the seat. Recommend that after every race/practice session you tighten the bolt and use a little thread locker.

Tire Rollout: Keep them even circumference and run wide rims. The narrow rims seemed to make the top end higher but made the low end suffer. Still testing this out.

Buying and fitting the engine: Buy from a reputable dealer and ensure the engine has the HPD seal. The clutches have the words "Honda Racing" and a logo on them. There have been a few people on eBay selling the utility engines and passing them off as HPD engines. Fitting the engine can be a little tricky. Expect to move the seat to the left. Disconnect the yellow oil disconnect wires by simply cutting the wire or pulling the connector off. If you do not, the engine will cut out on hard left turns. It is very frustrating...
I recommend putting a dirt bike style push button kill switch in reach of the driver. I picked one up at the local Honda motorcycle dealer and mounted it below the steering wheel. Wire it into the existing kill switch and attach the ground wire somewhere, we used a bolt on the floor pan.

Throttle Linkage: The throttle linkage is a little tricky - I suggest reaching out to the dealer you purchased it from, looking at the NTK club kart w/Honda or I can send you pics of ours. Also recommend you hit the throttle linkage and lower return spring with spray lubricant every once in a while. Our spring was sticking and the throttle was not very responsive. A little spray lube and it was running like a champ.

Getting assistance: I have reached out to HPD and received a response with in 24 hours. grmsadmin@hra.com is the email address I used. I have also reached out to the dealer I purchased the engine from and they have been fantastic. I have not found any active blogs on the Honda Kid Kart engine, that is why I am posting here. Time permitting, I may start a FB group or blog for this particular topic. If someone has a good source of information, please share.
Matt Graybiel
Leon Knox
Posts: 28
Joined: Sun Apr 24, 2011 9:21 am

Re: Honda Kid Kart Engine (GXH50) Lessons learned

Post by Leon Knox »

Good info thanks
Matt Graybiel
Posts: 42
Joined: Thu Jul 25, 2013 9:39 pm

Re: Honda Kid Kart Engine (GXH50) Lessons learned

Post by Matt Graybiel »

Leon - Valve Lash adjustment video. Check it when engine is cold. http://youtu.be/lTexCMEGw64" onclick="window.open(this.href);return false;
Matt Graybiel
Leon Knox
Posts: 28
Joined: Sun Apr 24, 2011 9:21 am

Re: Honda Kid Kart Engine (GXH50) Lessons learned

Post by Leon Knox »

Will do and make sure u check the clutch built came loss twice in last weeks race this week seems like,e it made it ok
Matt Graybiel
Posts: 42
Joined: Thu Jul 25, 2013 9:39 pm

Re: Honda Kid Kart Engine (GXH50) Lessons learned

Post by Matt Graybiel »

Similar issues with ours coming loose, even after I put thread locker on it. I am thinking about drilling a hole in the seat to make accessing the bolt on the clutch easier. Will let you know what we do after the new chassis comes in.
Matt Graybiel
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