A mods/fixes checklist for installing a Honda GXH50 frame mount kit

re: pedal crank

This is what had me confused (would confuse anyone):

Being a pragmatic planner would lead a person to reading the installation instructions before ordering. However, the installation instructions at bicycle-engines.com states:

"It is very important that the bike have a one-piece crank. Bicycles with cartridge type bottom brackets or three-piece cranks will be very difficult to use with the extra-wide one-piece crank included with the Whopper Stopper kit."

I re-checked the instructions at the grubee website and found that apparently they have both types of cranks available:

"Large bottom hole, approx. 52mm dia. ID is needed to accept our one piece pedal crank. Small bottom hole bikes can use our 3 piece wide pedal crank"

Therefore the question is, which version of the kit am I getting?

I emailed bicycle-engines.com to find out.

In the mean time, I placed an order for the conversion kit. I will return it if I don't need it.
 
I appreciate the heads up Pablo. I already determined that I don't need the conversion and successfully cancelled the order. In the future I will check out your site and the other sponsors first.
 
Sorry about that, I thought pretty much all the 4stroke kits came with the 3 piece style wide crank. I actually got mine from bicycle-engines like you did too.
Definitely check out Sick Bike Parts they have stuff you dont even know you want yet. Like a 415 chain 1/2 link that will allow you to make your chain the perfect length so you can do away with the noisy/ugly/cheap chain tensioner. A dirt cheap part that makes all the difference which you will not be finding at your local bike shop. Definitely no diss meant to SBP or the others by sending you to choppers-us, I just got mine there so I threw it out there and I wasn't aware SBP carried the bottom bracket conversion.
Another rather nice modification is a freewheel sprocket for the drive sprocket on the gearbox. You could pretty much call it a necessity if you ever plan to pedal without the motor, assuming all the gearboxes are as hard to turn as mine is!
 
Looks like my links work if quoted by one of you...Pablo or KeepnOn how about quoting my entire first post so the links can show??? (for now, I still hope to edit the first post eventually)
 
Checklist for Honda GXH50 Frame Mount Kit
Revision 1

Ordering the Kit
bicycle-engines.com has about the best prices (no tax, no shipping, $499) and they seem to have a good review by people on this forum who have used them. Of course, there are other retailers for the kit.

Installation Manual
The manual from bicycle-engines.com is "ok"... Not all issues are addressed and it's generic to HuaSheng/Honda. I have not found a GXH50-specific manual, but a somewhat better manual of the same type is available at the wholesale site for the kits: http://www.grubeeinc.com/USA/Stage III.htm

GXH50 Owners Manual
See the third post on this thread: http://www.motoredbikes.com/showthread.php?t=11224&highlight=GXH50

General Tips
Couldn't hurt to review this compilation of info and topic references:
http://www.motoredbikes.com/showthread.php?t=17401&highlight=GXH50&page=2

Throttle Issue
Apparently the factory throttle/spring mechanism on the engine doesn't provide enough force to pull back the throttle after twisting the throttle grip handle. Solutions include oiling the cable, eliminate tight bends, and create a custom throttle/spring assembly. Discussed here:
http://www.motoredbikes.com/showthread.php?t=7744&highlight=GXH50
and
http://www.motoredbikes.com/showthread.php?t=22690
also
http://www.motoredbikes.com/showthread.php?t=13962&highlight=GXH50

Exhaust Pipe Mounting
Using the exhaust pipe provided with the kit, it appears most people add a frame-mounted support. I've seen it in many photos and personally plan to improvise with a trip to the hardware store.

Front Pedal Sprocket Is Replaced
I haven't read about this anywhere, including in the sales website literature, but from photos I can tell that when installing the kit (specifically when you install the wide pedals shaft) you replace the front sprocket with a single sprocket - such that on a 18 or 21 speed bike you lose your front gears. No biggie to me, just thought it's worth pointing out.

One Piece -or- Three Piece Crank?
The kits can apparently come with either the one piece or three piece extra wide replacement crank. You have to find out which one your vendor sells and may need to buy a conversion kit if you don't have the corresponding type on your bike.

A kit for converting to a three piece crank is at http://www.sickbikeparts.com/catalog/index.php?cPath=23

Chain Tensioner
The tensioner that comes with the kit has a disappointing plastic roller. I have seen two alternatives. (1) get a toothed gear for the roller online or at a local go-kart shop. (2) adjust the chain just right and do away with the tensioner.

I did the second option with my 2-cycle kit - it required removing 2 or 3 links from the chain. To get the exact length needed, you may need a 1/2 link, available here: http://www.sickbikeparts.com/catalog/product_info.php?products_id=68

Fuel Tank Preparation
The Grubee installation guide suggests the tank should be "Kreemed" before use. Elsewhere I have seen it stressed that you should air blow the tank clean thoroughly before using it. The point being that the carb is very sensitive to debris so every precaution should be taken.

Adding a Fuel Filter
Is recommended. Here is one at Sick Bike Parts:
http://www.sickbikeparts.com/catalog/product_info.php?products_id=53

Engine Break In
The discussion of break in (http://www.motoredbikes.com/showthread.php?t=21085&highlight=GXH50) seems to have ended up with Honda's official position that there is no break in required. However, taking it easy for the first 10 hours or so, and changing the oil during that period would seem to be a good idea. And, do not run at idle or constant speed - varying speeds distributes oil better.

Switching to Heavy Duty Axle with Drum Brake
This is a nice idea, but sounds like a bit of work. The HD Axle kit is available from many of the kit vendors. Reviewed here: http://www.motoredbikes.com/showthread.php?t=7026&highlight=Heavy+Duty+Axle

Consider a Higher Gear - Other Sprocket Sizes
The kit comes with a 56 tooth sprocket, which people report equates to a fairly low gear. Fewer teeth gives a higher gear, which goes faster but requires more pedaling to start out. Several sprocket sizes are available.
Discussed here: http://www.motoredbikes.com/showthread.php?t=11680

Problems with Starting the Engine & Low Oil Sensor
Sounds like a few people have run into problems getting the engine started. This thread has some good diagnostic steps and discusses the Low Oil Sensor which can potentially kick in at the wrong time:
http://www.motoredbikes.com/showthread.php?t=17401&highlight=GXH50&page=2

Leaking Carb Problem
Sounds like a few people ran into this. It's discussed here: http://www.motoredbikes.com/showthread.php?t=21711&highlight=GXH50

Safety and Maintenance Tips
Here's a long thread with some humor but also with lots of very practical advice: http://www.motoredbikes.com/showthread.php?t=9519&highlight=GXH50
 
Last edited:
Checklist for Honda GXH50 Frame Mount Kit
Revision 1

Ordering the Kit
bicycle-engines.com has about the best prices (no tax, no shipping, $499) and they seem to have a good review by people on this forum who have used them. Of course, there are other retailers for the kit.

Installation Manual
The manual from bicycle-engines.com is "ok"... Not all issues are addressed and it's generic to HuaSheng/Honda. I have not found a GXH50-specific manual, but a somewhat better manual of the same type is available at the wholesale site for the kits: http://www.grubeeinc.com/USA/Stage III.htm

GXH50 Owners Manual
See the third post on this thread: http://www.motoredbikes.com/showthread.php?t=11224&highlight=GXH50

General Tips
Couldn't hurt to review this compilation of info and topic references:
http://www.motoredbikes.com/showthread.php?t=17401&highlight=GXH50&page=2

Throttle Issue
Apparently the factory throttle/spring mechanism on the engine doesn't provide enough force to pull back the throttle after twisting the throttle grip handle. Solutions include oiling the cable, eliminate tight bends, and create a custom throttle/spring assembly. Discussed here:
http://www.motoredbikes.com/showthread.php?t=7744&highlight=GXH50
and
http://www.motoredbikes.com/showthread.php?t=22690
also
http://www.motoredbikes.com/showthread.php?t=13962&highlight=GXH50

Exhaust Pipe Mounting
Using the exhaust pipe provided with the kit, it appears most people add a frame-mounted support. I've seen it in many photos and personally plan to improvise with a trip to the hardware store.

Front Pedal Sprocket Is Replaced
I haven't read about this anywhere, including in the sales website literature, but from photos I can tell that when installing the kit (specifically when you install the wide pedals shaft) you replace the front sprocket with a single sprocket - such that on a 18 or 21 speed bike you lose your front gears. No biggie to me, just thought it's worth pointing out.

One Piece -or- Three Piece Crank?
The kits can apparently come with either the one piece or three piece extra wide replacement crank. You have to find out which one your vendor sells and may need to buy a conversion kit if you don't have the corresponding type on your bike.

A kit for converting to a three piece crank is at http://www.sickbikeparts.com/catalog/index.php?cPath=23

Chain Tensioner
The tensioner that comes with the kit has a disappointing plastic roller. I have seen two alternatives. (1) get a toothed gear for the roller online or at a local go-kart shop. (2) adjust the chain just right and do away with the tensioner.

I did the second option with my 2-cycle kit - it required removing 2 or 3 links from the chain. To get the exact length needed, you may need a 1/2 link, available here: http://www.sickbikeparts.com/catalog/product_info.php?products_id=68

Fuel Tank Preparation
The Grubee installation guide suggests the tank should be "Kreemed" before use. Elsewhere I have seen it stressed that you should air blow the tank clean thoroughly before using it. The point being that the carb is very sensitive to debris so every precaution should be taken.

Adding a Fuel Filter
Is recommended. Here is one at Sick Bike Parts:
http://www.sickbikeparts.com/catalog/product_info.php?products_id=53

Engine Break In
The discussion of break in (http://www.motoredbikes.com/showthread.php?t=21085&highlight=GXH50) seems to have ended up with Honda's official position that there is no break in required. However, taking it easy for the first 10 hours or so, and changing the oil during that period would seem to be a good idea. And, do not run at idle or constant speed - varying speeds distributes oil better.

Switching to Heavy Duty Axle with Drum Brake
This is a nice idea, but sounds like a bit of work. The HD Axle kit is available from many of the kit vendors. Reviewed here: http://www.motoredbikes.com/showthread.php?t=7026&highlight=Heavy+Duty+Axle

Consider a Higher Gear - Other Sprocket Sizes
The kit comes with a 56 tooth sprocket, which people report equates to a fairly low gear. Fewer teeth gives a higher gear, which goes faster but requires more pedaling to start out. Several sprocket sizes are available.
Discussed here: http://www.motoredbikes.com/showthread.php?t=11680

Problems with Starting the Engine & Low Oil Sensor
Sounds like a few people have run into problems getting the engine started. This thread has some good diagnostic steps and discusses the Low Oil Sensor which can potentially kick in at the wrong time:
http://www.motoredbikes.com/showthread.php?t=17401&highlight=GXH50&page=2

Leaking Carb Problem
Sounds like a few people ran into this. It's discussed here: http://www.motoredbikes.com/showthread.php?t=21711&highlight=GXH50

Safety and Maintenance Tips
Here's a long thread with some humor but also with lots of very practical advice: http://www.motoredbikes.com/showthread.php?t=9519&highlight=GXH50

TEST
 
Bicycle-engines.com. I Like The Looks Of The New 4g Belt Tranny Kit For $399. With Free Shipping. If You Don`t Like The New Belt Drive You Can Buy The Other Tranny For $120 Later. Then You Would Only Spend 20 Bucks More And Have Both Trannys. Cogged Belts Are Tuff. They Run Car Camshafts With Them, Thats Tuff In My Book. Just A Thought. I Have Been Running My Titan/hs (same Engines, I Have Them Both) For Two Months And Never Have To Adjust Anything Since Day One. They Idle Perfect, Never Hesitate. Ron
 
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