Modified Chinese motors?

JoelC707

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I'm not sure if this would be the right place for it but it looks like a good spot. If not please move it where it needs to be.

I'm sure all this info is out there scattered around but I was curious if we could get it all in one place. What are your biggest complaints about the Chinese two stroke motors? If you could change ANYTHING on the motor what would it be? How much extra might you be willing to pay for those changes?

One thing I've been kicking around is taking the motors I have (Star Fire Gen II's, Gen II-A's and GT4's) and reboxing them and sorta rebadging them as a "modified" motor kit. The biggest thing I had in mind to replace were the bolts. I know everyone (including myself) says the Grubee motors have Japanese fasteners that are better than the Chinese parts but lets face it, they still aren't a match for a good old American bolt, even a low grade one. I know there are kits out there for this purpose but would you consider buying a kit that has the same modification already done?

The other thing that needs to be fixed is the muffler. I'm not sure about others but the screw that holds on the end cap of my mufflers flat out SUCKS. The hole it screws into doesn't give it much bite to begin with and ultimately loosens itself to the point the screw no longer holds. what we have been doing it taking a short stud (about the length of the exhaust stud on the enging), and welding it in place then you can put a nut on the outside with a lock washer, nylock or double nutted if you want.

So what else would you like to see changed for the better? I would of course continue to offer both the original, unmodified kit for those that prefer to do the work themselves or just don't care. But I suspect most would welcome an "upgraded" kit even if it costs a little more. What are your thoughts?

Joel
 
Longer front engine mounting bolts, and better still, wider spacing. The front mount seems to be a common area of aggravation. A decent spark plug (NGK) and external fuel filter. An inline kill switch rather than shorting out the coil to ground (duh). Automatic chain tensioner.
 
Thanks for the suggestions guys. Lets see what we have here.

On the longer mounting bolts and wider spacing I think we can cover you there, with two options even. We are currently building a "universal" front engine mount that also has an adjustment on it to pitch the front of the engine side to side. About the only type of frame it won't fit on is the oddball shaped ones, the ones that look more like a rectangle than an oval or round one. The other option we have is from a friend that works at Boeing. He has developed a solid rubber engine mount (front and back) that in our testing took out 80% of the vibration easily.

Decent spark plug. Have you really found aftermarket plugs to work better than the factory ones? I've always heard they foul out much quicker.

External fuel filter. I completely forgot about this. We put them on every bike we build for our own use or as a show bike. It only costs about a buck retail at an auto parts store and just makes good sense.

Inline kill switch. Got any links to those? I personally haven't seen a kill switch that doesn't short to ground.

Automatic chain tensioner. This is something we are brainstorming about now. Not sure how it is going to come out though.
 
Hi Joel
I think balancing the motor would be a big plus and a tear down and inspection of the entire assembly would go a long way to avoid early failures. I know I would pay for a engine that was gone over in that way. Torqued properly and had beefed up hardware and superior gaskets.
 
Hi Joel
I think balancing the motor would be a big plus and a tear down and inspection of the entire assembly would go a long way to avoid early failures. I know I would pay for a engine that was gone over in that way. Torqued properly and had beefed up hardware and superior gaskets.

That's a good idea but one little problem. I'd lose the 90 day factory warranty by opening up the motor. The advantage to it is the warranty wouldn't be of much use anymore because any potential failure points would be spotted and fixed or tossed back. If we did this the most we could offer warranty wise would be a DOA warranty, say 7 or maybe 30 days tops.
 
That's a good idea but one little problem. I'd lose the 90 day factory warranty by opening up the motor. The advantage to it is the warranty wouldn't be of much use anymore because any potential failure points would be spotted and fixed or tossed back. If we did this the most we could offer warranty wise would be a DOA warranty, say 7 or maybe 30 days tops.
Ambitious idea to think about upgrading quality of HTs.

What brought you to this conclusion that there might be a market in it?

I actually think that the HT has heeps going for it, except questionable quality. The market potential is huge for a good quality lightweight motor that mirrors the function of the HT so that it can be fitted to a commuter bicycles. I'd be interested to find out if anyone is doing it.
 
i have been upgrading motors for awhile now , and building a few from the ground up . i like to ad ported heads , advance the timing with a key , use larger intake manifolds , and carbs with v stack and nicer air cleaners , replace all the bolts with upgraded harder Allen heads and use locking washers , , motors don't rattle apart , and better performance. all pretty cheap stuff but makes a world of difference , the ported head is the spendy part but not too bad $50,00 bucks or so . and yes there is a market for it . there is nothing like a motor that starts on the first pull even on a cold start, your pull start last forever .
 
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