Possible changing form 2 stroke to 4 stroke. Questions

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Mar 25, 2017
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#1
I posted a couple days ago about issues with my 2 stroke set up and some one suggested I consider 4 strokes.
I did a little surfing and found that my frame is not large enough (4 stoke needs about 8 & 1/2 by 9 & 1/2 ?)
My frame is just short of that. So my only option with this frame is a rear engine mount friction drive.
Are they reliable? I've read that they are not very fast, like less than 20 mph?
From what I've read, these 4 stroke are mostly Chinese knock offs of a honda engine.
Please educate me on 4 stroke motorized bikes.
 


Frankenstein

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#2
I posted a couple days ago about issues with my 2 stroke set up and some one suggested I consider 4 strokes.
I did a little surfing and found that my frame is not large enough (4 stoke needs about 8 & 1/2 by 9 & 1/2 ?)
My frame is just short of that. So my only option with this frame is a rear engine mount friction drive.
Are they reliable? I've read that they are not very fast, like less than 20 mph?
From what I've read, these 4 stroke are mostly Chinese knock offs of a honda engine.
Please educate me on 4 stroke motorized bikes.
I'll start by saying that a friction drive isn't going to be very fun... You'll slip a lot up hills and in lightly wet weather....

Definitely reliable however regardless of them being clones.

When you got the measurements (which I'm not personally knowledgeable about when it comes to 4 stroke dimensions) did you account for it with or without the gas tank and muffler on it? I was looking at dimensions for a while for a different project and at first thought it wouldn't work, but later found out that I was using measurements with the tank on top and such..

I think you probably got it without the tank or muffler since 8.5x9.5 is pretty small... But if you didn't maybe check again. Also I noticed that those are overall dimensions, there are little dips into that with the shape of the engine. You still need to account for the size of the mount as well which can easily eat up a lot of the room in the frame...

If you want a 4 stroke you'll be putting a small one on the back that won't generate much power, a bigger one will just be a heavier one, and with that you'll get a top heavy bike, might be worth going with a different bike that can handle the motor in frame if you are set on 4 stroke..

2 strokes aren't bad, or even problematic, just very fussy. You'll be working on a 2 stroke more often than a 4 but you'll have better power than a 4s would give in the same size package.

It might just boil down to how much patience you have... No kit will be without problems eventually, and they'll all piss you off regardless, best not to forget they are just motors and chains, they all fail, usually when you are at least a couple miles away from home, because that's just how it rolls..
 
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#3
I'll start by saying that a friction drive isn't going to be very fun... You'll slip a lot up hills and in lightly wet weather....

Definitely reliable however regardless of them being clones.

When you got the measurements (which I'm not personally knowledgeable about when it comes to 4 stroke dimensions) did you account for it with or without the gas tank and muffler on it? I was looking at dimensions for a while for a different project and at first thought it wouldn't work, but later found out that I was using measurements with the tank on top and such..

I think you probably got it without the tank or muffler since 8.5x9.5 is pretty small... But if you didn't maybe check again. Also I noticed that those are overall dimensions, there are little dips into that with the shape of the engine. You still need to account for the size of the mount as well which can easily eat up a lot of the room in the frame...

If you want a 4 stroke you'll be putting a small one on the back that won't generate much power, a bigger one will just be a heavier one, and with that you'll get a top heavy bike, might be worth going with a different bike that can handle the motor in frame if you are set on 4 stroke..

2 strokes aren't bad, or even problematic, just very fussy. You'll be working on a 2 stroke more often than a 4 but you'll have better power than a 4s would give in the same size package.

It might just boil down to how much patience you have... No kit will be without problems eventually, and they'll all piss you off regardless, best not to forget they are just motors and chains, they all fail, usually when you are at least a couple miles away from home, because that's just how it rolls..
Well I guess the next logical question to ask is: Is there are kit to do a rear mount but not drive the wheel via friction, perhaps a chain or a belt, chain would be preferable?
I just want more reliablity, I don't want to have to wrench on it twice a week just to ride back and fouth to work and maybe a couple of local errand.
 

panmines

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#4
Well I guess the next logical question to ask is: Is there are kit to do a rear mount but not drive the wheel via friction, perhaps a chain or a belt, chain would be preferable?
I just want more reliablity, I don't want to have to wrench on it twice a week just to ride back and fouth to work and maybe a couple of local errand.
Yes, Staton Inc.. is all about rear mounting engines including chain drives. Unfortunately, they are twice as expensive as the standard Huashengtaishan in-frame kits and I have no idea why.
 

Frankenstein

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#5
Well I guess the next logical question to ask is: Is there are kit to do a rear mount but not drive the wheel via friction, perhaps a chain or a belt, chain would be preferable?
I just want more reliablity, I don't want to have to wrench on it twice a week just to ride back and fouth to work and maybe a couple of local errand.
Belt would be easier likely, but what trouble are you having now anyway? Broken stud right? Replace them and be over with it, these bikes once set straight are pretty good and trustworthy, once you start beefing them up for power you get more problems but if you just take it nice and easy and make sure you double down everything you should be good...

I don't know of any kits for a rear rack I wasn't interested in them so I can't be of value there. Belt would be easier simply because chains are more complicated and more of an exact science than a belt is. Also pulleys don't wear down like sprockets will when a chain stretches, belts are relatively cheap after considering the length of time they last compared to chains. Don't require oil either so no messy bullcrap to deal with.

Harley Davidson moved onto belts for a good simple reason, they worked, they worked on the first motorcycles so well they went back to using them again and stayed with it.

If I could convert my bike to belt drive I would, I know my nuvinci hub can be fitted with a belt cog, unfortunately that's the only part compatible.. My 2¢
 
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#6
An extraction kit is under $10 at harbor freight and m6 12.9 socket head screws are a couple bucks at home depot. Why not at least try to get your money's worth out of your existing build rather than completely scrap it? You're worried that you're going to have to constantly repair it, which is understandable given your bad experience, but what exactly are you referring to? Your one bad experience could have been avoided by replacing a few chinesium studs that most of us think is a mandatory upgrade. Seriously, nobody should be using chinesium mounting studs. Properly torqued 12.9 screws will never break from the vibration of these engines.
 
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#7
An extraction kit is under $10 at harbor freight and m6 12.9 socket head screws are a couple bucks at home depot. Why not at least try to get your money's worth out of your existing build rather than completely scrap it? You're worried that you're going to have to constantly repair it, which is understandable given your bad experience, but what exactly are you referring to? Your one bad experience could have been avoided by replacing a few chinesium studs that most of us think is a mandatory upgrade. Seriously, nobody should be using chinesium mounting studs. Properly torqued 12.9 screws will never break from the vibration of these engines.
Well broken stud are the problem now. But I've also broken the weld on two mufflers, even with the clamp in place. I've blown out an ehaust gasket, I jury rigged that with one made from a soda can.
So now I have two broken stud, broken flush with the block. Sure I guess I could try to get them out, which is more time and money. And it may or may not work.
Seems like it's a part time job keeping one of these thing running right and safe.
 

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