First 4 stroke build

[JerryAssburger]

CONGRATS, O.P, on trying the 4-stroke route! They've come down in price enough to be more competitive with the 2-strokes, and choice is NICE.

As you can tell from the above posts, the usual rules apply.... the wheels/bearings need attention and brakes are A THING. On my Cranbrook, I'm getting by with just a long-reach front brake- it slows my ample girth down pretty decently. I highly recommend ditching the rag-mount for the rear sprocket and going with one of the hub-mounts you can find on Ebay.

In your picture of the motor kit, it doesn't show what transmission you got with it. On the 4-stroke kits, the transmission set-up is almost everything. Using my own limited experience as an example, I purchased the cheapest 4-stroke kit that had the belt-drive reduction and said it was 53cc... what I got was a 49cc motor with a 5>1 reduction, and then the 48 tooth sprocket for the rear wheel (the default size for most kits). With that ratio, I would've topped out at 21 mph at redline- which I guess is okay if I wanted to climb trees with it, but I'm more of a flat-lander. (Even with 235 lb fat old guys on board, these things are capable of about 30 mph, stock.) My preference for relaxed 25 mph cruising was solved with a 36T rear sprocket. So, find out what transmission/ratio you have, and that can help determine the direction you take from there.

Otherwise, I can't say enough about how happy I am with my 4-stroke set-up, and good luck with yours.

 

[Karl Snarl]

It comes down to being more work than it's worth.
Your talking about fussing with 2 chains and what ever other drama to get it off the bike... opening and cleaning the hub out, inspecting the wear patterns, repacking it, reassembling it and getting the overlocks right and then fussing with the two chains again, fussing with wheel alignment, fussing with chain tensions...

ALL THAT FOR WHAT!?!?! To say you use an Unreliable, Unpredictable, old a** hub "with out issues"?!?!

You do you, but I'm gonna Nope right the hell out of that one! I love vintage but not enough to deal with that as part of "regularly scheduled maintenance"

It's bad enough I am stuck with an IGH coaster (Shimano 3cc "Cartridge Coaster") on the back of my trike... for now. The only upside to that is the jackshaft kit disables its functionality so the odds of it locking up are low... and I am contemplating a set up to be 4×3 12 speed with this DR70 (CRF70 clone) engine

Take's about 20 mins. I'm not sure bout you, but my safety is totally worth 20 mins. You life value may vary( jk). lol

Seriously though, you need to check ya bike regardless of what rims etc you use. These are not factory built motorcycles. These are motors slapped on a bike frame, sometimes modified. I see a lot of failures as I read back in the threads, almost all could have been avoided with a few mins of maintaining and some TLC.

I've almost had a rim failure, because I was a dummy and didn't do my pre-ride check.

 

[JeffP]

I've been running hydraulic disc brakes on front and vbrakes on back for over 10 years. 4g belt system with 10 tooth solid drive sprocket to 40 tooth rear sprocket. I run 26x2.5 tires and can hit 34 mph but cruise mainly between about 22 and 28 mph. I have Rockshox on the front end. I use a 1/8 inch drive chain and a custom built derailer style chain tensioner that runs smooth and quiet. It's my daily driver and I

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get lots of run time with very little maintenance. By the way, every dime I spent on those brakes and front end have come back to me 10 fold in accidents avoided. I love my Honda gxh 50 and just keep changing the oil and putting gas in the tank. Always willing to share knowledge if anyone is interested.

 

[Chainlube]

I've been running hydraulic disc brakes on front and vbrakes on back for over 10 years. 4g belt system with 10 tooth solid drive sprocket to 40 tooth rear sprocket. I run 26x2.5 tires and can hit 34 mph but cruise mainly between about 22 and 28 mph. I have Rockshox on the front end. I use a 1/8 inch drive chain and a custom built derailer style chain tensioner that runs smooth and quiet. It's my daily driver and I

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View attachment 175649
get lots of run time with very little maintenance. By the way, every dime I spent on those brakes and front end have come back to me 10 fold in accidents avoided. I love my Honda gxh 50 and just keep changing the oil and putting gas in the tank. Always willing to share knowledge if anyone is interested.

Ha ha, love your fuel tank.

 

[JeffP]

Ha ha, love your fuel tank.

1.4 gallons I think. It's a monkey bike tank.

 

[Chainlube]

1.4 gallons I think. It's a monkey bike tank.

Same as mine, I just have the black one though.

 

[Sidewinder Jerry]

Same as mine, I just have the black one though.

Mine is a 5 quart; it's transparent lol

 

[Sidewinder Jerry]

I've been running hydraulic disc brakes on front and vbrakes on back for over 10 years. 4g belt system with 10 tooth solid drive sprocket to 40 tooth rear sprocket. I run 26x2.5 tires and can hit 34 mph but cruise mainly between about 22 and 28 mph. I have Rockshox on the front end. I use a 1/8 inch drive chain and a custom built derailer style chain tensioner that runs smooth and quiet. It's my daily driver and I

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View attachment 175649
get lots of run time with very little maintenance. By the way, every dime I spent on those brakes and front end have come back to me 10 fold in accidents avoided. I love my Honda gxh 50 and just keep changing the oil and putting gas in the tank. Always willing to share knowledge if anyone is interested.

Is your transmission 4:1? That'd put you doing 7033 rpm on 26" tires using a 10:40 drive in order to do 34 mph. If your transmission is 5:1 you'd have to be doing 8792 rpm with your set up to go 34 mph. Your engine's max rpm recommendation is 7500 rpm. The max horsepower is at 6800 rpm.

 

[JeffP]

Is your transmission 4:1? That'd put you doing 7033 rpm on 26" tires using a 10:40 drive in order to do 34 mph. If your transmission is 5:1 you'd have to be doing 8792 rpm with your set up to go 34 mph. Your engines rpm recommendation is 7500 rpm.

Transmission is 5:1 but you don't take into account the larger circumference of the 2.5 size tires. My engine is definitely at its max when I'm doing 34

 

[JeffP]

Transmission is 5:1 but you don't take into account the larger circumference of the 2.5 size tires. My engine is definitely at its max when I'm doing 34

But that's why you pay extra for that Honda