Best way about going from 2 stroke to 4 stroke

i dont like the huasheng 50 anymore. seen three die. my first post here was to see if anyone knew what was up with the stinking thing, cus even after swapping carb to a mikuni slide, i couldnt get one to run nicely. a year left to rot out in the rain, and it changed its mind!!! still required a new carb but.

but i does like my li honda 25 on my brushcutter. faultless

i also like my huasheng 25's which are mere copies of the fuji robin.

i liked my hyosung 650 until...i just sold it today 120,000km + not bad for korean

but, my only, and really, its my ONLY gripe with any 4 stroke...they just arent designed for fitting to bicycles. not a definite, this is SOLELY for bicycle motorisation engine exists, other than the 2 stroke HT, or other similar type engines. they have been around since the 30's. 20's even.


oh. except for the whizzer 4 stroke engine! that WAS designed for bicycles!

but i shant discuss them, having never seen one in real life, therefore absolutely no experience with them.

someone needs to design one with DOHC, 50cc that will tear the pants off of ANYTHING else available a lil engine like that, if honda designed it, could sit at 16000 all day long!


it will also be expensive the whizzer is...

HeadSmess said:

someone needs to design one with DOHC, 50cc that will tear the pants off of ANYTHING else available a lil engine like that, if honda designed it, could sit at 16000 all day long!

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I agree.

If only Honda would make a replica 2-stroke Chinese motorized bicycle engine but manufacture it as a 4-stroke using a super sexy RCV sleeve valve gear reduction design

As compact as a 2-stroke with almost the simplicity of a 2-stroke, yet having the reduced noise and reduced exhaust sensitivity of a 4-stroke.

I keep getting replies about people having good luck w/ clones, usually after modification and usually silently tweeking their set-up w/ a new carb and cdi, not considering the time they spend adjusting---read on here.
aside from marine engines, my experience w/ 2stroker was a '02 Yamaha vino (2), also had '05 vino(4 stroke), the '02 had its exhaust deregulated, at red lights I would gun it (watching cross traffic signal I would time when to go) and vehicle next to me would have to floor it to keep from having a scooter out accelerate them, very funny to see. but when it came to hills, the stock 4 stroker would hold speed a lot better. from my experience on those scooters, one 2stroke (oil injected, no mixing) the other a unmodified 4stroke, I still opt for the 4stroke.
as far as I know, there are no reliable engines that were built for bikes. a 16k rpm 4stroker would need an intercooler like a turbo engine. yeah, big$$$, I'm getting flak for recommending a super reliable $400 Honda!
tanaka used to make a 47r 2stroke that spun @12 or 14,000rpm, hard to find now though. w/ my setup, that would be 55-60mph!
btw, I do love the smell of 2stroke exhaust, not as much as gunpowder, but close.

Fabian said:

I agree.

If only Honda would make a replica 2-stroke Chinese motorized bicycle engine but manufacture it as a 4-stroke using a super sexy RCV sleeve valve gear reduction design

As compact as a 2-stroke with almost the simplicity of a 2-stroke, yet having the reduced noise and reduced exhaust sensitivity of a 4-stroke.

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ahhhh, youve finally found out about the RCV? is a beautiful design. especially the SP with its already reduced output shaft

so much nicer than the napier sleeve valve design, which is a rather strange system, but was reliable enough to feature on many early aircraft engines.

they themselves started a 125cc prototype, based on the honda cub, aka ct110 type engine.

when i emailed them several years ago, the response was...


damn. no matches found! musta deleted it! i recall deleting the main contact just the other day too! getting rid of all these one time contacts. grrr.

anyway. they told me they had sold most of the rights to the military, for UAV/drone engines. that the prototype was no longer being considered as viable.

but then last time i checked their website it appeared i had been lied to?

http://www.rcvengines.com/applications_forestandgarden_engines.html


have go at contacting them. maybe theyll tell the truth this time...

http://www.rcvengines.com/applications_engine_development.html


hope you got a lot of financial backing

seanshonda said:

btw, I do love the smell of 2stroke exhaust, not as much as gunpowder, but close.

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mmmm, gunpowder real, oldschool blackpowder or the modern alternative?

when i had a pitbike/thumpster road registered and capable of doing 120km/h on the flats due to a lifan 140 and some cams... i was ALWAYS beating ANY bike at the lights....simply because they was so busy laughing!

then, 100 metres later, just as i was hitting 4th...they would fly past on the rear wheel, still in first, hoping i wouldnt see their red faces


i really really want a nsr 150-250 so i can make it some pipes. never had a 2 stroke road bike or that old yamaha twin 200 a friend had.

stupidest thing i ever saw was some idiot that had strapped an AMR300 supercharger to a scooter... (AMR? the tiny ones!) what a waste of supercharger! his pod had been half scraped off on the road, and...just...what a waste

HeadSmess said:

ahhhh, youve finally found out about the RCV?

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I just love the sleeve valve design and it's the logical method of operation.
Poppet valve design is an utterly stupid concept when compared to a sleeve valve system, and imagine where piston engine design would be if the sleeve valve method had 70 years of mechanical and materials development, particularly an electronically controlled and operated double sleeve valve system - ohh la la :drool5: i want some of that.

You guys are not mentioning the EPA factor in deciding which motors can be sold here, they're like gods.

darwin said:

You guys are not mentioning the EPA factor in deciding which motors can be sold here, they're like gods.

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oh yeah...nasty b***ards... unfortunately with 7 billion of us happily breeeding away with no thought of the consequences...the EPA is just a small blip on the radar. no concern to most... we're all doomed regardless. but we have to start somewhere.

the whole topic deserves its own thread, maybe the mods can do something about that... "sleeve valve options" would be a nice name, i guess.


fabians post was rather a case of thread hijacking after all, and was as much help in this situation as mine was...




^^^ the RCV 35cc 1.8kw answer to the gx35. ^^^

meets EU2 regs. 2.5 horsies!

can rev faster than any standard gx35, with no fear of destructive piston to valve contact, no possibility of valve bounce, no excess power consumed by compressing springs. is extremely simple, with a minimum of parts. higher compression with lower octane fuels. lightweight. not yet in production


maybe, with a new thread, outlining the requirements desired in our area of (sadly overlooked) motive power, filled with enough responses...a petition if you will... a company such as RCV and, say...huasheng, could get together and work on a high-production-volume-so-relatively-cheap, FOUR STROKE engine specifically for motorised bicycles.



just a thought? sleeve valves were good enough for rolls royce' last piston engine they developed(the eagle II i believe, just before the turbine took over, not too mention the hundreds of variants used in other aircraft at around the same time...), and are renowned for simplicity and reliabilty...so why are they no good for other applications?