Does a 4 stroke Chinese need an upgrade hardware kit?

[gera229]

Like on the 2 stroke motors to keep the reliable does a 4 stroke need any modifications like a high quality hardware/ stud kit?

Which are more reliable between 4 stroke and 2 stroke motors and why? Which one would last longer?

Which has more power and/or rides faster?

 

[scotto-]

No.

 

[GearNut]

Most any 4 stroke is more reliable due the nature of the design.

4 stroke has more low RPM torque.
2 stroke has more high RPM horsepower.
Both can have the same top speed if geared correctly, assuming both are rated at the same horsepower.

4 stroke usually lasts alot longer, again due to the nature of the design.

 

[gera229]

From thatsdax would it be better to buy a 2 stroke or a 4 stroke motor?
The 2 stroke is 240 shipped. Plus dax RT carb and cable which is 40 so it's 280 now. Plus I'm getting SBP hardware stuff and spark plugs with wire, filters, studs, gaskets, high quality clutch cable, etc. which would be about 50-60 shipped and manic mechanic intake for 23 shipped. Altogether this totals about: $353.

and the 4 stroke
titan xc35 with kit is about $360 shipped
titan xc50 with engine mount kit is about 380 shipped.
titan XC50S with kit is about 413 shipped.

I mainly want a chain drive engine. I know 4 strokes can fit on the inner frame which is what I want as well, but it might be difficult, and they are mainly to fit in the back of the bikes I think. Correct me if I am wrong.

 

[GearNut]

Purchasing a 2 stroke or 4 stroke is your decision. I cannot recommend what you want, only you can do that.
I have messed with the 2 strokes enough now that I no longer want to fiddle with another one. My next build will be a 4 stroke on a stout mountain bike frame.
Hundreds of folks have fit 4 stroke engines inside a bicycle frame.
Wander around in the 4-stroke section to learn more.

XC50 or XC50s would be my recommendations.
Until DAX has completed his version of an in frame kit I don't know of a primary reduction that will work with the titan engine.

There is also the Bicycle Engines . com kit that uses the HuaSheng engine with the respected 4G primary reduction drive. The final sprocket on the 4G does need to be welded solid to make it reliable though.
49cc 4G T Belt Drive Complete Gas Powered Engine Kit - $379.99

One of the best so far in primary reduction systems is the EZM one.
EZ MOTORBIKE COMPANY
They sell through authorized dealers, not direct through the EZM web site. Find one near you for pricing and shipping details.

Here's a thread on that one:
http://motorbicycling.com/f37/new-build-hf-79cc-trek-24247.html

 

[gera229]

What brand is HF? I will check that thread out.

 

[GearNut]

HF = Harbor Freight.
They recently switched to the "Predator" branded engine. They used to be called "Greyhound" engines. They are surprisingly powerful and well made considering the price, and you can purchase a good warranty for them too.
Check out scotto's thread for more information on the new 7 horsepower Predator.
http://motorbicycling.com/f37/peek-inside-7hp-hf-predator-32687.html
Yes, they make smaller and larger engines too.
Gas Engines at Harbor Freight Tools

 

[gera229]

Nice, I'm in CA so I will have to go with the ones that are certified for CA which probably have CARB addons. But does that affect the performance?

This for ex: Predator 173 cc OHV Vertical Shaft Gas Engine - Certified for California
This is probably a Lawn mower engine.
Not sure if that will fit a bike frame, but for $100?? Great price......

Maybe I can make my own mounts and such and buy custom throttles and everything and end up at about $250 total with engine?
And harbor freight are OEM in USA and not cloners/ chinese? And build high quality compared to Chinese 4 strokes?

What's the RPM of these HF motors?

These engines are pretty large, not sure how that man in the thread fit his engine inside his bike frame.

 

[GearNut]

CARB compliant means that it will run like crap compared to an non CARB engine.
They basically re-jet and restrict the exhaust to reduce the smog emissions and a side effect of all that, also reduce the total power.
The engine will actually run well.... just not as powerful as it could be.

*tinker, modify, re jet, custom exhaust, ect*

 

[gera229]

I added a few more questions to the previous post, sorry. Was editing it. Any more answers?

 

[GearNut]

They are very much Chinese clones. Made in China even!
They just happen to be well made too.

 

[gera229]

This is by far the cheapest chinese clones motors I have seen. It looks like a sprocket will need to be welded on them. Do HF engines have a clutch?

 

[GearNut]

They have no clutch. It is just an engine, nothing else. You add whatever transmission you choose to them, just research if the transmission will have the same bolt pattern that the engine has. I do not recommend welding a sprocket to the engine either.
As for attaching the engine to a bicycle frame, many vendors sell universal mount plate kits that will accommodate different bicycle frames and engines.

Keep in mind, the effort required to do a 4 stroke installation is greater than a cheap HT 2 stroke engine, but well worth it in the end.

 

[gera229]

Ok, so there is not way to idle it if you want to just pedal? How do you stop the motor?

 

[azbill]

most 4cycles are run with a centrifugal clutch of one kind or another
the EZM silent drive (discontinued) was the only in-frame setup that was a manual (AFAIK)

 

[cory151]

most 4cycles are run with a centrifugal clutch of one kind or another
the EZM silent drive (discontinued) was the only in-frame setup that was a manual (AFAIK)

Thats a shame too, I really like the versatility of a manual clutch.

 

[GearNut]

The primary drive should come with a clutch. Just be sure that the clutch supplied will fit the engine's shaft before you order it.
That said, do not confuse the primary drive kits that fit the smaller engines with the kits that fit the larger engines. They are specific to the engine style that they are designed for and will not interchange without alot of custom fabrication on your part.
Most of the smaller engines come with the inner portion of the clutch all ready installed and the primary drive comes with a matching clutch outer portion.
The larger engines only have an output shaft and the primary drive comes with a complete clutch that fits onto the engine's shaft.

The engine will idle normally and if pedaling is necessary with the engine off or running, the clutch will allow it.

You stop the engine with a kill switch or button that you install yourself. A few engines come with one all ready and you can wire up a handlebar mounted switch to it if you want to.

 

[locutus_1]

Like on the 2 stroke motors to keep the reliable does a 4 stroke need any modifications like a high quality hardware/ stud kit?

Which are more reliable between 4 stroke and 2 stroke motors and why? Which one would last longer?

Which has more power and/or rides faster?

i would upgrade every single bolt you have to a grad 8 or more and use lock tight on everything..

4 stroke last longer have les vibration dont have to mix fuel sound better not like a weed whacker you can run them all day 2 strokes you cant only for 30 minutes or less...

4 storkes are quieter not many mod options for a 4 storke.. but there is a better cam and carb.. and some headers thats about it.. rest is up to you..

 

[gera229]

i would upgrade every single bolt you have to a grad 8 or more and use lock tight on everything..

4 stroke last longer have les vibration dont have to mix fuel sound better not like a weed whacker you can run them all day 2 strokes you cant only for 30 minutes or less...

4 storkes are quieter not many mod options for a 4 storke.. but there is a better cam and carb.. and some headers thats about it.. rest is up to you..

30 minutes or less? In the 2 stroke section people report riding miles, long miles to work - about 30 miles everyday on the Chinese 2 stroke without a single bit of problem. And of course they say to break it in: do not ride it for longer than 30 minutes, but after it's all free.

 

[locutus_1]

30 minutes or less? In the 2 stroke section people report riding miles, long miles to work - about 30 miles everyday on the Chinese 2 stroke without a single bit of problem. And of course they say to break it in: do not ride it for longer than 30 minutes, but after it's all free.

yes 30 minutes max this is because its basically a weed whacker engine 2 strokes are hotter running than 4.. so idling isnt good 4 long

the 4 stroke are designed to run all day because they are utility engines ie water pumps small generators etc... the chinese make the 2 stroke under terrible conditions ive seen videos of how they r made terrible.. lets put it this way i bought one 40 miles later i was done bought a 4 stroke,,,but really the best thing is a harbor frieght motor and cvt tranny from a gocart place... if u really want power and quality