IRK or Flywheel Bike? What do you recommend for me

[Ricos]

Hey guys,

Im wondering if someone could shed me some more light in regards to IRK engines compared to the flywheel engines.
Basically im looking at a 150cc engine with a IRK but after doing some research there seems to be a big uproar about the engine stalling HEAPS (due to the IRK kit)

Of course this is not a good thing and a stalling engine on a brand new bike is the last thing that i want. Is this stalling issue a "real" problem or is it something that happens "occasionally" and not very often ? Once you get used to it, will you ever stall it?

The choice i have to make, is whether to get a 150 IRK engine or a 160 engine with a fly. If you were to line the two up together (150 IRK vs 160 Fly) who would win? Does a IRK mean less top speed? Is there much of a difference? Do engines with a flywheel still give you the "wow thats fast" factor as an IRK will when taking off in a hurry?

I will be doing all my riding on farms and trails.

I am really stuck and i dont no what engine to get!!! HELP!!

Thanks in advance

 

[xb80]

the iner roter kits only stall if u dont give it unuff throttel if u whant a nice cruise bike that u take of slow than get a fly wheel if u whant a bike that takes of realy hard and revs really quick than get an irk they only stall if u take of to slow irks are manly used 4 racing but can be run 4 every think both my bikes have irk and i use them 4 every think once used to it its not a prob lol.

 

[duff_boy]

Flywheel mass does not affect engine power output. All it does is affect how quickly the engine speed changes. Ie, less load on the engine means that it revs up(accelerates) faster when you blip the throttle, also means that engine speed drops faster as the engine has less inertia when its spinning. ie. when you pull the clutch in, let the throttle of and change gears etc. This can obviously make it harded to take off as well.

Lower flywheel mass might make the bike feel "faster" but it certainly doesn't add any power to the engine or increase actual acceleration of the bike. Just changes the way the engine reacts to throttle input.

 

[Cactus Jack]

The weight of a flywheel helps keep a motor turning over without stalling at low speeds and at idle ... it also helps to stop kick back on starting .... Also flywheel weight gives an engine more guts on take off and more power for climbing hills , stop start and stunt riding .... An engine with a heavy flywheel is harder to stall because once the flywheel is spinning it's also harder to stop it from spinning ....

A light flywheel gives quicker response ... but only if you slip the clutch more on take off and keep the engine revving in it's torque curve at all times thru the gears ... and in the right gear ...

Drag racers actually use a heavier than stock steel flywheel to help launch better off the line and also to help keep a big cammed engine from dropping "off the cam" and in it's ideal power band on gear shifts with a wide ratio transmission ...

Picture flywheel weight as being the hammer head on the end of a sledge hammer handle ... IF you swing the hammer with all your might at a brick wall , the weight will smash the bricks and you won't feel much jarring thru your hands ... but if you took the head off the hammer and did the same thing , chances are that you'd either snap the wooden handle or it would stop dead and you'd jar your hands and they'd hurt ...

The same thing happens in an engine ..... only the handle and hands are the conrod and piston ... which get loaded more because they have to do all the pushing without the inertia of the spinning flywheel weight to help ...

In industry , a small electric motor is used to turn a huge flywheel and the flywheel inertia is used to drive punches thru thick steel ... If the electric motor was used on it's own , it would stop dead in its tracks and probably snap the shaft after a few failed attempts ...

For trail riding and general play racing , hill climbing etc ... I'd go for the 160 with the flywheel ..... I think if you could talk to the manufacturer of the bike he'd give you a very , very sound reason why they have abandoned the IRK's used in the 150's and gone with a flywheel in the longer stroked 160's ...

If you feel you need more response and acceleration than the 160 can give ... then your best bet would be to fit a Lifan 150 or Daytona 150 style ORK ignition .... They are a sensible compromise in between a heavy stock flywheel and an IRK ... and that means reliability as well as rideability ...

Most people would learn to get used to riding a 150 with the IRK ... but a hell of a lot of people HATE how the bike behaves with them ... and IF you're a heavy rider .... DEFINITELY go with the 160 with the stock type flywheel ....