***Inner Rotor kits/CDI's***

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Dreamah

Dreamah

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Hiya Guys,

Thought I would through this one up as So Many "New comers" hear about CDI's & Inner rotor kits, And in Many new riders eyes they Seem like "The Best First Mod" (IMO)

Anyway, Obviously Most bikes are all Different, Some would benifit from A IRK & CDI ...

As Im reasonably new to Motards My self, Im Wondering If its worth Wacking a IRK on My MotoVert Expert, I Took of the Magneto Cover, And Without Taking the Magneto Off, It Really Doesnt seem that heavy..

"Would it be worth it, Or should i focus on something Else"


If anyone Can Shed Light on Other bikes, IE: PitPros, Thumpys, MSO Anything.. I think it would help some of the Less aware . . . .

Cheers Dreamah
 
They are a lot heavier than they look, irk would be at least a 10th of the weight.
and has been proven to up the acceleration rate dramatically.
 
i think the rotor in an irk is a little bit too light, you lose too much speed going up hill... but the extra power is worth it
 
Irk/cdi

Hi Bud :)


I have just fitted an IRK/CDI kit to my PITPRO 140.
And i can assure you bud, the standard magnito is quite heavy.
Once you have taken it all off, you can feel the weight of this lump of metal.
The new IRK KIT makes throttle responce excellent.
My person opinion, it's a good cheap mod.

Cheers

Marty :) :)
 
with an irk you loose the momentum of the engine and therefore do sometimes suffer going up hills but you can overcome this by revving it more and keeping the revs higher
 
I did the IRK and oil slinger on my
MSO Elite with the 1P55FMJ 140 motor and it was a little disapointing to tell you the truth now im not sure if its because i weigh 95 Kg or what but you definently loose a great deal of tourqe but im sure if you smaller and dont weigh a heaps like myself it might be the way to go Just my thoughts but i would still do it if you have the cash O and the fly wheel and oil slinger do weigh alot more than you would think that is for sure
 
Hmm Maybe I should Wack a Pro Ciruit Pipe on there.. I dont know at the moment.. Will try few different things to get it hammering abit harder..
It Goes pretty Bloddy well now :D REally need to start Saving for new RS 125
 
pumba said:
What do you mean loose speed?

With the irk dose torque suffer?
Click to expand...

If my understanding of an Inner Rotor Kit is correct, it is essentially a lightened rotor. The rotor attaches to the crankshaft etc etc etc.

What happens when u reduce weight on the crankshaft? You lose torque. If you've ever heard someone talking about putting a heavier flywheel on their motor, they are looking for increased talk at a trade off of quicker reving. I could give u an engineering reason for it all about the polar moment of inertia of the flywheel but who the hell wants to read that. Its a simple formular, heavier crank = more torque, lighter crank = easier revs.

The other trade off of putting an IRK on your crank is that if u keep your oil slinger as standard...the crank is going to be unballanced. This will cause vibration in your engine and eventually lead to bearings wearing out and lots of other detrimental things.

Anyway, hope this helps u out a bit

Matty
 
Ahhh.. lets think about what we're talking about here. The rotor is a weight ont he engine spinning. Lighten the rotor and the engine will spin up quicker, but doesn't actually effect the power or torque output of the engine! It makes it quicker to accelerate and decelerate it's speed. That's IT!

Great for motoX type bikes which need instant power, crap for road bikes and cars that want smooth ride.

That's what an inner rotor kit is.

NOW, if we're talking the ignition, this WILL effect the output of the engine.

But that's another story :)
 
if your engine is spinning up faster, its doing more work and thus making more power.
 
On a dyno you would see exactly the same hp figures at any given rpms from the same engine with and without lightened crankweight. But if you timed how long it took to get through the rpms the lighter crank engine will obviously get there quicker. The heavier crank once spinning has its own inertia energy and will help the bike through rough and sloping terrain. This same energy assists with starting and low speed riding as well. Basically makes the bike a lot more tractable. I personally prefer to shave the flywheel and slinger for a compromise between the two extremes. Cheaper too.

The whole out of balance fear also is baloney. For a start single cylinder engine cranks are built out of balance to counteract the rod and piston forces which are acting in a single direction from the crank. A thing called the 'balance factor' is determined by the factory and the crank set to this. When you get a new piston installed which is different than the stock one then you can have your crank 'balanced'. This is merely returning it to the original or a desired balance factor. When you are talking about weight on opposing ends of the crank it is a totally different story. You could run a balanced 10kg weight off one end and still retain the original 'balance'. What you would get though, is extra twisting forces on the crank. Every now and then the twisting force fear comes up too, but what do you think happens when the gearbox and clutch are engaged under full power on only one side of the crank.....
 
well said mack, ive been running just an irk for a while now and havent seen any probs but im interested as to how a lightened slinger would go
 
Dreamah why dont you go and bye the 140 lifan motor from DHZ and put the head off it onto the jailing block boar out and resleve your boar and put bigger piston in you can get the piston and sleve from http://www.akunar.com/
there real cheap and great to deal with and the lifan will only cost $300 and has a higher lift cam and bigger valves the your slock head well just and idea anyway
 
From reading this thread my understanding is that the inner rotor kit will give the engine gains everywhere except when climbing a hill.
Assuming that I am right because I will be using my bike for motard (98% flat road) this would help me a great deal.
Do I understand right? Correct me if I am wrong.

One more thing. Are any of these good?

eBay Australia: 110/125cc INNER ROTOR KIT (item 230117166862, end time 19-Apr-07 09:20:21 AEST)
eBay Australia: Mini Dirt Bike High Performance INNER Rotor Kit for 125 (item 270109352180, end time 17-Apr-07 21:25:53 AEST)
eBay Australia: NEW KITACO CLONE INNER ROTOR KIT CRF50 ALL PITBIKES (item 230115514475, end time 15-Apr-07 21:30:00 AEST)
 
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