lifan 138cc with irk and oil slinger

[ASR Rider]

wow this is a word war, its a great thread hahah, i got an irk like 6 months ago and i didn't put it on coz i have a ****** ducar, but i'm sure it would be fine to run with no slinger but the baskets are not designed to spin that fast. I just didn't put it on coz i am getting a 140. Having the IRK would most definatly free up Horse Power for obvious reasons like the engine doesn't need to work as hard to spin the stock stator and sling hence more power to turn the front sprocket, and also i agree with "no crf50 here" Purely Because he tries to help and u accuse him of "thinking he invented pitbikes", purely because he knows more than you or his opinion is different, seriously, And from my knowledge on the auto industry, what he is saying is mostly spot on...sorry to drag it out but some people need to grow up..oh and as for the answer to goodys Q: Worm Got It Right! pull the cover off and check that ****, if its smaller than the one in there now swap em if its not leave it...

 

[MasterSpoon]

From ducar gay spec




Dude you really need to stfu sometimes.

Brian from Maylands has repeatedly said you DO NOT NEED to run a lightened slinger.

www.mso.com.au!!!

sorry nothing at all to do with topic but if Brian from Maylands has said that why are you linking MSO's site to back that up?

 

[ASR Rider]

and that link is a dud.... it goes to melbourne symphanie orchestra....duh

 

[corey58]

yer irk kits free up the engine lettiing them rev higher and farster but u loss all your down low pull. to get the best combo i found meachineing down the steel slinger to the same size as the ally slinger give u the best all round combo giveing better revs and low down pull.

 

[michelin man]

yer irk kits free up the engine lettiing them rev higher and farster but u loss all your down low pull. to get the best combo i found meachineing down the steel slinger to the same size as the ally slinger give u the best all round combo giveing better revs and low down pull.

pretty good idea there mate

 

[themountain]

...to get the best combo i found meachineing down the steel slinger to the same size as the ally slinger give u the best all round combo giveing better revs and low down pull.

yeah...you got it Dude!!

 

[no_crf50_here]

I have half a dozen std slings here if anyone has lathe? I say lets try

 

[Dirtrider]

I mite give it a go just have to get a slinger and machine it down at work. I've got to replace the clutch and want to have a look at the shifter star to try and fix false neutral problem. So i will beable to do it all in one hit while the motor is out.

 

[ASR Rider]

i don't think it will work, i cud be wrong but i think it will just rev slower...which cud mean better low end but engines make peak power at a certain rpm hence why u install irk.... let me no what happens there i and keen to no, cause if it does i will do the same to my 140's one when i get it

 

[themountain]

here is a link how to do!!
http://www.miniriders.com.au/forum/tech-talk/14926-lightened-oil-sligner-2.html#post137919

 

[Mack]

IRK will not increase power, or change where power is made, allow to rev higher or any other performance increase. It simply allows the motor to accelerate (spin up) quicker.
You need to find the balance where you can have maximum accelleration on the verge of breaking traction all the time. So for example, a heavily worked engine has no trouble breaking traction in the dirt on one of these bikes with stock flywheel, so to have it spinning more by removing all crank weight is a waste and also loses stored energy advantage and smooth power delivery of a flywheel. So you add or remove crankweight depending on the rate you want the power delivered to make you faster round the track. If that track is tar then you will not spin and lose traction near as much so less crankweight can be greater advantage here. But you must balance it with less braking efficiency and traction out of corners. You want better lap times thats all.
A good dirt rider can use quick spinning motor by shifting weight forward into the burm, get the wheel spinning and the engine in its power range fast, then shift weight right back over the rear wheel and get power to the ground coming out. A lot of guys can't ride like this, but get sensation of having a wilder, faster bike with IRK, but really are just out of control and slower round the track. But hey they look good doing it with all that dirt going everywhere!

Now, as you increase power in your build, then obviously you have more to overcome resistance so the crankweight (feels) lighter to the engine. A good example is the yx150. They come with inner rotor cause some brainless dood in a factory thinks that is what everyone just wants, to make sales. Pitster and others are ripping them off and replacing with stock flywheels. Especially once they are built up. The power level of one of these built up big makes a stock china flywheel feels like inner rotor to it anyway. Build your engine to where you want it first then decide on inner rotors or reducing/adding crankweight after you ride it. If you want to lose some weight, shaved flywheel and spinner is the best place to start.

 

[Mack]

I would add too, that i suspect that some if not all the broken cranks you see are a result of flywheel shaving or unbalanced rotor kits. The flywheel shaving was big before china rotor kits and what I have never seen mentioned is that you will notice each flywheel has been balnced with drillings into its outer surface. After shaving these are mostly gone. Some are drilled twice. So put some thought into what you are doing...its not always easy to find someone to rebalance them. Be aware you may be putting it back on unbalanced. I will not shave a wheel with multiple drillings, find one with smallest drilling. Also I try to take some weight back off the drilled location. Then cross fingers. once you have one that is running sweet in an engine over time at revs, hang onto it!
If you sell the bike pull it and put back a stocker.