525 irs and straight axle engine differences?

[nacs697788]

Does anyone know the major differences between the ktm 525 engine that is in the irs model and the "s" models. The only thing I can come up with is that the polaris website does have different part numbers for the different models on the engine. I am building a "s" model and the irs engine seems easier to find. Thank you.

[brucealmighty33]

Hey, we have been racing the outlaws now for 3 years, and the irs engine will not fit into a straight axle chassis.

[nacs697788]

Allright, thank you. That is exactly what I needed to know.

[OutlawBill]

08, 09 ,10 450mx 525s and 525 IRS all use the same case

[brucealmighty33]

Originally posted by OutlawBill
08, 09 ,10 450mx 525s and 525 IRS all use the same case

An IRS does not use the exact same cases as a straight axle. I own multiple of both and i have tried to swap engines between them and they will not fit.

[OutlawBill]

Originally posted by brucealmighty33
An IRS does not use the exact same cases as a straight axle. I own multiple of both and i have tried to swap engines between them and they will not fit.
Part Number Part Description Quantity

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Polaris part # 1203731 Asm., Crankcase w/Bearing for all Outlaws 08, 09, and 2010. The 07 is different and the KTM is different

[brucealmighty33]

Well i've been working with polaris for a few years, helping develop the outlaw, and i've had conference calls with the race director, engineers, etc and i'm telling you that that is a error, one that we brought to the director attention and is being fixed. at the end of the day its your everyones own choose, but i'm just trying to save everyone some time & money.

[OutlawBill]

Originally posted by brucealmighty33
Well i've been working with polaris for a few years, helping develop the outlaw, and i've had conference calls with the race director, engineers, etc and i'm telling you that that is a error, one that we brought to the director attention and is being fixed. at the end of the day its your everyones own choose, but i'm just trying to save everyone some time & money.

thanks for the up date too bad there ATV race page sucks and is out of date.

[polaris bob]

Originally posted by brucealmighty33
Well I've been working with polaris for a few years, helping develop the outlaw, and I've had conference calls with the race director, engineers, etc and i'm telling you that that is a error, one that we brought to the director attention and is being fixed. at the end of the day its your everyones own choose, but i'm just trying to save everyone some time & money.



Instead of just saying that it wont fit, why not say what the difference between the two motors is !!! That way people will know what to look out for.

[OutlawBill]

Originally posted by polaris bob
Instead of just saying that it wont fit, why not say what the difference between the two motors is !!! That way people will know what to look out for.

My SWAG rear engine mount location the 450 and 525s have swing arms and IRS does not. There may even be a difference for the IRS between 07/08 and 09/10 due too chassis change