[400ex4ever]

Does any one know the difference in head pipe size from stock to say the HMF?

I have head that the YFZ head pipe stock is the same size as most of the aftermarket one's. That's why it respondes so well to just the slip-on. That got me thinking about the R head pipe. Any one know?

 

[fast]

PM hmf they may tell you

 

[kingofdunes]

if u are going to get an exhaust for the 450r I would go with the full system cause the stock head pipe is small compared to some of the aftermarket ones
just my .02