ASK THE MXPERTS: SWAPPING KX450SR PARTS OVER TO A STOCK KX450

SWAPPING KX450SR PARTS TO A STOCK KX450

Dear MXA,

Can I switch cylinder heads on my 2022 KX450 to the one from the KX450SR Special Racer? They have different part numbers. What are the differences? Plus, is there any benefit in getting a KX450SR exhaust system or the KX450SR ECU?

You are not going to like our answer. The KX450SR’s intake tract is ported and polished to a bright, shiny finish (and this is why it has a different part number). The SR cylinder head retails for $785. You could have your stock KX450F cylinder head’s intake tract ported and polished for a lot less money. The KX450SR comes with a Pro Circuit Ti-6 Pro titanium exhaust system. It retails for $1270 from Pro Circuit, and it does add power, and by the same token, it would also add power to your 2022 KX450. You might want to consider buying a stainless steel Pro Circuit T-6 KX450F exhaust system. It has the exact  dimensions and horsepower numbers as the Ti-6, but the only major difference is that the T6 is a little heavier than the Ti-6. However, it is $280 cheaper. MXA did exchange the stock 2022 KX450’s ECU for one from the 2022 KX450SR, and there was a significant boost in throttle response and power, but the black box from a KX450SR retails for $680. It would be much cheaper to send your stock black box to Twisted Development and have them remap it for half the price.

ASK THE MXPERTS: SWAPPING KX450SR PARTS OVER TO A STOCK KX450 Motocross Action Magazine.