Performance Modifications by Dynobike
Want to make a fast bike go faster? The WR450 in
this example was an 03 model all stock other than a slip on muffler.
On these bigger bikes it’s very import that you make sure
the crank will stand up to the work load, if in doubt rebuild the bottom
end and you won’t have to worry. So having checked that, remove the
stock piston and replace it with a Wiseco high comp forged piston.
Give the bore a very light hone and carefully fit the
new piston in the barrel... easier said than done.
The tricky bit’s the head, like the 250 it’s a fine line
between success and total failure so we spend a bit of time carefully porting
and flow testing to ensure it doesn’t become scrap metal.
Once we’ve got what we’re looking for, the seats are cut
and valves are seated and the whole thing is assembled. At this stage if
you’re the competitive type measure up the clearance between piston, valves
and head, if there is sufficient clearance you can squeeze some more compression
into it by removing the middle section of the gasket. I don’t recommend
this unless you have rebuilt the bottom end or it’s a new bike. After some
tuning on the dyno here’s the result: 52hp.
What it costs*:
Wiseco piston kit $190.00
Port and flow head $395.00
Gaskets $150.00
Strip and assemble $295.00
Dyno and tune $195.00
* Prices are subject to change without notice
Article on WR450 Engine Rebuild |
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