'12+ WR450F: Should I install a Heavier flywheel?

To the original poster.......

I hate asking the obvious....... but why are you trying to learn to ride on an open class bike?

As with all of life.... you need to get your priorities sorted first.

Very interesting topic.


I'm a reborn rider as well.  I rode 2 strokes back in the 80s and bought a WR450F last summer.  My rides too typically have some big, tough hills.  I too had some stalling issues.


The first part of the problem was that my bike was running way too fast.  It was idling at about 2500 RPM.  My friends bikes would run way slower than mine.  My bike was a lot better once I got the idle set correctly.


The second part was gearing.   My bike came stock with 14/50.  I dropped that down to 13/52, which I love.  This makes 1st gear a true stump puller and makes 2nd and even 3rd gear a lot more usable on hills.


The third part of the problem was the clutch.  The stock clutch is pretty vague.  I upgraded to a Magura hydraulic unit, which has a lot more feel.  You don't realize it until you spend some time in tight conditions how much of a difference it makes over the stock cable unit.


The 4th improvement I made was the exhaust.  I replaced the stock muffler with an FMF Quiet Core.  It made the engine much more responsive.


As far as the flywheel goes, I lightened mine significantly by removing the starter drive gears.  It too made the engine much more responsive.  In my mind that makes it easier to control because there is less lag between asking for more power and getting it.


As far throttle control goes, I don't find the WR450F to be difficult to control.  In fact, I find it to be a big teddy bear.   But then I grew up riding 2 strokes, with their hit and miss powerbands.  This was in the pre tunable exhaust port days. 


I will say this though... last year the engine braking of the WR450F totally threw me off in difficult conditions.  Even though I hadn't ridden much in 20 years, I was still used to the lack of engine braking that 2 strokes have.  Still am, as a matter of fact.   And in technical terrain, my instinct is to back off the throttle and coast through the tough section.  Which totally doesn't work on an WR450F.   I find the WR450F needs more clutch control than a 2 stroke but for very different reasons.   A 2 stroke needs clutch work to keep the engine on the pipe.   The WR450F needs clutch work to control the engine braking, especially on uphills.  Its the number 1 thing I need to work on with my riding.


The other thing that causes flame outs is riding too slow.   Its really easy to get in the habit of riding slow and lugging the 450 because it does it so well.  Unfortunately, if you ride too close to that line, it can flame out.  The best advice here is to simply ride faster and/or with more RPM.  And pull in the clutch when you want to coast through a section.


I have thought about putting a Rekluse on it.  My friends have Rekluses on their 4 stroke bikes. I've ridden them.  They make things much easier, especially on big climbs where you need to back off the throttle to get back in control and then hammer it to get your speed up to make the climb.  But I'm pretty sure that with a bit more experience I'm not going to be having any problems.


I will say something about Rekluses.  They are a pain in the butt if you ever stall the bike on a steep section.  The rear wheel freewheels when you least want it to.  The other thing I don't like about Rekluses is when wheelieing.  The cut in point can be a bit vague and it seems to change a bit as the clutch wears in.  And you lose the engine braking that brings the front wheel down when you want to control it, if you let the engine RPM fall a bit too much.  And Rekluses always seem to need maintenance. 


I haven't tried a different idle mixture yet.  I bought a Chinese Yamaha tuner box clone and I intend to richen the idle up a bit.  I think that will help with flame outs as well.


One REALLY nice thing about the WR450F is that it generally starts first kick when it does flame out.  In contrast to my friends bikes that need a kicking marathon.


As far as adding slack to the throttle cable, beware that the throttle slide needs to be in a fairly close range (not totally closed) for proper starting, especially with eStart.


If I was going to change the throttle cam in my bike, I'd probably go with a faster one.  I think it takes too much twist to go from idle to WOT.

Edited by MidlifeCrisisGuy

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