04 CR250 RC Powervalve Adjustment

[robm-951]

Hi Everybody,

I recently re-adjusted the powervavle cables on my 04 CR250 following a prodecure where you adjust the bottom of the rear cable adjuster 12mm above the butterfly.

Previously I had the cables adjusted correctly according to the factory manuals with very little cable slack.

What a huge difference this made on my bike (I already had the V-Force 3 and a JD jetting kit). Much better throttle response and overall much stronger feeling.

Now onto my questions:

My bike has never had a stop pin where the valve butterfly would stop against like the factory manual discusses, but there is a hole for one. Has anybody else seen this or do you guys actually have a stop pin pressed into the cylinder?

With the cables adjusted per the manual, the cables would pull the butterfly all the way against an internal limit (just past the hole where the stop pin would go). Now, the butterfly doesn't go to that point anymore and is shy of reaching the hole where the pin would go. Is this correct?

And finally. Has anybody tried different setting desides the factory manual and the 12mm procedure? Who came up with the 12mm procedure anyway?

Sorry for being long winded.

Thanks,
Rob

 

[SQUIRLEYMOFO]

Saw that earlier thought I would try it this weekend. On a side note my brother-in-law has a CR450F and has been talkin' smack about how much faster his bike was. Let's just say he won't be braggin' as much after this weekend. I rode his he rode mine.........something about him landing on his azz during a 4th gear wheelie.

 

[robm-951]

Yeah, my buddy's got one as well. There nice, but feel heavy to me. After trying out my bike for a while, he added an 06 YZ250 to his stable. It's a nice bike with awsome throttle response.

 

[Faded]

My bike has never had a stop pin where the valve butterfly would stop against like the factory manual discusses, but there is a hole for one. Has anybody else seen this or do you guys actually have a stop pin pressed into the cylinder?

There is a steel stop pin that is pressed into the cylinder.

With the cables adjusted per the manual, the cables would pull the butterfly all the way against an internal limit (just past the hole where the stop pin would go). Now, the butterfly doesn't go to that point anymore and is shy of reaching the hole where the pin would go. Is this correct?

The "internal limit" is the edges of the exhaust valves resting on the exhaust port floor. It is possible that the 12mm adjustment pulls all the slack out of the cable keeping the exhaust valves from completely resting on the exhaust port floor. Weather or not this is 100% right on your bike is hard to say, maybe experimenting in 1mm increments up and down will help you arrive at a more desirable setting.

And finally. Has anybody tried different setting desides the factory manual and the 12mm procedure? Who came up with the 12mm procedure anyway?

I stopped toying with my mine, the 12mm adjustment had a positive effect and I left it there. Henk Jager is the originator of the 12mm adjustment and it's outlined on his site:

http://www.he-ja.nl/hejatips-brits.htm

 

[robm-951]

Thanks Faded!