power valve rattle not chain slap

[GMP]

Noel,

If they are all in the same low position it sounds OK. The governer must be able to return to its relaxed position, this should be somewhat obvious. If a ball is dislodged, yes, you can compress the spring slightly and manipulate them back into position with a small screwdriver.

When you do the adjustment I described, it is important that the governer be pushed STRAIGHT into the case, as without the side cover there is no bearing to support it. Its eaiser to get it right the first time if you have someone to help, as its a PIA to hold the governer straight and slightly compressed and tighten the setscrew.

[Noel]

Originally Posted by GMP

Noel,

You have one of two problems, both require removal of the side cover. After the oil, coolant is drained and the cover is removed, you need to verify that the PV governer balls are not displaced and jammed, as this will prevent the PV from closing. This is usually caused by pulling on the actuator rod with the engine off, manually moving the governer and allowing the ball(s) to fall out of position. If this is the case you can manipulate the governer to reseat the balls.

If the governer is OK, then the position of lever #6 on lever axel #4 must be adjusted. Loosen setscrew #5, fix or hold the actuator plate to the stop bolt, and while pushing the governer assy straight into the case with a grip that will put just a slight preload on the governer spring, tighten setscrew #5. Its eaiser to jam the actuator plate against the stop with something unless you have a helper to hold it there. Its obvious when you have the side cover off. The idea is to provide just a slight preload (closed) to the mecanism by the governer spring. You may have to do it a couple times to get it right.

I'm sorry about no photos, but this PC has some USB system issues and my thumbdrive with the photos takes a very long time to be seen by the system.

Hi Guy’s

Finally went for a ride on Sunday after adjusting the power-valve by putting preload tension on the lever as per Glenn’s instructions. No more major rattles, as Glenn mention it did rattle a tad but it was of no concern.

This was a very easy process to carry out.

Special thanks to Glenn for his informative technical support on this issue and many others I have read in this forum

[rpduc]

Glad you got it Noel. I empathize with you on the rattle "doing your head."

I thought the new top end fixed mine. The new top end did eliminate a rattle I picked up at idle and I assumed it was the source of the "lugging" rattle but...
I had two good days of hard riding this weekend and the "other" rattle is still annoyingly there on occasion.

The preload on my actuator rod is minimal so I think I'll also try tweaking mine a tad per Glenn's instruction and see what happens.

Thanks for your report.

[101racing]

We have an 06 and 08 300's. The 06 has very little preload on the powervalve. The 08 had quite a bit more preload. We found that it is easy to slighty bend the actuator arm to adjust the preload. I always liked the 06 power characteristics better than the 08. We always thought that the powervalve opened sooner on the 06 for the reason of the power difference. I recently bent the actuater arm on the 08 to resemble the preload on the 06.Now the 08 runs very close to the 06. We have no noticable power valve rattles in either bike. I don't no if what we did is proper but there has been zero problems.

[enstanka]

I always liked the 06 power characteristics better than the 08

Since I have never ridden any other EC300 than my own 08,
I am very curious on the power caracteristics before and after your modification to your 08.

i.e how would my engine change in feel if I increase the PV pre load?

//

[GMP]

Bending the arm is not the best way to do it, there is an internal adjustment fot that.

[101racing]

Originally Posted by enstanka

Since I have never ridden any other EC300 than my own 08,
I am very curious on the power caracteristics before and after your modification to your 08.

i.e how would my engine change in feel if I increase the PV pre load?

//

I know this is a deceiving subject about powervalve timing but I will give you my opinion. On a modern KTM 250/300 with optional power valve springs RED/Yellow /Green the power characteristics change . Red is the weak spring and the power comes on early and strong. Green is the stiff spring and the powervalve opens real slow. When I rode with the green spring I only got to the mail box and turned around and put the red back in. I would describe the the power of the 06 GG like the the red spring in a 300 KTM and the 08 GG as having somewhere between the red and yellow spring on the KTM's.
If you look at the parts break down on the GG web sight under (water pump) you will see differences in preload washers behind the governor springs for the powervalve from 06 to 08. The are apparently different rate springs also.
Back to shortening the powervalve rod and putting more preload on the powervalve , this would slow the powervalve opening and give a softer bottom to mid transition of power. The 08 stock was mild bottom and early mid power and hit later on in the mid to upper range. the 06 has always had lots of low mid power and with the 08 rod adjusted with less preload it has similar power to the 06. We also pulled a 5 mm base out of the 08 , opened up the back intake port and gasket matched the transfers on the crankcase and cylinder.The powervalve itself needed some clean up also.
The 08 has an RB carb and now that I lowered the float some it has been working very well, I will soon send the head to Ron to work the magic on it also.
Overall the 08 rips hard and is very nice for real slow trail work also. The 06 still has a little better lower mid power but it won't when a drag race.Stop and and go its faster than the 08. The chassis seems better on the 08 .

[GMP]

There may be differences but there not documented accurately. It would be interesting to measure the spring rates and lengths, and the preload shims. Talking strictly about the springs and preload, preload should affect when the PV starts to open, and spring rate affect how fast it opens relative to an increase in RPM. Same as suspension.