LTR power valve cover
 

Hey guys, I have a new EC300 and was interested in trying the LTR power valve cover. The bike has a GG pipe on it, not an FMF Gnarly or Fatty. It makes good bottom end but I can use a bit more.

Anyone here have any input on the LTR cover on the 300 running the GG pipe? I believe Messico makes the stock pipe from what I've been reading.

Here's what "101 RACING" did to get more bottom end power from his 300:
For those of you who have been asking and wondering about the power valve timing adjustability , we have finally discovered what it takes.
We have been doing an on going search for the difference in power between an 06 DE 300 and a 08 EC 300. The 06 was bought used from a bank repo from a dealer. The 08 I bought new. We had the 08 before the 06 and when we got the 06 home and got it jetted for our altitude we realised it was a way different power delivery than the 08. We went for over a year trying to match port timing and compression only to make minor improvements to the 08. We finally realised that the rain sunshine switch was faulty and bipassed it at the CDI and that made a big difference but still didn't have the knarly off idle torque the 06 has. We started suspecting PV timing from our experience with KTM 300s. We ordered 2 sets of clutch cover gaskets along with water pump gaskets from Gofasters. We pulled the clutch side off of the 06 and discovered no shims behind the PV governor spring. This takes away preload and rate from the spring and allows it to open sooner and faster. We then pulled the side off the 08 and removed all the shims. The power delivery is now exactly like the 06.
The shims are very thin and we were apprehensive about whether removing them would make that much difference but it definatly worked.
As a side note there is pocedure that we discovered that works pretty well to disassemble the governor. Lay the bike over on its left side so the governor balls don't fall out all over the garage floor. When re-installing the governor balls, we just layed them in the cup and spun the cap until they all fell into their individual slots . It takes a little patients on this part and it helps to have a small ice pick to reach in and position some of the balls in there slots as you rotate the cap.

How did this affect the top end and over rev?

I installed Trusty Power Valve cover and just love it. It really help the bottom end. Not that the 300 needs any help.:D It good to have a little extra in the technical sections or big switch back hill climbs.

Im curious as well. How does this affect top end. I have heard alot about the power valve covers but I dont want loose the hit and top end.

Thanks for the info on the powervalve spring shims. So you guys are saying that by removing the shims, the spring tension is less, allowing the valve to open up sooner than it would with the shims in place?

Are you also talking about removing the entire clutch side engine cover, water pump, impeller, shaft and all to get to the spring?

Are there any other springs, like on the left side of the cylinder head or under the powervalve covers that can be modified instead of taking the side case off?

I want the bike to remain smooth during the transition onto the pipe. If by changing the opening time/rate makes it hit harder I do not want this. I ride the bike in rainy mode map position most of the time.

It is not as hard as it sounds to take out the shims.
If you can do a top end job, you could do it....

I did and got exactly what I wanted, more off idle grunt - a lot more !

If you have a good single-taper carb needle, like a CCK, it will be controllable,
too ! Not a wild hit, but more immediate, but still smooth, power off idle.

Same top end as the power valve ultimately ends up in the same place.....

Many thanks to Racer101 for the investigation and tip !

Jeff in Tahoe.

I think there were people on here referring to the PV cover and how that affects top end and over rev.
The PV cover makes no difference to top end or over rev, as the PV chamber is closed off when the PV opens.

Thanks guys.

Would this combo be stronger on the bottom?

CCK needle
LTR power valve cover
Remove the power valve shims
GG stock pipe

I don't ride the bike 100 mph, mainly light motocross outdoors, woods and a little street to and from thrown in. I don't race, I just wanted something very smooth, but with enough grunt in the lower revs. Over rev is my last concern, I love to lug.

Or how about this:

CCK needle
LTR power valve cover
Remove the power valve shims
FMF Gnarly
RB squish mod
Thinnest base gasket
RB carb mod

The Messico and stock GasGas pipes can't be beat on a 300 IMO. Other pipes can give you a stronger bottom end but always at the expense of the top end. Thinner cylinder base gasket and removing the powervalve shims may give you all you want but if you still want a little more the RB head mod is less than 100 bucks and worth every penny - better performance, better fuel mileage, and easier jetting.