'03 200 Powervalve cover
 

Hey guys,

As most of you know I have an '03 EC200. I love the bike to bits but i find its lacks a tad in the bottom end (like most small bore twos trokes do). I can't really loft over logs in tight singletrack and its hard to get up into the meat of the power on hillclimbs and again in the tight stuff.

I've got a 13T front sprocket and 50T rear sprocket, which im going to change to a 52T next time im due for a new set but im wondering whether an LTR Powervalve cover will get me that bottom end torque im looking for. e.g. will i actually notice it.

I've also got to learn to ride the bike higher in the rev range but its hard to get it there at the moment. So my theory is, more bottom end will help me to get to the top.

What do you guys think, will it help me?

Have you an additional flywheel weight on the bike? Having one can, on smaller motors, result in a slight delay that can make life difficult.

Alternatively just try giving a dip of clutch with a blip of throttle just before the log (about the same distance from the log as is high). Ditto for getting up hills, just slip the clutch a tad.

The gearing could also negatively effect things but I don't know the std gearing for the 200. In standard form the 200 should have no problems with the challenges you've described.

Bottom end is usually at the expense of top end. Improving the bottom end of the motor will negatively effect the top end. Good riders rarely rev the nuts off a bike and will usually be riding 1 gear higher than most other riders so getting the bike in the upper rev range isn't neccessarily a good idea.

I'm afraid I'm probably not much help but I rode trials for 15 years before riding enduros and the trials experience helped enormously with those sort of obstacles. To put it bluntly, I don't think it's the bike. It might be an idea to spend some time with a good enduro rider or a trials rider. Sorry if I'm being patronising but I don't have any idea about your abilities.

Have a great '08.

Yeah, i can loft the wheel over logs in first but not in second which is where i like to ride in the tight stuff.

And thanks, happy new year to you too and everyone else

Ah! Slip the clutch in second. As per description above.

Just had a look at your homepage. It make sense now. Lemmee guess, this is your second bike, the first was a KX80/YZ85? Don't worry, it'll come. Riding with a couple of older and experienced guys will help heaps. Those fat old farts (I'm one of 'em) can ride the tight stuff. A couple of rides with them will help you plenty. You might end up liking them too.

Hey Ben, you got any fires down your way? There was a story on the news this evening about some fires in Aus. Apparently three truckers burned to death.

Check out these vids: http://www.gasgasrider.org/forum/showthread.php?t=1483

Great guess. It is my second bike, first bike was an '06 CRF150f which my sister has commandeered now.

I ride wiht ym two uncle's, one on an '07 WR450f and one on an '06 GasGas FSE450. My dad rides too, he has the old '89 TT250. There's one more bloke i ride with who used to race locally with some pro guys. He used ot have my bike but now he has an 07 EC300

I know it will come eventually, i was just wondering if it will help me out.

No fires yet, dads a fire fighter locally though so ill find out soon enough if there is. I did hear about those truckers but i thought that was in WA, still pretty rough.

Thanks

We put an LTR Power-valve cover on my son's '05 EC200, and it seemed to help the bottom end response noticeably. Are you cleaning the left side
PV bearing and the area behind the cover regularly? This routine item seems to help the off idle response and the bottom end at least as much as the aftermarket cover - so much so, that we've
been pulling the cover and cleaning the PV after almost every ride (we use a little mineral spirits or WD-40 and a soft bristle brush and just scrub the whole thing very thoroughly). I'm not sure why this helps, but my theory is that the carbon deposits tend to gum up the PV bearing, thus slowing or retarding the action of the PV.

Also, how's your jetting? Our bike was four sizes too rich in the pilot, rich in the needle and lean in the main compared to the jetting we currently run
(#42 pilot, LTR #1 needle; clip in the middle position (very close to an NOZF) and a #180 main - but we're riding pretty much at sea level). After we got the jetting worked out, the bike pulled stronger everywhere.

That's interesting about PV cover. (since I don't know what exactly that PV does any way!) I'm on EC250 that has seemed to have lost just a bit of off idle response I am going to try cleaning the PV. Is there a gasket there & if so should I have a new one on hand before I take off the PV?
Thanks

A fresh exhaust repack helps the low end crispness as well.

Paul B

Power valve covers: the power valve cavity acts as a resonant cavity (as does the expansion chamber), the bigger the volume the lower the frequency (RPMs) for which the engine will be tuned. The pipe is also tuned for a particular frequency. That's why pipes on 250's are longer than those on 125's. They're tuned for lower rpms because 250's are lower revving than 125's. The power valve effectively adjusts the volume of the power valve cavity. So the entire system has one variable tuned cavity (power valve) and one fixed tuned cavity (pipe). If you're an electrical engineer it's like having two tuned circuits. Whether in parallel (which I suspect) or series I don't know.

I've always worked on the principle that the bike is almost certainly better than I am so I adjust my riding technique to suit the bike.

The jetting's great. I'll definitely give the cover a clean out, that sound sliek a good tip. The muffler packing was replaced about three rides ago so its all good.

I'll have a go at cleaning the cover and see if it makes much of a difference.

Thats a good prinicple to work by Tim, ill have to try it myself

Thanks for all the input.