Oversize powervalve cover.
- Thread starter Todd5774
- Start date
case-racing
New member
power valve cover
what does an oversized cover do ?
what does an oversized cover do ?
Some oversize covers don't have the center bolt like the OEM one.
In this case, leave the bolt out.
HuskyDude
Super Moderator
Theory is it increases your bottom end power by increasing your volume of the power valve chamber. In other words gives a bit better throttle response down low. Good for real technical riding.
I put a Trusty cover on mine. Not really sure if it's needed on a 300 but the damn thing won't stall now.
widebear
Banned
I'm not a fan. Dulls your low end throttle response but fattens the torque a bit, great for guys with less than perfect clutch ,throttle control or who dont like crisp zippy power.
Trailrider
Member
Power Valve cover
The hole should be plugged or preferably a drain line attached. I used a zerk fitting with the center drilled out and added some tubing.
The hole should be plugged or preferably a drain line attached. I used a zerk fitting with the center drilled out and added some tubing.
Some oversized covers have a vent tube attachment at the bottom - some don't...
He is referring to the one in the center of the cover that goes "into" the cylinder - it's for a mounting bolt.
Adding a PV cover helps more or less depending on the pipe you use - given that it adds volume to the exhaust - adding it to an already large torque pipe like the fmf gnarley or fatty isn't as notice-able as adding it with a doma or messico pipe, etc.
It provides gain on bottom and doesn't effect top end - as this chamber is shut off when the power valves are open (high rpm).
Jeff
He is referring to the one in the center of the cover that goes "into" the cylinder - it's for a mounting bolt.
Adding a PV cover helps more or less depending on the pipe you use - given that it adds volume to the exhaust - adding it to an already large torque pipe like the fmf gnarley or fatty isn't as notice-able as adding it with a doma or messico pipe, etc.
It provides gain on bottom and doesn't effect top end - as this chamber is shut off when the power valves are open (high rpm).
Jeff
Dulls? nope,, adds bottom end by adding volume that becomes a non issue once the pv opens. Never heard of it dulling the bike down.. gives it more grunt. odd you say that.. On my 03 it was needed,, the 03 was very weak off the bottom,, I did the big cover, messico pipe and a cdi from an 01 300xc and it was good. Oh, and ltr jett and special reeds I got directly from the boysen shop down the road.
![trusty-big-volume-gas-gas-powervalve-cover-3260-p[ekm]432x300[ekm].jpg](http://www.sandifordoffroad.co.uk/ekmps/shops/sandifordoff/images/trusty-big-volume-gas-gas-powervalve-cover-3260-p[ekm]432x300[ekm].jpg)
swazi_matt
Active member
so by the looks of it you could just machine a spacer of about 10mm (like a 10mm thick gasket) and use the original PV cover for the same effect? Anyone able to do me a favor and measure the difference between the original and the oversized so that i know how thick to make the spacer?
I know when Les at LT-Racing looked at the design of his cover - he considered using a spacer instead of a replacement cover. The fins on the existing cover will protrude out further - and there is a possibility of the fins slicing the nearby coolant line.
Can you use a spacer? Yes.
Is it a good idea? No.
BTW, Les is my best friend. But, he is no longer making PV covers - so I don't have a "dog in this fight'...
Jeff
Can you use a spacer? Yes.
Is it a good idea? No.
BTW, Les is my best friend. But, he is no longer making PV covers - so I don't have a "dog in this fight'...
Jeff
Todd5774
Gold Level Site Supporter
The one i have bought looks a copy of the Trusty cover.
So being as there are differing opinions on wether the hole should be plugged or not can anyone tell me if leaving the hole unplugged will damage anything inside?
I am using a Dep expansion pipe which is great up top, almost gives it a motocross feel, but is lacking abit of grunt down low, compared to the messico pipe i was using before, hence the powervalve cover.
So being as there are differing opinions on wether the hole should be plugged or not can anyone tell me if leaving the hole unplugged will damage anything inside?
I am using a Dep expansion pipe which is great up top, almost gives it a motocross feel, but is lacking abit of grunt down low, compared to the messico pipe i was using before, hence the powervalve cover.
Make it the thickness of the existing powervalve cover fins. That way it does not stick out any further than the original cover.
today i have installed the TRUSTY Adjustable Powervalve Cover
damme,what a difference
on -6 drive like a 50cc 2 stroke with lots off torque,mount slowly to his rpm
on +3 when you hit the trothle ,bwaaaaaaaaap,lots off power,even more than a mx bike
amaizig kit for 100?(i was suprised for that price)
damme,what a difference
on -6 drive like a 50cc 2 stroke with lots off torque,mount slowly to his rpm
on +3 when you hit the trothle ,bwaaaaaaaaap,lots off power,even more than a mx bike
amaizig kit for 100?(i was suprised for that price)
twowheels
New member
today i have installed the TRUSTY Adjustable Powervalve Cover
damme,what a difference
on -6 drive like a 50cc 2 stroke with lots off torque,mount slowly to his rpm
on +3 when you hit the trothle ,bwaaaaaaaaap,lots off power,even more than a mx bike
amaizig kit for 100?(i was suprised for that price)
Deluc, where did you find one for that price? Enquiring minds want to know, because the last US price was in the $350-400 range I thought.
