PV conversion Honda flapper?

[Tom250]

i open this thread as i read about the older gasgas 300 have way more torque than the newer ones, before 06, as they have a different powervalve flapper wich isnt available anymore from gg. member gassi mentioned he maked a change to a honda cr250 flapper with the result of way more torque, and im always after more torque
im on a 13 300e with as II 38mm, nedj needle #3, 38 and 175 jets. bike runs good and lugs down really well. squish is at 2,2 wich i want to leave because of sometimes very poor fuel quality.
what gassi mentioned is the honda flapper stays 1mm lower in the exhaustport with the result of more torque. my thought is about to modify either the stop-allen-screw or the actuator plate, to make the standard flapper stay more low in the port. as i did see there is a lot of room for the stadard flapper to stay more low in the port as i dismounted the actuator plate, he shouldnt touch the piston in any case, constructionwise.
before i try to mess around there, i wanted to ask if anybody have any experience with that, maybe somebody have done this. i was searching in the forum but couldnt find an thread wich is mathing this subject.

 

[Jakobi]

No experience tom, but like you I have wondered about modifying the actuator plate, as there potentially is much more room to have the pv sit down in the closed position. You'd have to pull the rhs engine cover and make sure that the governor throw out will have enough range to still completely open the PV, but other than that I can't see why it wouldn't boost the bottom end grunt.

 

[Tom250]

i did a modification on the stop screw were the actuator plats sits on in closed position. i didnt mesure but from what ive seen through the exhaust port i would say the flapper stays about 1mm lower in the port.
the bike works way better now at very low rpm. sometimes it happened that at very low rpm in a tricky uphill the power just left and bike ran out of power. this is completly gone now! my impression is also the torque over the complete powerband, until the point the valve opens, is grown significant! also the sound in the pipe changed a lot, its difficult to discribe, maybe its more grunty now not so tingeling anymore. in low rpm its so quiet now, if i pass a other rider he just sees the smoke out of the muffler but cant hear the bike running. i will post a picture the next couple of days from what i did to the screw. if anybody wants more torque, thats a cheap and fast way to get!

 

[zeuszuki]

i did a modification on the stop screw were the actuator plats sits on in closed position. i didnt mesure but from what ive seen through the exhaust port i would say the flapper stays about 1mm lower in the port.
the bike works way better now at very low rpm. sometimes it happened that at very low rpm in a tricky uphill the power just left and bike ran out of power. this is completly gone now! my impression is also the torque over the complete powerband, until the point the valve opens, is grown significant! also the sound in the pipe changed a lot, its difficult to discribe, maybe its more grunty now not so tingeling anymore. in low rpm its so quiet now, if i pass a other rider he just sees the smoke out of the muffler but cant hear the bike running. i will post a picture the next couple of days from what i did to the screw. if anybody wants more torque, thats a cheap and fast way to get!

When i did a very similar mod' the exhaust note changed heaps, it really 'barks' and has quite an aggressive 'tinging' sound now. At first i thought it had an exhaust leak, the sound changed that much!!!
The low end torque is quite an improvement. I had to adjust the air screw as well to richen it up a little ( 1/4 turn ).

 

[Tom250]

i ride a lot in the mountains with much elevation changes, so i cant say if i needed to richen it up, i always mess on the airscrew during a day. in the mountains the weather never is similar so its hard to say something about that. but since that modification it oils stronger out of the muffler. it could be the warmer weather now because i didnt change any jets, but from my experience i would say it drools stronger because of the lower flapper. dont interest me as long the torque is grown

 

[swazi_matt]

Pictures or we don't believe it is possible!!! ;-)