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RC valve help with video

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Hello,

 

I went to a dyno today to get my bike dynoed. It put out a whooping 31 rwhp :banghead:

 

We went on trying to diagnose where the horses were hiding and figured we´d take a look at the RC valve. Here´s a video of the valve under load. It is not opening fully. Furthermore it seems like it´s acting up as it vibrates back and forth during WOT.

 

https://www.youtube.com/watch?v=0IXMAvTR1Vs&feature=youtu.be

 

We then went on and unplugged the valve. Did one run with manually closed RC valve, one with fully opened. See the following dyno chart.

 

red = RC valve fully closed by hand.

blue = ECU controlled valve

green + purple = RC valve fully opened by hand

 

Slight difference in HP... :rolleyes:

 

I need some input now. Is the servo motor broken? Is the ECU sending faulty signals? Did I mess anything else up?

Ben-CR250-1.jpg

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Have you checked the RC valve cable adjustment ?  When these bikes first came out I read a couple of mx mags say they dynoed at 45hp you might be loosing a couple of hp if the jetting is off a little.

 

Edit: If the cable adj. is good - Check your RC motor next.

1. remove the cables from it.
2. remove & disconnect the 6P connector from it
3. connect 12V battery to servo motor side of the 6p connector, and verify that s-motor spins c-clockwise (white/blk=pos) (white/green=neg)
4. reverse the connection of the battery and verify that s-motor spins clockwise.
5. "replace if servo motor operation is abnormal".
6. check for resistance as follows: on servo motor side of the 6p connector,
measure Yellow/Red---Blue/Green. Needs 3.5--6.5 kOhms at 68F temp in the shop.
7. now connect 12V batt to servo motor side of the 6p connector, and measure resistance on servo motor side of the 6p connector using an ANALOGUE meter this time:
battery connection as follows: (white/blk=pos) (white/green=neg)
tester connection as follows: Lt. Green---Blue/Green
8. resistance is as follows: Repeat 0 to 3.5--6.5 kOhm
9. "replace if servo motor operation is abnormal"

Edited by H4L

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I didn´t tune it, just did a few runs measuring setups. Costs depend on your local dyno guy. Maybe 50, maybe 30, maybe 100.

 

Real tuning with carb setting will cost you a lot more (many hours involved).

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It looks like the stepper motor is roasted.. take it apart and check the gear drive also you might be binding on a crusty piece of grease. also like H4 said you need to check cable slack.

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your RC valve pully is installed upside down

 

here is a picture of what it should look like installed the correct way

 

 post-368409-0-18806700-1375866437_zpsc97

Edited by boris the blade
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I ordered the other servo motor and cancelled the order on the vision 400 motor. The servo I ordered is RS 365 SH. That´s the one I found in the bike, so I will take that particular one. Had some troubles finding it, but got lucky on ebay Germany.

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I rebuilt my CR250R when I pickjed it up - I realize he had the RC valve butterfly on incorrectly as well - he didn't have the washer behind it.

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You would see more wear on the arm without the washer I guess. But for the general operation and functionality, I doubt that would make a difference.

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Boris good observation didn't catch that !   That would cause the cables to be slack & not fully open the RC valve.. 

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All you guys still don't know if and when your powervalves are opening all the way. Do yourselves a favor, take off your exhaust and stick your finger up in the exhaust port while you hold a nice bright flashlight to see up in there. when you know it's open all the way by manually moving the butterfly, make 2 marks with a permanent black marker, that should line up when at full throttle and you can leave your exhaust valve butterfly cover off to observe on the dino or just off the dino revving it and testing it. All your motor work is a waste if you don't check the way the powervalve functions on these electric powervalve bikes. A powervalve is everything on a 2 stroke, very important to inspect it for proper operation, instead of going by how it runs and feels to assume it's opening all the way ETC. Takes 2 minutes to do this and then you just leave the cover off when you periodically check it as a maintenance item. Try it, make the index marks and start your bike, see how far it was off from opening or closing all the way from the factory, you will thank me later ? You also want to make sure your valve is not opening too far which will cause a chattering sound while at full throttle. it should be set as ilustrated in the pic below. Our 05-07 CR250's are about 50 RWHP stock. With some simple mods and head / cylinder work and a properly operating powervalve are about 60 RWHP. Pretty big difference in what they are capable of, and 60 RWHP is STOUT for a 212 pound motorcycle ! ! ! ! Will smoke the 4 stroke 450's EASY when it's running right.

 

Here is a picture of what i'm talking about doing. you guys all want to send your cylinder and heads out for work and to get your bike running at peak power, but you never checked if your power valve is operating perfectly, so all that head and cylinder work is a waste, if you just assume your valve is operating as it should. you will never know until you do this as seen in the picture below:

 

rc-adjustment-1.gif

 

 

rc-adjustment-2.gif

Edited by Atieri
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All you guys still don't know if and when your powervalves are opening all the way. Do yourselves a favor, take off your exhaust and stick your finger up in the exhaust port while you hold a nice bright flashlight to see up in there. when you know it's open all the way by manually moving the butterfly, make 2 marks with a permanent black marker, that should line up when at full throttle and you can leave your exhaust valve butterfly cover off to observe on the dino or just off the dino revving it and testing it. All your motor work is a waste if you don't check the way the powervalve functions on these electric powervalve bikes. A powervalve is everything on a 2 stroke, very important to inspect it for proper operation, instead of going by how it runs and feels to assume it's opening all the way ETC. Takes 2 minutes to do this and then you just leave the cover off when you periodically check it as a maintenance item. Try it, make the index marks and start your bike, see how far it was off from opening or closing all the way from the factory, you will thank me later ? You also want to make sure your valve is not opening too far which will cause a chattering sound while at full throttle. it should be set as ilustrated in the pic below. Our 05-07 CR250's are about 50 RWHP stock. With some simple mods and head / cylinder work and a properly operating powervalve are about 60 RWHP. Pretty big difference in what they are capable of, and 60 RWHP is STOUT for a 212 pound motorcycle ! ! ! ! Will smoke the 4 stroke 450's EASY when it's running right.

 

Here is a picture of what i'm talking about doing. you guys all want to send your cylinder and heads out for work and to get your bike running at peak power, but you never checked if your power valve is operating perfectly, so all that head and cylinder work is a waste, if you just assume your valve is operating as it should. you will never know until you do this as seen in the picture below:

 

rc-adjustment-1.gif

 

 

rc-adjustment-2.gif

Thats great info Atieri........i read somewhere that the RC valve is hard to accurately test when revving the bike as it fluctuates when in neutral, compared with actually riding and loading the engine?

I thought of mounting my gopro camera somehow and recording the RC butterfly on a ride to check it, but i might be wasting my time?

Any thoughts mate?

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These are from NSR world and HRC. for the NSR 2 stroke GP bikes that the idea for our valve came from. For the dirtbikes they never went into so much detail on how to do it right though.

Thanks Atieri, that will help.

 

Where did you get the illustrations you attached?

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I thought of somehow vidcamming it as well. try it, whats the worse that can happen ? maybe on the dyno the valve will not be so jittery  as it is when you try to test in neutral.

 

Thats great info Atieri........i read somewhere that the RC valve is hard to accurately test when revving the bike as it fluctuates when in neutral, compared with actually riding and loading the engine?

I thought of mounting my gopro camera somehow and recording the RC butterfly on a ride to check it, but i might be wasting my time?

Any thoughts mate?

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Do you have a link to the full article regarding the NSR power valve? Alternatively a workshop manual extract?

 

 

-edit-

 

nevermind, found it!

http://www.nsr-world.com/tuning/250-tuning/engine/

 

 

Atieri: how do you adjust the valves itself when using the NSR world method? I mean, mark the spot where they´re fully opening. Easy. Then switch off the engine, remove the pipe, feel with your finger where the exhaust valves sit while you turned the pulley to the marked position.

 

What if they´re not fully open but the valve´s "open" state has been reached by the pulley? How do you change the position of the valves on the shaft? The workshop manual doesn´t cover this.

Edited by twosmoke250

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