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Project MC18 Project - Brisbane

Discussion in 'Your 250cc Projects' started by Duggs63, Jul 26, 2013.

  1. Fox McScrooge

    Fox McScrooge Well-Known Member Premium Member Contributing Member

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    I got my main jets from Tyga. Haven't been able to find them anywhere else. I don't think you need to go a lot bigger; normally aim for an air/fuel of about 13. If the bike is stock I don't think the Tyga pipes will make a huge difference so I'd start at the stock main jets.

    Here is a link for stock carb settings and oil pump setting:

    http://tech.nsr-world.com/

    I would definitely test your PGM and power valve motor. Perhaps Briz may be able to help? You could try installing your power valve motor on his 18 and see if it works. No need to install the cables and everything; just hook up the wiring plugs and see if it cycles. If it does then your PGM is probably shot. You can find second hand ones on Yahoo Japan. Google Chrome will translate:

    http://auctions.search.yahoo.co.jp/search?p=NSR250+mc18&ei=UTF-8&rs=4
    http://auctions.search.yahoo.co.jp/search?p=NSR250+pgm&aq=-1&oq=&x=0&y=0&ei=UTF-8&auccat=&slider=0

    NSR World also has information on testing the PGM if you are handy with a multimeter.
     
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  2. Duggs63

    Duggs63 Well-Known Member

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    Update time.

    I took a mental health day off work today and took the opportunity to come back to the little beast after the lack lustre dyno day.

    I didn't get a great rundown on what the shop had done when I picked it up, so I decided to do a little poking around myself. After pulling the tank off, I noticed that they had drilled out 4 holes in the airbox to help ot breathe which was a nice surprise.

    20150616_120629.jpg

    I have been a bit sus on the power valves as the cause of my lack of power so I took one of the chambers off to find that the valves were set to full closed. After noticing that, i followed the various testing procedures on nsr-world and there was no sign of life at all, although there was a bit of conflicting information about the R2J models not cycling at all. After all this, i confirmed by started the bike and eventually taking it up to redline with no movement at all.

    There is my problem!!:D

    I then opened the valves by hand and took it around the block and now it goes like a cut snake!!!

    I took the opportunity while I was there to check the colour of the plugs which look ok to my untrained eye, although the front cylinder looks like it may be abit leaner than the rear cylinder? Would welcome input here from the more experienced 2-stroke guys.

    Front:
    20150616_152235.jpg

    Rear:
    20150616_151906.jpg

    I put 12v on the power valve motor and it cycles both ways, so the issue there may be either of the little black boxes behind the back seat of the PGM, but at least i know the motor is good :dance2:

    One more pic for good measure.

    20150616_121629.jpg
     
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  3. Mclaren

    Mclaren Well-Known Member Contributing Member

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    Good to hear get it sorted and back for another dyno run mate
     
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  4. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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  5. Fox McScrooge

    Fox McScrooge Well-Known Member Premium Member Contributing Member

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    Sounds like you are on the right track Duggs. I hate to say it but it's sounding more and more like you may need a replacement PGM. The PGM controls the power valve position via the power valve motor. If the motor is OK it's probably going to be the PGM.

    That's good info Maelstrom posted concerning reading the plugs. Main point is they need to be brand new unused plugs for each check you do.

    One other thing, if the bike has stock carbies etc then have a think about what has changed. You have installed a freer flowing exhaust and there are holes cut in the airbox. I pretty much guarantee you will need to go up on your main jets and I think the dyno graph confirms the bike is lean everywhere. The thing I find a bit odd is why is the bike so lean below 7K. Above 7K it looks slightly lean as you would expect with the jets you have in the bike and the air box / exhaust mods but below that it's off the scale. I'm thinking that could be PGM and/or air solenoid related. The PGM also controls when the air solenoids open and close. If they are open when they aren't meant to be, there will be too much air in the mix and the bike will be lean. Same goes if the solenoids are stuffed and stuck in the open position. I reckon best way to go is get the power valves working properly first, make sure the air solenoids are good and then worry about jetting the bike.
     
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  6. Duggs63

    Duggs63 Well-Known Member

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    Hi Fox!

    I am under the impression that the 2J MC18 has a separate box that controls the power valves but I am still trying to get a straight answer on that.

    I haven't considered the air solenoids as a potential issue. Good call! Is there a method of testing if they are working? The erratic behaviour of the AFR curve makes me wonder if the eg probes are up to scratch because I have never seen anything like that before but I suppose It could also be a solenoid issue.

    I am inclined to agree with your process, and I think I will touch base with the guy you used for your tune because I am hopeless with carb related things.

    As always mate, thanks for the help!
     
  7. kiffsta

    kiffsta Senior Member

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    I had 2 boxes on my MC18
     
  8. Fox McScrooge

    Fox McScrooge Well-Known Member Premium Member Contributing Member

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    Not sure about the solenoids to be honest. I'm not sure they are a simple on off; I think they may vary the air flow through the emulsion tubes depending on RPM. Might be worth searching NSR world for the info.
     
  9. Fox McScrooge

    Fox McScrooge Well-Known Member Premium Member Contributing Member

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    Sounds like a plan Duggs but I think the main thing is before you spend another few hundred bucks at the dyno it would be a good idea to get the bike working correctly.
     
  10. Mclaren

    Mclaren Well-Known Member Contributing Member

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    Was only 50 bucks for a run fox
     
  11. Fox McScrooge

    Fox McScrooge Well-Known Member Premium Member Contributing Member

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    That's good for a run. Think I might bring my bike down there once I finally get my ignitions back from Japan.
     
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  12. Mclaren

    Mclaren Well-Known Member Contributing Member

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    Every month there is a dyno day I post up here
     
  13. Fox McScrooge

    Fox McScrooge Well-Known Member Premium Member Contributing Member

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    Yeah I've seen the posts. Just seems like the Gods conspire against me every time. I'm either at work or waiting on parts. Like now. Damn it.
     
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  14. Duggs63

    Duggs63 Well-Known Member

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    So after being sidetracked with too multiple other projects, I got back to it yesterday with the help of afew of the lads.

    I'd previously eliminated the RC valve motor as the issue by putting 12v on it and confirming it rotated so that was good.

    After trying to decipher the jinglish in the manual without much success, we started substituting control units that I had in my box of spares, and trying to see if the power valves would cycle with ignition. Eventually we had a win! It ended up being the small black box on the side of the rear sub frame which was a win.
    image.jpg

    Now all that's really left is to get some main jets and get it down to the dyno :D
     
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  15. kiffsta

    kiffsta Senior Member

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    Make sure you hold on at 7500rpm, the **** is about to get real
     
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  16. Duggs63

    Duggs63 Well-Known Member

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    #150 main jets purchased as a starting point. Hopefully they will get me near where I need to be.
     
  17. Nathan Oliver

    Nathan Oliver Member

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    I think I might have to come down for the day
     
  18. Duggs63

    Duggs63 Well-Known Member

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    There is one this saturday but I doubt I will have the jets by then. If you are keen, let me know when you are going so I can come down and say hello.
     
  19. Nathan Oliver

    Nathan Oliver Member

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    Won't be able to make it this Saturday but I'll plan for one in the future, what's some more info about it ? Location-time dates ect
     
  20. Mclaren

    Mclaren Well-Known Member Contributing Member

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    This sat mate
     

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