Gotta Super Rat that quit firing

Discussion in 'Norm's 2 stroke repair center' started by sunshinebiker, Mar 24, 2013.

  1. sunshinebiker

    sunshinebiker New Member

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    Well, considering my luck, that isn't a surprise. Do you have anything to support the lack of EPA certs for the engine? That may be my way of getting BGF to replace it, since he sure wouldn't want an EPA rectal probe.
     
  2. nightcruiser

    nightcruiser New Member

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    Do you see an EPA sticker on the motor?
     
  3. sunshinebiker

    sunshinebiker New Member

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    There are no stickers on the motor. That seems to be telling right there...
     
  4. sunshinebiker

    sunshinebiker New Member

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    First, I will say this forum is a lot more civilized than some of the forums I have been on over the years.

    My latest findings:

    I put a volt meter across the spade terminal and ground, then pedaled to about 9 MPH. I let out the clutch and the voltage reading went to 16.1 volts before I started to slow down. Then, the voltage decreased as the bike slowed down.

    Does that sound about what it should be, or is it too low?

    Compression test shows about 70 PSIG, which would be ~6:1, based on 14.1 PSIA atmosphere at 1200 feet elevation. So, that seems on spec for a 2-stroke engine.

    Fuel mix is 16:1, which seems rich with oil to me, but that is what the manual said to use.

    Took off the air filter and checked for needle and sleeve travel in the little HT carburetor. That all looked good.

    Thoughts?
     
  5. nightcruiser

    nightcruiser New Member

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    I think your motor and ignition is prob fine, you're just going through the first timers blues...

    First off, contrary to what the manual says 16:1 is an excessive amount of oil. You do want to use extra oil in the first couple gallons of fuel to make sure the new/dry parts in the motor get oiled up as quick as possible but 16:1 is a lot of oil and you could end up flooded with a fouled plug etc.....

    If I were you this is what I would do.

    First I would pull out the spark plug then let the clutch out and roll the bike around a bit allowing the motor to turn over and cough out any excess fuel/oil that may be inside the cylinder. (Don't RIDE the bike, roll it around just to let it turn over a handful of times. Make sure there is no spark or flame around that could ignite any fuel that may come out of the spark plug hole while you do this)

    Next I would install a better spark plug, or the spare plug that came with the kit, or at least clean and dry out the plug you were using before you reinstall it.

    I would disconnect the kill switch for the time being, and make sure to isolate the white wire (or accessory power wire whatever color it may be, if it is present)

    I would check to make sure the spark plug boot is seated on the wire properly, and the parts inside the plug boot are all in proper order. Also, with most of the kit boots you need to unscrew the top of the spark plug, you should see a threaded rod on top of the spark plug, not the press on tip you may be used to. IMHO you are best off to get an automotive plug wire and boot and replace what came with your kit (and put the cap back on the spark plug) but since I haven't actually seen a Super Rat style CDI I can't comment on the quality of the wire. I suspect the wire and boot are still crap and you should replace it.....

    I would drain out the 16:1 fuel and make a fresh mix of 20:1 or 24:1 fuel and use that.

    I would make sure the air filter is not soaked with gas or oil, clean if necessary.

    Then I would turn on the fuel, immediately ride and pop the clutch and pedal her along until she fires (hopefully). If/when you get her running I would pull in the clutch (disengage the engine) and use the throttle to try and keep her running at as low of an idle as possible for a little while, if that goes well then gently start to ride and begin the breaking process. There are lots of schools of thought on break in, but I feel a couple gallons/couple hundred miles of break in fuel mix, riding moderately varying speed and RPM on the motor without riding WOT for extended periods but hitting it WOT for brief periods is a reasonable way to break in a HT motor.

    Hope this was helpful, good luck!
     
  6. sunshinebiker

    sunshinebiker New Member

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    That is very useful stuff! I'll work thru this and report back.
     
  7. sunshinebiker

    sunshinebiker New Member

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    Well, after doing all nightcruiser said and also changing out the fuel filter (clogged with oil from the previous 16:1 mix so fuel couldn't get to the carby), it took a couple of rides downhill and a bit of initial huffing and puffing, but I finally got it to start again and run this morning :) The mix is now 3 oz to a half gallon, which is roughly 22:1.

    After it started, I pedaled and let the motor "help out". I ran about 5 miles around my neighborhood and such at about 12-17 MPH (assuming the speedo is properly calibrated), which was maybe half throttle. I'll keep doing that for a gallon or two of fuel, and open it up wider occasionally.

    Any ideas on what the head nut torques should be? The BGF manual said 12 ft.-lbs, but I think that may have been written for 6 mm studs/nuts.

    I know on my VWs, 8 mm bolts are supposed to be tightened to 18-20 ft.-lbs. But, when I checked torque on the head nuts on the bike motor on the install, they felt much greater than that, because the torque wrench clicked and no movement occurred.

    One thing I noticed in my opening and closing of the magneto cover was that the little "fan" on the magnet wheel had rubbed on the inside of the magneto cover, since there was no gasket. So, I shimmed out the cover with some washers to add some clearance space. I should find something more permanent, but the cover can't completely seal anyway...
     
  8. 2door

    2door Moderator
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    Glad to hear you're up and running.

    The magneto cover really does need to be sealed. That encapsulated coil might not be as susceptible to moisture as the other more common ones but I still wouldn't want water in there. Splash back from the front tire or rain will get in. Also seal around the wires where they exit the case with a silicone sealant. Make a thicker gasket for the cover and you might want to make sure the rotor (magnet) is tight on the crankshaft.
    Worst case would be the crank has slipped in the bearings or the bearings have moved in the case allowing the crank to shift to the left.

    Head bolt/nut torque with 8mm studs should be around 120 to 140 inch pounds. Re-check them after the engine has reached operating temperature a couple of times. Don't tighten them unless they need it to get back to your original torque setting.

    Tom
     
  9. nightcruiser

    nightcruiser New Member

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    Congrats man, glad you got her running!
    As 2Door said, you should get a gasket back under that cover because you don't want moisture to get in there. Those fins are just there to move air and provide some cooling, so I see no problem in grinding them down a hair so they don't rub so you could seal the compartment off with silicone, but you're probably better off just replacing the gasket if you can.
    Good luck moving forward with your ride, we are here to help if you have any questions.... Have fun riding! .shft.
     
  10. dmb

    dmb Active Member

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    the cover has air vents from the factory to keep it cool. heat will kill a cdi.
     
  11. nightcruiser

    nightcruiser New Member

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    I don't have a super rat, but I know my cover doesn't have any vent holes in it, and I don't seem to see any in the pictures provided in this thread? I know this system with the entire CDI under the cover is quite a bit different than what the rest of us are running, on a regular HT motor getting moisture under the cover is a bigger threat than heat.
     
  12. MotorBicycleRacing

    MotorBicycleRacing Active Member

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    Holey billet Super Rat mag cover sold by Sick Bike Parts.

    [​IMG]
     
  13. nightcruiser

    nightcruiser New Member

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    I don't think the stock cover has vent holes but not sure cause I've never had a super rat and there wasn't a picture from every angle. I suppose the cdi with the built in magneto coil would make the ignition less susceptible to moisture but more susceptible to heat, so it makes sense to have the vent holes (and the fan fins)...
     
  14. MotorBicycleRacing

    MotorBicycleRacing Active Member

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    double double
     
    #34 MotorBicycleRacing, Apr 2, 2013
    Last edited: Apr 3, 2013
  15. MotorBicycleRacing

    MotorBicycleRacing Active Member

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    You are a tough nut to crack, :)
    the billet cover is copying the Super Rat mag cover.

    [​IMG]
     
  16. sunshinebiker

    sunshinebiker New Member

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    That may be why there was no gasket available for a Super Rat! It's hard to seal vent holes... (p)

    I only ride in when it's dry, so I can keep the shims in for a little while. Thanks to everyone for their input!
     
  17. nightcruiser

    nightcruiser New Member

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    drn2
    A regular CDI is sealed and pretty much water proof, this new CDI with built in coil looks to be sealed up in a similar manner so I guess it's all waterproof under the magneto cover on the super rat. So it would seem spacers should be ok, but I would prob just grind the fan fins down until they didn't rub the cover when the gasket is missing....
     
  18. sunshinebiker

    sunshinebiker New Member

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    Just a follow up: I now have 37 miles on the bike and have been slowly expanding the drive range. I run it mostly in the half throttle range, but I have taken it to WOT on the flat, and I'm just a tad south of 30 mph; pretty good since the bike weighs 62 lbs and I'm in the 180s. Thanks to all who shared advice and tips. Looks like my little super rat is going to be a great summer ride.
     
  19. Gp masta

    Gp masta New Member

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    Is there any gains on using the new style bottom ends??
     

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