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jnk

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About jnk

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    Greece
  1. jnk

    Not shifting into gear good.

    They look pretty rounded to me. I had my transmission undercut for the exact same problem and they were similarly rounded to yours. Keep in mind that the dog teeth do not engage fully so you can't just compare the rounded part to the entire length. This is not how it works. You need to also check the forks and the drum. In my transmission the channel of the 3rd in the drum had been chipped away from the dogs slipping out and hitting the fork. So the length of the dogs what were engaging was even smaller.
  2. Clutch drag alone is barely noticeable while riding around. What you describe is most probably the result of a notched clutch basket. What happens is that the discs have dug deep grooves in the basket fingers. These grooves are in a position corresponding to the discs being fully compressed. So when the bike is accelerating or decelerating the discs are squeezed into the compressed position inside the grooves. What you need to do is take out the clutch basket and file those notches down. Search google images for "notched clutch basket" to see what I am talking about.
  3. jnk

    Undercutting the transmission

    Did you recreate the original vertical slope on the dogs or a slightly negative one ? I imagine there needs to be substantial wear for a negative undercut to pop out. Right ? Way more than the original slight rounding. Or is it that the steel is only surface hardened and once you get past the outer layer everything goes downhill pretty fast ?
  4. jnk

    Undercutting the transmission

    Well, I checked the part numbers and on the 2011 model gear 3 and gear 5 on the mainshaft as well as the shift drum have been updated. Gear 3 and 5 on the main are the gears that 4 locks against to engage 4th and 5th. Which is exactly the problem I had. So it seems there was some issue there that has been addressed.
  5. jnk

    Undercutting the transmission

    Here is a picture from the patient after the operation
  6. What are your thoughts on undercutting the gear dogs ? My 09 450 started popping out of 4th gear four days before a race. I couldn't waits for parts to arrive so I had the dogs of both 4th and 5th undercut by a machinist that specializes in this kind of operation. The bike shifts just fine (normal and clutchless) and I got through the race without an issue. Now should I leave it as it is or should I search for original parts ? The machinist told me that the fix would last practically for ever and there is no need to replace the gears. Keep in mind that should I decide to replace the gears I will also have to replace the drum that was nicked by the fork guide slamming on it and quite possibly the fork that might have been slightly bent (this is not an issue now that the dogs pull the gears towards one another). So the cost adds up. What do you all think ? Has anyone else got an undercut gear box ? Did it last ?
  7. jnk

    Crf450r efi 2009 Hard to start

    Bike having trouble staring and then running fine could be the sign of bad fuel pump. The pump can't raise the pressure with the small power the kick starter is providing or there could be a pressure loss. Just a thought.
  8. jnk

    Worn clutch basket

    Hi everyone, the following is a clutch basket from a 09 crf450r. It has deep grooves where the discs contact the "fingers". However this is not my main concern. What worries me the most is that the gear which is pressed in the basket has become loose to the point that you can slide it in and out by hand (as can be seen in the photo above). This allows for a tiny bit of play of the basket when it is installed in the bike. I think I will go for an after market clutch basket. Wisesco most probably. Now after market baskets don't come with the gear that you have to press out of the original basket and press fit it in the new. However my gear has already come loose. Now should it be safe to assume that what has worn out in my case is the aluminum basket and not the steel gear and I will still be able to press fit it in the new basket ? Or is there a possibility that I will find the gear sliding in and out freely in the new basket as well ? What do you all think ?
  9. jnk

    Rear Brake Occasionally Not Engaging

    My guess is that the seal in the piston is damaged but still manages to seal 99% percent of the time. I have seen this happening where the break would work if you applied pressure on the pedal vertically and it will not work if you applied pressure slightly to the side. It turned out that the seal was torn and when the pedal was pushing the piston a bit to the side the tear would not seal and oil would pass through. Remove the piston and examine the seal carefully for tears.
  10. jnk

    Bleeding rear master cylinder

    You can speed up the process by bleeding the air out of the banjo bolts instead of the bleeding screw in the calipers. Once you build sufficient pressure you can then proceed to bleed the line from the calipers. That trick has always worked for me since I also find it nearly impossible to bleed it using the conventional method.
  11. jnk

    Seized 08 crf450r motor

    If you say that the shim was there at some point but is now missing what most probably happened is the valve retainer failed the valve fell into the piston and the piston seized. Possible reason could be that whoever installed the valve did not tap the stem as per the instructions and the keepers did not sit properly. But you will never know until you take it apart. Oh and you have to find the retainer the keepers and the sim. If they are not there you have to dig for them inside the engine.
  12. Valve clearances are right on spot. Unfortunately I don't have a leak down tester. I installed a new cam chain tensioner and gave the kickstart a go. The engine fired up immediately and run smoothly. So I think I have dodged the bullet this time. I debated going for a manual tensioner but I don't want to have another think to worry about. I would never be sure if I have tightened it too much or too little. Or if it needs adjustment. But that is just me. I not saying it is better or worse. As for taking the cylinder apart I think I will pass it for now. See how she runs first. I will come back and report when I finally come around to it. Thanks for all the input
  13. I was in the middle of a race when the bike started making a weird clanking noise. Now aside from the noise the bike was running just fine. So I called it quits loaded ip up and took it to my home where I found the cam chain tensioner spring snapped at the end and the cam chain tensioner fully rectracted. Now since the cam chain has not skipped any teeth and since the bike was running fine should I assume that everything is OK and a new cam chain tesnioner is all I need ? Or should I proceed to tear down the cylinder to check the piston and the valves ? I am of the opinion that a loose chain alone is not enough to make the timing go off all the way to the point where the valves would touch the piston. But I might as well get the opinion of the resident experts here.
  14. Well if you have access to the right side then you have no problem to begin with. The problem is how to keep your flywheel from turning without taking the right case off.
  15. I did a quick google search on the torque the bike produces and I found it is somewhere in the mid 30 lb-ft. So the torque you are applying to the nut is well above what the engine applies to the axle. But look at it this way: if the clutch could hold the flywheel still then what would be the need for the special tool everyone is using ?
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