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Why counter clockwise?

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Why do you need to turn the crank counter clockwise when checking valves, I mean you can get into the proper TDC clockwise as well, so what's the difference?

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Someone with more engine building experience could probably answer better than me, but I don't believe that you could even turn it clockwise, or in reverse.

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u can turn it clockwise. i did it when i was trying to do my valves but im not sure why it need to go cc i guess it b cuz thats how the engine fires?..

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CCW so you're not trying to undo the bolt and the starter motor is on 1-way bearings so CW and you're trying to turn the starter over too.

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Like Nordie said: The starter gear sprag bearing. This is basically a one way clutch that free-wheels as the engine runs so the starter gear train remains idle. When the engine is turned backwards the sprag engages and spins the full gear reduction and starter motor. Very tough to spin with all the reduction gearing involved. We've likely all heard this when we stop our bikes at just the right moment before TDC on the compression stoke and the piston never makes it through the stroke. The engine spins backwards quickly and spins the starter gear train at a fairly alarming rate of speed from the opposite gearing effect. The crank stops but the starter and gearing are still flying and continue to spin until things slow down. This is the reason the torque limiter device is needed in the starter gearing.... otherwise you end up with scraped out cases and other starter related components like on some of the 98 and part of 99 year model owners found out.🤣 The rotor retainer bolt is a right handed thread though. 👍

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Like Nordie said: The starter gear sprag bearing. This is basically a one way clutch that free-wheels as the engine runs so the starter gear train remains idle. When the engine is turned backwards the sprag engages and spins the full gear reduction and starter motor. Very tough to spin with all the reduction gearing involved. We've likely all heard this when we stop our bikes at just the right moment before TDC on the compression stoke and the piston never makes it through the stroke. The engine spins backwards quickly and spins the starter gear train at a fairly alarming rate of speed from the opposite gearing effect. The crank stops but the starter and gearing are still flying and continue to spin until things slow down. This is the reason the torque limiter device is needed in the starter gearing.... otherwise you end up with scraped out cases and other starter related components like on some of the 98 and part of 99 year model owners found out.🤣 The rotor retainer bolt is a right handed thread though. 👍
Ok thanks for the explanation Rob, so you risk loosening the bolt itself, and it will be a little tougher to spin because of the reduction gearing involved. Is that it?

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Ok thanks for the explanation Rob, so you risk loosening the bolt itself, and it will be a little tougher to spin because of the reduction gearing involved. Is that it?

No, the bolt is not a left handed thread so if you attempt to turn the crank in a clockwise direction you are tightening it.... Besides, this bolt is put on with 115 lb ft of torque... you ain't gonna loosen it turning the crank in any direction unless your are using a 1/2 impact wrench to turn the crank. 👍 ... and yeah, not just a little tougher to turn the crank CW..... a lot tougher.

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Ya' know, some boards where tech Q's get posted, there's no useful reply, or even speculative comments. And there's tech savvy riders out there who don't care to take the time to help.

But this TT DR forum's really great - fortunate to have members the likes of mx_rob and NorideBoy and others generously sharing their experience and know-how. It makes this a great tech resource. 👍 I'm sure to look to their expertise and support when performing the upcoming DR725 engine mod!

On CW/CCW topic... another reason to turn the DR CCW: turning CW (i.e. backwards) applies tension to the timing chain, such that the chain-tensioner side (i.e. the slack side) of chain becomes the 'tensioned' side (compresses the tensioner). Though it won't generally cause a problem, it's best to avoid, particularly with regard to measuring/checking crank position vs. valve timing. Chain slack can equate to half of a sprocket tooth on some motors - that can be significant.

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Good point... you hope your tensioner is in good enough shape to take out any play but it is not meant to do much arguing with valve springs under tension until it hits a ratchet stop..... so another good reason for not cranking your engine backwards. Certainly the direction you'd want to turn your engine in before making any adjustments is in the running direction. 👍

Awesome! Another Monster DR in the planning stage.🤣

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fortunate to have members the likes of mx_rob and NorideBoy and others generously sharing their experience and know-how.
All the way!👍

Well today was a lesson learned, the lesson being... don't second guess yourself!

I went and did a valve check again because I wasn't sure if I went CW or CCW, I applied a little force to see if I can spin the crank CW and forget it, you will really have to muscle it to get the crank to move which I wasn't able to do and didn't really want to, so I'm glad I went back and checked... need to run, think I left the oven on🤣

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Good info guys, I figured no cw in my earlier post based on the fact when I checked my valves recently, i barely got pushed past the mark on the compression stroke, you know, when it takes off on ya by itself, and carefully tried the cw to bring slightly back, and no give, not without allot of force I guess, I would never try something that it wasn't designed to do. Interesting though, my neighbors 2-cycle ski-doo sled has a reverse button that actually slows engine speed, and changes rotation of engine to run in reverse, pretty cool. Two-cycle is a whole different story though.

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