Predator 212 knock after installing ARC Flywheel
- Thread starter yellow azusa
- Start date
I removed the old cast iron flywheel, and coil, applied valve grinding compound, seated the new flywheel, cleaned off the compound, reinserted the key, then installed the new flywheel, pull start bell, coil. I thought it was gap'd at .03 but I can check it again. Would the coil gap being off cause the knock? Thanks!
Don't know but arc specs the gap wider and it should have been a paper with it in the directions. The rare earth magnet has a lot more pull and gapped too close can pull the flywheel to the coil laminations. make sure to gap it correctly, .030 is minimum but ARC says .060 to .065 works best. If you are at .030 I doubt it is causing the knock but if it is closer it could be. Just set it to .060 and see if it makes a difference. If it was hitting magnet I would think there would be witness marks on it. If you did not take anything else apart just the tins, and flywheel then it has to be something in that area.
Is the new flywheel all the way seated and the nut that holds it on tight with the correct torque spec and the correct air gap as mentioned previously? If you put on the old flywheel, does that resolve it? Did you get the correct non-hemi or hemi flywheel to match what you have?
https://www.OldMiniBikes.com/arc-billet-flywheel-new-predator-212cc-kohler-ch270.html
https://www.OldMiniBikes.com/arc-billet-flywheel-predator.html
https://www.OldMiniBikes.com/arc-billet-flywheel-new-predator-212cc-kohler-ch270.html
https://www.OldMiniBikes.com/arc-billet-flywheel-predator.html
Re-gapp'd the coil to .030 and torqued the flywheel to 54 pound ft. Still hear a knock at idle. Goes away when the rpms are a little higher. It was not anywhere near near 54 ft lbs. Took about another 3/4 turn with the torque wrench to get it there. I did a visual inspection of the flywheel and didn't see any witness marks. Also, my "impact wrench" is a dewalt 20w electric so I'm pretty sure it didn't do any damage. Should I go wider on on the gap?
Yes but I doubt it is the knock. You say it did not do that before correct? Did you make sure the flywheel key was not damaged although if it moved enough to knock I would think it would also kick back on you. Try to listen to where the knock is coming from. Does it sound like a rod knock or just like something is hitting a flywheel fin. you could also pull the plug and rotate the motor over to make sure the flywheel is not wobbling. You may want to put back the old flywheel to make sure knock goes away so you know it is something to do with the new flywheel.
Thanks Ole4. Really appreciate your help. I'm not an expert but it sounds like a rod knock. Kind of like the sound an engine makes when it is about to stall. The noise is definitely coming from the crank case (only at idle). When RPMs are slightly above idle, it goes away. I raised the idle so it doesn't make the sound but it has me worried.
You mention kick back. Is that when the pull chord gets ripped out of your hand when you try to start it? That HAS been happening since I installed the new flywheel. Doesn't happen every time. Just sometimes. My son is afraid to start it now because it is pretty violent. Don't understand how the timing could be off from the flywheel. It can only go on one way with the stock key. I do have the billet rod and mod 2 cam sitting in a box. Really don't feel like tearing the engine apart again but sounds like it might be the best option at this point. Don't want it to blow apart with my son riding it!
You mention kick back. Is that when the pull chord gets ripped out of your hand when you try to start it? That HAS been happening since I installed the new flywheel. Doesn't happen every time. Just sometimes. My son is afraid to start it now because it is pretty violent. Don't understand how the timing could be off from the flywheel. It can only go on one way with the stock key. I do have the billet rod and mod 2 cam sitting in a box. Really don't feel like tearing the engine apart again but sounds like it might be the best option at this point. Don't want it to blow apart with my son riding it!
This links may be helpful. Also, you may want to check crankshaft end play with both flywheels to insure they are about the same. Sometimes when taking off the flywheel, you can get things in a bind - hopefully that is not the case, and if ran in that condition can cause abnormal wear which will impact your end play once the bind is out, but the damage is already done...
https://www.facebook.com/billetbyarc/posts/710295415669286
https://www.oldminibikes.com/forum/honda-clone-predator/66852-predator-212cc-crank-shaft-play.html
https://www.facebook.com/billetbyarc/posts/710295415669286
https://www.oldminibikes.com/forum/honda-clone-predator/66852-predator-212cc-crank-shaft-play.html
hopefully its not the rod, you could verify by putting the old wheel back on...I wonder if it could it be the magnet moving up against the roll pins as it passes the coil? I have a arc flywheel that makes noise, its the magnet only noticeable at idle. there is more advance built into the arc over the stock wheel, so yes kickback can occur, especially if the key is partially/ fully sheared. a snow blower pull handle helps alot on hard to pull engines.
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