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Post by mkksat13 on Aug 9, 2023 10:29:26 GMT -5
Just installed 70bbk on my 2T Zuma, the old Malossi Sport cylinder finally failed after 17,000. It’s been rattling from install but thought it was the starter gear. I deleted it to see and it’s still there. The bike runs strong, just has an obvious rattle. Is that a ring or clip noise? Video is attached. If I have to take it back apart, can I just cut the 2 gaskets (one at the base and another at the cylinder head) since I don’t have replacements handy? youtube.com/shorts/P6dpX-JM2yI?feature=shareThanks. |
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Post by aeroxbud on Aug 9, 2023 14:51:38 GMT -5
Did you check the squish and ring gap before installation?
What kit is it?
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Post by mkksat13 on Aug 9, 2023 16:33:03 GMT -5
Ughhh....I did not check either. I matched up the new piston & cylinder with my old one and everything was identical size-wise. What should the ring gap be and would it cause the rattle if it were too large or small? The bike doesn't make the noise when I put her under a load, but when I'm idling or lightly cruising around under 30 mph I can hear it. I thought originally it was my speedo cable, then my electric start, and now I realize it's in the cylinder. How would the rings rattle since they are compressed on the piston and into the cylinder? I did make sure to line up the "divets" when I put the rings on though. Thanks for the help and advise, I've done a lot of things to my scoot but this is my first kit, which is a replacement from the old Malossi Sport. I wonder if one of those cir-clips came off, that could be the noise.
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Post by aeroxbud on Aug 10, 2023 4:36:47 GMT -5
Too much gap and compression gases will blow by, causing loss of power and torque. Too little gap and the rings can over-expand and cause damage to the engine.
It easy to check the squish with some solder. It always a good idea to do this as you don't want the piston hitting the head.
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Post by Lucass2T on Aug 10, 2023 8:48:21 GMT -5
Did you check the squish and ring gap before installation? What kit is it? You don't really need to with a Malossi cast iron kit. These are build with such big margins you'll never run into clearance issues. Rattling can be anything. Does it sound rpm related (revs), load related (throttle), heat related (more/less rattle during hot or cold), time related (riding time), weight related (sounds like a heavy part or maybe a thin piece of sheet metal?) metallic or plastic sounding, etc etc etc |
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Post by zerotothirty on Mar 9, 2024 13:03:11 GMT -5
Too much gap and compression gases will blow by, causing loss of power and torque. Too little gap and the rings can over-expand and cause damage to the engine. It easy to check the squish with some solder. It always a good idea to do this as you don't want the piston hitting the head. Planning on checking clearance from here on out, is there a standard end gap tolerance by piston size? I recently saw a video of rolling wrench checking all the rings before install, would love to know more Edit: Just came across this article, not sure how relevant it is to smaller engines though |
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Post by aeroxbud on Mar 9, 2024 15:22:49 GMT -5
Too much gap and compression gases will blow by, causing loss of power and torque. Too little gap and the rings can over-expand and cause damage to the engine. It easy to check the squish with some solder. It always a good idea to do this as you don't want the piston hitting the head. Planning on checking clearance from here on out, is there a standard end gap tolerance by piston size? I recently saw a video of rolling wrench checking all the rings before install, would love to know more Edit: Just came across this article, not sure how relevant it is to smaller engines though Brent has a calculator on the side bar on the left. www.49ccscoot.com/calculators.html |
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