Hey all I’m new to the site! I have a 1985 ATC 250r I just restored with all new oem bearings, gaskets, etc. the only part of the motor that isn’t oem is the hot rods crank. Still doesn’t even have an hour on the rebuild and when I came to a stop, I noticed everytime I suddenly punched the throttle I could hear a clunk noise. It’s not the usual knocking sound you hear from these while running but it was always one solid clunk in the beginning of hitting the throttle. And sadly I can’t remember if it did that from the start or if it just started. It’s one clunk sound that only happens on the beginning of the revving up of the motor. So I thought the flywheel might have been coming loose and its not loose and there’s no up and down or left and right play in crank but if I push the flywheel in and out towards the cases it will move back and forth slightly and I hear a clunk sound. Has anyone else ever had this? How bad is this? Really was fearing tearing this thing down after I just put so much work into it.
Clunk sound at beginning of revving engine
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- clunk engine noise knock
CamHillman03
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Hey all I’m new to the site! I have a 1985 ATC 250r I just restored with all new oem bearings, gaskets, etc. the only part of the motor that isn’t oem is the hot rods crank. Still doesn’t even have an hour on the rebuild and when I came to a stop, I noticed everytime I suddenly punched the throttle I could hear a clunk noise. It’s not the usual knocking sound you hear from these while running but it was always one solid clunk in the beginning of hitting the throttle. And sadly I can’t remember if it did that from the start or if it just started. It’s one clunk sound that only happens on the beginning of the revving up of the motor. So I thought the flywheel might have been coming loose and its not loose and there’s no up and down or left and right play in crank but if I push the flywheel in and out towards the cases it will move back and forth slightly and I hear a clunk sound. Has anyone else ever had this? How bad is this? Really was fearing tearing this thing down after I just put so much work into it.
Did you use a crank puller to pull the crank into the left and right case halves? Seems like there is nothing to clunk except the crank and the crank bearing.
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Yes I used a puller. There’s a video on YouTube of Dave Moore building a motor and I did everything he did
my 1986 TRX250R engine is in process of rebuild. I have a hotrods crank pulled into both halves of the case and the case buttoned up. No jug, stator, or main crank gear installed yet. I have zero play side to side with crank/flywheel assembly. That's the extent of my knowledge. But there are quite a few on this forum that have TONS of experience.
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And when u say side to side you mean in towards the cases, pulling the flywheel straight out
I was thinking zero play left to right when looking down the jug to the crank. Really, zero play in any direction for crank assembly. Given, there is a little side to side play with connector rod. But none between crank/flywheel and case/bearings at all. side to side or up and down.
Can you tell where the clunk sound is from? Could it be from stator, or from tranny/balancer?
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