Ping Sound 250yz

ezmoto
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ezmoto
Edited Date/Time 7/7/2020 9:15am
Hello,

I already had one topic in here but this is an update.
My bike is pinging after piston change (look video) https://youtu.be/IhHTsXnJHi4

I repacked the exhaust (there’s a very small crack in the expansion chamber, but i don’t thinks that’s it), main jet is 190 so plenty of fuel, I tried running 100 octane with 5% ethanol... and it still pings...

Some guys told me that’s it is fine, and it’s because of better compression and that I should be happy, but I’m nervous...

Piston is a vertex (very good brand).

I took some pictures of the piston after 1 hour of riding.

THE VERY WIERD THING IS, first time I started it (after piston change ) it sounded perfect! I let i arm up, and only used half throttle up and down the road for 3 min. 2 days later on the track it started with the pinging.. Does anyone have any idea of what is going on... I’m going on a race trip soon and don’t want it to blow up Sad (

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DynoDan22
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DynoDan22 7/3/2020 11:49am
7/3/2020 11:49am
I'm hearing a bit of a bearing growl. Almost sounds like a bad big end bearing of the connecting rod or a bad main bearing. Listening to videos is very difficult to diagnose and it's way better to hear in person. For sure something doesn't sound right to me. I would inspect the lower end rod bearing for radial play and take the stator cover off and try to wiggle the flywheel up and down and back and forth. You already have it torn down, you might as well inspect everything to avoid a catastrophic failure.
1
ezmoto
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ezmoto 7/3/2020 7:09pm
7/3/2020 7:09pm
DynoDan22 wrote:
I'm hearing a bit of a bearing growl. Almost sounds like a bad big end bearing of the connecting rod or a bad main bearing. Listening...
I'm hearing a bit of a bearing growl. Almost sounds like a bad big end bearing of the connecting rod or a bad main bearing. Listening to videos is very difficult to diagnose and it's way better to hear in person. For sure something doesn't sound right to me. I would inspect the lower end rod bearing for radial play and take the stator cover off and try to wiggle the flywheel up and down and back and forth. You already have it torn down, you might as well inspect everything to avoid a catastrophic failure.
Sounds scary :/ the jetting is already Rich, so ill try so look up the squish... but i dont hear anything from the crank personally :/
FGR01
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FGR01 7/5/2020 7:50am
7/5/2020 7:50am
Just saw this after your other thread.

When you had the top end apart, did you clean the powervalve very well and verify free movement and complete range of operation?

When the powervalve gets sticky (or parts broken) it can hang partially open and not close completely. When this happens you get some combustion escaping into the expansion chamber on the low end and it makes a pang-pang-pang or pinging or banging sound in the chamber.

Try running the bike with the right side cylinder power valve cover removed so you can watch for complete range of the actuator army when revving low to high.
1
ezmoto
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ezmoto 7/5/2020 8:28am
7/5/2020 8:28am
FGR01 wrote:
Just saw this after your other thread. When you had the top end apart, did you clean the powervalve very well and verify free movement and...
Just saw this after your other thread.

When you had the top end apart, did you clean the powervalve very well and verify free movement and complete range of operation?

When the powervalve gets sticky (or parts broken) it can hang partially open and not close completely. When this happens you get some combustion escaping into the expansion chamber on the low end and it makes a pang-pang-pang or pinging or banging sound in the chamber.

Try running the bike with the right side cylinder power valve cover removed so you can watch for complete range of the actuator army when revving low to high.
Did not clean it at all :/ But i found out my squish is very small at 1,14 mm, so ill run another base gasket i think... Ill try celaning the power valve too!

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ezmoto
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ezmoto 7/6/2020 8:30am
7/6/2020 8:30am
FGR01 wrote:
Just saw this after your other thread. When you had the top end apart, did you clean the powervalve very well and verify free movement and...
Just saw this after your other thread.

When you had the top end apart, did you clean the powervalve very well and verify free movement and complete range of operation?

When the powervalve gets sticky (or parts broken) it can hang partially open and not close completely. When this happens you get some combustion escaping into the expansion chamber on the low end and it makes a pang-pang-pang or pinging or banging sound in the chamber.

Try running the bike with the right side cylinder power valve cover removed so you can watch for complete range of the actuator army when revving low to high.
UPDATE: There were a totally noise bolt in the powervalve!! the middel one, which caused it not to open fully, and for some wierd reason make ik Ping in the exhaust
FGR01
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FGR01 7/7/2020 9:15am
7/7/2020 9:15am
ezmoto wrote:
UPDATE: There were a totally noise bolt in the powervalve!! the middel one, which caused it not to open fully, and for some wierd reason make...
UPDATE: There were a totally noise bolt in the powervalve!! the middel one, which caused it not to open fully, and for some wierd reason make ik Ping in the exhaust
Good deal.

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