RXE 250 Sprocket seal popping out.

Blackhawk7188 · 10-09-2024, 05:39 PM

So it's weird that's it's happened twice now. About 5k miles on my RXE 250 and it just started leaking oil out of nowhere. Checked the the seal behind the front sprocket was pushed out. I pushed it back in and seemed fine. 2 days later and it popped out again.

Think it's just a worn out seal or something else? I am going to order a seal on Amazon to eliminate the worn out part of it. The TT250 seems to take a 34x20x7 in that position so going to go with that as I have a Zongshen too.

Any suggestions are appreciated.

Thumper · 10-09-2024, 06:54 PM

Make sure you clean off any oil and dry it well. To really get the oil off you can use a paper towel and get it wet with carb cleaner. The seal should fit snug with enough friction to prevent it from popping out.

Regarding the engine (correct seal size), is that a 169-FMM or 167-FMM? The engine model number is on the left side behind the gear shift lever. Also, you can measure your existing seal when it pops out again.

Blackhawk7188 · 10-09-2024, 07:01 PM

Quote:

Originally Posted by Thumper

Make sure you clean off any oil and dry it well. To really get the oil off you can use a paper towel and get it wet with carb cleaner. The seal should fit snug with enough friction to prevent it from popping out.

Regarding the engine (correct seal size), is that a 169-FMM or 167-FMM? The engine model number is on the left side behind the gear shift lever. Also, you can measure your existing seal when it pops out again.

Thanks for the quick reply.
167FMM is what's on the top row of the plate behind the shifter.

I found 2 seals online. A 20x34x7 and a 20x35x7. The 20x35 seems more common.

Bruces · 10-09-2024, 09:24 PM

Check your vent on the top of the engine case ,it’s building up pressure and pushing out the seal .

Blackhawk7188 · Yesterday, 08:01 PM

Update.
Checked the breather and it's clear. There was a screen? inside the canister and I punched that out. There was a plate in the air box on top of the breather inlets, removed that for now. I ran the bike with the breather disconnected from the air box and you can hear and feel air coming from it so it's clear. No fluid in the air box.

Seals come in in a couple days and will see from there. It has gotten much colder this week and wonder if it's from the temperature swing.

buzz · Today, 07:10 AM

Put lock tight on seal and you will be good to go.

dirtbkr188 · Today, 07:58 AM

Just an FYI, the seal size can usually be found on the face of the seal, to make sure you get the correct replacement for your application.

10-09-2024, 05:39 PM	#1
Blackhawk7188 Join Date: Mar 2024 Posts: 3	RXE 250 Sprocket seal popping out. So it's weird that's it's happened twice now. About 5k miles on my RXE 250 and it just started leaking oil out of nowhere. Checked the the seal behind the front sprocket was pushed out. I pushed it back in and seemed fine. 2 days later and it popped out again. Think it's just a worn out seal or something else? I am going to order a seal on Amazon to eliminate the worn out part of it. The TT250 seems to take a 34x20x7 in that position so going to go with that as I have a Zongshen too. Any suggestions are appreciated.
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10-09-2024, 06:54 PM	#2
Thumper Join Date: Feb 2021 Location: Kansas City Posts: 2,663	Make sure you clean off any oil and dry it well. To really get the oil off you can use a paper towel and get it wet with carb cleaner. The seal should fit snug with enough friction to prevent it from popping out. Regarding the engine (correct seal size), is that a 169-FMM or 167-FMM? The engine model number is on the left side behind the gear shift lever. Also, you can measure your existing seal when it pops out again. __________________ -NOS 2020 KTM 250SX (2-stroke motocross)
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Yesterday, 08:01 PM	#5
Blackhawk7188 Join Date: Mar 2024 Posts: 3	Update. Checked the breather and it's clear. There was a screen? inside the canister and I punched that out. There was a plate in the air box on top of the breather inlets, removed that for now. I ran the bike with the breather disconnected from the air box and you can hear and feel air coming from it so it's clear. No fluid in the air box. Seals come in in a couple days and will see from there. It has gotten much colder this week and wonder if it's from the temperature swing. Attached Thumbnails
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10-09-2024, 09:24 PM	#4
Bruces Join Date: May 2018 Posts: 1,646	Check your vent on the top of the engine case ,it’s building up pressure and pushing out the seal .
	1

Today, 07:10 AM	#6
buzz Join Date: Dec 2020 Location: Dayton Pa. Posts: 947	Put lock tight on seal and you will be good to go.
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Today, 07:58 AM	#7
dirtbkr188 Join Date: Aug 2009 Posts: 566	Just an FYI, the seal size can usually be found on the face of the seal, to make sure you get the correct replacement for your application.
	0