my exhaust is leak PLEASE HELP

Joined
May 9, 2007
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#1
i just bought a 1999 model cr125 and my exhaust is leaking and im wondering if anyone can help is it coz my fuel is to rich
 
Joined
Mar 12, 2007
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#2
CR125 is a 2stroke bike. 2 Strokes tend to dribble some at the exhaust, both at the header area where the pipe connects to the cylinder and at the junction between the silencer and pipe. Additionally, they also spew a bit out the end of the silencer. I'd be more worried if it didn't...

That said, if you supply the forum with some additional information we can help you dial in your jetting a bit closer so the amount of oil spewed is minimized.

1 What octane gas are you running?
2 What oil are you using?
3 What is the pre-mix ratio you are using?
4 What spark plug are you using?
5 Is the spark plug properly gapped?
6 What's the elevation of the area you ride in?
7 What are your current jet sizes?
8 Is your air filter properly cleaned and oiled?
 
Joined
Apr 26, 2007
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#4
twostrokes4life said:
i just found a little oil leaking out of one of the nuts on the head is this normal 2
It sounds like your head gasket is leaking. Your bike uses a gasket and not o-rings. I would replace the gasket and make sure the head was properly torqued. I'd also check the head to be sure it's not warped. It's also possible that it was leaking into the water jacket so the coolant should be changed as well.
 
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#6
Well, yes, typically a torque wrench. The manual should have the torque spec. Also, they are tightened a criss-cross pattern so the head gets tightened down evenly. It should also be done in 3 passes. For example, if the torque spec is 40 ft/lbs, I'd do the 1st pass at say 20, the next a 30, then the final at 40. It's more critical they they are all tightened evenly to each other than to hit the number exactly. Uneven torque may lead to warpage when exposed to multiple heating/cooling cycles. That's why I suggested that you check the head for warpage. All's that's needed is a piece of modern glass (float glass) and a feeler gauge. The manual will give a spec. on the maximum warpage amount. Select a feeler gauge that matches that amount. Place the head on the glass and try to slip it under the head. If it will slip between the head and the glass, it's warped excessively and should be replaced.
 
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May 13, 2007
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#7
Hey, I have the same question about the exhaust leaking. I have a 1999 yz 250 and its leaking from the exhaust pretty bad.

Ive been running mid grade fuel and a kind a 2 stoke oil from autozone. I have a feeling that may be my problem, so Im going to premium fuel and switching to yamalube today.

I live at 6000 ft elevation, so that may effect it too. Im running 34/1. the manual says 30/1 but it seemed like it was running a little too rich. 34/1 is running great, but I did foul a plug yesterday and it has been leaking alot.

BTW, new here. Nice to find a good forum like this.
 
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#8
Although fuel and oil type will have an effect on things, it's relatively minor. You have jetting issues. There are numerous posts and a sticky at the top of this forum that cover the subject extensively.

Marc -
 
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Jul 25, 2006
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#9
Don't run a 2stroke oil from the zone :coocoo: A two stroke mx bike is a totaly different beast than those oils were designed for.