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Breather pipe

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So the txt 280 pro is up and running, gets up to temperature fine and the fan kicks in like it should and seems to ride fine. I have noticed that the small breather pipe exiting the casing near the gear lever is slightly dripping oil, seems and smells like gearbox or atf oil. The pip is routed out by the bottom of the rear shock. Seems to drip only when revs are increase. Is this normal? Sorry I am just not that clued up with these little 2 strokes, gimme a Japanese 4 stroke 4 cyclinder race bike any day of the week 😂

You might try routing it up. It is the vent for the transmission. If you ever in the clutch side make sure the center bolt holding the clutch on is hollow. A hole is through the bolt.

On 11/23/2023 at 6:08 PM, iank said:

So the txt 280 pro is up and running, gets up to temperature fine and the fan kicks in like it should and seems to ride fine. I have noticed that the small breather pipe exiting the casing near the gear lever is slightly dripping oil, seems and smells like gearbox or atf oil. The pip is routed out by the bottom of the rear shock. Seems to drip only when revs are increase. Is this normal? Sorry I am just not that clued up with these little 2 strokes, gimme a Japanese 4 stroke 4 cyclinder race bike any day of the week 😂

i have experienced the same with the correct oil amount and everything as it should be and i just fitted a long piece of tubing that ran up to area above the fan shroud and the oil did not syphon up and out the tube it just moved up sometimes and then drained back into the case when the pressure in the case reduced. Here is something interesting not a GasGas obviously but shows it is a thing . https://youtu.be/V_RoMVsMDkg?feature=shared

Rule of thumb is vent pipes go up, drain pipes go down.  

Add that trials bike transmissions should not have a source of positive pressure, even a Montesa 4RT has a transmission that is separate from the crankcase oil.  If air is being pumped into your 2 stroke transmission it must be leaking past a crankcase seal, which is not intended by design.

13 hours ago, lemur said:

Rule of thumb is vent pipes go up, drain pipes go down.  

Add that trials bike transmissions should not have a source of positive pressure, even a Montesa 4RT has a transmission that is separate from the crankcase oil.  If air is being pumped into your 2 stroke transmission it must be leaking past a crankcase seal, which is not intended by design.

You are absolutely right of course but it is probably just less than a teaspoon of oil burbling about in a very thin bit of tubing on an old trials bike that can be used for years in that condition if only ridden once a month like a lot of people do owing to work/family commitments. Its not really worth rebuilding the motor just to try and stop that happening when the motor will happily run for 4 hrs at a time for a practice or competition session without problem. 

  • Author

Thanks guys, routed it up and been out on it for the 4 hours today practicing with a mate of mine. Absolutely loved it!! First trial entered for next weekend! God help me 

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