Gearbox failure
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wrote on 19 Jan 2021, 08:23 last edited by
@lllDennis Two-stroke piston seizures are either thermal-related or lubrication-failure-related. That one appears to me to be lubrication in nature. Could be overly rich jetting that allowed liquid fuel to wash oil off of the piston skirt as the fuel comes through the transfer ports, causing a lubrication failure.
If you need a gearbox have a couple of complete low mileage boxes can do you cheap. -
wrote on 19 Jan 2021, 20:08 last edited byThis post is deleted!
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@lllDennis Two-stroke piston seizures are either thermal-related or lubrication-failure-related. That one appears to me to be lubrication in nature. Could be overly rich jetting that allowed liquid fuel to wash oil off of the piston skirt as the fuel comes through the transfer ports, causing a lubrication failure.
If you need a gearbox have a couple of complete low mileage boxes can do you cheap.wrote on 19 Jan 2021, 20:16 last edited byHey guys thanks for the replies. It's probably the harder break in tha caused the damage. I only had 300km's on it and probably forced it with the top speed run.
I also opened the gearbox and seem to have stripped a gear. Lots of heat was Involved.
I included some pictures below. I've never seen damage like this before. Is this normal?
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wrote on 19 Jan 2021, 20:19 last edited byThis post is deleted!
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@lllDennis Two-stroke piston seizures are either thermal-related or lubrication-failure-related. That one appears to me to be lubrication in nature. Could be overly rich jetting that allowed liquid fuel to wash oil off of the piston skirt as the fuel comes through the transfer ports, causing a lubrication failure.
If you need a gearbox have a couple of complete low mileage boxes can do you cheap.wrote on 19 Jan 2021, 20:27 last edited by@theportingmaster The jetting was extremely rich. Apparently there are 2 sorts of mikuni jet 'sizes'. In my carb there was a 250 mikuni jet. So i ordered aftermarket 250-300 for the Athena kit to test with. But the aftermarket 180 size is the same as original 250.
It was overlay rich while tuning the carb until i figured this out.
If you got a excellent low milage gearbox for me send me a message with some details. Really appreciate it
I looked at new original parts but it's a little expensive for my student wallet
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@theportingmaster The jetting was extremely rich. Apparently there are 2 sorts of mikuni jet 'sizes'. In my carb there was a 250 mikuni jet. So i ordered aftermarket 250-300 for the Athena kit to test with. But the aftermarket 180 size is the same as original 250.
It was overlay rich while tuning the carb until i figured this out.
If you got a excellent low milage gearbox for me send me a message with some details. Really appreciate it
I looked at new original parts but it's a little expensive for my student walletwrote on 19 Jan 2021, 20:56 last edited by@llldennis dayum, that's not a stripped gear, that's completely melted
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wrote on 20 Jan 2021, 09:32 last edited by
@lllDennis Best jetting for Athena 170 is 300 main jet on the
Mikuni tm28 but with the powerjet blocked off. Just cut the
rubber tube in half from the float chamber to the powerjet then block the 2 halves of the rubber tube with a couple of 5mm threaded bolts or similar. -
@llldennis dayum, that's not a stripped gear, that's completely melted
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@calum Any recommendations on a crankshaft? While everything is open I want to replace it anyway (Has some small grooves where the bearing is). Best with original or aftermarket?
wrote on 26 Jan 2021, 17:49 last edited by@llldennis Didn't know they do aftermarket cranks?
Always Originate, Never Pirate!
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@llldennis Didn't know they do aftermarket cranks?
wrote on 27 Jan 2021, 12:47 last edited byThere's some on ebay for less than £200
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@llldennis Didn't know they do aftermarket cranks?
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There's some on ebay for less than £200
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wrote on 7 Feb 2021, 17:25 last edited by
@jimmydc98 Cheap
That's good to know at least. Connecting Rod for my RS is that price alone
