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Sounds like the gear dogs have worn and under pressure the get forced out, ie the selector fork can’t hold the gear in (not that it’s meant to hold it in, its only meant to select the gear and the dogs lock in).
Saw a similar thing on a WR450. It had sent the selector fork blue.
The fix is to strip it down and replace the worn parts.
When its apart you’ll see tha fault its usually obvious.
Sam’s third gear on his KTM250 had a different problem. It felt like neutral, no jumping at all. The gear dogs litterally blew off and were sitting in the bottom of the box.
I may still have the WR gears here I’ll have a look and post a photo.
Below is Sam’s problem
[attachment=2850]KTM250Gear1.jpg[/attachment]
[attachment=2851]KTM250Gear2.jpg[/attachment]
Adam.
Found a pair of the 450’s gears. The previous owner had the problem, pulled the box apart, tried to grind the dogs square (without success), put it back together and flogged it off on Ebay to a mate of Sam’s :whistle:
It cost him a couple of hundred dollars in parts and two cases of beer but he got it back together and going.
Now if Sam’s mate can do it anyone can
All you need to do is read the instructions :dry: Something he had trouble with :laugh:
[attachment=2852]WR450Gear.jpg[/attachment]
Adam.
adam wrote:Sounds like the gear dogs have worn and under pressure the get forced out, ie the selector fork can’t hold the gear in (not that it’s meant to hold it in, its only meant to select the gear and the dogs lock in).Saw a similar thing on a WR450. It had sent the selector fork blue.
The fix is to strip it down and replace the worn parts.
When its apart you’ll see tha fault its usually obvious.
Sam’s third gear on his KTM250 had a different problem. It felt like neutral, no jumping at all. The gear dogs litterally blew off and were sitting in the bottom of the box.
I may still have the WR gears here I’ll have a look and post a photo.
Below is Sam’s problem
[attachment=2850]KTM250Gear1.jpg[/attachment]
[attachment=2851]KTM250Gear2.jpg[/attachment]
Adam.
Is thats Sams new 250 :ohmy:
TB
Trailboss wrote:adam wrote:Sounds like the gear dogs have worn and under pressure the get forced out, ie the selector fork can’t hold the gear in (not that it’s meant to hold it in, its only meant to select the gear and the dogs lock in).Saw a similar thing on a WR450. It had sent the selector fork blue.
The fix is to strip it down and replace the worn parts.
When its apart you’ll see tha fault its usually obvious.
Sam’s third gear on his KTM250 had a different problem. It felt like neutral, no jumping at all. The gear dogs litterally blew off and were sitting in the bottom of the box.
I may still have the WR gears here I’ll have a look and post a photo.
Below is Sam’s problem
[attachment=2850]KTM250Gear1.jpg[/attachment]
[attachment=2851]KTM250Gear2.jpg[/attachment]
Adam.
Is thats Sams new 250 :ohmy:
TB
Unfortunately yes
Happened on the second or third lap at last weekends AORC sweep.
He spent the rest of the weekend on Moose’s 250 with no problems.
There was no sign of any form of wear on any of the dogs, one dog that broke off had a slight mark on the edge probably where it hit the selector fork.
Interestingly one of the split cage roller bearings had a roller missing :unsure:
Looks like it was missing from its initial assembly. I doubt it had anything to do with the gear failure.
Ordered the new parts and doing a new piston as well
I’m quiet with work so it has given me something to do other than keeping the boss happy with jobs around the house :whistle:
Adam.
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