Gear shift problems

Magic Pickle · Jan 20, 2003

Sometimes when I shift into second on my 2002 yz 250, the bike doesn't quite sound or feel right when power is applied. It even drops back into nuetral on occasion. Any guesses as to what may be going on. Pretty sure its not user error.

cr25096er · Jan 20, 2003

is the clutch slipping? does it literly drop back down into nuetral or does it feel like nuetral then take off? id inspect the clutch and shift star.

Magic Pickle · Jan 20, 2003

It feels like a rough second then drops back down to neutral

David Trustrum · Jan 20, 2003

It isn't engaging far enough so it doesn’t drop fully into position. It will feel rough as the gears are rubbing on their thrust washers causing friction.

Try to sort this out before gear dog damage is done.

Suspect the easy stuff first. 1-2 is the longest change (has to get over neutral).

Check that your lever is tight & positioned so that you get a good toe up position. Check it can’t rub on anything at top of stroke. Check the shaft it runs on isn’t bent from a crash.

Then I’d have a look at that star as stated above. Perhaps a stamping flaw needs tickling out. Failing that several internal flaws are possible, but try the easy stuff first.

bscottr · Jan 21, 2003

Good stuff from cr250 and David. :thumb:

Take a look at # 8 (the spring) as well. If it’s weak it could cause the problem. The best way to inspect it and the shift star is to pull the right side cover and shift from 1st to 2nd, 2nd to 1st several times. The follower wheel should pass over the neutral position and bottom in the 1st/2nd position. If it “balances” on top of one of the peaks (i.e. the peak between neutral and 2nd) you may have a weak detent spring or as David mentioned, a shift star (#5) needs the file treatment.

Hopefully the dogs are OK, but it will not take long to damage them. Keep us posted on your inspection.

marcusgunby · Jan 21, 2003

late model cr 125 have a bad shift from 1st to 2nd-its something they do even when new.Mine often popped back to neutral-has it got worse recently??

David Trustrum · Jan 21, 2003

Wouldn’t have expected a 2002 to have a weak spring yet but it is definitely worth a look. Also that the lever that spring is on is free & not bound up on bolt ‘10’ by a flaw making the spring less effective. Thanks for picture, makes it well easy to see.

I had an issue with my old RZ350 years back so I got a stiffer spring made. When I tried it, it was way too stiff so I couldn’t use it. Taught me only subtle changes where springs are concerned.

On problem bikes you can undercut the gears so they ‘pull in’, but it requires careful checking that they don’t come in too far & drag, have performed this with air tools before successfully.

Faded · Jan 21, 2003

I'm with Marcus, for some reason my 02 CR250 didn't want to shift into second as easily as I thought it should....definately not 'positive' engagement. Anyone have any ideas or similiar findings?

David Trustrum · Jan 21, 2003

Um,. . . ?? except Marcus is talking about the 125 & more pertinent the thread is about a YZ250.

marcusgunby · Jan 21, 2003

It is about a 250 but i was trying to say, some bikes dont shift well from 1st to 2nd even when perfect.If it has always been this way then its unlikely it will be repaired by replacing parts.

Faded · Jan 22, 2003

I reread the subject topic:

Gear shift problems

Thought I'd post my similiar problem here rather than start a new thread just because my bike is a different color. Sorry if I was out of line.

David Trustrum · Jan 22, 2003

No lines here to be crossed, just got a bit confused. :thumb:

darringer · Jan 22, 2003

Maybe try changing to a different tranny oil. I have noticed quite a difference in shifting with gear oils. Also, I change mine every other ride. If I don't, the shifting gets a little tight.

Faded · Jan 23, 2003

I've changed mine about every other ride so the frequency is there. I've tried the Honda stuff, ATF type F, and Mobil 15-50. Type F shifted the smoothest, but I found under high load/heat conditions (sand) it would break down really fast. The same with the Honda stuff, but with somewhat notchier shifting. I haven't tested the Mobil at the sand dunes, so I don't know how it holds up. I'm going to try picking up something motorcycle specific this year, maybe Torco, I'm not sure.

Regaurdless, with any of these the 1-2 shift is as described. Just doesn't feel like it's engaging all the way like the other gears. I'm also going to try a little longer lever (off a CR125) to see if the leverage will help gear changes.

David Trustrum · Jan 23, 2003

Yes that may help if more force is required- but it may make things worse as the shift distance over neutral position is longer, so if your ankle travel isn’t that far then it may be an issue.

I’ve found a notable improvement in shifting using Spectro oil (though some doubt on clutch, may be subjective).

Faded · Jan 23, 2003

No issues, the stock lever seems a little on the short side for my (big) foot, which might account for the harder 1-2 shifts which seem to require more shift lever travel. Also, the knurled toe-end is a little larger keeping the increased ankle travel to a minimum.

Magic Pickle · Jan 24, 2003

Thanks you all. It was a big help.

bscottr · Jan 25, 2003

Magic,
If you found the problem and was able to fix it, post the results here. Makes the forum much more effective AND helps the next guy. :thumb:

DEANSFASTWAY · Jan 30, 2003

On that picture of parts Ive had to replace broken # 7 more than once or twice on newer YZs while we are there we replace the spring also and torgue the bolts and screws and loctite them . Espescially on the shift star /shift drum bolt. Good Luck

Gear shift problems

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David Trustrum

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