250 The 1999 YZ250
- Thread starter Trfsrfr
- Start date
After getting thrown from that nasty pig WR Saturday morning, I find that its damn hard to pick that thing back up afterwards. Especially when you've just had your daily beating.
Add some mud and its 300 lbs. Enough is enough.
So I'm resurrecting the YZ250. It's 50 lbs lighter, and thats a done deal. If you'll recall it got parked last year with a ticking noise.
Compression with the carb off and not running for 6 months tested out at 201psi, then I tore down the top end and had a look.
Everything looked okay except for the ring end gap was at the max .037, and there was some play in the wrist pin bearing, which I'm hoping is the ticking noise. Everything else looked good. Cylinder measurements are near stock.
I put in a piston kit, an OE bearing, and I'm waiting on head seals. I'll know Wed if the ticking noise is gone...
Add some mud and its 300 lbs. Enough is enough.
So I'm resurrecting the YZ250. It's 50 lbs lighter, and thats a done deal. If you'll recall it got parked last year with a ticking noise.
Compression with the carb off and not running for 6 months tested out at 201psi, then I tore down the top end and had a look.
Everything looked okay except for the ring end gap was at the max .037, and there was some play in the wrist pin bearing, which I'm hoping is the ticking noise. Everything else looked good. Cylinder measurements are near stock.
I put in a piston kit, an OE bearing, and I'm waiting on head seals. I'll know Wed if the ticking noise is gone...
Time keeps on ticking, ticking, into the future.
Time to fly like an eagle.
Time to fly like an eagle.
Haha, I was expecting that!
Nice! I just took my YZ out for a final ride about 3 weeks ago before selling it since we're possibly moving in the next couple of months. The 4-stroke is newer and I probably rip better laps on it, but I miss the YZ already 
If nothing else, I miss having the security of a backup bike since the YZ is so easy to work on. Even the forks on my kx250f are a pain to work on 
Anyway, when I took out the '99 YZ250 for the last ride, I forgot how much it wants to take off! I feel like I am starting to ring out the 4-stroke to keep it moving, but that YZ will just happily pull you along for the ride. I love it
Actually, for family reasons the wife and I are looking towards AZ. Not to hijack the thread too much, but @Trfsrfr does anywhere around Chandler/Gilbert have good places to ride (I ride mostly track, but riding is riding lol)? I'm sure better than Illinois (read: if I drive 3 hours round trip to get to the track 2x/week. but now it is starting to get cold and riding season is ending ).
If we make it out there, I may end up with another YZ
-RageD
If nothing else, I miss having the security of a backup bike since the YZ is so easy to work on. Even the forks on my kx250f are a pain to work on Anyway, when I took out the '99 YZ250 for the last ride, I forgot how much it wants to take off! I feel like I am starting to ring out the 4-stroke to keep it moving, but that YZ will just happily pull you along for the ride. I love it
Actually, for family reasons the wife and I are looking towards AZ. Not to hijack the thread too much, but @Trfsrfr does anywhere around Chandler/Gilbert have good places to ride (I ride mostly track, but riding is riding lol)? I'm sure better than Illinois (read: if I drive 3 hours round trip to get to the track 2x/week. but now it is starting to get cold and riding season is ending
).If we make it out there, I may end up with another YZ
-RageD
Some thoughts on the yz today;
1 - It was a good day at the track. It's so much easier to ride a lighter bike. I'm not nearly as tired now afterwards as I was with the WR. Add my new track skills to re-learning how to ride a 2-stroke, and it made for a fun day.
2 - She still has that ticking noise, maybe even louder now, but I'm not sure. Since I just replaced a bunch of top end stuff I'm thinking it's not from there. I also dont believe its from the bottom end, as that felt tight. I'm hoping its from the power valve assembly. I didn't touch that when I had it apart.
3 - I fouled a new plug in the first 10 minutes of riding. Ended up lowering the float (got one of those float measurement tools) from 6mm to 7mm. Spec is between 5.5 & 7.5. I might go further if I cant get rid of the sputter.
4 - It sputters still, but now from about 3/4 throttle up. I started the day with a 170 MJ, then put in a 172 with no noticeable change. I cant tell if its sputtering from being lean or rich. It feels like rich, but I'm gonna keep going bigger on the main until I'm satisfied it needs to go the other way. If I get up to 178 and it dont change, I may just drop the float to 7.5mm and restart with the 172MJ.
5 - Forks - I bottomed them a bunch. I spun in my top clickers on the advice of one of the other riders and it seemed to help, but I need a crash course on clickers and MX suspension setup/geometry. I know very little in this area.
All in all it runs better now with the exception of that ticking noise. Throttle is crisp and makes good power. Just gotta get the little things fixed and she'll be a fun track bike. It was good to get back on a smoker again.
@2Wheels - that teflon trick is probably one of the best, most useful hacks I have seen. Worked like a charm, thanks again.
1 - It was a good day at the track. It's so much easier to ride a lighter bike. I'm not nearly as tired now afterwards as I was with the WR. Add my new track skills to re-learning how to ride a 2-stroke, and it made for a fun day.
2 - She still has that ticking noise, maybe even louder now, but I'm not sure. Since I just replaced a bunch of top end stuff I'm thinking it's not from there. I also dont believe its from the bottom end, as that felt tight. I'm hoping its from the power valve assembly. I didn't touch that when I had it apart.
3 - I fouled a new plug in the first 10 minutes of riding. Ended up lowering the float (got one of those float measurement tools) from 6mm to 7mm. Spec is between 5.5 & 7.5. I might go further if I cant get rid of the sputter.
4 - It sputters still, but now from about 3/4 throttle up. I started the day with a 170 MJ, then put in a 172 with no noticeable change. I cant tell if its sputtering from being lean or rich. It feels like rich, but I'm gonna keep going bigger on the main until I'm satisfied it needs to go the other way. If I get up to 178 and it dont change, I may just drop the float to 7.5mm and restart with the 172MJ.
5 - Forks - I bottomed them a bunch. I spun in my top clickers on the advice of one of the other riders and it seemed to help, but I need a crash course on clickers and MX suspension setup/geometry. I know very little in this area.
All in all it runs better now with the exception of that ticking noise. Throttle is crisp and makes good power. Just gotta get the little things fixed and she'll be a fun track bike. It was good to get back on a smoker again.
@2Wheels - that teflon trick is probably one of the best, most useful hacks I have seen. Worked like a charm, thanks again.
Try a 40 leak jet, and reset everything to stock, then go from there.
Another tidbit from Tech-care. Also, I believe (and I always screw this up and can be 50% correct-LOL) the compression is bottom, and rebound is top, or visa/visa of course. But I think comp bottom. I was looking for the right page, and I have a worksheet at the CA house that I pulled from this site, just not in CA until tomorrow eve.
Now you got me wondering. I made all sorts of adjustments today, with no idea what I was doing.