03 yz85 lost power overnight

[cowasucky]

I recently bought my 11yr old an 03 yz85 in immaculate condition. When I got it home and got a chance to really ride it, that s.o.b. would freakin' fly ! I was amazed at the power and a little concerned that it may be a little much for my son. Well, he surprised me and handled it well.....powerband and all. So it was time for gas and the guy I bought it from said 32:1 and he used Klotz. I had BelRay so I used it 32:1 with 87 octane. I realized what I had done after riding it fot 10 min or so, drained the tank, and put in a fresh 32:1 mix with 93 octane. Almost to the bottom of that tank and it's just never ran like it did when we brought it home through that first tank. I've cleaned the plug and that seemed to help a good bit at first, and I clean the air filter after every ride. I was thinking maybe the guy had a tank of 40:1 mix to sell the bike.....you know so when I test drove it it would scream (which it did). Does this sound right ? Or am I missing somthing ? Honestly, I don't know a whole hell of a lot about troubleshooting or working these 2strokes. All I know is that I love 'em and won't buy or ride anything else nomatter how big a pain in the ass they can be. So help me out guys, I apreciate it a lot !!!

 

[_JOE_]

If the performance changed the drastically overnight I would suspect a bearing seizing up. It might be a good idea to pop the cylinder off and have a look inside before it ruins the cases or something.

 

[cowasucky]

First of all, thanks for the feedback. I always respect and apreciate someone taking the time to lend a hand. My thinking here is wouldn't a bearing seizing cause more than just making the bike a little slower?? It stil runs excellent. No different sound, no rough idle.....it just doesn't seem to have the same ummfff it had with the origional tank of gas. It will be so easy to prove or disprove my theory as soon as this damn rain stops!!! I thought today was the day, we had a 2 day break in the clouds. I woke up this morning and I'll be damned if it didn't rain last night.....the weather man sure didn't call this one. Anyway, thanks again and if 40:1 doesn't do the trick I'll check the bearings. Thanks again !!!!

 

[_JOE_]

Was there much of a temperature or humidity difference between rides?

 

[Chili]

Start with a new fresh plug not a cleaned one and then take it from there. My guess is it's jetted a bit rich and the plug is fouling, 40-1 vs 32-1 won't make that kind of difference in performance.

If it doesn't perk back up with a fresh plug I'd check the compression.

 

[cowasucky]

Ok, I'll pick up the plug tommorow. Now after cleaning it, it was a nice golden tannish color. I thought that meant it was ok. I don't doubt your advice though. If I knew more than you I'd be answering questions instead of asking them. Thanks !

 

[cowasucky]

And Joe.....yes, it's been extremely humid....its been raining for what seems like a year straight. Good old south Louisiana springtime !!!

 

[_JOE_]

A 2 dollar spark plug is always a good start. Temp and humidity can cause a noticeable difference in performance, so if the plug doesn't help you might try jetting it.

 

[cowasucky]

The spark plug did it !!! Man, that's a strong ass little bike when it's running right.. Thanks again !!!