90 YZ250 loses power
- Thread starter Bside003
- Start date
Could be just jetting or dirty carb. A tired motor usually loses power off bottom.
rmc_olderthandirt
~SPONSOR~
- Apr 18, 2006
- 1,533
- 8
The power valve could be stuck. I had mine gum up and it was like there was no top end at all. Easy fix, remove the power valve, clean, reassemble. 30 minute job the first time I did it, probably a 10 minute job now that I know how.
If the bike has issues that the seller doesn't want to fix then it is a good bet that other maintenance on the bike has been deferred as well. When considering the value of the bike factor in the condition the tires are in, brake pads, chain guides and other wear items. These are all easily fixed items it just takes a few $$.
The power issues could be something simple but you should consider the probability that it needs the carburetor cleaned and the top end rebuilt. A new set of carburetor gaskets will probably cost around $20 and I would recommend changing the float valve, around $40. A top end rebuild, if done now before things get destroyed, will be around $200.
Rod
If the bike has issues that the seller doesn't want to fix then it is a good bet that other maintenance on the bike has been deferred as well. When considering the value of the bike factor in the condition the tires are in, brake pads, chain guides and other wear items. These are all easily fixed items it just takes a few $$.
The power issues could be something simple but you should consider the probability that it needs the carburetor cleaned and the top end rebuilt. A new set of carburetor gaskets will probably cost around $20 and I would recommend changing the float valve, around $40. A top end rebuild, if done now before things get destroyed, will be around $200.
Rod
I bought a 95' YZ 250 this spring from a guy that rode it 2 maybe 3 times a year for the past 10. He changed the oil and cleaned the carb every spring and that was it. He too was getting out of the sport as time and age were not his friend anymore.
The power valve was REALLY gummy. The bike had the same performance you describe. Ran good on the bottom with a decent mid and no top. After cleaning the valve it was a new bike. Listed are somethings to consider that your bike will probably need as mine needed them and it was in decent shape.
New chain/sprockets
New wheel bearings/seals front and rear
Cleaned the carb
changed oil 2 times to make sure it is clean
brake pads
fork seals
new handlebars/grips
These are things I knew about so the paying price reflected this. If you have a compression guage then that is a good tool to have when inspecting the bike as well.
The power valve was REALLY gummy. The bike had the same performance you describe. Ran good on the bottom with a decent mid and no top. After cleaning the valve it was a new bike. Listed are somethings to consider that your bike will probably need as mine needed them and it was in decent shape.
New chain/sprockets
New wheel bearings/seals front and rear
Cleaned the carb
changed oil 2 times to make sure it is clean
brake pads
fork seals
new handlebars/grips
These are things I knew about so the paying price reflected this. If you have a compression guage then that is a good tool to have when inspecting the bike as well.
rmc_olderthandirt
~SPONSOR~
- Apr 18, 2006
- 1,533
- 8
Another thought I had:
The seller says it "loses" power at the top end. That may be different than "just doesn't have the power" at top end.
If it has the power initially and then dies out it could be that the carburetor float valve is a little messed up and not allowing enough gas to flow. A good carburetor cleaning should clear that up.
Rod
The seller says it "loses" power at the top end. That may be different than "just doesn't have the power" at top end.
If it has the power initially and then dies out it could be that the carburetor float valve is a little messed up and not allowing enough gas to flow. A good carburetor cleaning should clear that up.
Rod
- Thread starter
- #8
Well I finally got to see what she was made of.
The top end power issue was only a carb adjustment, the guy I bought it from had his friend tweak it in and it has power throughout the ranges now, but if I run her cold she is very boggy until she gets warmed up(kinda like my wife :laugh: ) then plenty of power.
I went out to "The Mounds" ORV park and let her rip, the only thing I found annoying was if I laid the bike down to help someone else out, it was very difficult to get re-started, at least 10-12 kicks, sometimes more, otherwise she starts on the first kick.
I am planning on cleaning out the carb 'cause I'm thinkin it's probably got something to do with the float.
The bike has fairly new handlebars and grips, I'm definately gonna change the oil, a new chain is in order, and the fork seals are leaking pretty good, but for $600 I think I got a good deal :nod:
The top end power issue was only a carb adjustment, the guy I bought it from had his friend tweak it in and it has power throughout the ranges now, but if I run her cold she is very boggy until she gets warmed up(kinda like my wife :laugh: ) then plenty of power.
I went out to "The Mounds" ORV park and let her rip, the only thing I found annoying was if I laid the bike down to help someone else out, it was very difficult to get re-started, at least 10-12 kicks, sometimes more, otherwise she starts on the first kick.
I am planning on cleaning out the carb 'cause I'm thinkin it's probably got something to do with the float.
The bike has fairly new handlebars and grips, I'm definately gonna change the oil, a new chain is in order, and the fork seals are leaking pretty good, but for $600 I think I got a good deal :nod:
