mike-evans
Member
- Sep 16, 2009
- 142
- 0
IndyMX said:Your local bike shop is wrong. They always come a bit rich from the factory. I doubt that the factory knows exactly what elevation, temperature and whatnot every bike leaving the factory is going to be ridden at. So, they send em out rich.
If you have a 50 in there now, and want to go down a size, 52 is not the right direction. That's bigger.
Don't listen to the guys at the local bike shop, read the jetting guides, and read your bike.
If it's bogging, there's a reason. Try leaning out the pilot & needle a step at a time, one at a time and compare the results.
If it gets better, you know you are on the right track. Also, talk to others who ride in your area and see what they are doing.
For all we know, that guy at the shop only rides street and doesn't really know much about 2 stroke MX bikes.
whenfoxforks-ruled said:Take the radiator cap off and start the bike. Do you see bubbles streaming in when revved? Does the smoke smell sweet? The pic just wreaks of a head gasket leak!
mike-evans said:Coolant in radiator does not loose a drop.
Its smokes, but its a blueish colour which I believe is the colour 2ts gives off?
Why do you think its head gasket?
Bike is on standard jetting which I think is rich??
whenfoxforks-ruled said:Lugging the engine around, as opposed to riding it like you stole it, will cause spooge build up.
whenfoxforks-ruled said:You could put like a 38 pilot in there, and as long as you do not run it for hours on end, will not cause issues. Warm it up, take it for a ride and see/feel/and hear what the engine is doing. The adjustment for highest idle, is just for pilot sizing, not race riding, it needs fine tuning still, after adjusting makes a difference/you have the correct size jet. The 50 is way big for a 250, in most applications! Personally, I hope you have some more pilot jets, 48, 45 and so on? It really is not difficult, once you get on the right path, and try it out.
whenfoxforks-ruled said:I will box up some snow, and the cold, to trade if that is better? Try JD jetting, he MAY be able to help with an assortment of jets. He may have some killer needles also! The guys at your shop are going to believe you are insane? Keep going smaller till the air screw is effective. It really is not that dramatic. The first time, everyone goes through it. Your bike does not have to only run good, when its running out of gas, or getting ready to blow up. Jet it.
adam728 said:50 jet is stock in a 01 YZ250, and most people agree it's too rich. I can't imagine running a 55 or even a 52. I run a 45 90% of the time in my 05, occasionally stepping up to a 48 for really cold weather (last ride was mid 20's).
You really need to:
- Go through the carb and make sure every bit of it is spotless.
- Set the float height.
- Make sure all the breather lines are clean and not clogged up. Do these first three before messing with the jetting.
- Does your bike use any transmission oil? Disapearing tranny oil can get sucked through the right side crank seal, burn with a ton of smoke, foul plugs, etc, mimicing rich jetting.
- Make sure the bike is up to temp before messing with the air screw and throttle response, meaning you've ridden it around some. Idling a few minutes and then reving it while sitting on the stand will get you no where when trying to work out jetting.
- A bog is typically lean. Blubbering is too rich. A hesitation, then "cleaning out" is too rich as well.
As was said earlier, all bikes are different. There's a big thread on another forum about what jetting YZ riders are using. I don't know your altitude or temps, but in most "normal" conditions (say 0-3000 ft, 50-80F) guys are finding generally
45-50 pilot
Stock needle on 2nd or 3rd clip from top
168-178 main
I typically run 45 pilot, stock needle 2nd clip from top, and 172 main, and I'm far from being too lean. Then again someone else with the same bike as mine might find they need to be 2 sizes richer.
Its like a blueish/witte, I'll know when I change the tranny oil soon...mxer9 said:blueish. I would definitely suspect the right side crank seal
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