yz 426 starting problems, its like its locked up?


8 replies to this topic
  • codynewman13

Posted January 19, 2012 - 12:12 PM

#1

i have a 2001 yz426f its bone stock, it recently died on me once and when i tried to start it it was hard to kick over, so i got it back to my shop and tried again and it felt like it was locked up even with the decompression lever pulled in so i put it in gear moved it back and forth and it would kick again it started for a brief second then dide, usually it runs fine and nevr dies on its own, so i put it in gear and tried again and it started and ran fine i rode it around maybe 5 minutes and when i pulled my clutch in it instantly died on me and was hard to kick again. im not sure what it is i dont believe its anything to do with the piston or rings because the compression is right where it should be when it wants to kick and it doesnt smoke when running. it keeps doing this what could it be?

  • briangriff321

Posted January 19, 2012 - 01:54 PM

#2

Crankbearings prob toast and locking up in one spot

  • codynewman13

Posted January 19, 2012 - 02:21 PM

#3

but sometimes it can stay running for up to ten minutes and then do it? and it runs fine up until then so i dont think so

  • grayracer513

Posted January 19, 2012 - 04:06 PM

#4

If the rod bearing cage fails, it can do that. The bearings roll correctly for a while, then a couple of them get skewed, they jam themselves. But other things can cause stuff like this too, so I'm afraid expolratory surgery is in order.

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  • homernukem

Posted January 19, 2012 - 04:19 PM

#5

I agree with Grey racer. I bought several 426's with bad rod bearings. Supposedly the people before me rode them that way. You'll have to pull the head, cylinder ect. to verify it. Your problem may also be piston is shot. Sorry man. Even fixing it yourself it's going to be at least 500 bones to get it going again (seals, gaskets, oil, crank, piston, rings, cylinder, valves, water pump seals, or whatever else you find once you get into it).

  • codynewman13

Posted January 19, 2012 - 06:09 PM

#6

do you min the rod bearing in the bottom end or the bearing on the top of the rod for the piston? sorry new to this stuff

  • banda

Posted January 19, 2012 - 06:38 PM

#7

Con rod big end bearing. A known weakness. A new crank is just about the same price as getting a new big end bearing installed on the crank you have, unless you yourself are a crank builder.

  • briangriff321

Posted January 20, 2012 - 04:01 AM

#8

Once it cools it frees up ...when its hot metal expands which is why you can get it to run for a few minutes

  • crf-500

Posted January 20, 2012 - 06:51 PM

#9

i been watching ebay for rod kits and pistions and bearings etc. my 99 yz 400 third gear packed it in and i got to thinking its apart now why not rebuild it? cost could be the reason. can anyone recomend a good place to deal? and yes i know cheapest isnt best. i,m thinking about making it a 426 and weighing my options ,so far i got a transmission and tranie bearings and a 426 head any segestions would be apreciated





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