YZ426 won't start

It ran like 2 weeks ago, then just died? I have done the following and still won't start:

- Cleaned air filter

- New gas

- Replaced plug

- Checked ohms on coils and magneto (per manual)

- I replaced coil and magneto with spares I had.

- I checked ohms on kill button and neutral switches (per manual)

- I cleaned out carb (it was rebuilt last year)

- Im getting a nice blue spark

- I checked all electrical connections.

You and kick start with the choke pulled to your hearts content, nothing! Floods. Even tired without the choke and with hot start. :thumbsup: It will back fire time to time. Bout to set this one on fire! CDI next? Help!

Check to see if TDC indicated on the flywheel is actual TDC by probing the piston through the spark plug hole. Then check your cam timing.

I will double check that tomorrow. But why? For just in case? How would it get out of sync?

I will double check that tomorrow. But why? For just in case? How would it get out of sync?

because cam chains get old, stretch and can jump teeth on the cams. Then you are out of time.

I will double check that tomorrow. But why? For just in case? How would it get out of sync?
Because:

  1. The flywheel key can shear and cause the timing to move to a place far away from where it belongs, and
  2. The cams can jump time for a variety of reasons

my 2001 426 did the exact same thing!

started it on friday, ran fine for 10mins.

drove 3 hours to go riding saturday, unloaded bike, got all my gear on, started the bike. Idled for 10 seconds with choke on, as soon as i turned the choke off it cut out. Which isnt highly unusual when its cold.

then kicked and kicked and pushed it down hills, then back up. Finally towed it with our 4x4, still wouldnt go. plug looked fine.

Its at my mechanics now, so if u figure it out pls let me know! I have a 150kilometre ride planned in 2 weeks and need this bike going!

thanks

I have never seen a chain jump time without tearing up all the gear teeth, but I will check.

OK, all the marks line up, chain is tight, cam lobes are good and valves are all within spec.

my 2001 426 did the exact same thing!

started it on friday, ran fine for 10mins.

drove 3 hours to go riding saturday, unloaded bike, got all my gear on, started the bike. Idled for 10 seconds with choke on, as soon as i turned the choke off it cut out. Which isnt highly unusual when its cold.

then kicked and kicked and pushed it down hills, then back up. Finally towed it with our 4x4, still wouldnt go. plug looked fine.

Its at my mechanics now, so if u figure it out pls let me know! I have a 150kilometre ride planned in 2 weeks and need this bike going!

thanks

Welcome to my world brother!

I installed a another (used) magneto and coil I got off of ebay, and I noticed the spark was blue and fat (not like it was, white and weak). I will try out tonight and see. Of course, as I was putting it together last night, the NGK CR8E plug broke off the threads in the head POS! Extract that out and hopefully fire up tonight! :thumbsup:

may sound silly, but is there enough compression? broken ring etc.If its backfiring there is petrol and spark atleast,just not in the correct order maybe.I would go through evrything again, slowly, easy to miss something.

On the compression stoke, all 220#'s of me cannot kick it through! Compression is not a problem!

my bike is alive!

checked spark...had spark.

checked pretty much everything else...still no start.

put a new plug in it just to be double sure and it started first kick :thumbsup:

that sucks about yours breaking the threads, hope u get it sorted out soon!

......now i just need to fix the broken shift fork or whatever the jolt is in the gearbox lol

my bike is alive!

checked spark...had spark.

checked pretty much everything else...still no start.

put a new plug in it just to be double sure and it started first kick :thumbsup:

that sucks about yours breaking the threads, hope u get it sorted out soon!

......now i just need to fix the broken shift fork or whatever the jolt is in the gearbox lol

Man your lucky! What kind of plug did you use?

I put it all together (again), and nothing. Will not run! Any suggestions before I take it to the shop?

not sure on the exact plug, but was an NGK.

picking the bike up tonight from my mechanic, will let u know then.

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