Z wont Start

[IrideMHSC]

I rode my z a few times and it ran fair but was a little slow to start. I noticed some things were needing tuned on it so I replaced the spark plug cleaned the carb and the air filter as well as made sure the boots were tight on the carb... now when we try to start it, it still wont fire up it seems like its getting real close but never will stay running. its also back firing some... any suggestions?

[cady#1]

I have the same problem. Mine would stall under hard braking and backfires some. I checked the valves and they were off. I talked to my mechcanie and he said that the stock intake valves are soft and probaly starting to push into the head. As of right now after adjusting my valves and riding for a lilttle it wont start. That sounds like you are having the same problem, but I don't know it could be something simple.

[Z-Racer-5c]

I had the same problem with the hard braking. I did have my heads redone and a set of race cams. Still had a little problem and went 1 cooler spark plug. I didn,t check the ohms on the old plug but I just tried to start it after 3 month of no ridding and it fired on the first try. I wish I had the total answer but I did to many things at once to pin it down. I would replace the plug again just to make sure.

[exrider7510]

i have the same problem with stalling out after slowing down from high speeds . i get into 4th 0r 5th and bring it down quick and it will almost always stall. It will fire up again but will bogg and hesitate for a second and then run fine again. I think i heard somewhere it might have something to do with the rev limiter not too sure though . Does anybody have any ideas why it cuts out always.

[Raptor430]

hey, i would check the timing. i had a bunch of motor work on mine done and it got to where it wouldn't start and it kept backfiring when i tried to. i bought a brand new battery and it still did the same thing. i took it to the shop and they said my timing was off. hope this helps.

[Bigun55]

Originally posted by Raptor430
hey, i would check the timing. i had a bunch of motor work on mine done and it got to where it wouldn't start and it kept backfiring when i tried to. i bought a brand new battery and it still did the same thing. i took it to the shop and they said my timing was off. hope this helps.

Exactly what he said. check the timeing, my buddys got a kfx and had the same prob. and it was the timing. He's gettin it fixed right now actually. its in the shop right now. this is the 3rd time also.

[Taz14racer]

i had that exact problem on my Z and it turned out to be the cam chain timing and the valve wasnt closing all the way. i had to get a new valve and chain.


03 Z400
WB exhaust
AC pro.
Alba action grapics
Razars
K&N
Dura Blue axle
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[kawai 521]

Sounds to me like a valve adj. is needed. when the valves are not adjusted right the quad will be hard to start. as for the backfiring problem, it you have a 03 Z check the harness from the CDI box. The wires run between the palstic and frame, and have a tendancy to get rubbed raw. This is a problem that i had when i had my 03. It would run and cut out alot. hope this helps.