bah, i smoked another z

[zzmegad]

well out at the ice fishing derby yesterday i was giving my z hell and she didnt take it well. Moving down the lake at WOT and she bogged out. I knew it wasnt good. It doesnt feel like anything is broken, i can kick it over smoothly, I believe everything is intact, but there is no compression. Im gonna pray for the rest of the day and remove the head when I get home. :wondering

[badass350x]

Good luck, Hope its not real bad!!!

[Silverado]

You say you smoked ANOTHER z....what did you do to the first one ?

[zzmegad]

my first z died at the ice fishing derby 2 years ago, I bought it in pieces and fixed up/put back together everything. The bottom end was intact when I got it and I made the mistake of not redoing it. So that about wrecked the whole motor when it fell apart. For all know there could have been a screw or something down there...

[cattle-dog]

you should rejet your carb for winter riding in my book some say no but colder air is more condenced so more fuel is needed even in race cars we rejet for colder weather.
a little winter tuning can save you a engine.

[zzmegad]

hey cattle-dog that could be the problem although i did bump the main 1 size higher, I didn't feel like it was running lean and the motor did not run hot, we'll see when I pop the top. maybe it did seize and the piston is no longer connected to the rod. when i turned it over with my hand on the kickstarter it did feel like everything was there, just no compression, but that just doesnt make sence. man what a bummer, I cant wait to get home and check this thing out

[zzmegad]

well everything is still in working order :D some scoring can be seen on the cylinder but I saw this before through the exhaust port. When I recieved this Z, the carb was all messed up, running WAY to lean. I think I went up 4-5 sizes on the main and 2 on the pilot. The plug in the pic was used for approx 1/2 hour of alot of WOT. Im not sure why it lost compression, I guess it could only be the head or base gasket or maybe a cracked head. I didnt see any cracks in the head after a quick inspection. Anyways, Im gonna order up 2 top end gasket sets and see what happens. :wondering

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[swifty]

looks like you need new piston kit and bore job it has no compression because the rings are burnt scored to the piston... gaskets aint gonna fix it

[zzmegad]

dam, so then I guess I was running to lean... :(

[zzmegad]

i guess I just need to take it further apart for more inspection

[cattle-dog]

see how white that tip is way lean.

[zzmegad]

i was thinking the tip didnt get a chance to show it's real color, but I'll take your word for it and get some bigger jets. I did want to go up another size on the main too, but didnt have what i needed :crazy:

[zzmegad]

heres the plug that was in there before, this plug has had a tank or so ran on it, not the best picture but you can see its not that bad, I still agree I should richen it up

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[Chazz of Blades]

Here's an idea, stop taking Z's to ice fishing derby's.


Take a honda, you'll never be able to kill it.

[Thorpe]

You keep mentioning main jets and pilots... Dont forget the adjust your needle too

[k00leo]

got any pictures of the z? i love seeing pictures of them

[bcredneck]

check the crank before putting a new pistion and rings i asumed it was ok on a yz 125 2 days later a crank berring got stuck bettwen the pistion and a port big mess ill never do that again lucky we had a spare motor

[zmpolaristech]

In my professional opinion... it looks like cold seizure to me, since the aluminum is transfered at the intake ports and not just at the exhaust. Ie: to much WOT without the engine being completely warmed up to temp first... and I mean at least 150 degrees trailprotrailpro WOT... otherwise the piston (being aluminum) will expand at a much faster rate than the cast steel cylinder (ESPECIALLY IN COLD WEATHER!), and the piston will "tighten up" in the bore and friction takes over from there. then, you end up with what you have there... a melted piston.

[hondamaniac]

In my professional opinion... it looks like cold seizure to me, since the aluminum is transfered at the intake ports and not just at the exhaust. Ie: to much WOT without the engine being completely warmed up to temp first... and I mean at least 150 degrees trailprotrailpro WOT... otherwise the piston (being aluminum) will expand at a much faster rate than the cast steel cylinder (ESPECIALLY IN COLD WEATHER!), and the piston will "tighten up" in the bore and friction takes over from there. then, you end up with what you have there... a melted piston.


great info!

[cr480r]

it looks like cold seizure to me, since the aluminum is transfered at the intake ports and not just at the exhaust.

i agree.. .

[zzmegad]

yeah, I think maybe many mini cold siezures over the day until its final rip when it really burned up. On that final rip I was going for quite some time though, I'll deff be fatening up that main too. I was out at 4am and on and off the thing all day just beating it. It would get cold quick sitting on the lake when unused. It was a pain to start too once it got really cold. I was aware of cold seizures too and I thought I was letting it warm enough but I also thought I was ok on my jetting. So I need a bore job and piston kit, I guess I should consider myself lucky. I should just redo the bottom too. Ive never done a bottom end before.

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[zzmegad]

another pic
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[bcredneck]

changing crank berrings is expensive you can just pull it out and use a flashlight to look in the slit on the bottom of the rod
the bearring crowns tend to break at high temp when your running low on oil that makes the bearrings go sideways and the
$h!t realy hits the fan one losse bearring in a 2 stroke can kill a jug piston and head and it will run great right up to when the rear wheels lock up some times they run for a long time with that crap bouncing around in there the bearrings are realy hard metal and can cut a 1/4 inch deep in the inside of the jug

[Mosh]

You should pull your water pump cover and make sure the impeller is still attached to the shaft.

Damage pics look evident of that problem.

[zzmegad]

You should pull your water pump cover and make sure the impeller is still attached to the shaft.

dude as soon as I seen this i did a facepalm and moved out to the shed to check, but everything was ok... but thanks for mentioning, cause that slipped my mind