Head rebuild-ALT125.

[Havoxx]

Hey peeps, as you all know I have 2 Suzuki ALT125's, ones running great, however, the other smoked like hell, so we ripped apart the engine, and this is what we found, my dad thought it was the connecting rod, but that looks straight as can be.

If anyone can offer any insight as to what caused this, We'd greatly appreciate it.
http://img2.putfile.com/thumb/2/3113003084.jpg (http://www.putfile.com/pic.php?img=7594568)
http://img2.putfile.com/thumb/2/3113003025.jpg (http://www.putfile.com/pic.php?img=7594567)
http://img2.putfile.com/thumb/2/3113003036.jpg (http://www.putfile.com/pic.php?img=7594566)

[SWIGIN]

what am i looking for?

[RedRider_AK]

Bent connecting rod wouldn't make it smoke. Looks like it was run really hard, maybe jetted wrong or run without an air filter, which caused overheating and warped the piston.

[Havoxx]

Yea, dad says he used to run it in the mud all the time and would have to take the spark-plug out to take the water out, what causes the smoking though? It's a white nasty smelling smoke lol.

[money89tractors]

Check the cylinder and piston for out-of-roundness. Looks like there was a lot of oil getting into the cylinder, judging by the buildup on the piston. Check the valve seats and guides to make use they werent dumping oil into the cylinder.

-Phil

EDIT: i posted just before your post was put up. With him running it through the mud, its very likely it was overheated. The white smoke is oil burning inside the cylinder. Like i said, check the cylinder for out-of-roundness, along with the piston. If theyre both good, put a new ring set it in and it should be fine (assuming the valve guides are not leaking.)

[Havoxx]

Thank you for all your help, soon as my dad gets home hes gonna check that out, since I'm not a mechanic :P, I just take the stuff apart ;). He says back in the day he changed the valve seats.

You know, I thought it was gonna be a big piston, looks like a toy, and messed up like that, it STILL started, nothing like japanese engineering :P.

Any case, thanks again. I'll have some videos up soon once we get it running :).

[brapp]

sounds leik tim for a top end and a good fluch out fo the water and mud in the bottom end. my foreman is goign trough the same thign and it have been nicknamed the yellow submarine

[TeamGeek6]

Looks like Copper Coat gasket spray was used on the jug from the orange-ish color. Piston and cylinder walls are burnt to a crisp.

Rods arent "looked at" for straightness. eyes cant tell that.

Lots of burnt oil in the head and piston crown. Cylinder walls worn smooth. Burnt up pretty bad.

Id say thats what not changing the oil looks like. The shiny cylinder walls are due to the piston rubbing, and that cant happen unless the oil breaks down, or the rod bearings are bad,

[Havoxx]

Yea, after cleaning up a bit, the piston looks to actually be in good shape, isn't really that scarred, as for the oil, not sure how many times my dad changed it, but I know he's not one to neglect that, though he did run the hell out of the bike :D. We called it a night already, but I already got all the gaskets shaved off, and cleaned up a bit, tomorrow we're gonna check out the valves and rods, make sure they are good, as for telling :D, we have the tools, that's not a problem.

Hopefully it's not too screwed up, and we can get it running well again :D.

[RedRider_AK]

It will probably need to be rebored to the next size over, or the new rings won't seal up correctly.

[Havoxx]

Well, got a little update, we haven't honed it yet, but just sitting without rings it has a miniscule gap between the piston/head, so not sure if that's good or not, haven't checked with the dial.

As for the guides, they're fine according to the guide in the manual, though were checking with the dial on monday. The intake seat was perfect, the exhaust seat is gone though.

Heres some pictures after the cleanup, and of the bike with it's new/used plastics :P.
http://img2.putfile.com/thumb/2/3217581279.jpg (http://www.putfile.com/pic.php?img=7600702)http://img2.putfile.com/thumb/2/3217581218.jpg (http://www.putfile.com/pic.php?img=7600701)
http://img2.putfile.com/thumb/2/3217581288.jpg (http://www.putfile.com/pic.php?img=7600700)http://img2.putfile.com/thumb/2/3217581297.jpg (http://www.putfile.com/pic.php?img=7600699)
http://img2.putfile.com/thumb/2/3217581278.jpg (http://www.putfile.com/pic.php?img=7600698)http://img2.putfile.com/thumb/2/3217581262.jpg (http://www.putfile.com/pic.php?img=7600697)
http://img2.putfile.com/thumb/2/3217581117.jpg (http://www.putfile.com/pic.php?img=7600696)http://img2.putfile.com/thumb/2/3217581147.jpg (http://www.putfile.com/pic.php?img=7600695)

Those gaskets are a pain to remove as well, still working on doing that without ruining the metal itself.

[RedRider_AK]

That head is probably warped. Check it on a pane of glass or a perfectly flat table.

[Havoxx]

That head is probably warped. Check it on a pane of glass or a perfectly flat table.

How would I know if it's warped? it would move around or something? Like, it wouldn't be flat?

[TeamGeek6]

Get a piece of carbon paper and plain paper, make a head gasket from it and tighten the head down, the papers will print wherever the head touches the deck. With that much abuse, just assume its warped badly. Thats WAAAAY too much work to do to not true the head and deck.

I like to grind all the flat surfaces, engine cases included.

OVen cleaner spray will dissolve valve deposits and old gaskets(with methelyne chloride)

Id take an hour with a die grinder and relieve those sharp edges in the dome around the spark plug, thatll wake that lil engine up.

[Havoxx]

Heh, You know the funny thing, once we cleaned it up, the metal itself is really nice without many nicks/scratches, but yea, that will wait for tomorrow morning, good thing is if it is a bit skewed my dad can fix it at his workplace :D.

Btw, anyone know where I can get a head kit for this? you know, gaskets, seals, guides, and all that other fun stuff? :P

[TeamGeek6]

Nicks and scrateches arent usually the problem, its where the parts bolt together - the torque and heat tend to warp the surfaces. Thats where the leaks happen.

[Havoxx]

Nicks and scrateches arent usually the problem, its where the parts bolt together - the torque and heat tend to warp the surfaces. Thats where the leaks happen.


Well, I did the carbon paper thing, and not surprising to me :D, It's perfect actually, marked the whole area of the gasket, nothing missing, nothing darker, man I love this old suzuki :D.

[TeamGeek6]

THATS impressive.

[Havoxx]

Yea, like I said, it was sitting for 15 years with all that gunk on it, and it still started, it definitely is a piece of craftsmanship if I've seen it lol. But uh, it isn't made in china :P, so that would probably help! lol.

[Havoxx]

Heh, heres the head after a run in the parts washer :D, it looks like new if ya ask me :D.
http://img2.putfile.com/thumb/2/3818272733.jpg (http://www.putfile.com/pic.php?img=7642361)
http://img2.putfile.com/thumb/2/3818272753.jpg (http://www.putfile.com/pic.php?img=7642360)

Got the topend kit getting here on tuesday, I'll update on that ,after I get it running :D.

[Havoxx]

Ah, now after I got everything cleaned I finally got around to measuring the valves, and the intake has wasted down by about .2mm, so I got that one coming after the kit unfortunately, I'll have to wait to put the head on it. Heres the pics of it all nice and clean though, the bottom portion has some surface rust on it from a huge storm the other day, but it's fine, gotta clean it off.

http://img2.putfile.com/thumb/2/4120090314.jpg (http://www.putfile.com/pic/7659532)http://img2.putfile.com/thumb/2/4120090439.jpg (http://www.putfile.com/pic/7659533)http://img2.putfile.com/thumb/2/4120090334.jpg (http://www.putfile.com/pic/7659531)



My dad washed the top, but the paint didn't strip off, so I can only figure he repainted it when he did the valve seats back in the day, all the original paint is gone now :D.