By daddybrad on Unrecorded Date: Edit

I just bought an attex super cheif for 350.00 very clean. It does need a little motor adjustment, but for the price can I go wrong??? Thanks, Brad Hudson

By K.Boyle on Unrecorded Date: Edit

Sounds like a good find Brad. Get some pictures up
so we can check it out

By pete6x6 on Unrecorded Date: Edit

Brad,

Sounds like a good find! What 500 is in it? Those things scream!

By chris cerrato on Unrecorded Date: Edit

Need some Attex Superchief help!!! What is the correct spark plug for this machine??? Is it the NGK B8ES?? Also what is the correct Mikuni carb size for the machine??

Any help from Superchief owners would be appreciated!!!

By Eric Magyor on Unrecorded Date: Edit

My 500 Superchief has the earlier G50B engine. It has a VM32 Mikuni carb. I use NGK B8ES plugs and that seems to work best. You can experiment with different NGK plugs to see which works best for your engine.

By chris cerrato on Unrecorded Date: Edit

More Attex Superchief help needed!! Thanks for the feedback Eric on plugs and carb. My Superchief had blown inner and outer crank seals and I just had them replaced by a professional mechanic. He even split the case to change inner seal. Also put in new muffler provided by Richard. Machine ran great for about an hour after fix and seals blew again!!

Anybody else encounter this?? Ideas on cause?? My mechanic says muffler is too small and caused Back pressure eventhough muffler is correct for machine. Any other possibilites you can think of?? Feedback is appreciated!!!

By roadwolf on Unrecorded Date: Edit

chris,
were the first seals blown?
or did you just want to replace w/new ones?
what do you actually mean blown?
the muffler shouldn't be a problem.
is it hard to start?
a bent crank will let air in around a seal.
hmmmm, where the replacement's oem seals?
how old were they?
is this motor a reed valve or pistion/port?
one last thing ( aleast for now ), if you just changed the seals for fresher ones, and the mechanic performed a post assembly pressure test of over 12 psi, that may have damaged the new seals.
reply-o-

By david berger (Davidrrrd) on Unrecorded Date: Edit

chris, could it be the mbte fule?(joke)

By chris cerrato on Unrecorded Date: Edit

First seals were blown and needed to be replaced. Both the inner and outer were shot and partially shredded.
When I got it back from mechanic (he split case too), was very easy to start and ran great. After 1-2 hour use, seals blew again and has become hard to start.
Machine will now "pop"out of the carb under load. Seals were correct ones that went into the machine and were fresh!!

This situation is definitely very strange. Any ideas as to what may raise pressure inside head to blow seals after such as short time period??

By ISAAC EISENMAN (Tropicjungleboy) on Unrecorded Date: Edit

HEY CHRIS:

check for the follow stuff:

a) if seal's outside measure and engine hole match...( some engines are designed on metric values)...and between sae and metric measures you can find little differences that will be enough to "displace" seal under compresion + heat + pressurized oil......a perfect formula to blow out a non enough "pressure fit" seal...also check for little "scrach" on crankshaft...if you found it you can "reduce it" with 1000 emeril paper or lapping compound ( the same used to fine tunning engine valves).......bottom line is that a powerless engine on aatv doesn't bounce great!!!

By Mike Longest on Unrecorded Date: Edit

Chris:

A two cycle requires vac in the crankcase to run. There is no way that too much pressure blew the seals as then the engine would not have run correctly

Mike Longest

By TJ on Unrecorded Date: Edit

a two stroke engine requires both vacuum and pressure in the crankcase to operate. as the piston travel's upward, it creates a vacuum in the crankcase, allowing the fuel/air charge to be drawn in. as it travel's down it creates pressure in the crankcase, causing the fuel/air mixture to travel thru the transfer ports, into the cylinder, where it's compressed as the piston travel's back up. i scrolled back thru this thread and i didn't see where chris told us what engine he has, since it's a superchief i imagine it's a two cylinder. all of the older 2 cylinder, 2 strokes i've seen have to have the crank disassembled to install the inner seal's. i'm not trying to make life hard for the guy who wrenched on the engine but, there isn't many shop's that can disassemble a crankshaft and reassemble it, as well as phase it. and i didn't see any mention of the crank bearing's being replaced, that throw's a flag with me. i've built allot of 2 stroke twin's, and i've never seen a "shredded" seal. i can't think of what would shred both the inner and outer seal's, and not be found when you had the crank out. chris, i'm in wichita,ks if your close, i'll help you with it.

By chris cerrato on Unrecorded Date: Edit

Thanks for the help on this. Thanks for the offer TJ, but I live in WA. Alas, too far away. We'll see what the mechanic has to say when he looks at machine again. I was incorrect, only outer seals were shredded. He never replaced inner seals-my misunderstanding.

Should know more next week.

Chris

By TJ on Unrecorded Date: Edit

allot of times, when someone is having problem's with an older 2 stroke engine. the culprit is an air leak, down stream of the carb. if you decide to test your crankcase, i'd recommend not to exceed 5psi. i would also recommend that you pull a vacuum on it, i pull them down to 5"s, if they lose less than 1psi/1" in 5 minutes i'll accept it. if they lose more than that, i find out where, why and correct the problem. it's very easy to do these test's yourself. e-mail me if you have any question's. i'll help as much as i can.

By david berger (Davidrrrd) on Unrecorded Date: Edit

cris, also in adition too what tj has said if there was an air leak prehaps a lean condition may have caused a flash in the crankcase, pow !
did you say it was poping and coughing from the carb befor the trouble? defenatly an ignition of the crankcase fumes would do the seals in,

By zerbo on Unrecorded Date: Edit

just bought a thunder chief 440 with twin mikuni carbs,when i tried to start it i noticed gas poring out of little hole on bottom of bowl,the other carb has a little bb in the hole,do i need to replase bowl or just block it of.

By flower on Unrecorded Date: Edit

i want to buy a hustler or a argo super sport i need some help making a decision please talk to me

By david berger (Davidrrrd) on Unrecorded Date: Edit

flower, thats a tough question, both are good strong preformers, are these choices from vehicles you have already found?
can you tell us anything about condition of them?
or have you decided to look for an aatv and only narrowed your wish list to one from this pair?