How bad must you melt a piston before it has to be replaced?

[ws6transam]

Pinging, by its very nature is indicative of the insidiousness malfeases within the bowels of the energy transforming unit. the resulting physical deformation of the primary mechanical entity pales in comparison to the potential catastrophic collateral damage that will likely occur if the primary cause of the pinging goes undetermined and unrectified. Kentuckifed engineering is no solution to the malfeases, utilize proper resolution techniques to ensure reliable performance when venturing out in the abyss.

Sending chills down my spine, man.... the scariest part was that I read it at full speed and didn't even have to re-read it once, which is proof beyond all reasonable doubt that my geekiness is manifesting the longer I stay away from the race car and the trail bike.

I am putting a fuel line with increased reliability and flow onto the machine to address the issue of inadequate fuel delivery. A re-route of the line plus fuel filter replacement and tank cleaning should correct much of the malfeasance.

In other news, the cylinder is bolted in, and the piston looks like jewelry in there, as does the cylinder wall. It ought to as it cost enough! I'm probably about an hour from getting it running again.

 

[_JOE_]

If you still have the pinging after ensuring adequate fuel flow and proper jetting I would suggest sending the head to Forward Motion. Eric can probably mod the head to alleviate the pinging. Shouldn't cost much at all.

 

[ws6transam]

Thanks Joe,

Forward Motion already modified the cylinder head and he ported the cylinder. I haven't really had many issues with pinging until that fateful 97 degree day. I must say, ever since Eric did his thing to the cylinder, and Garry from EFM Autoclutch custom CNC'ed that centrifugal clutch basket, this WR500 has been a dream for slow-poking in the woods and also ripping up the fire trails. It never fouls a plug , starts on the first kick, and you also can't stall it anymore! It also weighs 262 pounds when fueled up- A bit heavy for a two stroke but probably right in the ballpark with modern 4T machines of comparable power.

Thanks for all the suggestions everyone,
-Dan

 

[dirt bike dave]

Have you considered eliminating the fuel filter altogether?

 

[ws6transam]

The fuel filter is there because I put that "Blue Lightning" tank sealer into my plastic fuel tank. Unfortunately it doesn't work on plastic tanks, no matter what anyone says. My extensive surface preparation efforts were all in vain. There's no way to get that stuff to stick to a used fuel tank. I was hoping to keep the vapors from discoloring the plastic and bubbling the tank decals, but it failed miserably. As a result, I now get little green flakes of tank sealer in the fuel which play heck on the needle/seat and jetting. The fuel filter is necessary until I find and replace the tank. I can't justify spending $500 for a new one.

 

[jsantapau]

The fuel filter is there because I put that "Blue Lightning" tank sealer into my plastic fuel tank. Unfortunately it doesn't work on plastic tanks, no matter what anyone says. My extensive surface preparation efforts were all in vain. There's no way to get that stuff to stick to a used fuel tank. I was hoping to keep the vapors from discoloring the plastic and bubbling the tank decals, but it failed miserably. As a result, I now get little green flakes of tank sealer in the fuel which play heck on the needle/seat and jetting. The fuel filter is necessary until I find and replace the tank. I can't justify spending $500 for a new one.[/QUOTE]


no offense but how much did you spend on this rebuild? how about if you flushed the tank out well to get the gas and vapors out , threw a handfull of B-Bs or ball bearings and borrowed the local hardware stores paint shaker for a bit? and then reflushed to get the debris out?

 

[ws6transam]

No offense taken. This stuff is stuck in that tank for pretty much ever... It's impervious to chemicals and when it peels, it seems to peel in big sheets. I dont think screws or BBs will touch it. I'm going to keep looking for a used tank that is in good shape They are rather hard to find though, as maybe 1500 or 2000 units were ever made world-wide. They do pop up on occasion.

$500 for a new tank though... >whew<. I'm used to spending money on motor parts but plastic, on the other hand... It's a paradigm I haven't been able to quite get my head around yet. However it is the only part on this machine that hasn't been gone over, so you never know. In retrospect, had I bought the tank straight off, I might've saved the $40 for that blue lightning, another $80 on the bubbled tank decals and probably the $200 piston and $200 cylinder repair. Man, I just don't like math problems that add up that way.

How much is a 20 year-old Yamaha 500 worth, anyway?

 

[Rich Rohrich]

If you use a good quality tank sealer you should be able to eliminate the problem.

http://www.kbs-coatings.com/tank-sealer-directions.html

 

[jsantapau]

http://justgastanks.com/product_info.php?products_id=428 maybe?

 

[ws6transam]

Actuallly I was thinking of using this stuff:

http://justgastanks.com/product_info.php?products_id=568

It might immobilize any flakes from the failed sealer.

 

[MikeT]

Put a new piston in it. I'd be surprised if the cylinder doesn't need a re-plate as well. Should go without saying that you need to fix your jetting. Pinging is bad....

Just think I need to re-quote this. This post is exactly correct.

 

[jason33]

i would suggest you fix it the right way, new piston/rings ect.. im sure theres a used tank in a salvage yard somewhere, try dirt cycle salvage or a couple places east

crappy work can kill someone! a law suit is the least of someones worries , i know most ppl on here would hate to give wrong info, and see anyone get hurt, if it locks up wide open there could be/have been srious injuries, good luck with your project