seizure mystery needing to be solved

[jaguar]

hi gang
sorry I've been away but I've needed more memory to use Netscape 6 to access this new site.
anyway the other day I installed a new power valve, started it and it ran fine, smoke was coming out of the exhaust
like normal so I shut it down without riding it. (My bike injects engine oil via an injector pump).
Today I rode 3 blocks, stopped for a little gas, then a few blocks down the road it seized. I wasn't even screaming
the engine but I was riding agressively. restarted it and slowly rode back. dissasembled to find wide seizure on the
intake side of the piston (almost
new with almost new rings). Piston was coated with gray sludge (aluminum/oil mix).
Crank is still good from the new bearings and seals installed weeks earlier.
Nothing was changed except I turned out the idle air screw 1/4 turn to idle stronger.
Any ideas? Anyone know how to check for proper operation of an oil injector? (I know it's putting out oil but I don't know if it's enough)

 

[Ede]

Hello Jaguar,

bad luck.

1. Eric Gorr's has a very interesting page about pistons:
http://www.eric-gorr.com/techarticles/pistondiaguide_ta.html

2. About Oil Injection: I replaced the black tubes with clear tubes so I can see that there is oil in the system. For the amount of oil just calculate how much gasoline and how much oil you need. On my bike the small oil tube near the intake was one time not ok. So I had an average mixture of about 60:1. After I changed this tube the mixture is about 40:1

 

[jaguar]

mine has clear output tubing.
But the output of oil at idle is small, maybe one drop every minute.
I put in the old piston and rings so I can ride today. I'll probably just add some oil to the gas tank for now.
thanks Ede

 

[jaguar]

final chapter

I started to go riding again but was zipping around the neighborhood with an ear to the motor.
It started to make pre-seizure sounds so I let off the gas and tiptoed back home.
There I removed the oil injector control cable and added premix.
Went riding for 3 hours in the boonies with no engine problems (but since I was so distracted I had forgot
to tighten the radiator cap and so lost it. Also as luck would have it the damn kickstarter fell off while riding
without my realizing it. dirty rotten luck. )
I had a great ride pretending I was **** Burleson.
I need to loctite all nuts since theres more vibration with this Pro Circuit pipe.
:-)

 

[G. Gearloose]

jaguar,
If you pre-mix it now, it may be best to check the jetting with a plug chop to be safe. Premix will run leaner than straight gas.

 

[B]

Arhh man.

I hope the bike Ok now.:(

My little tip. When distrubing the motor I always run at lease a tank of pre mix.

Whats your cylinder like? Mine has scuffing on the carb side but its not too bad.

B

 

[jaguar]

replies

hi guys
Actually I can tell pretty good what jet is needed by just riding it with different ones. I definitely need a richer one now.

My cylinder had some aluminum stuck to it which I used a dremel like tool to grind it off. Since it was below the lowest
ring line I figured it'd be OK. The cylinder really needs to be replated since it has a couple small cracks in it. If business does OK
thru the summer then I may send it off to get it bored to 220 and also have porting done to beef up the midrange power.
Right now the old piston in it is causing slapping sounds but the power ain't too bad.
:-)