Hole, what hole?

bhodge · Full Member Joined: Dec 02, 2008 Posts: 11

Well guys, this is only my second post but I have been doing a bunch of research here. Thank you all for your contributions. I decided to start a bobber project with a 1980 Special II with 6600 miles that I picked up for a slick $100.00. After all of the prep work it was ready to fire up. It ran really good for about five minutes before the left intake valve stuck. I pulled the motor last night and pulled the head tonight to find a nice hole in the top of the piston. I was hoping to get away with just some head work, but the piston says no way!!! So, my dillemma. What do I do with a very limited budget? I have it all the way down, so what can I get away with leaving alone? I will post pics asap, but I want a rat bobber that is on the cheap. I have a new bike that I have just put a bunch of money in, so I promised the wife I would go easy on this one. Thanks for the help.

Brent

xs1961 · Posted: January 30, 2009, 6:34 am Post subject: Re: Hole, what hole?

Check the bores for scoring , prob damage there.. as far as the bottom end goes I wouldnt strip it ,just drop the sump, flush the motor out a few times with parrafin or diesel to make sure theres no particles left down there .
New valve, new piston - cheap repair probably.. Wink

BigGeorge · Full Member Joined: Apr 13, 2008 Posts: 267

Item 150324171304 on e-bay right now, cheap no reserve. Cylinders with matching pistons...........BG

bhodge · Full Member Joined: Dec 02, 2008 Posts: 11

Pics as promised. Exhaust and intake are both bent. It drove the guide out a little. I hope the head is not ruined.

Brent

jayel · Posted: February 2, 2009, 12:04 am Post subject: Re: Hole, what hole?

just clean the sump out good that piston isn't melted, it just got hammered,
melt I would be afraid of crap in the bearings but you're probably looking at a couple big chunks there, valve either hung up or the keepers popped out

oldskoolcool · Full Member Joined: Sep 08, 2007 Posts: 372

what bent valve? .... Shocked

jpowell · Posted: February 4, 2009, 9:29 pm Post subject: Re: Hole, what hole?

Hell i'd say just leave it. But I had a plug foul, and can tell you, this bike can't get out of it's own way on one cylinder...

jpowell · Posted: February 4, 2009, 9:31 pm Post subject: Re: Hole, what hole?

Whats the bore on that? I bought some ring sets stupidly not looking. My cylinder was bored 1st over. I bought original size.

SO, that being said, if that motor has never been bored, which I'd expect with that low of miles, I got a brand new set of rings I'll make ya a deal on.

JP

bhodge · Full Member Joined: Dec 02, 2008 Posts: 11

JP,

I have already ordered everything from Mixes XS. Thanks for looking out! Everything should be here on Monday, so off to the machine shop we go! Hope to have back together by the weekend!

Brent

bhodge · Full Member Joined: Dec 02, 2008 Posts: 11

The machine shop just called and said that it looks like the side that I had the damage on the piston was hitting the head. I didn't notice anything, so I am wondering if I have a spun rod bearing. I think that I saw somewhere these are problematic. I am going to see if I can tell when I get home from work. Any suggestions? Can I buy a new crank if it is messed up? It may be cheaper to have the journals turned.

Thanks,

Brent

jayel · Posted: February 12, 2009, 12:29 am Post subject: Re: Hole, what hole?

the rod bearing is a roller bearing check for up/down movement and wear at small end of rod but with only 6000 miles shouldn't be worn out, head doesn't look hit tho'

Shannon60 · Posted: February 12, 2009, 1:12 am Post subject: Re: Hole, what hole?

top ends of the rods tend to wear out soon, as far as the head check the one valve guide closly as for the other it will need replacement and then fitting and a valve job. it may be a bunch cheaper to find another head, they are still plentiful

Shannon60 · Posted: February 12, 2009, 1:17 am Post subject: Re: Hole, what hole?

also i find it hard to believe that the piston was hitting the head since i regularly cut .050" off the top of the cylinders on race motors to raise the compression and do not have that problem. however it is common for valves to stick on motors that have sat awhile especially ones with iron valve guides.

bhodge · Full Member Joined: Dec 02, 2008 Posts: 11

Thanks for the help! I am going to put it back together and turn it over by hand to check for clearances. I checked the rods tonight and they seem fine on the crank, no up and down at all. They had a slight left to right, but it seems normal. I think what he was seeing was where everything got mangled from the valve. We will see! Thanks again!

Brent

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