PDA

View Full Version : 250SX Aftermarket Cam



drsung
04-03-2015, 09:03 PM
Warning, this will be picture heavy!

Anyone here know about aftermarket cams for the 250sx?

My recently purchased 87 250sx had plenty of what looked to be JBWeld above the spark plug hole where the head cover meets the head. It also had a broken head bolt which was causing some oil seepage so I decided it would be a good time to take it apart and fix it.

After getting enough of the JB Weld off I found what appears to be a hole in the head. After further inspection the hole looks to be part of a head modification to accommodate a aftermarket cam.

Plenty of pictures follow. My question, is this what it is supposed to look like or did someone try to machine this in their garage, screw up, and came up with this as a resolution? The Cam is a Megacycle #15700NB which appears to be a correct cam for the 250sx.

Assuming this is a major hack job, there doesn't appear to be a way to fix this other than to replace the head and head cover. If I am going to do that I will probably just go back in with the stock cam. What would a used cam and perhaps the HD springs be worth?

http://i86.photobucket.com/albums/k118/drsung/20150403_194357_zpstwuqq3xk.jpg (http://s86.photobucket.com/user/drsung/media/20150403_194357_zpstwuqq3xk.jpg.html)
http://i86.photobucket.com/albums/k118/drsung/20150403_194244_zpsymsstbxb.jpg (http://s86.photobucket.com/user/drsung/media/20150403_194244_zpsymsstbxb.jpg.html)
http://i86.photobucket.com/albums/k118/drsung/20150403_194037_zpscsj7pbce.jpg (http://s86.photobucket.com/user/drsung/media/20150403_194037_zpscsj7pbce.jpg.html)
http://i86.photobucket.com/albums/k118/drsung/20150401_225131_zpstkh84xs3.jpg (http://s86.photobucket.com/user/drsung/media/20150401_225131_zpstkh84xs3.jpg.html)

Jmoozy27
04-03-2015, 09:22 PM
Excuse me if I'm wrong but I think there is a plastic cap that goes where all of that crap is. That's how it is on my big red. There is a cap that fits on the end. Looks like that may be a cam for 250 or 300x. Just a guess. I'm sure others will chime in with facts.

Jmoozy27
04-03-2015, 09:24 PM
I'm sorry I think the cap goes o. The other end of the cam. So I'm basically clueless.

ironchop
04-04-2015, 02:15 PM
that's the most F@#$*D up thing I`ve ever seen.

there`s not supposed to be anything n the back of that head behind the cam but a wall of aluminum . That end bearing outer race should bottom in the hole (which is a flat bottom and not an angled one.

Looks to me like someone took a big drill bit and drilled into the back of that rear journal for some dumb reason (that angle is identical to a drill bit), broke out the other side, then tried to JB Weld their mistake.

That head is trashed and I`ll bet the valve cover is a mirror image of the head. Throw them both away. Call Megacycles and get the cam specs, measure yours to determine wear. It may be ok to run and even if it isn`t I think Web or MC will do rewelds on their cams for much less than a new one. Definitely replace that rear needle bearing that was up against the JB Plug.... Are there any worn spots on the lobe faces? With high ridges on each side?

Just my opinion

ironchop
04-04-2015, 02:20 PM
should look like this one (stolen pic from Fleabay).......


213638

honda4h
04-05-2015, 12:15 AM
wow speechless wow

drsung
08-13-2015, 11:55 PM
Just a quick update to this cluster. The head and the valve cover were obviously trashed. I had a parts bike with a head that had a bent valve. I sent that head off to G&H for a rebuild. The cylinder and piston were still within spec so I put the newly rebuilt head, valve cover and stock cam back in and she is purring like a kitten again.

If anyone is interested in the megacycle cam shoot me a PM. I don't plan on reusing it and would like to sell it.

JGW3
08-16-2015, 09:52 PM
How did you like the work G and H did? They are local to me and have a project or 2 I'm thinking about throwing that way.

drsung
08-23-2015, 06:55 PM
G&H did a great job. The turn around was pretty quick. The head was thoroughly cleaned when I got it back. They offer a bead blast option although I told them not to bead blast it because I wanted to keep it black. It bolted right on and is running great! I would definitely use them again.

barnett468
08-23-2015, 07:28 PM
If anyone is interested in the megacycle cam shoot me a PM. I don't plan on reusing it and would like to sell it.

Does it come with the "special" JB WELD plug?

drsung
08-24-2015, 07:49 PM
I can include it but it's going to be extra! :D:D