Topic: My 78F. Should it stay or should it go?

[billyfrank]

So I previously talked about a top end noise in my 750f motor and discovered that there was no oil going to the cam on cylinders 3-4.  So I pulled the gas tank and started to remove the valve cover, your getting this right.  I removed the valve cover with the motor in the bike.  Damn!  The PO had cut the lower frame tubes out to do the top end. They are gone but heck I can fix it no biggie.  Well the valve cover comes off and I find that the #4 cam tower is cracked and the cam lobes are all wiped.  It didn't look like any oil ever got there after the PO's top end work.  So do I do the money pit fix, find another bike that can use my parts or part it out?  Sucks because it was titled and actually runs pretty good all things considered.
Thanks,
Billy

[Roach]

why not find a new motor or top end? mind you he did cut the frame up..

[billyfrank]

Yeah I thought about sending the top end out to APE and having it done right.  The frame can also be fixed.  I guess you could call it an Ohh Sh@t moment.  I will now go back to drinking my beer and staring at my junk(the bike).
Thanks,
Billy

[Mandic]

I'd consider repairing it.  There aren't enough of the super sports around(I like my 77 quite a bit).  However I'm sure you could make a buck parting it out.  I can think of one or two things I'd probably buy if the price were right.

[billyfrank]

You know what sucks the most.  I've only had the bike about a week and I feel like I am already vested in it because I have spent so much time reading things on this board.  It started out as "just a little project" and from reading around this forum, people have gotten me kinda excited about it.  I will say this, if I do part it the prices will be right.  I don't like to profit off of people in the hobby.  Don't let that be the motivation to talk me into parting it though

Are the cam towers sold separate anywhere? or do i have to find a complete top end to rebuild?
Thanks,
Billy

[mickey6]

i may consider buying the whole bike if you want to be rid of it. I already have a 76 supersort, but I wouldn't mind adding yours to my stable if you do sell..... personally I would buy another f motor to put in the bike, and then workout the kinds in the one in the bike. It will take away the urge to "just get it going" while you fix things and it will give you a second motor for when things go wrong, and keep you on the road

[bollingball]

Actually ran pretty good? For how long? If I have one valve ticking it drives me nuts. I would try to fix it it is to good a bike to part out. Maybe try to find a whole parts bike as long as the parts you need are there we allways need extra parts. Sorry about the P.O. or should we call him P.O.S. also now would be a perfect time for a Gordon frame kit.

[Ryan6838]

This is how id spin it. Pick up a head cheap and do all the fun stuff to the f heads that had problems. then get one of the frame kits and have a shop install the kit and replace the tubing. In ohio titles everything so id keep it and just get the parts i need to fix. " Yeah hunny i just geting it running" 

[billyfrank]

Where are the oiling holes in the top end?  They are not even mentioned in my Clymers manual.  One side had great oiling but 3 and 4, they got nothing.
Thanks,
Billy

[Mandic]

Under the cam towers there are 2 oil restrictors next to 2 of the cylinder studs.

The big thing, I am not sure if you are aware of this, but you have to get an F head if you are going to do that route.  78 F pistons with a K head would be a no go.

[GammaFlat]

You know what sucks the most.  I've only had the bike about a week and I feel like I am already vested in it because I have spent so much time reading things on this board.  It started out as "just a little project" and from reading around this forum, people have gotten me kinda excited about it.  

Welcome to the vortex.  You can get in but you can't get out.    

I doubt you need a new head.  You'll likely need new cam towers, cam, rocker shafts, possibly rockers.  All of that can be stripped from another more common "K" head.  Depending on the year of your "F", the cam may be different but will work from another more common "K" motor.  I'm sure many folks on this board have all the parts you need to fix up the top end (I think I do).  Somebody correct me if I'm wrong on the compatibility of parts here.  

Good luck and come on in, the swirling water is fine.  

[billyfrank]

Do you think the valve guides could survive the abuse?  If so, theoretically changing out the valve train and finding the oiling issue could solve the motor problem.  I can fix the frame as I am ok with a welder.  Everything together just dismayed me a bit.
So which parts interchange?  Any one have a complete head so that I have spares for later?  1978 CB750F parts needed.

Thanks all,
Billy

[GammaFlat]

PM "Big Bob" to see if he has an "F" head.  I've heard conflicting reports about whether the valve angle had changed on the F3 heads.  If it did, that might have affected the tower because the rocker shafts might need to be re-located (further from the cam).  I'm feeling skeptical about this F3 valve angle difference but open to someone that can enlighten.  

Where are you?  Maybe it makes sense to compare your parts next to some "K" parts.