Topic: Scored CB750 motor today

[Davez134]

I've been wanting to start another project, so I've been looking for motor/frame near me for cheap. (Everyone in the southwest part of the country wants to sell these bikes for waaaaay too much) scored this for a steal today, but no frame yet. Hopefully soon so I can start a new project thread! Serial number puts it as a '72. No damage, turns over freely. Just a bad paint job!




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[edwardmorris]

Looks intact, I'd say start tearing it open, the frame will show up sooner or later. IIRC there were some listed right here on our FS forum too. Never hurts to have a 750 project thread going

[Jerry Rxman Griffin aka MuthaF'er]

Is that goop used on the valve cover gasket? If so the rest of the engine could be suspect too.

[Davez134]

Is that goop used on the valve cover gasket? If so the rest of the engine could be suspect too.

Yeah I noticed that too. I trust nothing. I'm going through the whole motor. Just a bonus, less headache that it's not stuck.

[flybox1]

That red stuff is RTV sealant.  Bad stuff.
It flakes off and cloggs oil pump intakes and the oil jets under the cam towers.
Get that valve cover off and look for signs of oil starvation.
you'll need to get into every oil passageway in the case and cylinders, as well as those tiny oiler holes in the trans shafts.
Dont overlook anything.

[edwardmorris]

Dave, if you succeed in acquiring the frame from Finnigan, look into the K2 seanbarney is parting out. Not a whole lot to salvage, but the hubs, forks and other solid stuff will be nice to have....

[AbbyRider]

I'm curious what 750 motors go in various parts of the western half of N. America? I rarely see motors come up for sale here in the Vancouver area, but have recently seen a few in the Seattle area for between $300 and $500 (advertised as "good compression").

[flybox1]

Scored mine for $100

[lrutt]

RTV is not bad if you know how to apply it. I can put it on gaskets and have virtually none squeeze out. And I just don't have problems with leaks either. There is no magic to it.

A quick pull of the pan and valve cover though will tell the story. Nice chrome covers.

[flybox1]

RTV is not bad if you know how to apply it. I can put it on gaskets and have virtually none squeeze out. And I just don't have problems with leaks either. There is no magic to it.

More is not better in this instance.  Sealants dont need to be applied like toothpaste!
Betcha the 'squeeze-out' is the same on the inside 

[goldarrow]

RTV is not bad if you know how to apply it. I can put it on gaskets and have virtually none squeeze out. And I just don't have problems with leaks either. There is no magic to it.

More is not better in this instance.  Sealants dont need to be applied like toothpaste!
Betcha the 'squeeze-out' is the same on the inside 

even with toothpaste you don't put on all that much, size of pea is more than enough! 
https://www.google.com/search?q=how+much+to+use+toothpaste&es_sm=93&source=lnms&tbm=isch&sa=X&ei=70_RU4nBMKTUiwKfyoHwAg&ved=0CAoQ_AUoAw&biw=1383&bih=951#imgdii=_

[Davez134]

Dave, if you succeed in acquiring the frame from Finnigan, look into the K2 seanbarney is parting out. Not a whole lot to salvage, but the hubs, forks and other solid stuff will be nice to have....

Thanks, Ive been browsing that thread. As for the RTV sealant, it's obvious that they were in no way careful with it, but again don't really care as I'm goinf through everything anyways. Chrome covers are in excellent condition, not a chip or mark on them since ive wiped them down. Also, no broken fins on head or cylinders.

[Vinhead1957]

Nice looks like someone tried but lacked the follow through! Good luck

[Davez134]

Started tearing down today, got the top end apart and no major issues, no signs of oil starvation or major wear. Only took about 30 minutes, everything came apart easily. Only things I noticed are one of the dowels on cylinders is bent up, (shown in picture) couple missing bolts on cam cover. That's all so far.






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[Davez134]

Getting into cases tomorrow. I'm planning on 836cc for this motor, for sure want to get head ported, cleaned up.

[seanbarney41]

Dave, if you succeed in acquiring the frame from Finnigan, look into the K2 seanbarney is parting out. Not a whole lot to salvage, but the hubs, forks and other solid stuff will be nice to have....

Thanks, Ive been browsing that thread. As for the RTV sealant, it's obvious that they were in no way careful with it, but again don't really care as I'm goinf through everything anyways. Chrome covers are in excellent condition, not a chip or mark on them since ive wiped them down. Also, no broken fins on head or cylinders.

Dave, feel free to pm me for stuff you need.  I have spares of just about everything, but I am not always looking to get rid of some of the scarce parts.  I have no idea what Nevada's title laws are like but will have a k4'ish frame with no title very soon.  Also have titled k6 with slightly bent rear subframe.  Would be a good  cafe/brat hoop candidate.  Frames can ship Greyhound for around $80-$90.

[Davez134]

Thanks! I have a frame lined up from a member here, as soon as I get my hands on that, Ill move this over to project threads. I wont need any scarce parts, as I'm not going to "restore" this one. I'm thinking more resto-mod on this one with performance emphasis. I'll lake a look at your listing, see what you've sold and what's left I may need. Thanks again.