Topic: 1974 CB750K Frame Modification

[nmbloke]

Anyone heard of modifying the top horizontal frame tubes to access and readily remove the valve cover?  Seems like it would work but may weaken the structural integrity.

[nteek754]

Hey there
well yes you can do that I aquired a stock frame that  P O made a chopper out of it and then it sat for years and years well I revived it  put a good engine on it and it has an 8 inch over front end  it goes great now keep in mind its a chopper one of four 750s I have right now and I dont ride it like I do my baby 1973 K with a few mods  Im sure if you cut those tubes you will defantly feel it flex in the corners and you have to remember the laws in your state  shhhhh I see nothing good luck   Craig seven fifty four ever

[Noel]

I'd be willing to bet that if you remove the top tube the bottom portion of the cradle will simply fold up. If not immediately, then soon.

And even if by some made-in-Japan miracle it didn't, the resulting bike would be a wallowing, weaving nightmare.

If you really can't stand the thought of removing the engine to work on the head, I'd trade for a 550/500.

YMMV, as usual.

[6adan]

I have seen several 750's in a salvage yard with the two smaller top tubes cut out. I have seen a frame on ebay that been modified with those tubes made removable by cutting and modified so they could be bolted back on.Dannie

[STLrocker]

i have a 750 with the 2 smaller tubes and the braces cut so that the section can be removed. i got the bike this way. ive put a lot of mile on it without problem. even crashed once and didnt effect anything.

 the section is held in place with steel sleeves that slide over the cuts in the tubes. they fit snug and are held in place by some set screws. the triange braces between the tubes are held together by small steel plates that are bolted to both sides across the cuts.

i woldnt recomend removing the tubes all together. the top tube is thin walled and i wouldnt think it would be up to the task alone. there is also not enough support at the neck without the smaller tubes. i have seen people remove the smaller tubes all together and replace the top tube with thick wall tubing and gusseting at the neck. that is usuall done to run a different tank that wont fit otherwise. it's pretty involved though if you are just trying to get better access to the top end.