Topic: fork lowers question

[sinks88]

Hello, I've had some recent issues with getting my front end buttoned up:
I have 77-78 CB 750 forks, but the caliper mount holes are lower then my brake rotor will allow....my questions are how easy is it to change just the lowers? and what do I need to do for that.  I do have some lowers that do fit the larger 6mm rotor.  2nd question, what rotor will fit these lower with the correct mounting?  I don't exactly know what yr my front wheel setup is, and don't want to make a mistake trying to buy a new/used rotor that is smaller in overall dimension, but have the same offset and width.

Let me know what other information will help me solve this...as this is my first custom build and Im running into compatibility issues.

Thanks!

[bollingball]

You may get better results in the project shop

[sinks88]

ok thanks!

[sinks88]

I did post in the projects also....here is some updated info:

I believe I have a front wheel set up from a 74 CB550...so my question I guess is will a 77-79 CB 750 brake rotor work on my 74 cb550 wheels and brake caliper?  (as the caliper looks to line up mounting wise just fine, but the rotor is a larger diameter so it sits up on the fork mounting to high about a half inch.)

[Kong]

I don't know about your parts interchangeability issue but I can tell you that changing fork lower legs is a pretty easy job, particularly if your front wheel and fender are already off.

With the wheel/axle removed drain the fork oil.  Then you will find an Allen-headed bolt that enters the lower leg in its center from the bottom, remove the lower bolt and the lower leg will pull down and right off.  You might want to stick a new set of seals in it while you have it apart.  Oh, if you have trouble getting the bolt out because it spins too freely just use an impact wrench on it, the thing will pop right off.  Reassembly is the reverse but be sure to put a new coper washer on the end of the bolt before you put it back together.  If you don't have a new washer anneal the old one.

[sinks88]

great thanks!!!!  I didn't know if it would be that easy!

[sinks88]

do I put back in 5.1 or 5.2 oz or 5.8 oz oil for these forks? they are 1978 CB750F forks...i see that the cb750K do a 5.1.  Is there even a difference in forks from the K to F model?