Topic: 81 cb650c, backyard hack cafe

[626]

I've had this bike for 5 years now, I abuse it daily. I try to make things for it rather than buy them, I've bought plenty though. I want that raw, mad max vibe. This is what it looked like when I brought it home(after a lot of polishing).



This is where I'm at today after mounting new rubber and changing the tail section for the 3rd time.





Tonight I'm going Change the front turn signals to match and start building a fiberglass cover/cowl for the seat. I want to kind of match the lines of the tank in reverse and cover it with chrome vinyl wrap. I should start a seat from scratch. Alloy would be sweet, feel like it would be beyond my limitations.

[SOHC4 Cafe Racer Fan]

It looks like you dropped the forks about 4 inches through the trees.  Are you okay clearance-wise between the fairing and front wheel at full compression?

[626]

Its lowered just shy of 2 inches. I haven't been able to make it hit at moderate speeds, I tried to make it hit. I searched around and found specs listing it as 5.3 inches of travel. With the forks unloaded there is more than that. It sure does look like more than 2 inches though doesn't it.

[calj737]

5.3!  Yeow... Droppng the top clamp two inches has changed your rake angle a lot. Are you still also running stock wheel sizes?

* Sorry, hit submit prematurely.

[626]

Ya wheels are stock. Should I be worried?

I've been riding it this way for a while don't really notice a difference in handling. I lowered it just enough for the joining tube of the air assist to clear the top fuse panel. I figured with the custom having longer tubes then non custom it would be ok. I could cut the plate, relocate the choke and raise it some.

[626]

So rather than Working on a seat cowl, tinkering with signals last night, I took the time to read about rake and trail.

While I haven't noticed any stability problems, they likely wouldn't make themselves known until under hard braking at higher speed. When that would fully compress the fork and turn that into a 7.3 inch change. So I loosened it all back up and changed it to less than half an inch and lowered the rear with the preload as much as I could. I'm in the 160# range so we'll see how that goes.


I thank you for putting me down that path!

[calj737]

  You never know what you don’t know until you know 

[SOHC4 Cafe Racer Fan]

Reducing the race on the 1980-82 CB650 model might not be such a bad think, since those models appear to have a larger rake (for a cruiser style bike).

I believe the stock 550 and 1979 CB650 have a rake of 26 degrees and trail of about 105 mm. I believe that the 1980-82 model CB650 bikes had a higher degree of rake.

As long as you don't make the rake too sharp and preserve enough trial for stability -- and enough travel so that your fairing is not banging on the fender -- you'll be okay. 

[seanbarney41]

Yeah, with that leading axle front end, the bike should have some very lazy trail numbers