Topic: WILL COMSTAR WHEELS FIT A 72 CB750K2..?

[UKCB750CAFERACERS]

Dear SOHCers.....

Has anyone ever fitted COMSTAR wheels to a 750K2..?

The CB650Z and CB750KZ (DOHC) had Comstars but with a DRUM rear brake in Europe....US models had spokes initially I think....

The CB750F2s...common and easy to find wheels for....have a DISC rear which needs a set-up for the master cylinder etc etc,so I thought why not use those from a 650 instead....

Any ideas please...?Im looking to keep a rear drum brake set up......

Thanks

and...safe rides

[ProTeal55]

Why would you want to replace the beautiful spokes with those mags ?
Spoke wheels make these bikes.
My 2cents.....

[Geeto67]

Dear SOHCers.....

Has anyone ever fitted COMSTAR wheels to a 750K2..?

The CB650Z and CB750KZ (DOHC) had Comstars but with a DRUM rear brake in Europe....US models had spokes initially I think....

The CB750F2s...common and easy to find wheels for....have a DISC rear which needs a set-up for the master cylinder etc etc,so I thought why not use those from a 650 instead....

Any ideas please...?Im looking to keep a rear drum brake set up......

Thanks

and...safe rides

lots of people do this swap in reverse, switching the comstars for spokes, but the process is the same. The comstar wheels use a different brake system than other cb750s so to use a comstar rim on the front you have to do a complete front end swap. With a little more work you can swap in a modern sport bike front end so nobody really does the comstar swap but there are K bikes with cbr and fzr front ends.

For the rear you will need to replace the swing arm to take advantage of the rear disc, or make the necessary mods you your existing swing arm to accomidate the rear disc brake. Since these mods would be the same amount of work as putting a cbr rear rim on (plus custom axle spacers but the F2/F3 use the same rear axle size as a cb750) post people opt for that instead. As far as I know the 1979 Europe KZ with the drum will work on an earlier K bike but you will still need custom axle spacers or swapping the swing arm. You can make a DOHC swinger fit in a SOHC frame by chopping down the pivot width, and a lot of people prefer this because the DOHC swinger is longer and lowers the rear of the bike. Chain line would be a different story as some of those DOHCs got pretty wide tires toward the end but as far as I can see my 1979 F comstars are the same as on my 1978 F (keep in mind that the F2 has a wider chain line than the K2).

Not everybody likes comstars.

[bill440cars]

           You know, when opinions are asked for, sometimes people have a tendacy to just flatly try
     to lead the person off in another direction. Some simply try to supply the information that's asked
     for. and others may try to give the info and give their own opinion (but making it clear that it is
     their own opinion) about what the person should do. Some people seem to think that everyone
     has money to burn. Myself, If the guy wants to try comstars, then go for it. Surely someone has
     done this and can supply the info he needs. Then, if he doesn't really care for them, he can start
     thinking about which direction he wants to go then. I'm getting my plans together to eventually
     build 2 CB550Ks. 1 will have spoke wheels and 1 will have comstars. I have previously asked for
     info and advice. It seems like my post was almost totally ignored. Terry (cb650) is the main one
     who tried to help me and I appreciate that. If I see a post, that I don't really know that much
     about, I'll tell who might be able to help them (if I know of anyone). Anyway, I don't the info he
     needs but, if someone does, I sure wish they'd speak up.  Later on , Bill

[nteek754]

Hey there I been running a 73 750 K for a few decades now years ago I put a 1981 comstar on the rear  a 16 inch but had to  grind off about 3/16ths of the brake drum didnt have the whole set up but still think the swing arms were widder on the newwer bikes  now this is with the drum brake it works great  and yeah the brakes work great I also put a 19 inch comstar on the fron with no mods just the spedo cable mounts on oppisite side  only work when Im going backwards  HA J K work fine  I like the looks and much easier to keep clean  good luck  seven fifty four ever  Craig

[Geeto67]

           You know, when opinions are asked for, sometimes people have a tendacy to just flatly try
     to lead the person off in another direction. Some simply try to supply the information that's asked
     for. and others may try to give the info and give their own opinion (but making it clear that it is
     their own opinion) about what the person should do. Some people seem to think that everyone
     has money to burn. Myself, If the guy wants to try comstars, then go for it. Surely someone has
     done this and can supply the info he needs. Then, if he doesn't really care for them, he can start
     thinking about which direction he wants to go then. I'm getting my plans together to eventually
     build 2 CB550Ks. 1 will have spoke wheels and 1 will have comstars. I have previously asked for
     info and advice. It seems like my post was almost totally ignored. Terry (cb650) is the main one
     who tried to help me and I appreciate that. If I see a post, that I don't really know that much
     about, I'll tell who might be able to help them (if I know of anyone). Anyway, I don't the info he
     needs but, if someone does, I sure wish they'd speak up.  Later on , Bill

not entierly sure who this is directed at but let me clarify a few things as to someone would be asking Why replace spokes with comstars?

Fact #1: Comstars are not the best designed mag wheel.
-  The centers are steel and the rim is aluminum. While this may seem like a good combo for strength, dissimilar metal corrosion can occur where the spokes attach to the rim. Furthermore the aluminum rim is not the strongest out there and comstars are prone to bending. A spoke wheel is just about the strongest wheel there is, even the aluminum ones, but they are not all that light and definatly not aerodynamic. The only advantage a comstar has over the spoke rims is they they are slightly more aerodynamic and the models they came on had improved brakes. However the amount of work it takes to put a comstar on, one might as well consider a more modern aluminum one piece mag wheel.


Craig, How did you get a comstar on the front with no mods? the brakes don't line up.

[nteek754]

there is only one year that fits and its of coarse got to be the one with the single disc and it has to be the disc off the comstar cant put the spoke disc on the comstar  lined up perfect  back a while ago I got a comstar with dual disc thought  it would fit and just leave the right disc empty  till I got the rest to  put another caliper on but nope wouldnt go  but yeah  got one on there and works great good luck  Craig seven fifty four ever

[Egil]

To put new`r comstar on, you have to Chang's the frontfork and caliper if you go for newer wheels because of the thickness of the disk.
Disk are not the same diameter Ø size The F1 has 300mm dick and F2 2800mm disk  , BUT you can try to get the 77>78 F Comstar wheels
Those are  listed in "classic Motorcycle  Mechanics No 173 march 2002  under the "Mira Files"from page 46 >page 51 .
And yes my bike have comstars  http://www.sohc4.us/forums/index.php?topic=3436.msg25453#msg25453
My bike has CB900 F2 Bol`dors wheels and brake.

[nteek754]

geeto sorry for late response   it has to be the single disc and you cant take the disc off the stock spoke wheel and replace on the comstar  diff bolt  amount and obviously pattern  wow it did bolt right up trust me  just gotta be the right year  Craig in Maine