Topic: '75 CB400F Kickstart knuckle

[Joshrma]

So. Here's the knuckle, split in a few places, but removed from service before it fell apart completely.
As many before me, I've discovered that replacements from other 350/fours or 400fs  are near impossible to find, so I'm wondering if there are solutions out there that have worked for others.

- Is there a knuckle and/or arm from another bike that will fit without interfering with the brake lever or exhaust? -- I tried the knuckle/lever from a cb360. It fits on the spline, but catches on the brake lever, so it's on only as a temporary/emergency back up for the electric start.
 
- None of the local shops I've asked are willing to attempt a weld, but if someone has a suggestion about who might be able to pull if off, I'm all ears.

-I've considered braising it together, possibly with a cap over the open end for additional strength, but that's a learning curve I haven't dipped into yet.

[bryanj]

You need to find a welder that you can convince you are not going to blame when it eventualy fails again, everybody is frightened of the blame culture

[Oddjob]

How about a cb550f kickstart, that folded out to avoid hitting the 4 into 1 system as well.

[Joshrma]

Anyone know if the 400 and 500 spline size is the same? -- I wouldn't know where to find the specs on those, and I'd be surprised if that worked and wasn't common knowledge at this point.

[Oddjob]

It's a reasonable chance they are the same but the reason it's not common knowledge is that it can be hard to source a 550F kickstart, NOT the 550k as that will probably be the same as the 500.

[jonda500]

The 77/78 550K kick start is different, giving more clearance than the earlier K ones, but not as much as the F kicker.

When I had an oem 550F 4 into 1 on my 500 I was able to kick it over with a 77 550K kick start - it did scrape the four into 1 on it's way past though.
John

[carnivorous chicken]

Anyone know if the 400 and 500 spline size is the same? -- I wouldn't know where to find the specs on those, and I'd be surprised if that worked and wasn't common knowledge at this point.

I have used 550F kickers on 350Fs with 400F exhaust, with no issues. I did have one guy who I told this to tell me that he counted the teeth and they were slightly off and therefore he wasn't going to do it, blah blah blah, but it has worked for me (on 350Fs with 400F exhaust, that is). Now, will it work on a 400f? So presumably the spline's not the issue, but rather fitment. The 550F kicker's body sits back from where it mounts -- that's the part that folds out to clear the 550F exhaust. I don't imagine there would be an issue with a 400F, but I'm not exactly sure.

350F/400F kickers do come up on Ebay, however. They used to be cheap -- $30 -- but so did everything a few years ago. Dunno what they fetch now.

[Oddjob]

Another one to possibly consider is the 750F kickstart, that also folds so should clear the 4 into system as it had 4 into 1 itself. They are much easier to find and a lot cheaper.

A quick search on Ebay for a 550F kickstart shows them to be available but very expensive. Maybe easier and cheaper to find in the USA.

Maybe someone with a 400 and a 550F or a 750F can check if the splines match. Be interesting to know.

[bryanj]

750 has a huge squareish lump at shaft spline so doubt that will fit

[Oddjob]

We won't know for certain though until someone tries Bryan. Surely someone has a 750F and a 400F and it's not a huge job to try the fitment.

[Ozzybud]

The shaft/ splines are the same diameter 14mm. The knuckle on the Cb750F is way to big and would not clear the case on the 400f

[scottly]

It appears the 750F  kicker is the same as a K7, which has a different "knuckle" and off-set than the earlier 750.

[Bodi]

I spent way too much time going through wreckers' lever bins (they have A LOT) and I think it's unique.
I had mine welded and it lasted quite a while but is cracked again. I was advised that it must be preheated a lot, but have not tried again.
One problem is that the metal isn't known.

[Don R]

   Don't lose the spring if you have it, they are unobtanium also. There's one on ebay at machIV motors.

[Tim2005]

I think from past conversations only 350f and 400f will work. Nobody makes repros either, but if they were a true repro they would crack too. Best bet is to use the electric start all the time

[carnivorous chicken]

I have used 550F kickers on 350Fs with 400F exhaust, with no issues.

Just throwing this back out there. Although I haven't done it, I bet it'd work just fine.