Topic: Kerker Help on a 78 cb750k

[tinyrobot]

I have a Kerker 4-1 ready to go the bike.  Today was warm enough here in Chicago to start the bike up for a while and run some gas through it.  I got a little antsy and wanted to try and put on the Kerker.

First the collars that came with it I assume are for pre 77 bikes.  The are just a clamp.  The 77-78s have collars with holes to mount to studs on the the head.

Second the stock collars are too big to use with just the header.  The stock 78 has split exhaust shims to wedge between the collar and the pipes.

My question is will pre 77 exhaust "spigots" work.  Can I just bolt them to the head and then clamp the header to the spigots?  Will they take up the 1/8" gap around the header to the stock 78 collars?  Any one with a 77-78 CB750 K done this before?

[tinyrobot]

If I find part #11 in the last picture and bolt those to my head can I then use the clamp/collars to connect the header?

[fuzzybutt]

the header doesnt have flanges on it to either bolt to the head or use the factory studs and nuts? can you post of pic of the new header?

[tinyrobot]

No flanges on the header, just straight tubes with a notch in them for compression.  I assume they work just like the pre 77 pipes?  I will try for pics today maybe tomorrow.

[eurban]

Yes you can install the pre 77 spiggots on the 77/78 exhaust ports.  Get the spiggots, flower clamps and the bolts for mounting the spiggots.

[tinyrobot]

Do I have to remove the studs or will the spigots bolt to with enough room for the flower clamps?

[eurban]

Don't know for sure but the stock spiggot bolts are beveled to fit the chamfer in the spiggots.  When installed they are flush which may or may not be just for looks.  Probably best to remove the studs and install the correct size and and type of bolt.  I believe that they do have the same thread pitch.  It will probably be easiest to find used stock flower clamps but if not there are various aftermarket options that range from simple clamps to blinged up flowers.  Check with Cycle Exchange, ebay and I believe that the TTR400 website has some alloy ones that will work on the 750. . . .Its too bad that you have a header designed for the earlier bikes as the flange type ends would fit on your 78 nicely and allow you to loose a few more pounds of weight.  IMHO it will look sweeter with the flowers tho.  Hope this helps.

[tinyrobot]

I received the flowers with the header and I found some nice looking spigots on ebay right now for pretty reasonable.  I hope this works out.

Thanks for the help guys!

[Alan F.]

I have the same header on my 750K3 it sounds great, you'll enjoy it. 

One tip I'll offer is to make shims from some aluminum flashing, or fold a double thickness of beer can, make shims that fit under the 'flower' clamps, just in case your clamps (like mine) tighten completely without actually sealing.

The other tip is to be sure to use item #12 in the diagram, it's a copper 'crush' washer to seal the spigots to the head, word is that sometimes it takes two, but I haven't gone there yet, maybe I'll use the search feature on that sometime.

CHEERS!

[tinyrobot]

Thanks for the tip Alan!

I got some spigots yesterday on ebay for $15 buck which looked pretty good, just need to be cleaned up.  I already have the copper gaskets ready to.  So when these come in and we get a bit of warmer weather here in Chicago I will get back on this.