Topic: 1978 CB750 K8 Carb Question

[mjrascoe]

Hi All,

      New to the forum and have a question about the carb/throttle assy on a 1978 CB750 K8.  I picked up the bike complete for short money the other day and started tearing into the carbs.  The thing i learned the hard way about cleaning the carbs on my CM400E when i rebuilt those was make sure all O-rings and gaskets are removed before soaking overnight in carb cleaner.  Well i thought i had all of them, even the little pesky ones on the air screw, but after about an hour of soaking i realized i missed some.  The ones i missed are for the carb/throttle shaft seal where the throttle shaft passes through the carb.  I cant find a part # for them in the manual or the schematics on bike bandit.  any ideas on where i could get these?  I've attached a pic from the manual with an arrow pointing to where the o-ring goes if a photo of my actual carb is needed let me know

EDIT: Whoops forgot to attach the pic, now its up

[madmtnmotors]

I think those are felt washers and I seem to recall numerous posts on their lack of availabilty. Some have suggested making your own, or let the carb bodies lay in the sun till the seals dry and the a few drops of oil maybe? I haven't had to tear my K8 carbs down in a while so I'm not sure if they are felt or rubber on the K8. I did soak mine with those seals in place (once) and put the carbs back together without replacing them with no seemingly ill effects.

[brandEn]

Yep Felt washers. I just ran through this same problem. I only lost one so hopefully it will all work out with it missing...

[MasterChief750]

I used rubber o rings approximately the correct size or I have heard of people making their own. I just got the rubbers and lubed them a little to prevent binding.

[knowsnothing]

I ended up doing the same thing and lost a few of the felt ones.  I ended up making my own and they seem to be working out fine.  I have a .pdf some awesome forum member (can't remember who) sent me with pictures on how to do it if you are interested.  PM me your email address and i will send it over.

[mjrascoe]

thanks for the quick replies everyone.  It looks like some of the seals had O-Rings while others had the felt washers.  I guess someone has torn these carbs apart before me, not surprising considering the bike has 36k miles on it.  Knowsnothing thanks for the offer i'll shoot my email over to you right away.  While were on the topic , where is the cheapest place to grab carb kits for the K8.  Cheapest I have found is around $30 for each kit and an additional $20 for the accelerator pump.

[markreimer]

Any chance you can tell me where you bought your rebuild kit from? I've been searching forever and most places don't have full rebuild kits for the k8, just a few gaskets and o-rings. I need to rebuild my carb asap as well as the acc. pump. Can you share where you found yours?

Thanks

[78CB750CAFE]

rebuild kits and accelerator pumps are still readily available from your local Honda shop though they are expensive ($78 for accel pump!) K&L makes good but cheaper ones your local dealer may be able to get also.

Drew

[Radam]

You can find them here too. http://www.cb750supply.com/products/6/fuel-system