Author Topic: 1978 - CB 750 K4 - * F seat on a K? Same year... (Read 4173 times)

SKTP · « **on:** June 14, 2006, 09:52:27 AM »

Hello SOHC 4s,

Very happy to have found this great online resource. I am a new first-time bike owner. I got myself a 1978 - CB 750 K4. I got it in running condition. It basically needs a brake rebuild, new tires, new seat cover, new gauges, a good cleaning and a paint job. I was told it had been sitting outside for awhile before I got it. It still started with 1 kick or a puch of the starter. So I gave it an oil change and drained the tanks and re-filled it with new gas...It started right up and I ran it for about 30-40 minutes. I then turned it off, let it cool and gave it a good cleaning...Now, here's the bad part. It since, has not started again? The battery is now completely dead. I'm guessing that's the problem, But shouldn't I still be able to kick it over with no battery? Very thankful for any infomation regarding this matter...thanks!

- My next step of the plan is to get new plugs and re-charge or buy a new battery (the current battery looks clean and the levels are correct)

csendker · « **Reply #1 on:** June 14, 2006, 09:57:27 AM »

Welcome aboard. And yes, you need a functioning battery to start, even with the kicker. Many, many past threads about this one, has been a hot topic on & off. The alternator doesn't produce enough juice to power the bike when running below about 2K RPM - until then, the bike needs the battery to provide enough power just to run. Idle long enough and you'll kill the battery.

SKTP · « **Reply #2 on:** June 14, 2006, 10:03:45 AM »

Wow, that was fast!

Thanks csendker you have put my mind at ease...I did search the forum for this topic...sorry I created a repost. I plan to keep all my questions in this threat so as to not polute the board...Here's a stupid question...where in the heck are the fuses? I Have the CB 750 manual, a Clymer book and a Haynes book but I can figure out where they are...I'm guessing in the electrical panel but where exaclty? I know/think there's 3...but I don't see 3 of anything that look like fuses? Sorry about this questiuon...I feel pretty foolish

kghost · « **Reply #3 on:** June 14, 2006, 10:04:32 AM »

It will not start without a battery.

If it had a magneto it would but magnetos make their own current.

What you have are points and coils.

The way this basically works is power (from the battery) is run through the primary windings of the coils. When the points open it breaks the circuit. Dropping the voltage through the coils because of course with an open in the circuit (the points) current can no longer flow. (capacitors are with the points btw to keep them from arcing and pitting when they open)

At this point as the current drops in the primary windings of the coil a wonderful thing called inductance happens.

This essentially causes current and high voltage to be developed in the Secondary windings of the coil. Its this voltage that goes to the Spark plug.

Course this is a pretty simplistic description of what is happening but you get the idea yes? No battery to power the primary windings no sparkie sparkie.

You need the battery btw to power the alternator too. The battery provides excitation for the alternator unlike a generator but thats another post

csendker · « **Reply #4 on:** June 14, 2006, 10:11:38 AM »

No sweat, you'll get the hang of what to put in the search box to get an answer. This happens to be one of those topics that gets plenty of air time.

The fuses on my 550 are behind the left plastic side cover. That would be the very brittle, 30-year old plastic side cover. It should have 3 tabs, 2 on top, one on bottom. Pull VERY GENTLY at the tabs and try not to break it. The rubber grommets can turn hard and make it tough to pop off. I spray the grommets with some silicon spray before I pop the cover back on.

And when you find them, a typical problem is a cruddy fuse block. Pull the fuses and clean the block up real good. If you replace the fuse, look for the proper length; 1", not the 1-1/4" auto size. The longer fuse will not fully seat, leading to hot spots and all sorts of other problems.

SKTP · « **Reply #5 on:** June 25, 2006, 03:50:16 PM »

I am refinishing/painting my tank...I am going to go without badges/emblems...

Abov, is a picture showing the mounts (marked with the arrows)...are they welded in there or can I pull them out...?

I figure they stay in and I'll just bondo right over them...but they do seem to stick-out slightly...Any advise very welcome...

Below are the before shots...I'll update my progress in this post (if you're interested)...Thanks!

That dent really shows up on the left in these shots...It will be my first body work/dent fill ever...wish me luck!

ProTeal55 · « **Reply #6 on:** June 25, 2006, 07:15:21 PM »

I used some Bondo to cover up my emblem "brackets" , or what ever you wanna call them.
Did a few light coats, sanding in-between each of them, then used lots of sandable primer, then the actuall paint.
It was a rattlecan job, so I wasnt looking for "sandcast" quality, and came out pretty good.
If you look hard enough, you can see a fait outline of the bracket, but not a big concern.

As far as your battery goes, ditch the old and start off clean with a new one.
Not worth risking the old battery stranding you somewhere...
My 4cents...

SKTP · « **Reply #7 on:** June 25, 2006, 08:04:15 PM »

Thanks for the advise...you wrapped your headers...I'm going to do that also...how much wrap did you require?

Your gallery is awsome...the tank swap picture makes me wonder if I should even bother filling my tank? lol...but I'm trying to keep this first project as affordable as possible...so far, bike included I'm at around $500 US

Here's the beast in question...

Going to have to do something about that MASSIVE rear tail light....its so HUGE!!!

I just made my first ebay purchase ever...a new speedo for 6 bucks! I'm stoked....many more question to follow...so happy to have found this place...

Jerry Rxman Griffin aka MuthaF'er · « **Reply #8 on:** June 25, 2006, 08:56:38 PM »

Helluva deal for $500 !!!!! Looks like you got a great deal and a fantastic start. Thats just a small down payment of whats to come once you're hooked. Individual parts can cost $500. Doesn't look like you need to do much. Buy yourself a Battery Tender when you get that new battery and make sure you fully charge it before installing it. Keep it plugged in when not riding especially after letting it idle for so long. My new Battery Tender Plus has already paid off by bringing my 9.6V Craftsman drill battery back to life when it's charger couldn't.

Anyway, welcome and enjoy.

Jerry

cbjunkie · « **Reply #9 on:** June 25, 2006, 09:07:53 PM »

I'm with ProTeal on this tank question - Strip that paint off and Bondo in several careful layers - take your time with the sanding and then build it back up where you need to - you should be able to feather out the small protrusions without serious problems.

The bike already looks like a lot of fun! Enjoy!

csendker · « **Reply #10 on:** June 26, 2006, 04:34:26 AM »

Here's my fix for the tail light and rear turn signals...

ProTeal55 · « **Reply #11 on:** June 26, 2006, 06:09:36 AM »

SKTP--->
Ya, I wrapped the header pipes on my bike, while they were ON the bike

Why I didn't take them off I am unsure, but I still got it done. I forgot how much I actually ordered, but I know I have enough left over to do another set..
I think I ordered two 50ft. rolls. Make sure you get the black wrap, as the reg. white/tan stuff looks like ass in about a week...

Thanks for the kind words on my gallery.

I try and keep it simple and to the point. Need to upload some more pics of my new headlight setup I did over this past weekend..That tank swap pic is one on my favorites...

As far as your taillight goes, your options are endless. I just took a reg. old cateye l.e.d taillight and mounted it to the side of the bike, along with those little bullet lights. All act as both running lights as well as brake lights. My buddies tell me they can see me for miles down the road (which is a good thing). You can never have too many brake lights on a motorcycle, as it might just save your life one day...

Great bike , and have fun tearing it apart !

SKTP · « **Reply #12 on:** July 09, 2006, 07:30:00 PM »

Here's my first go at the tank...I think for now I am goin gto run it raw-dog/Mad Max style...I think it looks pretty frickin' rad, dents and all...

Chesse-ball photo, post beers and chemical stripper high...what do you think? (that's my friend's 54 Triumph)

I plan on glossing up the black section and adding white pin-stripes along the edge of the black area...right now its just a clear coat and black primer

and now the next debate; white walls? (shot taken pre-the black top stripe)

Carb re-build questions coming soon!!!

kghost · « **Reply #13 on:** July 09, 2006, 09:06:45 PM »

Hmmmm......

My opinion...and its just mine....the white walls don't go with the 4-4 exhaust. Takes away from the clean lines of the flowing exhaust.

Save the whitewalls for the chopper project you'll wanna build next

SKTP · « **Reply #14 on:** August 15, 2006, 12:04:53 PM »

I think I have found a Giuliari seat...it says it will fit a K2 to K6....I have a K8. How much different is there between the K2-6 versus K8 mounts?

sparty · « **Reply #15 on:** August 15, 2006, 12:25:51 PM »

Quote from: SKTP on June 25, 2006, 03:50:16 PM

I am refinishing/painting my tank...I am going to go without badges/emblems...

Abov, is a picture showing the mounts (marked with the arrows)...are they welded in there or can I pull them out...?

I figure they stay in and I'll just bondo right over them...but they do seem to stick-out slightly...Any advise very welcome...

Below are the before shots...I'll update my progress in this post (if you're interested)...Thanks!

That dent really shows up on the left in these shots...It will be my first body work/dent fill ever...wish me luck!

If I were you, I would grind down the higher parts of the metal then hit it with bondo, that will give you the best results.

Sparty

ProTeal55 · « **Reply #16 on:** August 15, 2006, 12:32:01 PM »

SKTP -->
I like the direction your bike is going in

I agree with the others on the white walls.
I think a blackwall tire will look cleaner on your bike than a WW.

As far as the seat goes, I am not sure what differences their are from a k2-k6-k8 ?
I know when I first got my CB750K2 it had a K8 tank on it, with the stock K2 seat.
These seats look too good to pass up...

Make it fit !!!

mrbreeze · « **Reply #17 on:** August 15, 2006, 01:15:32 PM »

The first thing I noticed when reading this post is that is a 1978 K4.WRONG!!! It is a K8! A K4 is a 1974.I think you got a fantastic deal for $500. As far as the seat goes,they changed in 1977. The 76 & prior hinged on the right..lock on left.Also(and I found this out the hard way!),the rear fender and grab bar are different.Hey....do you know anyone that wants to buy a 1978 rear fender and grab bar (that won't fit my K5)?

SKTP · « **Reply #18 on:** August 15, 2006, 01:38:46 PM »

Thanks guys...I agree on the make it fit part...that looks frickin' sweet PT...

and yes, I finally figured out that I have a K8...

SKTP · « **Reply #19 on:** August 15, 2006, 09:53:53 PM »

So basically I need a seat real badly...will a 1978 F seat fit on a 1978 K with out major modifications?

mrbreez, the grab bar might be cool? But all my friends say that if I put one on the ladies won't have to hold on to me?!

SKTP · « **Reply #20 on:** August 19, 2006, 06:51:05 PM »

Carb kits on the way...just an update pic here...the search for a seat continues

mrbreeze · « **Reply #21 on:** August 19, 2006, 08:14:51 PM »

If you want the grab bar or rear fender or even the tail light assembly,let me know.

mrbreeze · « **Reply #22 on:** August 19, 2006, 08:24:26 PM »

If you end up getting one of those "F" seats or some kinda cafe deal,the grab bar won't work anyways.It would still work if you get another stock seat or have your's revamped.I just had my stock pan gone through by Corbin ($350).....same hinges,lock,etc. and it is stepped for 2 up(not one of those butt-ugly king-queen POS lookin' seats)....Being that its on the stock seat pan,my grab bar stays.And when I have mama on back,it ain't about hold the grab bar! Its about hold on to me tight cause you never know when we're going go or stop fast!!!

News:

Author Topic: 1978 - CB 750 K4 - * F seat on a K? Same year... (Read 4173 times)