Topic: My first bike: '78 CB750k

[seanbarney41]

17" is stock for 78k...

[fendersrule]

Thanks for the sanity check!

http://www.classicbikes.com/750.html

That guy recommends:

100/90V19 Front (Dunlop GT501). I have "3-50-19 Dunlop Gold Seal K70," whatever that means.

120/90V18 Rear. I have "4.50H 17a K112 Continental," whatever that means.

I would agree with him, in that the stock sizes are a little "wussy' looking.

I'd like to see how these sizes look on a rear:

http://www.jpcycles.com/product/ZZ21201
http://www.jpcycles.com/product/ZZ26135

Would be nice to see someone post a 90 tall rear tire. The 100/90V19 is an easy choice on the front...but I'd like to see the rear at different heights.

So the only option going with a GT501 would be 140/80-17. But that's a little too wide.

[Stev-o]

I put Dunlop 404's on my K8, 130/90-17 on the back. 

IRC? You can do better. The Bridgestone is a great tire, have them on my K4.

Install new tubes and rim strips too.

[fendersrule]

Can you post some pics if your rear tire? Side shot, etc. 

[fendersrule]

Hi all,

I should have some exciting updates in the next couple days. Let's just say that I found a killer seat for a killer price...I'm hoping that it falls through.

I'm going to create a separate thread about tire sizes and chain sprocket recommendations so my questions can be better addressed there.

Here's a few questions that I have to help me get started on some new things:

1) On the latch studs on the underside of the seat: can those be replaced without removing the foam?

2) Do you guys have any method/recommendations for replacing both handle grips?

3) My turn signal switch seems to be a 5 way switch. The electrics are messed up. Sometimes moving the switch causes the blinkers to stay on (steady without a pulse). The wiring should be looked at, but I also wanted to confirm if the switch is working as intended. Shouldn't this be a three-way switch?

4) On the horn button, I have to really push/hold it down. It doesn't work with a light tap. I'm thinking that these switches should be cleaned with some contact cleaner.

[toytuff]

Here's the progress that I made today.

Here's my current front fender:



One ugly crease, and about 5 dents. It's no good.

Picked this up today for a good price. Cleaned it up. 9.5/10 condition...I think there's only one tiny ding that's hard to see:



Every day, I'm going to do some polishing. I cleaned up the left side pretty good:



Replaced the driver's foot pad:



I'm mostly a stock guy...mostly, but I dig this. Probably need to clean/oil them up for good measure:



I replaced the broken horn (check out the lovely flat black paint) with a nice horn that I found today. The horn also works!:



A bonus:

Lovely OEM exhaust:

The silver horn is correct for the year. If it's a 78 keep the 78 seat. Just my 2cents.

Lucky on the exhaust. Rare as hens teeth. Only used two years.

tt

[fendersrule]

There's only a couple things I'm willing to "mix and match" parts on, and not all of it is for "stylistic" reasons.

The '77 seat, even though I've never sat my fat ass on one, looks like it will suit taller riders better than the '78 seat will. The '78 suits me just fine, but I really can't say because i've only put 5 miles on the bike. The '79 seat doesn't fit me very well and forces me to sit too far forward. Not only will the '77 seat be better for my size, I like the flatter profile of the '77 seat; more like the classic CBs. Even if I chose to find a '78 seat, I'd have to shave the foam to increase comfort, and then it's not a '78 seat anymore. I'd rather buy a stock '77 seat, and leave it wholesome and complete and mount it up. Plus, it won't do anything to the value of the bike, and it will make it look more flat.

The second thing, which is purely stylistic, is that I'm not a fan of the '78 side cover emblems. I don't like the font styling at all. I'm not crazy on the '77 side cover emblems' cursive style either. So I may just found some really good looking emblems.

The paint will be Freedom Green, with classic style pin-striping.

Those are my end goals. It's going to be full CB Honda, with real CB Honda parts, but it's going to be a '78 that has more classic styling and more reminiscent of an older CB. The Hagan shocks I'm going with have shock covers, because I prefer that classic look.

The bike will look ultra sexy, and it will still be 100% Honda CB750 that has some of the better stylized options that Honda started deviating from.

[Stev-o]

A few responses to your questions:

Your switches/wiring is 30+ years old, it may need repairs if not working properly.
I think you could replace the seat studs w/o replacing the foam. Put whatever seat you want on it, so it is comfortable for you. Many guys mod the foam to their desire.
Cut you grips off with a utility knife. Use hairspray when in staling the new. Really.
Don't use the cover emblems if you don't like them. Fill em and paint green, sounds good!

[fendersrule]

Thanks Steve-o. I'll take some vice grips and remove them (along with some penetrating oil), being hopefully they are "studs" and not bolts.

Heard of the hairspray trick. You do that with bicycles grips too!

I'm actually a fan of this styling for emblems:
http://www.ebay.com/itm/Honda-Factory-CB750K-Side-Cover-Emblems-1973-1976-/281022688960?pt=Motorcycles_Parts_Accessories&hash=item416e41eec0&vxp=mtr

Never thought about going bare covers. I think those emblems would look sweet.

Anyhow, not much of an update tonight guys. Still waiting on parts to come in.

I've been experimenting with polishing aluminum. Here's the method I found to work quite well (I used these for the front forks...check out how great they came out):

(1) Red scotch pad w/ blue magic polish. The purpose here is to remove the corrosion and to "even" the surface. Works like a charm, and you don't need to put too much muscle at all.

(2) 600 grit wetsand, followed by 1200 grit wetsand.

(3) Reapply the blue magic polish with either a rag or fine steel wool:




I took a fine brush and scraped off any surface corrosion around the header entries:




Again, just minor stuff, but I thought I'd post an update.

[fendersrule]

Got my new handle bar grips in today. I can't stand the "flexible" grips that are on there right now.











Notice how there's a gap that exposes the throttle sleeve. Is this normal, or is it a mis-matched throttle sleeve?

[Stev-o]

It's fairly common but I don't like it. I seem to remember trimming the tube on one of my bikes.

[fendersrule]

Hmm...sounds like I may need to take my grip back off.

Which side did you trim?

[Stev-o]

The outer side

[fendersrule]

Well, the outer side is flush with the steel handlebar.

I think sliding the throttle unit towards the edge more, then taking a fine hacksaw will do the track; taking measurements of course first.

I'm with you. Maybe I'm picky, but I like it flush. Hopefully I can make do with the stock cables with the slightly different than stock handlebars. At least I think they are not stock.

[fendersrule]

Got it moved forward, and ready for the hacksaw. It's all measured up. The cables were limited by the dumb front turn signal, so I removed it.

On a side note, my choke is a little hard to engage. It stays where I leave it, but just that initial pull requires strength.

I took some steal wool and used some 3 in 1 oil on the shaft, but not sure if that helped. I'll play around with it some more, but is there an adjustment of some sort?

[Stev-o]

The choke is stock and is cable, right?  If lube doesn't do the trick, may be time for a new cable. 

Mine does not stay on when once you pull it, wish it did.  Prefer the lever on the carbs like the earlier model.

[fendersrule]

Yeah, it's the stock cable. It stays wherever I place it (well, it stays good enough to not hassle a replacement). The real issue is that initial pull.

I'll spray some lithium grease around the shaft and use some more steel wool to aid it a bit more. Maybe I'll stick to my handy dandy 3-in-1 oil instead...not sure. I just wanted to see if there was some sort of an adjustment, but I guess not.

Pictures to come later.

By the way, I JUST PURCHASED A '77 CB750 SEAT FOR $60 SHIPPED! It doesn't need a seat cover either...just some studs, and it's ready to mount...

So happy!!!!!!!! I'll have my favorite seat on that bike real soon. Good bye to the bent up seat that needs to be recovered.

[fendersrule]

Here you go Stev-o:



Joseph's hand-made urethane side covers came in today. Very nice covers, and stronger than OEM. Just need to do some VERY MINOR cleanup around some of the edges, and then prime + sand + paint. I'll do this along with the tank body repairs later this winter. Got a dent to work out that's around the rim of the gas lid; should be fun. Good thing I know a thing or two about bodywork. But not so much about mechanicals; I can barely screech by in that department.




I polished these spokes, and hope to never do it again:


Things I have on the way:

Bridgestone Battlax BT45 100/90/19
Bridgestone Battlax BT45 120/90/17
Front Sprocket (630)
Rear Sprocket (630)
DID O-ring Chain (630)
Front wheel bearings and seal
Front wheel brake pads
Rear wheel bearings and seals
Rear wheel brake shoes
Tank grommets
side stand rubber
various other grommets
'77 CB750 seat
Front trim mount + honda logo for fork
Headlight reflectors and rubbers
Turn signal assembles
Hagon Type P Shocks (w/ chrome shroud)



STILL NEED:
FORK EARS!!!!!!!!

Can you guys believe I soon will have every part? Quite amazing. I guess I've been antsy.

[fendersrule]

Here's the seat that I scored from someone in Florida. Thanks to Craigslist.

Consider myself very very lucky.

[fendersrule]

Well Stev-o, it looks like a zap of lithium grease on the choke lever/mechanism that sits above the carbs worked like magic. The chock pulls nice now! It was really that simple...

Since I had the gas tank off while doing this, I thought I'd go ahead and get the valve covers polished.



Right side is polished. This is showing a great before and after. I didn't use my whole process (listed above) for this as I ended after the blue polish + red scotchpad.



There you have it!



I thought I would clean these pod filters. I usually let these type of filters presoak for a little bit with soap + warm water. I didn't have any K&N filter cleaner (crap is expensive too), so I used engine degreaser, and sprayed as much as possible, and worked it in with my fingers. Seemed to work great; you can see the tainted dirty scum/water come right out of it. Going to be oiling them soon.

That's about it for today....probably all rather boring for most of you. Haha!

[Stev-o]

Nice find on the seat.  I also found one for my K7 out of Florida. Coincidence?!

It's amazing what a little lube will do, you may want to lube the other cables.

[fendersrule]

4) On the horn button, I have to really push/hold it down. It doesn't work with a light tap. I'm thinking that these switches should be cleaned with some contact cleaner.

I removed horn button and reseated the spring (and used some contact cleaner while I was there. The horn now works consistently with a normal tap. The problem the spring which was poorly seated.

Also replaced several fasteners, including headlight bolts, clutch/brake control hardware, etc.

Cut off the crappy looking turn signals (had to cut the wire, of course). The turn signal switch looks it works as it should under further investigation. The buzzer works on both sides. Because the wires are not hooked up anymore, the indicators on the dash does not work. Will play with this more when my stuff comes in.

By the way, I located some mint condition ears (77), turn signals assemblies (77), headlight reflectors/bolts (78), air box (77), fork trim plate/emblem (78), and a powder-coated chain guard (77) for a killer price off craigslist.

I have all the parts on the way now, or at least 99%. Kickin this bike's ass. Until next week.....

[toytuff]

The choke is stock and is cable, right?  If lube doesn't do the trick, may be time for a new cable. 

Mine does not stay on when once you pull it, wish it did.  Prefer the lever on the carbs like the earlier model.

The choke cable at the top should have a plastic ferrel. Once you pull the choke tighten the ferrel. Choke will stay in position.

tt

[fendersrule]

Ill try that toytuff today.

As I'm waiting for all these nice parts, I thought I'd delve deeper into my ignition switch.

I usually have to turn the ignition key back and forth until the lights come on in the "center" position, which is the start position. Sometimes I'm lucky for it to work on the first try. Sometimes I have to switch back and forth 6 times.

How big of a job is it to remove the ignition switch and to take a gander at what the hell is going on? Anyone have any advice/tips?

[Stev-o]

I would buy another switch.


Here are a couple pics of my K8, look familiar? All original, 25K miles.