Topic: My first 750: '76 CB750F

[Bankerdanny]

The revs at highway speed are where the two are very different as well.  Where the 550 is in the upper rev range to stay at 80 mph, the 750 is much less urgent.

The 750F has shorter gearing internally than the K, it rev's out to similar numbers as my 550.

[SOHC4 Cafe Racer Fan]

The revs at highway speed are where the two are very different as well.  Where the 550 is in the upper rev range to stay at 80 mph, the 750 is much less urgent.

The 750F has shorter gearing internally than the K, it rev's out to similar numbers as my 550.

Even in 5th?

[Bankerdanny]

Finished what should be the last job for this season, replaced the OEM rear master with an inexpensive generic master. Seems to work fine, I have a rear brake and it isn't locking up the way the prior version was. Now I hope to enjoy it for the next couple of months and over the winter it will get new paint and wheels.

[Bankerdanny]

Got out for another short ride Sunday afternoon, about 20 slow (25-40mph) miles up Sheridan road, which hugs the Lake Michigan shoreline from Chicago all the way to Milwaukee. My ride was from my home in Evanston up to the big dollar suburb of Lake Forest. On the way back I took mostly highway. In both cases the bike performed very well. The idle isn't as stable as I would like, but then again I didn't do a lot of playing with the carbs beyond the normal cleaning and setting of the floats.

So far after about 100 miles or so there is no sign of oil leaks at the head. My experience with my 550 was that high RPM highway time seems to bring that out and after about 90 minutes of riding 65-75 mph no sign.

I am wondering if I went with too large of a rear sprocket. I am turning 6k rpms at 70mph, which seems high.

[Jerry Rxman Griffin aka MuthaF'er]

Danny, mine does 70 at 5k with 17/48 and 75 with 18/48

[Bankerdanny]

I am wondering if I went with too large of a rear sprocket. I am turning 6k rpms at 70mph, which seems high.

In 5th gear?

Yes, in 5th. I am running the stock 17-48.

It is possible that the issue is with the tach or tach drive gear. I know the speedometer is reasonably accurate based on the GPS speedo on my phone.

[RAFster122s]

Got access to a small tach dwell unit like those made by Sun or others? It could tell you your rpm when at speed if it handles the wasted spark. That would be what I would use. I have one about 4 x 6 inches square and then a bigger shop unit that is about 1/2 a tank top in
L x W measurements.

[Bankerdanny]

Got access to a small tach dwell unit like those made by Sun or others? It could tell you your rpm when at speed if it handles the wasted spark. That would be what I would use. I have one about 4 x 6 inches square and then a bigger shop unit that is about 1/2 a tank top in
L x W measurements.

In fact I  do

[Don R]

 I think the F trans is lower in 4th and 5th. I liked the 18 tooth front on mine. (530 of course) It got mine below 5K at my favorite cruising speed. My speedo read 5200 at 75 stock, I think the 18 got it to around 4800to 4900. It just takes the edge off of it, seemed more relaxing to me. L0L!

 Mine was that color but didn't have the stripe. The 78 I just got has the stripe too.

[Bankerdanny]

A while back I pulled the baffle out of the replacement Kerker I bought. It had separated from the cone, so I cleaned it and the cone up, painted them, then cheaped out and put them back together with JB Weld instead of welding them.

The quickly separated and the cone flapped around while the bike was running. I thought about drilling and installing a 2nd screw, but the muffler body is in such nice shape I didn't want to add a hole. So I just ignored it.

2 weekends ago while cruising on the highway it suddenly got much louder. A quick check confirmed, yep, no more baffle or cone. Fortunately you can buy replacements, unfortunately they cost $130. *sigh* more good money after stupidity.

Short-term I'm just going to finish the season without it. It sounds pretty good, but too loud for the long-term and for the residential neighborhood where I live.

[Jerry Rxman Griffin aka MuthaF'er]

Hey Danny, I just saw the tach vs speed post. At 17/48 at 5000rpm you should be doing 70 and 18/48 it should be 75. Of course it's also dependent on the tire size.

[Bankerdanny]

Ordered a set of front and rear wheel bearings.

I'm going to replace the bearings in the rear Lester even though I am pretty sure it has never been mounted on a bike. With 0 miles on it one would think the wheel bearings are fine, but I have decided to just replace them anyway.

The front Lester is the one that was on my 550 and I put 6,000 miles on that bike with no indication of issues. I'll just add the front bearings to my parts bin and if I ever need them they will be handy.

I'm taking a few days off to dog sit for my sister early next month, so the plan is to haul the bike down with me and swap the wheels and (hopefully) the F3 front fork and brakes onto it, install the new Delkavic header (although I still haven't had the inside coated as I intend to), and the parts I bought from HondaMan a few weeks back including a HondaMan ignition, resistors to use with 3ohm Accel coils I got a while back, and an ignition saver relay.

Then there's the F3 fork and brake caliper swap. I need to order a new front master and maybe caliper piston seals, lower hoses and fork seals.

Last but not least the tank needs to come off for a good inspection to make sure I have no holes, then over to someone to remove the couple dents it has. Finally I need to settle on a color that I want to paint it and to get some paint ordered.

March and April are going to be very busy but it should pay off as I have multiple shows and events I plan to attend around Illinois/Wisconsin/Michigan/Ohio this summer along with a 2 week trip out to the Carolinas and back (including Mid-Ohio) at the end of June/beginning of July.

[Bankerdanny]

Mounted the Delkevic today after having the inside ceramic coated. I had hoped to re-use my Kerker muffler,  but no go, the angle is all wrong. I'm going to order the matching Delkevic today.  I have a new front master cylinder coming and when that gets here I can swap out the stock fork for the F3 and dual disks.

[Bankerdanny]

Hondaman ignition mostly installed. Before I finish I need to install the Accel coils and resistors.

[Godffery]

Mounted the Delkevic today after having the inside ceramic coated. I had hoped to re-use my Kerker muffler,  but no go, the angle is all wrong. I'm going to order the matching Delkevic today.  I have a new front master cylinder coming and when that gets here I can swap out the stock fork for the F3 and dual disks.

What'cha gun'a do wit the old Kerker can? I may have use for one.

[Bankerdanny]

Mounted the Delkevic today after having the inside ceramic coated. I had hoped to re-use my Kerker muffler,  but no go, the angle is all wrong. I'm going to order the matching Delkevic today.  I have a new front master cylinder coming and when that gets here I can swap out the stock fork for the F3 and dual disks.

What'cha gun'a do wit the old Kerker can? I may have use for one.

I don't have a plan right now.  It's the shell only, the baffle blew out last Fall. Its in nice shape though, no rust holes, good chrome.

[Godffery]

Mounted the Delkevic today after having the inside ceramic coated. I had hoped to re-use my Kerker muffler,  but no go, the angle is all wrong. I'm going to order the matching Delkevic today.  I have a new front master cylinder coming and when that gets here I can swap out the stock fork for the F3 and dual disks.

What'cha gun'a do wit the old Kerker can? I may have use for one.

I don't have a plan right now.  It's the shell only, the baffle blew out last Fall. Its in nice shape though, no rust holes, good chrome.

Okay, I might be able to make a baffle with spare parts around the shop?  LMK if you decide to part with it.

[Bankerdanny]

Time for my pre-Spring season to-do list:

- Install new exhaust
- Install new tail light assembly
- Order brake hoses for new twin disk front brake setup
- Cut new Accel plug wires to length and install coil side connectors.
- Complete installation of Hondaman Ignition and connect to coils using appropriate resistor kit. Ended up using stock coils. Couldn't get Accels to work
- Install starter switch saver relay
- Repair starter switch (again) so power gets to starter solenoid 100% of the time
- Test system to make sure bike starts and runs clean.
- Install new tires on Lesters
- Remove "old" tires (installed last year and only have about 200 miles on them) from stock F1 wheels and install them on the Comstars on my buddy's F3, add old wheels to parts stash
- Install thinned and drilled brake rotors from Godffrey on Lesters, put rear wheel on bike.
- Replace seals on F3 forks
- Install new piston seals on front calipers
- Remove F1 fork legs and replace with F3
- Install and plumb front brake calipers and new front master
- Strip old paint from fuel tank, have dents removed, prep for paint
- prep tail section for paint
- Paint tail and tank

Well, that is a much longer list than I expected.

[Bankerdanny]

Reasonably productive day today. I got the coil side plug wire connectors from NAPA and also bought 4 more spark plugs to get the screw on adapters  so the plug connectors would fit properly. Installed my new muffler and made the bracket for it, repaired and reinstalled my seat lock, and last but not least levered new tires on the Lesters. The rear required taking a sawzall to the old tire that was on the rim.

Yesterday evening I did a basic fit of my new tail light.

Still lots top do,  but should be ready to go by mid April except for paint.

[Bankerdanny]

Temporarily installed the Lester on the back yesterday. The thinned and drilled rotor is on its way back to me from Godffrey and I should have it permanently installed next weekend.

Discovered that the drive flange from a Comstar won't work with the Lester. Unfortunately I figured that out after I had installed a new bearing in it to replace the OEM bearing that was only sealed on the sprocket side. Not a huge deal, but annoying.

I used my new master cylinder to push out the pistons from my F3 calipers. They are shiny and free of pitting, so next week they get a nice cleaning and new seals and should be ready to go on the bike along with the front Lester and freshly thinned and drilled rotors.

I installed the coil side terminals on my Accel plug wires, but I am still having problems with fitting up the coils, but I will get it sorted.

I installed the center stand so I could get the rear wheel off. I haven't decided if that will be permanent or not.

[scottly]

I used my new master cylinder to push out the pistons from my F3 calipers. They are shiny and free of pitting, so next week they get a nice cleaning and new seals and should be ready to go on the bike along with the front Lester and freshly thinned and drilled rotors.

I thought you were going to do the twin-piston caliper upgrade?

[Bankerdanny]

I used my new master cylinder to push out the pistons from my F3 calipers. They are shiny and free of pitting, so next week they get a nice cleaning and new seals and should be ready to go on the bike along with the front Lester and freshly thinned and drilled rotors.

I thought you were going to do the twin-piston caliper upgrade?

Maybe eventually. Right now I am going to stick with stock. I've spent quite a bit more than I intended and still need to buy paint. the twin piston calipers may be next year's update.

[Bankerdanny]

Slow progress continues to be made. Today was all about the wheels and brakes.

The F3 got a good cleaning and fresh piston seals. The pistons themselves were in great shape with no pitting.

A couple weeks ago I sent 3 brake rotors to Godffrey for thinning and drilling, 2 550 fronts and one rear. Scottly recalled that the 550 rotors would work with the F3 forks and calipers and Lester front wheel for my twin disk conversion. They are definitely the same diameter as the ones on the Comstar front. We should know for sure in a couple weeks.

I installed the rotors on the wheel, but first modified the right side rotor to hold the F3 speedo drive. I had to mess up the freshly painted center of the rotor, but you can't tell unless you get down and look really closely.

I pulled off the rear Lester I had installed last weekend, polished up the outer rim, installed the rotor, and back on the bike.

I also took time to take pictures of the wire wheel drive flange and the Comstar flange side-by-side. If you look you can see the obvious differences.

[Bankerdanny]

Here are the drive flanges. The one on the left is the wire wheel and the one on the right is from the Comstar.

[scottly]

Danny, the speedo drive plate needs to be underneath the rotor hub, not on top of it. You need to cut the recesses on the back side of the hub, and the plate should be trimmed so it fits loosely through the center hole. The rotor hub basically replaces the stock thin chrome plated drive retainer.