Start of refurb

[david451]

Bought two usa cbs, 750, 74 and 77 models they have the oil tanks with the cap on the outside.

What's the best way to get the engine out, lift it out or lift the frame off the engine on it's side.

The chain drive was a bit noisy so took off the chain and had a look at the front sprocket, it seems to be a bit loose on the shaft, it needs a new chain and sprocket set so perhaps the wear is in the sprocket?

Is it acceptable to spray and lacquer the frames or does it have to be powder coating, don't know much about these things in my day the frames got painted.

Anybody give me some ball park figures for chroming, say a wheel perhaps and perhaps my exhausts once I repair them, they seem to be about 1k to replace so that's most of my budget out the window, so it is going to have to be a repair.

Do I need to restore the painted areas on the engine or can I polish all the engine up, and if it's going to have to be painted again, that grey primer colour is there a special paint you get to prevent it flaking off with the heat or can I use normal paint with heat resistant lacquer.

[Spitfire]

Hi there, and welcome, if you are going for a rebuild I would definately recommend taking lots of photos during the process, and storing parts in labelled ziploc bags. When you come to put it all back together it can be a pain trying to remember cable and tubing runs and a lot of the detail stuff.
For engine removal I took everything that I could off the bike and was left with a frame and an engine, the engine drops out of the frame side, though it would be easier to lay it on it's side and lift the frame off. I've not removed an engine that way only replaced one in it's nice shiny powdercoated frame.
I powered coated my frame as the powder coating process produces a tough long lasting finish, it's not as shiny or smooth as paint, so you pays your money and you takes your chances.
The front engine sprocket is a loose fit on the shaft due to the way it is retained.
Most chromers will not touch old exhausts as they mess up their bath, so rechroming is not usually an option.
For engine paint I used VHT aluminium paint, a lot of engines are bare aluminium but I would not recommend it on a UK bike, use the "search" funtion on the site to look at types of paint. There's a lot of info here.

Hope this helps

Cheers

Den

[david451]

Hi there, and welcome, if you are going for a rebuild I would definately recommend taking lots of photos during the process, and storing parts in labelled ziploc bags. When you come to put it all back together it can be a pain trying to remember cable and tubing runs and a lot of the detail stuff.
For engine removal I took everything that I could off the bike and was left with a frame and an engine, the engine drops out of the frame side, though it would be easier to lay it on it's side and lift the frame off. I've not removed an engine that way only replaced one in it's nice shiny powdercoated frame.
I powered coated my frame as the powder coating process produces a tough long lasting finish, it's not as shiny or smooth as paint, so you pays your money and you takes your chances.
The front engine sprocket is a loose fit on the shaft due to the way it is retained.
Most chromers will not touch old exhausts as they mess up their bath, so rechroming is not usually an option.
For engine paint I used VHT aluminium paint, a lot of engines are bare aluminium but I would not recommend it on a UK bike, use the "search" funtion on the site to look at types of paint. There's a lot of info here.

Hope this helps

Cheers

Den

The gearbox sounded a bit clattery, at 25k is there problems with them that's why I thought the sprocket was to blame, is there a check I can do. I was running it on the centre stand mind you and just comparing it to the other one which is not so noisy.

[mick]

Hi David the clattery sound you describe could be clutch noise which is common on these 750's usually at tickover if your carbs are out of balance they can sound like a bag of spanners  usually opening the throttle slightly or pulling in the clutch can quieten things down some, i would imagine by the time you have given it a thorough tune up most of the noises will disappear , cheers Mick.

[Spitfire]

As Mick says these bikes can sound terminally ill on tick over if not set up right, some sound terrible at tick over even when set up right !

Cheers

Den

[david451]

As Mick says these bikes can sound terminally ill on tick over if not set up right, some sound terrible at tick over even when set up right !

Cheers

Den

I was running the old girl through the gears on the centre stand, not a good idea but I can't run her on a road at the minute, no brakes is one of the reasons.

One of my bikes has two new tyres on it and it's a spitfire on the front, you making tyres on the side then.

[K2-K6]

The gearboxes are really quite tough in my experience especially for a standard output motor but they can sound a bit jangly if the tickover is not as smooth as you can get it.

Oil in good condition is an absolute must to look after many aspects of smooth running and long life on these, many owners are not aware of just how much this pays off so if you are not confident of this it's one of the first things to do.

[K2-K6]

Oh also forgot, check the Rear wheel cush drive as if you are running on the stand through the gears if this is worn/baggy the inertia of the rim will certainly help clatter the gearbox if not under constant load.

[david451]

The gearboxes are really quite tough in my experience especially for a standard output motor but they can sound a bit jangly if the tickover is not as smooth as you can get it.

Oil in good condition is an absolute must to look after many aspects of smooth running and long life on these, many owners are not aware of just how much this pays off so if you are not confident of this it's one of the first things to do.

Probably have to wait and see what happens on the road, hope the gearbox is ok, honda reliability.

Doing a bit of research and I recon mine are the K model, if its as simple as that then one would be a k4 because it's a 1974 model and the other a k7.

Would it be a sin to convert one to a cafe, I still have the bug in my bones from the 70s and need to complete this before I get too old to ride her.

[david451]

Oh also forgot, check the Rear wheel cush drive as if you are running on the stand through the gears if this is worn/baggy the inertia of the rim will certainly help clatter the gearbox if not under constant load.

Took the chain off to see if it got worse, probably needs to be under load on the road, might try it again tomorrow with the brake applied if I can get it working.

Found somebody to powder coat my frames 120 quid for each so gona go that route instead of painting them.

[K2-K6]

I thought the K7 had the oil tank cap covered, and maybe had a 630 size chain and sprockets similar to F2.

[david451]

I thought the K7 had the oil tank cap covered, and maybe had a 630 size chain and sprockets similar to F2.

Both look the same other than the early one has the tank tap on the right.

[K2-K6]

K7 also had 17inch rear wheel and is more related to F2 engine-wise with the later type carbs that have the lift mechanism enclosed unlike earlier models.

Seems as they are between K2 and K6 models from your description.

The oil tank filler was cover by the side panel from F1 through F2 and K7 so if original gives a clear distinction.

Fuel taps can differ from model to model and also have dual/single pipes running to the carbs depending on fitment. My K2 has a tap on the right, I would guess that the position on most bikes may have been more standardised to the left on later models as it's easier to switch to reserve and still be in control of the throttle.

[david451]

K7 also had 17inch rear wheel and is more related to F2 engine-wise with the later type carbs that have the lift mechanism enclosed unlike earlier models.

Seems as they are between K2 and K6 models from your description.

The oil tank filler was cover by the side panel from F1 through F2 and K7 so if original gives a clear distinction.

Fuel taps can differ from model to model and also have dual/single pipes running to the carbs depending on fitment. My K2 has a tap on the right, I would guess that the position on most bikes may have been more standardised to the left on later models as it's easier to switch to reserve and still be in control of the throttle.

The early one has a 18 and the later one a 17 as you say, both carburator lift mechanisms are external and the same

Both the oil caps are exposed, they look like the model that came after the sandcast ones, the side panels don't have the vents on them

[K2-K6]

The 17inch wheel maybe a bit of a curve-ball and could have been retro-fitted to it.

They certainly sound like mid production series models from the details.

I guess if you "cafe" one of them you'll only be doing what others have and will only know how you feel about in years to come. It's quite personal how anyone has their bikes though so free choice really.

If you didn't get them they may not have been back running at all, and it can be done so that it's possible to return to original if the mods are all bolt together.