Fuel (Lead additive) and front caliper replacement

[JackL]

Hi, I've had a few classic cars that needed lead additive to protect the valves. Does a '76 CB750 need anything like this?

Second question, I'd like to upgrade the suicidely weak front brake caliper. Is there anything from a more modern bike with mulyiple pistons that bolts right on?

Thanks

Jack

 

[UK K6]

I don't use additives on any of my old bikes or my 50s car. No problems. I do avoid E10 though.

On my 750k6, I replaced the brake lines with braided (black sleeved, so look stock), replaced the pads and removed the pivot pin, cleaned it up nice, greased it and new o-rings. The brakes are now acceptable. I was finding I needed to use both front and back regularly, now I mainly just use the front, even for heavy braking. They're not the equivalent of modern brakes' performance and feel, but they suit the thin forks and front tyre contact patch adequately, in my view.

 

[86FJNJ]

You may be able to purchase leaded ethanol free gasoline from your nearest small airport, it's more expensive than regular gas. I use "Yamalube Ring Free Plus Fuel Additive" in my gas. You can buy it on amazon. It's not cheap but it helps keep the fuel from messing up your carbs. I've run it in my yamaha for a while and have used it in my CB, just follow the instructions for dosage and you'll be fine.

 

[hinksy]

The factory recommends 91 octane low lead and say leaded fuel may be used if no choice . Most people used to get another fork leg , brake caliper and lines to run dual calipers . Of course you would have to upgrade the master aswell . https://www.cb750.com/threads/69-78-k0-k8-dual-front-discs-with-leading-calipers.1862/

 

[AutoMac]

The factory recommends 91 octane low lead and say leaded fuel may be used if no choice . Most people used to get another fork leg , brake caliper and lines to run dual calipers . Of course you would have to upgrade the master aswell . https://www.cb750.com/threads/69-78-k0-k8-dual-front-discs-with-leading-calipers.1862/

This is exactly what we used to do in my youth we would scour the local bike breakers for a CB 750 F set of fork legs and all the rest of the bits needed for a Honda twin disc set up . Sadly few back street bike breakers exist any longer but eBay comes up with a few things now and then. But the standard single disc when refreshed is way better than the TLS fitted to my BSA A65.

As for unleaded fuel, for years I have run my Japanese bikes on E5 with no issues. In the UK E10 is more common now but my local supermarket still has an E5 pump so I always go to that.
I recently changed my 1976 Austin Mini 850cc engine for a A+ ( unleaded head ) 1275cc engine. On inspection of the old 850 lump I found no problem of valve set regression or valve burn out and again I ran it on the E5 fuel pump, but on occasion once in blue moon I ran some octane booster through a full tank of fuel and maybe it was wishful thinking but I swear I could tell the difference. So the occasional additive or n a tank full of fuel now and then maybe an easier problem solver.

 

[JackL]

Thanks everyone. Great information.

Jack

 

[hinksy]

This is exactly what we used to do in my youth we would scour the local bike breakers for a CB 750 F set of fork legs and all the rest of the bits needed for a Honda twin disc set up . Sadly few back street bike breakers exist any longer but eBay comes up with a few things now and then. But the standard single disc when refreshed is way better than the TLS fitted to my BSA A65.

As for unleaded fuel, for years I have run my Japanese bikes on E5 with no issues. In the UK E10 is more common now but my local supermarket still has an E5 pump so I always go to that.
I recently changed my 1976 Austin Mini 850cc engine for a A+ ( unleaded head ) 1275cc engine. On inspection of the old 850 lump I found no problem of valve set regression or valve burn out and again I ran it on the E5 fuel pump, but on occasion once in blue moon I ran some octane booster through a full tank of fuel and maybe it was wishful thinking but I swear I could tell the difference. So the occasional additive or n a tank full of fuel now and then maybe an easier problem solver.

Automac , Sadly bike breakers are getting fewer and fewer . We used to have two i( back in the day ) n my little town of 78 000 people and you could basically get anything , for a price . Now we are cracking 240 000 and everything is gone . I think the main problem with ethanol is the ethanol . It attracts water and rots rubber , so you have to change everything that comes in contact with it and change the oil regularly aswell as dont leave fuel in the carb bowls for extended periods . Man I have seen some horror stories from it .

 

[AutoMac]

Hi Hinksey, I know what you mean regarding new fuels .
I try to use my machines all year around
( weather and arthritis permitting ) but I also use a product called “Stabul fuel additive “ which I add to a full tank of fuel if the bike is going to be stored .

Once added to the tank then shaken to mix it up ( like an old pre mix two stroke) I run the machine to get the additive into the float bowls and then shut off the engine and fuel tap. A full tank helps prevent moisture contamination and the Stabul stops the modern fuel “ going off” as quickly.

I also use a smart battery tender attached to the machine. I know some people don’t like them but I have done this routine for some years and come spring I change the engine oil and filter and ( touch wood ) my old bikes start up after their slumber.

The Brit bikes do their own oil change usually by “wet sumping” into a drip pan under the bike which I then forget to attend to and eventually it over flows onto the workshop floor over winter