Topic: Bonjour à tous from Grenoble France

[Mushu]

I leave near Grenoble in France.

I bought a CB 750 K1 Candy Gold in November 2002 and I refurbished it within 6 months.

Since restoration, I have been using it mainly in the mountains around Grenoble.
I used it for 30000 km after restoration and I don't know the initial mileage.

I recently got oil pressure problem with red light up to 3000 rpm when engine is at high temperature.

I changed four o rings as recommended by Hondaman but the duck is still alive as we say in French.

I plan to refurbish completely the engine during winter period and I am starting to prepare this project.

I try to keep my CB close to original but it is not to put it in a museum.

I suppose that I will have to change rods bearings and probably main bearings.

I will change pistons after a rebore to 0.25. When opening engine in 2002, I saw that cylinders were just at the limit before a rebore.

As you can see, my English is not so good but may improve during the project 

I forgot to tell you that Mushu is the name of my cat.

I will need some help during this project and I may, with my little experience, provide help on some problems that I already faced.

My bike after restoration in 2003:

https://flic.kr/p/4vDPCC

[seanbarney41]

Mushu welcome... if the oil pressure light is the only thing wrong with your engine, you might check a couple things before tearing it apart.  I would install an oil pressure gauge to confirm what the pressure actually is.  The factory sender has been known to malfunction occasionally.  Also, I am curious what viscosity oil you have been using?  Oil  pump and pressure senders fail much more often than main/rod bearings on these, especially if it has been well used and cared for.

[vfourfreak]

Bonjour et bienvenue Mushu !

Si vous avez besoin d'aide ou d'une traduction, appelez moi.

Kev

[Mushu]

Many thanks for your welcome.

To seanbarney41: I use SAE 15-40 mineral oil. In the past year Oil red light was lighting only at idle with a warm engine. When the engine is cold, light is off. It starts after 10 to 15 kms. It seems that Oil pressure sensor react correctly, that's why a did not install an oil pressure gauge. Anyway, I was thinking to install one after refurbishing engine.
From your advise, I will anticipate and buy one. I will let you know the result of it during last quarter of 2015.

To  vfourfreak : Many thanks for your proposal. I saw already when reading some posts that I get difficulties with some words/sentences coming from usual language. I will let you know when I get trouble.

[seanbarney41]

15w-40 is certainly good, but 20w-50 would be better if you still want to ride a bit before any repairs, and after too.

From your description, it is entirely possible that your rod/main bearings are the culprit, but the oil pressure sender has been reported to gradually weaken in ways that mimic the symptoms of worn rod/main bearings.  Obviously, it is much easier to replace the oil pressure sender than to split the case.

Now I am curious how many miles your bike has done?

[70CB750]

Welcome!

[dusterdude]

Welcome,grenoble,the home of andre the giant,rip

[Stev-o]

Welcome from Texas.

[70CB750]

Your command of English is quite good, no worries 

I am a foreigner myself, moved from Prague to Virginia 18 years ago.

[Mushu]

To Seanbarney41:

I got an Oil pressure gauge from Joker an installed it today.

With cold engine a get 70 PSI at 1200 RPM and 80 PSI at 5000 RPM. Oil light is off

After 20 mn on the road, I get 20 PSI at 1200 RPM and 60 PSI at 4000 RPM. Oil light is on at 1200 RPM and start to disappear at 2500 RPM.

After 30 mn, I get 10 PSI at 1200 RPM and 50 PSI at 4000 RPM Oil light is on from 1200 RPM to 3500 RPM.

From what I understand, Oil pressure sensor is dead and needs to be replaced.

I will search for SAE 20/50 with is more difficult to find than 10 years ago to use it during summer as I did in the past years and replace it with 10/40 during winter.

Many thanks for your advice.

Philippe M

[70CB750]

Yeah, safe to say the sensor is dead.

[seanbarney41]

That's good news Philippe....gotta love these old bikes...and thanks for posting accurate information on the solution of your problem.