Starting Honda cafe bike build today

Another part for the pile.

 

Been a while, Don
Jonesing for an update.

 

Well I have finished cleaning and painting and replacing all the parts.
In side my house I have all the electrical stuff and more parts.

I am also replacing the valve guide seals without removing the cylinder head.
I made a special tool.

The frame should be back from powder coating in about a week.
Then I can start to put it all together but....wait... I still have to decide if I want to do a complete top end job. It is a hard decision because of the cost and even though the engine only had 29,000 miles which is not much for CB750 it is the years that have gone by that concern me. Like 33 years.
I have no history on the bike. All I know is it sat around for a long time.

A sketch of where I am headed.

 

This is epic.

 

^^^ +1

and I love the concept

 

Don that's one sweet looking bike. Very clean and simple. Might need a front fender of some type for getting caught in water. One of those that taper narrow at the ends and are self supporting.

I was looking at all the parts in your one picture and was naming them and where they go. :crazy: I thought I would have for gotten that by now.

 

I am replacing the valve guide seals just in case on this engine because I do not know its history.

I am putting together an engine stand today and tomorrow it will be ready to put the engine on the stand. I will post photos tomorrow. This way I can run the engine and fully test it for leaks and compression before putting it in the frame. Get the carbs partly dialed in.

If it needs new rings it is better to find out now instead of having to take the engine out again.

 

I agree about the fender. One of those Rickman looking things.
Did you guess what all the parts on the table were Mr. GREY?

 

Oh yea. Which one do you want to know about???:smile:

 

Here is a photo of that engine stand. $39.+tax at Harbor freight.
I used the parts that came with the stand to make the engine mount plate.
No additional parts were needed. Of course I will nee to make a mount for the oil tank and fuel tank etc.,.

 

That stand looks good, you guys are so spoilt with all the cool stuff available over there. Motor looking great too, did you win with the valve stem seals?

 

You will like this story.

I went to Harbor Freight to get a valve spring compressor.
It was after 5 pm and I needed that tool.
Here is a photo.

It looks exactly like this.
But here is the unbelievable part. See that knob on top.
When you turn the knob it is supposed to screw the forks down to compress the spring.
But on this HF one, the handle will not turn either way.
Then I opened up the jaws and found out that if the jaws are opened up all the way
then the knob will spin but there is no screw function to make it go up or down.
I took it all apart and found out there is NO SCREW threads at all. The shaft will just spin if the jaws are open all the way. Thats it!!
I thought the threads were just hidden from view or a tube hiding the screw inside. Nope.

It is as if someone looked at a similar tool and copied it from a photo but did not know what its purpose was!!!

I am taking it back today but I am going to tell the manager that it cannot function.

And the photo of one that will work because it has threads.

 

that's hilarious Don. Really funny that HF is selling the useless thing too.

 

Just the thing for desmo-ducs.

 

It was funny!!!

Anyway this morning I modified the tool I had made so that it would depress the valve spring about 1/8 inch more and it worked!!
I was able to quickly move onto the other valve guide seals and finished them.
About 2 hours total. Just sat on a 5 gallon bucket and took my time.
Now I will start getting the engine ready to run on my test stand.


So there it is .Replacing valve guide seals without removing the cylinder head on a CB750 Honda. 2 hour job.

 

Yes ...I was able to get the valve guide seals installed after modification of my home made tool.
See POST #155 above Bryan88

 

My question was more about how you kept the valves from falling down, looked like you were using compressed air?

 

Bryan88,

I kept the valve from falling down by inserting a 1/4 inch rope into the spark plug hole. Piston at TDC. Must do.
I did not used compressed air. The reason I did not used compressed air is because it can cause the engine to spin around if the engine is not in the vehicle.
The vehicle would have to be in gear with the brake on.

On a motorcycle engine that is not in the motorcycle there would be nothing to stop the compressed air from spinning the engine around. IT would be dangerous.

By putting the 1/4 inch rope in the spark plug hole it is safer and quiet.
On this CB750 engine the rope worked better on the intakes than on the exhausts.
But it did work.

One more thing. If you use this method - make sure you do not turn the engine over before pulling the rope out!!

Bryan88 Go back and see the green rope in the photo, post #155.

 

Oh right, that makes sense. I mistook the rope for an air-hose (time for that eye test!) I've changed a broken valve spring on a car before with a specially customised tool (bent rod) before. Keep it up, the bike is gonna be magic when its finished.

 

I understand now.
The only time I have ever seen a braided covering on an air hose in the USA is on a bicycle tire pump.