Topic: 1975 CB750F build - enjoy the ride , ideas, how to's, and opinions welcome

[ofreen]

There is a drain tube that goes top to bottom in the gas cap compartment.  It is welded to both top and bottom.

[dieselndixie]

that would explain why it wont come apart 

anyway, I guess I will be cutting around that piece.

question on my carbs...should i go ahead and change the jets from stock?  I know its a hot topic, but I want a performance free flowing exhaust and carb setup...so stock may not work.  any ideas on what I should go ahead and put in there to start with?

got a new bike lift today....works AWESOME! and can easily wheel around the garage.  i am going to cut the "crotch" section out of that old tank and make a tail out of it...pics coming very soon.

[dieselndixie]

i started to work on sandblasting the rims (for painting) and saw this.......

i gotta know how to get big tires/wheels front and back....help a brother out!

[Jerry Rxman Griffin aka MuthaF'er]

I believe the biggest rear you can go with using your 18" is a 130. Most guys that are doing cafes are using 16" rims laced to the stock hub. Front I do not know.

Please save that nice tank! They are hard to come by and getting more scarce each time one is butchered. Maybe we can find you a one thats a little more "used".

[rachet]

I think he wants to match the width of the front tire, to the back tire.  I would think that you could lace a wider Rim to the front hub, but I can only imagine major clearance issues between the stock 750 forks/triple trees.

Rach-

[dieselndixie]

as far as the tank goes.  I am going to use the stock 75f tank, I was refering to a tank i mentioned earlier that a buddy gave me off of a 81 cb650 that he bobbered out.   so I am cutting up that tank, not MY stocker.

although I am having to cut into my stock tank just to make some repairs to some rust holes.  going to give me a great chance to clean it out perfectly while its split open.

[dieselndixie]

so i got the carbs rebuilt and now I am onto the motor.

few things.  its got 13k miles, and has been sitting since 1988   was running fine - per owner   all other parts are in great shape, but carbs were very very gunky.

what should i do to the motor?  I just want a flat black rat-ish bike that just runs right...not worried about cosmetics.  its just a toy...

do I do a full rebuild?    just replace oil and go?  take it fully apart and just replace all gaskets with an athena kit?  other?

thakns all.   i ready to get moving on it, just dont know if I should even mess with it being such low miles and in good shape.

here is where i am

[Jerry Rxman Griffin aka MuthaF'er]

If it's in good shape just leave it alone. Check compression and hope for the best. It's a great engine to start with.

[BeSeeingYou]

After the compression check, adjust valves and cam chain then change the oil and go.  Mine has 7k on it and sat for 25 years.  No problems

[dieselndixie]

ive been a "bolt on" guy up until now...not much motor experience.  what is the best way to go about doing a compression check?

[dieselndixie]

also, just a quick pic of the latest tank and tail mock up....tail is an old cb650 tank.   going to keep and use the original tank, but boy is it in bad shape.  rusted out and holes in lots of places.   let the fabrication begin....even thinking of welding a steel cupholder recessed into the top part of the tank near the seat.  its a bike night special anyway....why not hold a beverage.

[Do0ki3 PWNS]

good stuff keep up the good work!

[Spillman]

ive been a "bolt on" guy up until now...not much motor experience.  what is the best way to go about doing a compression check?

best way I know is a compression tester but kinda need to turn motor over for it to work. Or another way in take a spark plug out and stick your finger in the hole and kick it over and it should blow your finger out with force

[dieselndixie]

yeah, motor just sitting on the bench so cant test it.

is there another way?


is there something you recomend me cleaning out while I have it?  some internal filter?   what about cleaning, since i have had the valve cover off, could dust and dirt have gotten in?  flush it with something?

thanks guys...anything helps.

[MRieck]

yeah, motor just sitting on the bench so cant test it.

is there another way?


is there something you recomend me cleaning out while I have it?  some internal filter?   what about cleaning, since i have had the valve cover off, could dust and dirt have gotten in?  flush it with something?

thanks guys...anything helps.

You can perform a leakdown test with the engine on the bench.