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Discussion Starter #1
I just purchased my very first bike. It is a 1979 CB750F that had an engine rebuild a few years ago and has sat in storage since. The bike itself is cosmetically very clean and the engine does look like its been through a cleaning cycle. Apparently the previous owner was a racer and had intended to do some nostalgia races. for whatever reason he never finished up the bike and walked away from it. The guy selling the bike is not the owner and is trying to recoupe the storage fees (he does have the ownership). Anyway, I got the bike for a song so I won't be suprised if I have to put a little money into it, but I have a couple of questions.

What is the correct shift pattern for this bike?
Where can I get reliable info on setting up the carb (other than a manual)?
If the bike was in neutral, why would it be very, very difficult to move forward?

Thanks!
 

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Shift pattern - 1 down, 4 up. That's a pretty standard shift pattern for almost all motorcycles. Brakes are probably dragging,making it hard to move. Plus that's a heavy bike to begin with.

Post pics.
 

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1 down 4 up, look in the links on the header for some of the 4cyl Honda sites, any number of reasons why it may be a pig to push, frozen brakes, frozen wheel bearings, clutch dragging....


Good luck.

FR
 

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Jeff,
The original shift pattern was one down and four up. If the PO was a racer he may have reversed the pattern to 1 up and 4 down. Which is correct? Which ever you prefer. I like the reversed pattern.

Good luck on the carbs. I would clean them and set them to stock specs which you should be able to find on the net. Google is your friend.

The difficulty pushing is probably dragging brakes. If it is on the rear check for a clogged bleed back orifice in the master cylinder. You can't see it until you remove the little silver metal piece in the bottom.

Ken

AHRMA 412
Vintage racing - old guys on old bikes
 

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Before you do what Ken said, tap on the caliper with a mallet or plastic dead blow hammer. Usually frees 'em up enough to roll around. Calipers could probably use a good cleaning/rebuild. Pretty easy to do.

Get the carbs professionally cleaned and rebuilt or do a THOROUGH job yourself. Save a ton of hassle and don't skimp on this.

In my humble experience when waking up an old bike (or car) thats been sitting a long time, consider any and all rubber or plastic parts having to do w/ the engine, suspension or brakes (seals especially) to be suspect. Inspect everything carefully and at least prepare yourself for the possibility of having to chase a small army of gremlins and replace a bunch 'o' shit.

If I'm wrong, well then, sweet.




Honda go sideways!
 

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cb1100f.net - home of the 79-83 cb 750/900/1100F bikes.

throw some pics here and I'll try to tell you the issues I see.
 

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Discussion Starter #8
I got the bike home and the tips you gave me were right on. The rear caliper was hanging up and the pattern seems to be reversed. However I noticed that she would sometimes slip back into gear, and was much easier to push when I pulled in the clutch than when she was in neutral. Any ideas?
 

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quote:
I got the bike home and the tips you gave me were right on. The rear caliper was hanging up and the pattern seems to be reversed. However I noticed that she would sometimes slip back into gear, and was much easier to push when I pulled in the clutch than when she was in neutral. Any ideas?
some of the clutch plates might be sticking together from sitting. You can disassemble it to break them free or you can just get the bike running and then drive around the block pulling the clutch in and out.

pics of the bike?
I always love to see pics of "hot rodded" F's because there was a huge aftermarket for them when new but not much today. Some of the old stuff is kinda rare too getting a look at it will tell you if you have some standard stuff or you need to get outside parts sources (eg. a popular swap was and CR carbs but you can't get parts for those carbs from a honda dealer)


Edited by - geeto67 on Jun 01 2007 2:20:33 PM
 

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Discussion Starter #10
Pics are coming tonight. Any good books you would recomend? I dl'd a manual the other for $10 just to get started.
 

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did you buy a clymer manual or a factory shop manual? if you bought a clymer, you can download the factory shop manual here (it is nice to have both):

http://www.cb1100f.net/modules.php?name=Forums&file=viewforum&f=9

also there is a honda general shop manual that is a goo thing to just flip through.

DOHC cbF's are wetsump "shared case" oiling systems meaning that the engine oil is also the tranny oil and there is no oil tank, just an oil pan like a car. The faster you get the old oil out and fresh stuff in there the faster the bike will respond to any kind of tuning you will need to do to get it running.

oh , and make sure the inside of your tank is clean. It is a rookie mistake to clean a set of carbs and then run rusty gas through them.

With any cbF, if it is not in pieces then clean the carbs, new plugs, new battery, new fluids and try to start her.
 

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Discussion Starter #14
pics are on their way. i just finished working 7am to 10:30pm got home at 11 and decided to work on her a bit. the engine is now turning over, carbs are off, air box is off, mufflers are off, cigarette lighter is gone, aftermarket fog light is gone, clutch cover is off.
 

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some of the things I spot:

- stock carbs
- stock pipes
- nice stock 1979 black bodywork
- really nice drilled rotos (not stock)
- 1981-82 wheels
- stock brakes and forks.
- really cool 1979-1980 only fender without the weird spoiler.

What boggles my mind is that the P/O went out of his way to to put later wheels on it but did not do the upgrade to the brakes. The 79 single piston pots are ok, but the twin piston front brakes the 1981-82 bikes had are un friggin believable for a vintage bike, and with the right pads almost as good as new sport bike brakes.

anyway, looks like an easy fix, so far. Only other thing I would check is the starter clutch (they always loosen on these bikes) then fire her up.

BTW, stock carbs are CV and bog city. Test the cv slide with an air hose to make sure it works because sometimes they don't.
 

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Discussion Starter #18
Will do. Other than fixing the wiring mess he made adding a fog light and replacing the missing hoses etc... I have 3 problems.

1) the starter seems to have 2 gears, and the are not lined up (?).
2) rear caliper is seized (understatement of the year)
3) the bike only seems to shift 3 times. I looked at the linkage and it didn't seem to be cycling properly with the roller stopper pins. It does look stock so I don't think the p/o changed the pattern.

If you don't mind Geeto, I have more pictures to email you of what I have done so far and I would greatly appreciate your input.
 

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I don't mind.

remember motorcycles are 1 down and then 4 up for their gear boxes. you kinda have to have the motor rolling over for you to fully engage shifts which is why you may be only seeing a few.
 

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Discussion Starter #20
I noticed on page 4-13 of the service manual (link previously posted)the top picture shows what looks like a vacuum line with a "T" splitter joining the two pairs of carbs.

All the lines involving the carb on my bike were missing when I bought it. What is that line, and where should it be hooked up to on the other side?



Edited by - jeffkmeyer on Jun 10 2007 07:39:35 AM
 
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