Topic: Carb Rebuild. Job for a Newbie?

[cafe2be]

I need to rebuild the carbs on my 77 cb750f. I have the complete rebuild kits and a new diapram. I also bought new larger jets as well. Is there any secrets for rebuilding? Straight forward. Clean the hell out of them and replace old parts with new? My bike has pods and a yoshi pipe too. Went with 125 jets. Advise?

[Bob Wessner]

It was a first time for me a few years ago when I did mine. Though it was a K0 and the carbs can't get much simpler than those, you shouldn't have much trouble. Keep the parts for each carb separate (I used some old Tupperware containers) and take your time. Hope you have a diagram from the manual, that helps a lot. If you have a digicam, it wouldn't hurt to take a few pics along the way, particularly if the entire process spans several days due to time constraints, etc. It helps jog the memory.

[mystic_1]

+1 to Bob's comments.  No reason you can't tackle this yourself is you have a modicum of mechanical ability and common sense.  It can get tricky if the carbs are in REALLY bad shape, as in lots of corrosion and so forth.  Aside from that, yes its mostly "clean the hell out of them and replace old parts with new". 

Get yourself a bucket of carb cleaner dip from the autoparts store, a workshop manual, exploded diagram of the carbs (from www.cmsnl.com for example), and do a search on "carb cleaning" from HERE.  That should get you going.

Take lots of pics if you can before and during disassembly, definitely makes reassembly much easier.

mystic_1

[cafe2be]

The carbs are actually in great shape. No build up etc.. They look like they have been rebuilt a couple years ago. Seems like a easy project. I am very meticulous with cleaning and have mechanical skills. Never owned carbs though. I am most nervous about all the settings, a/f screw, needle height etc.

[mystic_1]

You'll need to reset the screw settings on post-assembly tuning anyway, expecially since you're re-jetting, so that's not too much of a worry.  If you want, check and record the current screw settings by turning the screws in until they seat lightly, counting screw turns as you go.

Needle height, also, will need to be tuned for the larger jets, assuming they're even adjustable on your carbs, so just leave the clips where they are for now and worry about that during tuning.

cheers
mystic_1

[KB02]

You've gotta start somewhere... 

If memory serves me correctly, you shouldn't have to worry about needle height as I don't think it's adjustable on the 77 carbs (I could be wrong). Even if they are adjustable, it's a "C" clip around a post. Unless you loose the clip because you "needed" to take it off "just because" and the little bugger goes flying into the tash can next to your work bench and you spend the next hour sifting through trash and greasy rags and god knows what else looking for it... it's pretty hard to mess it up. 

As for the a/f screw, the first step is turn the screw all the way in, counting the turns it took to bottom out the screw (counting in 1/8 turns if you need to) and then resetting it to the same when you put them back in.

[cafe2be]

Thank you guys very much for the help. Just printed out the shop manual too. Is the 77 f2 pretty much the same as the F3?

[upperlake04]

 Identical, carburator-wise. The only difference I'm aware of between the F2 and F3 is the script style on the side covers.

[mrbreeze]

No clips on the 77-78 needles. Be gentle taking the float pins out...if they are stuck...its easy to break an ear off.

[cafe2be]

You guys have been extremely helpful and making me more comfortable with this process. I will starting friday afterwork.

One last question. What bars are you guys using? I bought a set of drag bars. Thinking of going clubmans. Like the look of clubmans though just think it would hurt the back after some long riding. 

[KB02]

use the search function on that question.     On my first cafe bike I used clip ons. I'm glad I went with that choice vs the clubmans, but if I were to have replaced them, I would have gone with drags.

Drags have the best feel for your back, clubmans look the part the best. It's all up to you as to which way you want to go.

-Bob

[cafe2be]

KO that is the answer I was looking for. Thank you! Andrew

[fixahonda]

Carb rebuilds are THE job for newbies.
They are the indoctrination of the motorcycle enthusiast. Once you've tackled them and the bike is purring along nicely you will have the confidence to go further than before.

Aside from that, I have read many horror stories about people paying $100s of dollars getting their carbs "professionally" rebuilt, only to have a huge mess on their hands when they get them back.
We have to face the fact that a good percentage of people working at the motorcycle shops these days may have never even been into a carb before. This problem gets worse at the years go on, the old timers retire and the new bikes all have FI.

[fastbroshi]

  A big +1 on that, I dropped my car off at a friend/mechanic's shop today and I walked around the shop and behind for a bit with one of the other mechanics, astounded at the amount of work they do on older cars.  I'm talking at least 30 years old here. 
  I said to him damn, you guys must be good, but he replied that they're one of the few shops around that will actually lay their hands on them.  He said lots of mechanics out there now don't know what to do without an OBD port to hook a cpu up to. 
  They had a good array of old cars including:  '52 Hudson Hornet Sedan, a disco painted '77 Vette,  '64 Cadillac Sedan Deville, '94 Vette LT-1, '67 Impala, '64-1/2 Mustang, all kinds of stuff.  Even had a DeLorean.

[cafe2be]

Well I took the carbs apart lastnight and they were clean inside! I did the usual routine and cleaned them anyway and replaced all of the gaskets. Used a friends parts washer and they are nice and new looking again. Took the diapram out and it looked like crap, replaced it and blew out all of the holes with carb spray and and air compressor.
PROBLEM!!! Is on the 4th carb I noticed there was no jet in there. Yes you read it right. NO JET. I am missing the stem that holds the jet into the carb body. I have the new jets, just no shaft.

DOES ANYONE have this piece laying around that they could spare. I will pay for it. Prefer local to NYC so I can pick it up, but will pay for shipping too. Please help.

Andrew