How Many Hours Do You Think It Takes To Do Carbs?

Just wondering what the other members think as far as time for a complete tear down (throttle shafts out) down to bare bodys. Build back up to complete bench sync'd carbs ready to put back on the bike.
How long to you think it should take? (we are keeping track of our time and will post when we are done)

MN

 

Depends how many times you've done it before, how many problem situations you've run into before, how many stuck fasteners, etc.

Dunking in carb dip "overnight" is a 12-hour affair, and unless you've got a couple of dip buckets, then that's 24 hours right there.........

 

First time it took me three hours. The second time I cleaned them it took me an hour and a half. and thats with replacing idle mixture screw o rings and lubing all my diaphrams with RnR fluid.
A skilled XJer should probably only take about an hour. Not counting the taking them off the bike.
Just my .002
-SLKid
(and yes .002. Thats about what my .02 is worth these days)

 

Not counting soak over night . Just labor time you would spend on inspecting and detailing parts. So it goes back togeather nice. Remember we pulled the throttle shafts.

 

When I rebuilt mine I had torn them down twice before. I think it took be about 2 hours not counting the boiling - cleaning etc just tear down and reassembly.

 

Starting with pulling the carbs off the bike, complete dis-assembly, proper passage cleaning and testing, cleaning of all parts to be re-installed (but not including soaking), re-assembly, bench synch, float height/fuel-level check and adjustment, and re-installation on bike is a good 10 hours. A good, solid 10+ hours.

That is, if you've done it more than a few times before. Start applying whole number multipliers to that "10" number if you haven't.

P.S. 90% of the people who do it in less time eventually end up doing it that 2nd, 3rd, and 4th time when they discover that their engine still doesn't run right.......or at all!

Assuming good compression, proper valve clearances, a decent ignition system, and properly adjusted idle mixture screws, these bikes should start up immediately, idle nicely in any climate except perhaps winters in Northrn Alaska (above the Arctic Circle) or at the top of K2, and pull strongly and smoothly from idle up to the red-line, where they will scream with delight.

If not, there's usually something amiss within the carbs.........

 

Took me 3 weeks.

hah, I work 80+ hours, so it was a multi-stage even.

In total, without counting dip time... 5 hours full tear down and cleaning.
Then about 4 put back together.

Honestly, I think the only people pushing over 10 hours are probably detailing the exterior of the carbs...
If you add time for bowl screw extraction, and anything else stuck or broken... yeah, add more time.

I think 10+ hours is possible if you are in need of extracting things, or don't have the right tools.
Hell, bluepotpie (on here) stopped over with the enrichment jet drill bit and the mans probe kit. So I had everything I needed really. All my new gasket etc.

Only thing I didn't do for the carbs: float check. My drain screws are nasty, so when I fix my float (doh!) problem, I will get those out. Lennnnn.... I need those allen screws.... O_O Gotta figure out what else I need from you too!

 

Without pulling the rack apart. About 3-4 hours for me off the bike and on the bench. Everything apart that you can remove without splitting the rack. Of course my bike also never sat much and I have never had any varnish issues since I have owned it. For you guys resurrecting long stored bikes I you would have to soak them.


while mine starts right up chacal I find in the mid 20's it takes a few minutes to get warmed up enough to actually drive. It start idles you can kick off the choke but don't dare take off for about 2 min. above 40 you are golden.

 

Yes, most carbureted engines are cold-natured beasts, and the evaporation of fuel is an "exo-thermic" physical process, meaning the heat (energy) needed to power such a reaction (of evaporation) comes from outside the process itself.....it comes from the surrounding air.....which means the air temp drops even more (inside the carbs) during start ups. Carb freezing and denser fuel is a possibility under such conditions. A few moments warm up is normally necessary, and prudent anyway, to allow the internal engine parts (journals, bearings, pistons, etc.) to expand to near operating temp sizes, and thus prevent accelerated wear of components that have not "re-sized" themselves (expanded with heat) properly.

 

I'm with Chacal. On a virgin set of carbs that's been sitting with fuel in them for + one year, coming all the way down to replace the shaft seals takes me at least 10 hours. A quick disassemble and clean can be done in a couple of hours but if its the first time thru a bunch more. I've got a set on the bench right now that are clean enough inside but are corroded to H#ll on the outside. The biggest time consuming item is getting the idle mixture screws that some PO mangled removed without destroying the bodies. There is no sense in rushing a carb rebuild. If you do you will just have to go back in again. Another thing that determines the amount of time it takes is how much money do you want to send our friendly neighborhood parts guy. If it wasn't for the budget there wouldn't be any challenges

 

Carbs off the bike and completely disassembled: 1.5 hours (got this part down)

Carbs back on the bike: When I'm done! :mrgreen: ...or anywhere from 3 hours to 2 days depending on what's on the todo list.

 

I'm with Chacal as well. I did mine in 6 hours. The next day, I did them in 5 hours. The third time - a week later - I did them in 3 hours.

Better to put the time in, get them right, and not have to bother with those pesky carb-airbox boots any more than you have to.

This is an interesting thread, though. I would love to see a list of "par" times for a series of different jobs. In addition, it might be interesting to have a list of "par" costs for different jobs.

Obviously, every bike is different and each job would vary but a general average could be fairly helpful. My guess: most jobs end up taking more time than we think.

 

Well, I'm going to be doing my carbs soon, and since I've got at (somewhat usual) 8 hour work day, get home around 5:30 or so, I'll start a journal of what I do with the carbs each day, and how long it takes. Probably do a photojournal too, just to help out with more pictures.

 

Just so you guys know the carbs we are working on were not what I would concider nasty. Pretty good shape to say the least. Just plain and simple in need of attention. No brown goo in the float bowls, Just alittle dry gas film. Carb dip took that right off. All screws came out and one stuck mixture screw on #4 carb. #1 carb had a EZ out still installed in it. We will post pics of that later. So far Kerrinstoch has about 7 hours into take apart and cleaning all the peices. Polishing the brass parts and just looking everything over so we could get an accurate parts order togeather.
My Hatachi's were so corroded I glass beaded the outsides and had to clean all the passages. I'm to the point where I can put my throttle shafts back in once I get my parts order. Then put the rack back togeather.

 

Yeah, the majority of that time was spent scrubbing, cleaning and inspecting all those tiny little parts...The up side is, these will be damn near brand new when we're done though - pretty much a complete ground up rebuild, including all new seals across the board.

After doing this, I can see why so many people hate doing their carbs and try to short cut it. It's also easy to see why so many sellers seem to think that "a little carb work and it'll be fine" is a selling point in their ads... :?

 

Now that's nice...........

Hope you're going to keep it and frame it as a trophy.

Every first-time carb rebuilder should be required to read and memorize what Motorduck posted, and not allowed anywhere near a toolbox or a bike until they can successfully recite, word for word, his experience.

Think of it as an "MSF Course" for carb (or, almost anything else) rebuilding methods and result.

 

We are going to coin that mixture screw with the EZ out in it as "Mukuni Mixture screw on a stick".
Here in MN, living within two miles of the State Fair they have all kinds of stuff on a stick from deep fryed snickers bars to deep fryed pickles. Now we have "a mixture screw on a stick"

 

10 hours and still going.

This includes doing what Rick said - polishing those damned jets until they look like they just came out of the package.

In one way, they were fairly clean, in another, they were filthy. There was around an 1/8th of an inch of crud in the bottom - some caked on, some rust, etc.

Seeing all that rust I realized that this was going to take really detailed scrubbing.

...

Oh, I am still wondering if it is an issue if I find verticle scoring on a starter plunger - enrichment plunger. Can I just clean the thing so there is nothing in there or do I need to do serious polishing to remove the abrasions?

 

Just polish it up good

 

The plunger shaft doesn't really regulate the fuel flow, so you should be okay, but the plunger tip needs to be gouge-free.

 

Cool. That's what I hoped. The tip *looks" fine but I haven't done any magnification and my eyes have lost a lot of closeup focus in the last year or so. Used to be I could make out a gnat's gender with these eyes close up ...

 

Chorca if you do do that, make sure you account for the time you take to write all your times and tasks done, and remove that from your numbers

As far as the overall time thing goes, it really depends on how far you go.

Like, I didn't polish ANY brass. Just because it's a darker shade, doesn't mean the 'tarnish' is going to come off and block a jet...
Everything is free and clean, no 'soot' or varnish, and all holes have been checked out.

Honestly, my WHOLE rack looked good, except under the hat had a lot of varnish looking substance, and the bowl was full or brown crud. When I say full, I mean there was a few pools in each corner, and the starter jet was clogged solid (borrowed bluepotpies drillbit, awesome Len!)
Once that was clear, I was basically just removing a layer of light varnish and discoloration everywhere.

So it depends on how far you go, the problems you run into, etc.

 

So the other day, from the time I pulled up at the door (real close to 9am, on a Saturday, even) to the time I left the place (right around 6...) it took 9 hours to:

Remove carbs
Completely disassemble every single part
Replace all seals (air and fuel)
Replace butterfly hardware
Clean all metal pieces with carb cleaner
Inspect diaphragms and jets
Clean externals of everything with parts cleaner
Reassemble and replace
Install new valve shims (keep in mind, the measuring had been done earlier and the new parts had already been ordered from Chacal and were on hand, so this was just a question of swapping)
Replace valve cover gasket and all the blasted rubber things on the valve cover bolts

Start to finish.

So, it CAN be done. MiCarl helped on some of the tricky parts, like the valves. If you can get a buddy involved for some of those steps, you'll be a much happier man.

HOWEVER, I should point out that I have done this several times (I guess I should say at this point, HEED CHACAL'S WARNINGS and just do it right the first time...) and I basically have the Hitachi carbs memorized, so that helps a lot.

I'd say I've had the carbs off the bike about 10 times in the 4 (or so) years I've had the thing.

 

I'd say it's taking me 4 hours to break down, clean and reassemble each carb.
This is what the carbs looked like when I started. I sprayed them with carb cleaner and used a toothbrush to clean them.


This is as dirty as they were. Not bad for 28 years!


Here is a good shot of what you need as far as a clean enrichment well.


This is as far as I broke them down.


I did not remove the pilot jet or the pilot air jet. I did not have a tool to fit them.
*note to Chacal - offer tools for these two jets and I'd have bought them!
I sprayed them both good and used guitar string to poke out the jets. I'm quite sure they were clear to start with.

I still need to re-assemble the rack, sync etc. Probably gonna be a week or two before I find out how well my cleaning did.

 

I know, I know.....working on it, almost done.

I have absolutely NO idea of why Mikuni stuck the pilot fuel jet way up inside that well. But boy, if one is stuck, and you booger up the head, it's all over but the cryin'..........


Beautiful picture of a clean starter jet. Your bike will start up in a jiffy.

 

Yep, we already got the pics of that part. We'll have to post it along with the rest of the re-assembly pics when we get them.

RangerG, the insides of your carbs look about the same as mine did. The up sides for cleaning these that thoroughly for me are that now I know for a fact when they were last done, and that they were done right thanks to Mn-Maxim's help and knowledge.

 

Ranger that's about the same as the inside of my Hitachi's too.

But my GOD, those exteriors are IMPECCABLE! Amazing.
Mine look like they god dragged through a truck stop!

Probably due to the PO's lack of knowledge of the leaking valve cover gasket and road grime built up on the front of the gasket, slowly creeping it's way back and blasting the carbs... O_O

 

Ranger, I had to take and grind a screwdriver skinner but one with the proper blade width to get them out without stripping the heads. I have made two of these so far as for some reason whenever I go to clean the carbs on the bike or sled(both mikuni's the driver I ground down is MIA.

 

I made a set of Mikuni Jet Screwdrivers. The Pilot Fuel Jet Tool is a Precision Instrument.

Its an old MAC Tools Phillips Screwdriver.
The business end was cut flat across and the "Blade" fabricated using a Dremel Tool Cutting Wafer.
Once the Tip is close to the right width ... you don't let it get hot from being cut.
Dip the Tip in a cup of ice-water to keep the end from getting soft.

The nice thing about an old MAC Phillips Screwdriver is the Hex Section at where the shank meets the Handle.
You thread the Box end of a 10mm Box Wrench on the shank and grab the Hex.
Put the Driver in the Pilot Jet hole.
Seat the Tip in the Slot.
Put some constant and very firm Undo Torque on the Jet.
Whack the Wrench with a Hammer Handle and the Jet breaks loose.