A Newbies Adventures in Maintenanceland!

9am53 wrote:

I got my carbs in the mail today. Installing carbs with no airbox is sSOOO much easier than with the box!!! I love it!!!

I am drunk now so this will be short, BUT the carbs are sick now!! The idle was still hanging, but as I realized a few weeks ago my throttle cable needs some adjusting, it is not returning to the rest position on the adjusting bolt. I will check it out tomorrow. It seemed like the pilot jets were off, but I will get the idle working properly before I start fuggin around with the screws. The idle screws are out 2.5 turns, is this a good starting point for BS34's with pods and pipe with dynojet stage 3?

Thanks, I am now going to watch Ottawa win...

The 2.5 turns out is default setting for the dynajet kit. Variations in engine perameters like different cams, will throw things off some.

Get the throttle set with a little play before it starts to pull up the throttle, and you should be good to go.

If it still hangs slightly after throttle adjust, turn the screws (all 4) out a half turn and the idle should rise. You'll enrichening the idle circuit.

ok, I thought those screws let more air in as they were loosened. You say loosening them will richen things up a bit?

I will post back with more results...sofar, I am a pods convert...airboxes can suck my toe.

9am53 wrote:

ok, I thought those screws let more air in as they were loosened. You say loosening them will richen things up a bit?

I will post back with more results...sofar, I am a pods convert...airboxes can suck my toe.

On BS34 carb this is a pilot mixture adjustment screw whereby loosening them (screwing out counterclockwise) richens by letting in more mixture. See diagram below.

Some of the mechanical slide (non-CV) carbs also have a pilot mixture adjustment screw which is usually located at bottom of carb toward the engine side and accessed from the bottom.

While other mechanical slide (non-CV) carbs have a pilot air adjustment screw which is usually located on the side of carb toward the airbox side, readily visible and easily accessed.

The side located pilot air adjustment screw regulates amount of air allowed to the pilot jet, whereby screwing it in clockwise reduces air and thereby enrichens the pilot mixture. And screwing it out counterclockwise increases air to thereby lean the pilot mixture.

Good Fortune!

BS34 carb diagram

[Click on image to enhance view.]

Here's an example of side-located pilot air adjustment screw on mechanical slide (non-CV) carb.

Good Fortune!

[Click on image to enhance view.]

Mikuni 29mm smoothbore carb

Thanks man, I get it now. You learn something new everyday!

I wonder if a homemade baking soda blaster would be a good option for cleaning you pistons and cylinder head.
I first found info about the baking soda blaster on this website and I'm dying to make one and try it out.

Doh!
Disregard my last post. I did not notice there were twenty-one pages of postings in this thread until after I posted and then I thought, "Geeez, i'm such a dork! By now this guy has cleaned the head and pistons and put the engine back together!"

But this whole thread is really cool. If I can find a new job soon, (before I lose my house) I'd like to rebuild my Kz1000 next winter. The info and pictures you have put up here make a great reference source for someone like me. I've been riding a long time, but I am also a newb, when it comes to rebuilding a bike engine.
Thanks

So today I went out to get the bikes throttle issues worked out. My new motion pro throttle cable was too short, so even with all adjustments made to give me as much slack as possible it was too short. What I ended up doing was where the cable comes out of the right handlebar control there was an adjustment with a little lock nut type deal. There is a throttle adjustment in the middle of the cable, so I don;t really need the locknut at the handlebar position, so I removed that little 1/8" locknut. This gave me just the perfect amount of slack and my revving throttle issue is now a thing of the past.

The fuel mixture screw needed adjusting. It was set at 2.5 turns out and was too lean, so I turned them all out to 3 turns. It was better but still no good, so I turned it out to 3.5 turns and voila! the bike revved nice and smooth in neutral. I took it out for another little spin around the block to see how the carbs work and the dynojets and pods work amazing, except for one problem spot - around 2000 RPM. While accelerating from a stop the bike has great power, nice and smooth from idle up to around 2000 rpm at which point it kind of stutters along slowly up to about 2500 rpm where the bike takes off again up to the 6500 or so rpm that I have been taking it up to. I only have been driving it moderately hard, so from idle to the problem area I have been going easy on the throttle, I have not hammered it from idle through 2500 rpm, so I don't know how throttle position affects the flat spot. Could the mixture screws still need another richening, or is it more an issue of the pilots at that rpm area, or is it not dependent on the rpm, more just the throttle position?

Thanks everyone! I am almost there! :woohoo:

If you dont have a decent tach or vacuum guage, then you're forced to have to set your mixture screws by ear, or throttle drop.

OK, so setting the mixture screws by throttle dropping/for best response: Get the bike warmed up off choke, like a quick five minute ride.
Then setup so that you can adjust your mixture screws easily with fuel flowing to carbs.
Using no more than 1/4 throttle, twist the throttle to 1/4 and hold it till the rpm goes past half max rpm.
Release, and watch the bikes tach.
If the needle falls slowly down to just returning to idle, its too lean. Turn the mixture screws out further.
If it falls back to below set idle, then rises to norm, its too rich. Turn screws in to lean the circuits some.

The idea is to find the spot where the needle falls quickly back to idle dead on, not dipping below, or slowly falling.

For those who stumble upon this info, it applies to Mikuni BS34 carbs, and those with mixture screws that are on the front half portion of the carbs closest to engine.

Make sure your advancer is not sticking at all.

RPM makes little difference in judging carburetion, its all about throttle position. If your using 1/4 throttle and it hesitates, get up to doing some half throttle pulls and see what happens. If it is still hesitating with your setup, I would say you need mor fuel/turn those screws out till the throttle snaps back to idle nicely.

The Dynajet kit you have installed, does not affect the pilot circuit, however with the J cams installed on your bike, the pilot requirement may be larger/smaller thatn stock. If you end up at 3 1/2 turns out+ on the mixture screws you'll need larger pilots. (1 size!)

You can still ride around like that od course, just wont be perfect

GL!

I will try out the throttle dropping, but I think it is actually good as is. In neutral the throttle response is great and drops quickly back to idle speed, not below or anything.

Looking at the pic it seems that the J and K models have the same pilot jet anyways. Since I now have the new Dynojet needle that is for the J model, would having the K model needle jet and pilot air jet maybe be causing the stumbling?

It is rideable, and I will get my plate sticker today so I can take it out for a proper ride.

Thats a formidable question :laugh:
...and there are many possibilities.

For 1, the idle will return to normal on CV carbs reletively quickly, normally. Finding the point at which the mixture screws are correct is usually done per carb with a vacuum guage/tach, thus turning all 4 equally is ballpark. If you turn them out another half, and the engine rpm increases, then they were not correct and could cause problems.

Well, there is a quick way to find out whats happening in there at least. Take the bike for a ride, and hold the throttle/rpm in that stumble spot for a good couple mins. Then killswitch the bike without releasing the throttle and pull the clutch. Pull over and check your plugs.
White = lean. Black = rich.

Change a carb circuit and retest...
Try mixture screws out/in more...
Try raising needle...

Just be carefull if the spot is lean around the cruising / 1/8th - 1/4 throttle position, the bike could overheat on longer than 10min cruises.
Better to err on the side of slightly rich.
Whenever you find the most power is the best spot to stay at in jetting, as it will already be slightly rich. Power doesn't continue to increase constantly as a circuit gets leaner. After the already safe point is when it starts to booooooaaaaang and bog too lean!

GL!

I will go for a ride hopefully tonight and I will try the plug chop at the stumble point. I just don't know if I can hold it as that position for very long as it really stumbles a lot...we'll see.