Bringing a 1994 250R back to life - Beyond confused

[cableguy]

Hello all! First I'd like to say thanks to everyone here for the wealth of info on this forum. I'd also like to introduce myself - Name is Adam and a new owner of a friend of a friends 1994 250R that didn't run... and really still doesn't.

Background on me:

Very technically inclined but never worked on a carb larger than a lawnmower / snowblower. Worked on and rebuilt many cars including full engine teardowns. (Had a machine shop do the machining work) Currently have a '16 FZ09 and this 250R that I wanted to turn into a bike similar to ChicagoDan or whatever is name is... can't remember it offhand... but a near naked bike to cruise around town on.

The bike:

1994 250R - 18.5K miles - Last owner said it didn't run in 5 years. Last plate on it is 09, so I'd guess it hasn't run in 6+ years.

What I've done -

1. Tore bike apart
2. Cleaned gas tank the best I could
3. Replaced vac petcock with manual petcock
4. Rebuilt and cleaned VERY VERY dirty carbs
5. Added inline 90* fuel filter
6. Took out stock airbox
7. Minor other small fixes (plugs, etc.)
8. Put carb back on bike and both of the carbs overflowed out of the front ports
9. Pulled carbs and ordered rebuild kits for new float needles. Noticed that the new float needles actually compress - ha.
10. Added 108 jets (going to use air pod + modified stock exhaust + from what I'm reading the stock 105's run lean anyway)
11. Put carbs back on, and only one carb overflowed, head nearly exploded, tapped carb and bike started with no overflowing anymore.
12. Bike wouldn't run right. It would either run $ 4000-6000RPM or would run at 800-1K RPM and would be so rich it would burn your eyes. I am starting it with NO FILTER (shouldn't matter, right?) Checked for air leaks with brake clean and map gas - couldn't find anything.
13. Took carbs back off, found a little gunk in one of the idle mix screws so I cleaned that again and set them back to 2.5 turns.
14. Tested float needles by blowing air into carbs facing down on my work bench and no air leaked.
15. Put carbs back on 2-4 more times doing this same thing thinking I missed something.
16. Would start but would bog with anything over 1/8 throttle. Had no power.
17. Had buddy come over to check it out, also not a carb guy, and we spent all day doing the same things over and over,
18. We put the stock 105's back in
19. Set turn to 2.5, 2 and 1 and really no change in richness
20. With the 105 and 1 turn it now runs SO RICH that the gas fumes collect on the fiberglass resonators and actually drip pure gas into the ground from the bottom of the muffler - How do I know, blowtorch = mass of flames.
    

I'm at a loss - No idea where to go. The insides of the carbs look super clean. I've taken everything apart at least 5 times, some parts 8-10 times.

I've read something about the float level but I haven't seen a good way to check that and I don't have the proper tools and I never messed with it to begin with.

I've read the valves can cause some issues if not adjusted so I may do that next... sigh, so confused.


A lot of people have said a "bog" is lean, but rest assured mine is rich. You can taste the gas in the air 'when' it starts.

[Triple Jim]

Hi Adam, it's good to meet you. I don't like to make a lot of changes at once, because if it doesn't run right, it's hard to figure out which change or changes caused the problem. But attacking it from where you are now...

The main jet doesn't have anything to do with idle and midrange, so if it's really rich in those ranges, I'd guess that something is happening like the float valves are still leaking and overfilling the float bowls. How do the little tabs that push on the ends of the needles look? If one or both have a dent worn, that can make things hang up and not move freely, for example. If it really is bogging from being too rich, then closing the petcock should make it clean up and run better for a short time. That might be a good test.

Cleaning carbs can be tricky, because they can look perfect, and still have a tiny passage somewhere that's clogged, and that's all it takes to cause bad symptoms. You have to check every square millimeter for evidence of a little hole, tube, or passage to clean. Sometimes white corrosion completely hides them. And with these vacuum operated CV carbs, there are even more places to get clogged.

[Z1R rider]

Floats set too high or needle not sealing on seat, had the same problem with one of mine even after new needles. Mine was not sealing on the seat as the seat had some corrosion on the seat area, I cleaned mine with a Q-tip dipped in muriatic acid, little dab will do ya.

and welcome to the board!

[cableguy]

Originally Posted by Triple Jim

Hi Adam, it's good to meet you. I don't like to make a lot of changes at once, because if it doesn't run right, it's hard to figure out which change or changes caused the problem. But attacking it from where you are now...

The main jet doesn't have anything to do with idle and midrange, so if it's really rich in those ranges, I'd guess that something is happening like the float valves are still leaking and overfilling the float bowls. How do the little tabs that push on the ends of the needles look? If one or both have a dent worn, that can make things hang up and not move freely, for example. If it really is bogging from being too rich, then closing the petcock should make it clean up and run better for a short time. That might be a good test.

Cleaning carbs can be tricky, because they can look perfect, and still have a tiny passage somewhere that's clogged, and that's all it takes to cause bad symptoms. You have to check every square millimeter for evidence of a little hole, tube, or passage to clean. Sometimes white corrosion completely hides them. And with these vacuum operated CV carbs, there are even more places to get clogged.

Thanks for the response and I agree 100% Jim - It wasn't running at all and was hoping that the 108's + no airbox would get me to a point to where I could have a baseline to start tuning from.

I don't fully understand what you mean by "tabs" and "dent worn". The float needle has a "spring" like attachment at the end that goes over a metal piece attached to the float itself. Is this where you are talking about?

Originally Posted by Z1R rider

Floats set too high or needle not sealing on seat, had the same problem with one of mine even after new needles. Mine was not sealing on the seat as the seat had some corrosion on the seat area, I cleaned mine with a Q-tip dipped in muriatic acid, little dab will do ya.
and welcome to the board!

Thanks for the response. I thought that and what I did was put the carbs upside down on my bench, hooked a hose to the fuel line and blew into it and I had no leaks, totally sealed... I think?

After that, I took a q-tip attached to a drill and "polished" the seat for about 15 seconds and tested that again and still didn't have a leak with a decent amount of mouth air pressure.

[Motofool]

Originally Posted by cableguy

........I've read something about the float level but I haven't seen a good way to check that and I don't have the proper tools and I never messed with it to begin with......

Welcome, Adam !!!

Take a look at these:
https://www.ninjette.org/forums/showthread.php?t=227561

https://www.ninjette.org/forums/showthread.php?t=147048

[cableguy]

Re-reading all of the carbs stuff I have a queston as now I'm REALLY confused!!

I never did the step in bold so I just ripped the carbs off and did it and well.. are the carbs at all hooked together besides for vacuum? When I spray liquid in on of the pilot holes in the front of the carb (two little holes that face the intake box) and plug the pilot hole, I get liquid out of BOTH carbs -the other carbs' pilot hole and the carb that I am plugging mixture screw. Comng through the fuel line?

Now, take the straw from the can of carb cleaner, press it into the port on the carb for the pilot circuit, and spray carb cleaner into the circuit. Carb cleaner should spray out of the port in the float bowl that you removed the pilot jet from.
When you have a good steady stream of carb cleaner coming out of there, press your finger against the pilot jet port and spray carb cleaner again into the circuit. This time you should have carb cleaner spraying out of the mixture screw port, where you removed the mixture screw, the spring, the o-ring and the washer from.
Once you have cleaner coming out of the mixture screw, install the mixture screw and parts back into the port and screw it all the way in until it just seats (don't crank it down). Now back it out 2 1/2 turns, make sure your finger is still covering the pilot jet port, and spray again. This time you should see cleaner coming out of the mixture screw port on the engine side of the carb at a tiny little hole.

[Triple Jim]

Originally Posted by cableguy

I don't fully understand what you mean by "tabs" and "dent worn". The float needle has a "spring" like attachment at the end that goes over a metal piece attached to the float itself. Is this where you are talking about?

Yes, if the metal piece gets a dent worn in it, things can stop working smoothly. When it has happened to me, it was different carbs, but they'd overflow when I first turned on the petcock, until I banged on the side of the carbs with a screwdriver handle. That would jiggle things and get them to move freely again for a while. The cure is to file the metal tab smooth. This may not have anything to do with your problem, but it might be worth looking next time that carbs are apart.

[cableguy]

Jim, I added some photos.

[cableguy]

Originally Posted by Motofool

Welcome, Adam !!!

Take a look at these:
https://www.ninjette.org/forums/showthread.php?t=227561

https://www.ninjette.org/forums/showthread.php?t=147048

Thank you! Will see if I can figure this out.

[cableguy]

@Motofool

In regards to that first picture on the second link - When I remove all pilot jets and remove all mix screws and plug one pilot jet and spary carb cleaner into the hole on the front of the carb, carb cleaner comes out of BOTH pilot jet holes.

Looking at my carb and that picture, those outlets go to a little diaphragm looking thing on the side of the carb....

1. Is this normal and/or
2. Is this diaphragm thing bad?

[Motofool]

Originally Posted by cableguy

@Motofool

In regards to that first picture on the second link - When I remove all pilot jets and remove all mix screws and plug one pilot jet and spary carb cleaner into the hole on the front of the carb, carb cleaner comes out of BOTH pilot jet holes.

Looking at my carb and that picture, those outlets go to a little diaphragm looking thing on the side of the carb....

1. Is this normal and/or
2. Is this diaphragm thing bad?

There are three circuits or delivery systems: main, idle and choke.
You may be talking about the idle circuit.
That is a micro carburetor within the big one.
Air comes from the intake hole, mixes with the fuel sucked up through the idle jet, both go through the idle mix adjusting valves and are discharged downstream the butterfly valve.

The side diaphragm is the enricher and it has nothing to do with those:
https://www.ninjette.org/forums/showthread.php?t=151139

See how the whole contraption works (above enricher not shown):

Link to original page on YouTube.

[cableguy]

Originally Posted by Motofool

There are three circuits or delivery systems: main, idle and choke.
You may be talking about the idle circuit.
That is a micro carburetor within the big one.
Air comes from the intake hole, mixes with the fuel sucked up through the idle jet, both go through the idle mix adjusting valves and are discharged downstream the butterfly valve.

The side diaphragm is the enricher and it has nothing to do with those:
https://www.ninjette.org/forums/showthread.php?t=151139

Ahh makes sense! Would spraying carb cleaner into that destroy it? (I didnt spray it into it, but I sprayed it into the pilot circuit and it come out of both bilot holes)

[Motofool]

Originally Posted by cableguy

......Ahh makes sense! Would spraying carb cleaner into that destroy it? (I didnt spray it into it, but I sprayed it into the pilot circuit and it come out of both bilot holes)

The only things that are sensitive to chemicals are the two big diaphragms.
Keep them dry and handle those in a delicate way because they are fragile, easy to reap and expensive to replace.

The other things to handle with care are the floats, which are calibrated to float and fully close the two little valves at specific height of fuel inside the bowls.

Take a break; tomorrow things will make more sense.

[cableguy]

Originally Posted by Motofool

The only things that are sensitive to chemicals are the two big diaphragms.
Keep them dry and handle those in a delicate way because they are fragile, easy to reap and expensive to replace.

The other things to handle with care are the floats, which are calibrated to float and fully close the two little valves at specific height of fuel inside the bowls.

Take a break; tomorrow things will make more sense.

Probably a good idea - Just made dinner and I'm enjoying a very rare Goose Island Bourbon Country Stout. A rare seasonal brew from a local brewer here in MI.

Thanks for all the help and the quick responses.

[cableguy]

So here is where I am at:

I was able to take this video of how the bike is running... hopefully someone can make some sense of it.

Link to original page on YouTube.

After this video I took the bike for a spin.

It felt like it had "some" power to get to around 6-7K and then it fell on it face, but if I messed with the throttle and then went nearly full throttle I could rev it to 11-12K and it felt great... pulled hard for a 250.

I looked behind me in the dark(night @ 6pm now) and it was all smoke and when I came into my garage at 4-5K in first a cloud of "gas" smoke followed me.


Also, let me add the "smoke" is *NOT* buring oil. Big difference in smell.

The only thing I have not done is check the float height which is next.

[cableguy]

Just an update - Still couldn't get it to run properly... I'm thinking it has something to do with the floats.

I took the front end of the bike apart and adjusted the valves... got through all of them and the last rocker broke or was already broken. As soon as I went to loosen it, it just shifted off of the valve. Bought a new rocker on eBay (used) as the new ones are $60.

[Z1R rider]

Originally Posted by cableguy

I was able to take this video of how the bike is running... hopefully someone can make some sense of it.

The only thing I have not done is check the float height which is next.

In the video you show the "choke" (not really a choke but an enriching circuit) is in the on position, that will make it very rich at idle and make the throttle hang at higher RPM's and flood out at low RPM's. I'm surprised it will even run with full enriching, there may be a vacuum leak between the carbs and head. Have you had the manifolds off and checked for tears or splits, especially where it pushes onto the head. They like to tear under the clamp. Float height is very important. I set my floats on the bench so I don't have to install and remove the carbs hundreds of times. Rig up a fuel feed of some sort and put a clear hose on the nipple on the bottom of the fuel bowl. Route the hoses up alongside the carbs and open the drain valve, then let the fuel run in and monitor the fuel level in the hoses. I mount my carbs at an angle like they are mounted on the motor. I also noticed you don't have the airbox on, they will not carburet properly with out it, the rubber boots between the airbox and the carbs direct the incoming air properly into and past the opening at the back of the carbs. The carbs like non turbulent air coming into them, that's why they like airboxes.

Originally Posted by cableguy

the last rocker broke or was already broken. As soon as I went to loosen it, it just shifted off of the valve.

Did you find the little "ear" that broke off? If not, go looking for it as it could cause havok if left in the motor!

[cableguy]

Originally Posted by Z1R rider

In the video you show the "choke" (not really a choke but an enriching circuit) is in the on position, that will make it very rich at idle and make the throttle hang at higher RPM's and flood out at low RPM's. I'm surprised it will even run with full enriching, there may be a vacuum leak between the carbs and head. Have you had the manifolds off and checked for tears or splits, especially where it pushes onto the head. They like to tear under the clamp. Float height is very important. I set my floats on the bench so I don't have to install and remove the carbs hundreds of times. Rig up a fuel feed of some sort and put a clear hose on the nipple on the bottom of the fuel bowl. Route the hoses up alongside the carbs and open the drain valve, then let the fuel run in and monitor the fuel level in the hoses. I mount my carbs at an angle like they are mounted on the motor. I also noticed you don't have the airbox on, they will not carburet properly with out it, the rubber boots between the airbox and the carbs direct the incoming air properly into and past the opening at the back of the carbs. The carbs like non turbulent air coming into them, that's why they like airboxes.




Did you find the little "ear" that broke off? If not, go looking for it as it could cause havok if left in the motor!

A ton of good info! Thanks for all of it!

Regarding the choke position - My handle bars are worn and I can't tell what is on or off. Most of the time I didnt have the choke cable attached because I was removing the carbs so often.


Regarding float height - What fluid did you use? I thought about doing this but didn't want to add water but it may be easier to set them and then dry them using water then taking them of 10+ times that I have.

[Z1R rider]

Originally Posted by cableguy

What fluid did you use?

Gas...water has a different specific gravity (heavier), so if you did use it your float level would be wrong with gas.

[sh123469]

When the choke handle at the bars is pulled toward you, it is choked (enriched). When pushed as far forward as it goes, it is unchoked (normal run).

Have you verified float height? Verified that it is actually unchoked by checking at the carbs?

[cableguy]

Originally Posted by sh123469

When the choke handle at the bars is pulled toward you, it is choked (enriched). When pushed as far forward as it goes, it is unchoked (normal run).

Have you verified float height? Verified that it is actually unchoked by checking at the carbs?

Good to know! The bars are so faded I can't see anything.

I'm going to create a video to go into more detail, but in a nutshell, the bike is running like a CHAMP! Still a pretty big stutter @ 6-7K but I'm running stock jets and stock needle height. Going to go to larger jets (108's) and then mess with the needle height.

Thanks everyone for the help thus far! More questions to come!

[Z1R rider]

Originally Posted by cableguy

but I'm running stock jets and stock needle height. Going to go to larger jets (108's) and then mess with the needle height.

#2 son put on a full exhaust (Muzzy) and with stock airbox and stock jetting it was still a little rich. I know, goes against everything you hear on the net. We have a "control" bike to test against, they were dead even going down the straight when stock on stock, after the Muzzy the control bike was faster....jetted up, control bike was even faster. Stock jetting and 10% ethanol and it finally could outrun the control bike.

Glad it's running good!!