Gunson Colortune Issues

So I've been working on my XJ700n for several years and it's been running okay the last 2-3. I don't need choke/enricher to start it and when I do use it, it normally doesn't start. Most times I have to start the bike with a little throttle until it warms up. Every couple of rides it would have trouble starting and seemed to be running on only 3 cylinders because it had no power and was fighting itself. I routinely had (what seemed like) fuel leaks and it was running too rich. I'd take the carbs off, take the bowls, flats, etc. off and nothing seemed to be wrong.

I finally broke down and bought a Gunson Colortune and Carbtune Pro to get everything dialed in correctly (thanks chacal!), starting with the colortune. I warmed it up a little yesterday and put the Colortune on C1. I got a weird yellow/blue color and when I adjusted the air/fuel mixture screw the color did not change. I took it all the way down to seated and still no change, but it did begin to stutter. Same with C2. Didn't have a chance to check the rest of the cylinders. When I cracked the throttle, it would change to bright yellow, then bunsen blue like it's supposed to, but at idle it's a weird yellow/blue mix. (I'll try to post a video if it uploads). When I took the plugs out, they were wet with fuel. I do have white smoke coming out of the pipes, especially when I raise the rpm.

Hogfiddles did a total carb overhaul 3ish years ago.
Valves are in spec.
New petcock internals last year.
I'm going to check for air leaks, but that doesn't seem right since it's running rich.

Only thing that I can think of is that the air filter got fuel on it last time it flooded into the airbox so that might be restricting the air too much and causing a rich condition. But, that still doesn't explain why I have no adjustment in the air/fuel mixture screw.

Thanks for the continued help guys!

 

is your gas old from end of last year? how do you store your bike for the winter?
are you running a stock air filter or the uni or possibly K&N filters?
I do understand your reluctance to replace a 45$ oem air filter.

never having to use the choke does sound like you have extra fuel flowing in the pilot jet circuit or restricted air
are the enrichment plungers fully seated?

may be time to do a spring cleaning of the carbs not a rack splitter but spray cleaner through the jets (remove the mixture screws)

how old are the spark plugs did you check the gap?

when were the valves last in spec?

do you run carb cleaner in the fuel at beginning and end of year?

pull the air filter see if it starts with the choke.

 

The air filter are the paper ones through chacal ($70), where do you find them for $45? (bike came with pods, found an airbox online and that solved so many issues...)

The fuel is old, but I put in new fuel (premium) with Sea foam at 1 oz per gallon. My end of season storage wasn't the best since the bike pretty much died, I limped it home in the fall, parked it, and got caught up with other things, but I did put a treatment in it, but don't think I ran it because it was having issues.

The spark plugs only have a few hundred miles on them at most. Since it's never quite run right (not fully tuned), I've gone through a few sets and whenever I popped a new set in, it would fire up and run well enough to scratch the itch as I kept working towards a tune.

I did take the carbs off and sprayed them down with carb cleaner and brushed them out, but didn't remove any jets. They did look really clean though, not quite hogfiddles eat-out-of-them-for-supper clean, but clean nonetheless. Looking back, I probably should've...

The valves were last in spec within 800 miles.

I'll try the air filter trick and see what happens and report back. Its 37 degrees out right now and snowed this morning so it's definitely on the colder end of operating temps.

 

I do want to note: It's been benched synched, but not Carbtuned to the bike yet because I read that happens last after the air/fuel mix has been done. If I got that backwards, just let me know and I'll Carbtune and then Colortune.

 

there are some who sync after each cylinder is color tuned,
do a sync then do color tune then sync again

 

So I tried the filter/no filter test. I got the bike started with the filter and some throttle. After it was slightly warm it would fire right up with or w/o the air filter in place.

With the filter: zero turns out on the air/fuel mix gave me blue
w/o filter: 1 turn out gave me blue, 1.5 started giving me the yellow/blue

I threw it on the Carbtune and the results are in the photo. This is with all mix screws at 2.5

 

Since the vacuum line is on C3, would that be throwing it off since it's vacuum is lower than the rest?

I'll do a synch now and see if that helps.

 

Update: in the process of doing the synch, I realized that there was fuel in the airbox. Cleaned it up and fired her up w/o the filter, turns out I have an abundance of fuel in the crank so I'll be doing an oil change and picking this all up tomorrow. Hope that helps with the diagnosis.

Then I'll try the running synch again.
Then the colortune.
Then synch again.

In the meantime, if anyone has any ideas why it's running so rich I'd love some input. Before I was chasing a hanging idle and we figured out what that was, now I'm chasing a rich-flooding condition

 

So I'm reading about the starter jet in another forum...can someone send a pic with an arrow of what I should be looking for to make sure it is clean...

https://www.xjbikes.com/forums/threads/i-need-some-guidance-with-my-bike.127461/page-4

 

not sure what this means. by vacuum line do you refere to petcock line? if so you do the sync on prime and the tool is all that is hooked to nipples.

 

fuel in the air box would make it run rich as it would be drawn into carbs. the question is why is there fuel in the air box.
may be time to clean replace floatvalve needle assemblies

 

starter jet is the long brass tube in that goes into the well on the sidewall of the carb bowl

 

Okay, that's what I thought they were referring to.

I have the brass needles and floats were wet set by hogfiddles so those are new and/or acceptable from when he cleaned it. Not discounting that they could be the issue, but they are the good parts.

With the fuel in the crank, when I cracked the throttle, it would spew up the vent tube and into the airbox. Don't know if that helps, but it was like a fountain coming out of there.

I also posted a pic of the current state of the filter after several soakings. I won't replace it til I get the rich condition figured out, but then I'll get one. No sense in buying another one when I know it's going to flood again.

 

P.S. how do you know when your starter jet is really, truly, zestfully clean? One of two ways:

a) shine a strong penlight or mini flashlight into the bottom of the bowl, where this jet passage "intake" is located. Look through the top of the bowl down into the jet passage "outflow" passage (this is the passage that the brass suction tube in the bottom of the carb body actually fits down into). Focus your eye carefully on the jet opening and make sure it's clean. P.S. it helps to do all this while in a darkened area.........see the picture "starter-jet.jpg" on page 2 of this forum thread topic for a great image of what you want to see!. It's post #23 by user FinnogAngela...........picture is titled starter-jet.jpg:

http://xjbikes.com/forums/index.php?threads/4050

Because the carbs are over-flowing (the needle valves are not seating properly, worn, or etc.) and that RAISES the fuel level in the bowls (and if nothing resolves their leakage, then eventually the bowls over-fill and the excess fuel goes into the airbox and into the cylinders, past the piston rings, and into the crankcase......even while the engine is off............this also means your petcock is either leaking, or was left in the PR (prime) position).

Even if it weren't over-flowing, a greatly increased fuel level in the bowls will make an engine run very rich.

 

Well the internals were all new when they left here. The rack shouldn’t have any issues other than needing the standard wetset/running sync/colortune routine. I’m wondering if you have an abundance of dirt in your tank that may be causing fuel valves to load up and hang open.

If worse comes to worst, send the rack back and I’ll go in and take a look at things. Maybe something has since worn out.....

 

@hogfiddles Did you wet set it when you did the cleaning, changed the float needles and looked at the floats? I thought you did, but if you didn't, that would explain some of it anyway.

I do have a sintered brass inline fuel filter connected to help, don't know if junk can still get through that or not.

To check if the petcock is leaking: do I just set it to ON and see if the hose will drip into a bowl/paper towel overnight?

I'm going to do an oil change, check to see if the starter jet is clean, and possibly check the wetset. I don't have a float height gauge, so I'll be checking the level based on the actual fuel level alongside the carb. For the XJ700 aircooled, it says 1mm +/- 1mm, so I should basically be right at the level of the lip where the bowl is recessed into the carb body, correct?

 

Correct.

This is the only way to actually check the fuel level; the float height gauge/ruler/etc. is just a method of seeing what "float drop" is occurring, and then using such a measurement to set the other floats at a similar position, the idea being that all four carbs are identical in the translation between "float drop" and the resulting "fuel level" (which is generally true, but not always).

See page 8:

http://www.xj4ever.com/setting fuel levels.pdf

 

Okay, that’s what I thought, just confirming. Got the carbs off the bike and now I’m checking levels. We will see where they’re at.

 

I set the floats to inital dry height. It is the owners responsibility to do their own dialing in. As well as for them to do the colortuning and running syncs.

 

Okay, well they were almost dead on, C2 was just a touch higher than it should be +1 mm above spec, but the others are all dead on at 1mm below the carb body. When I took the carbs off there was fuel in the airbox to carb boots in C1,2,4 but there may have been some in C3 too.

Update: Wet set is done, now I'm working on cleaning out the starter jet passages because they seem to be a little clogged.

Petcock does not seem to be leaking when set to "ON"

 

Can’t seem to edit the last post, but petcock is leaking approx 1/4oz an hr.

Starter jets and passages are clean.

I uploaded a pic of the wet set, can someone confirm that it’s the correct level? All 4 are at that level.

also there is a mesh screen under the float needle that was pretty gunky. How do I get it out to clean it? I spray it out with carb cleaner and got most of it, but what to make sure it’s good to go.

anything else I should be checking while I have it apart?

I’ll be checking the valves too since I’m already at this point.

 

Hmmmm

 

@hogfiddles Guess I’ll be checking the tank too

I know it has a little rust in it that I’ve tried to clean out before. Have any suggestions on how to clean out the dirt/grim/rust? Last time I took the petcock off and tried to get everything through that hole in the bottom but I had a problem with flash rusting after I washed the inside with water.

 

Water causes rust!!
Use phosphoric acid

 

Can you give me your process for cleaning it out and I’ll make sure I follow it to the T. I can send pics of the inside of the tank if you need to see what I’m dealing with.

And would it be better to get new internals for the petcock or just get a in-line fuel shutoff?

 

Do a search in the forums for “phosphoric acid” and you got all the reading you could ever want.

rebuilding the petcock give you a rebuilt petcock, but I have an snowmobile fuel line shutoff in my fuel line anyway. Fwiw

 

Chacal sent me a link to this (https://www.xjbikes.com/forums/threads/rebuilding-the-yamaha-vacuum-fuel-valve-w-pics.25058/) which I've read before. I got a replacement petcock internals through Chacal last year, but since I have a drip-drip-drip, do you think it's worth trying to bend the flat disc spring to get a better seal and see if that stops the leak?

 

There is, iirc, a little instruction that a lot of people miss.......something about hitting the piston, or disc, or washer....something...... in the PETCOCK to make it seat better. Otherwise it will continue to do that. Best have Len point that out to you, cuz I’m not finding it at the moment.

dave

 

@hogfiddles @chacal

Ya I saw it somewhere and just read back through the guide and I can't find it again. I might just throw an on/off in the fuel line and call it good, but since I'm cleaning the tank anyway, it's worth trying to bend it and get the o-ring to seat better.

I know the tall in-tank fuel filter is in rough shape, since I have an inline fuel filter, do I need to replace the in-tank one?

 

The in-tank one gets some stuff, but it’s more for knowing when to switch to reserve

 

those little screens should have come out with valve body . put an inline filter in your fuel hose and throw the caps away or get new ones and still do a fuel filter.

 

While I have them off the bike and apart, is there anything else that I should look at before I put them back together and on the bike?

I got the little screens out, just pressed on one side, they spun in the channel vertically and then you can grab them with needle nose pliers and pull them out.

I’m checking valves next. Is there a specific thread for checking them like there is for the wet set?

BTW: Jets are 36.5 and 107 with the float valve seat one at 2.0

 

Setting the fuel levels

also back flush the chamber back out the fuel tee to get any crud out of the chamber above the screens

valve shims
Bigfitz's AIRHEAD VALVE ADJUSTMENT with Pics - parts I & II

 

Thanks for the links!

and I blasted those passages and clean hitting every passage so they keep getting soaked just in case anything is left.

Anyone have the link to that flat disc adjustment in the petcock? Or can I just add a washer behind the spring to give it some more force? I’m taking the petcock apart tomorrow and cleaning the tank too.

 

I might have bigger issues now...went to drain the oil and put some cheaper stuff in to flush out the gas and it didn’t come out which was weird because the gassy oil seemed to drain no problem. I put more in and still nothing. I’ve got 2.5 quarts in and it’s not coming out. I put it in 1st and 2nd and rocked it and the engine seems seized...any suggestions on how to fix this bugger without shelling out for a new engine...

When it died while I was Carbtuning it, it didn’t just die, the rpms just slowly came down like it was starved for fuel with no engine knocking or bad noises so hopefully that’s a good sign...

 

from the rebuild link just below photo with washer

In both pairs, the replacement springs are on the left. You can also use a washer as shown to increase spring tension and improve sealing; but if your seat is in good shape it should not be required.from catalog

HCP663 Aftermarket vacuum control module vacuum diaphram SPRING SHIM WASHER. This washer goes behind the vacuum diaphram plunger spring and acts as a tension shim to allow the spring to put more pressure on the replacement-style o-ringed plunger tip, and thus allowing it to seat and seal properly. Used on all XJ550, 1984-85 FJ600, 1986-88 FZ600, all XJ650 (except Turbo), all XJ700, XJ750RL, XJ750-X, XJ900RK, RL, N/FN, and F models, and all XS1100 Standard model petcocks,and the vacuum control unit on XJ1100, XS1100 Special, and XS1100 Midnight Special models. This washer goes under the spring and fits into the recessed well in the cover plate.

 

oil not coming out drain plug hole? maybe hole is plugged with chain guide gently push something into hole see if it clears and drains filter oil both batches through a screen look for bits of plastic

 

Not coming out drain plug hole or filter hole, I tilted the bike on it's side and center stand and nothing was coming out.

I put all of the plugs and bolts back in so hopefully as if my magic, it will fix itself

 

you mentioned a fuel leak into crank case. I picked up a 650 last year if it did not start on first try cylinders would fill with fuel and stop motor from turning over pulled out spark plug and fuel blew out the sparrk plug holes.

 

Ya the petcock was dripping around 1/4 oz an hour so it put a lot of fuel into the crank over the winter when it was parked and like an idiot I didn't change the oil before messing with it. I didn't know the oil was in the crank at that point, found out later.

So is there any way to assess the possible damage? I've never torn into the engine/piston/transmission portion of the engine before minus checking valve clearances so this is new territory for me.

I'm going to pour some Marvel Mystery Oil in the tops of the cylinder through the spark plug holes (saw it on YouTube and I don't have Acetone to mix with my ATF) and then tomorrow I'll see if the 19mm bolt turns on the crankshaft.

 

With the oil that diluted, that doesn’t sound good. Can you Look into the drain hole? Does it turn over With the starter? Don’t spin it long, just enough to make sure it turns!

 

Ya, anything in particular that I’m looking for? I’ll see with the starter tomorrow. Should I see if the crank spins with a wrench first or try the starter first?

in the process of pulling the plugs I learned that I was right about the carb synch so that means I’m at least learning something. C1, 2 had higher vacuum and those plugs were wet which is why I couldn’t get the colortune correct. 3 looked good and 4 was a little black but not bad which all lines up perfectly with what the carbtune was telling me.

 

Just put in neutral and hit the starter to verify that it turns over.

 

In neutral without spark plugs it does turnover and the pistons move freely!

so I definitely didn’t get nearly the amount of oil out of it that’s currently in it. I have the drain plus on the left side and the front oil filter both removed and the bike is on the center stand. I can see oil when I look through the filler hole but it’s not coming out the bottom holes like it should be. After an initial rush, the rest of it is coming in short bursts about 1 minute apart and it’s only 2-3 oz at most but it’s still pretty gassy. Not as bad as before but still a lot thinner than 10W-40. Any ideas why the oil is stuck in it?

 

I wish I could go back and delete a whole lot of posts...I’m an idiot tons of oil now flows out the bottom can someone tell me the purpose of the Allen plug on the side of the crankcase...because man that looked like an oil plug when I took it off and oil cane out of it...low and behold I checked the manual and forgot that you had to lay on the ground with your head between the pipes to find the real oil plug lol

now I clean the petcock, clean the tank this weekend, put it back together and go ride while keeping the rubber side down!

 

Nope, that’s not the drain plug. You found the right one finally... right below the filter

 

what is it called then?

What do you use to seal up the bottom of the tank with the phosphoric acid solution?

 

I use either heavy piece of plastic and an old gasket, bolt hem on like the PETCOCK and sending unit would mount, or a piece of metal backed rubber bolted on

 

So bike is back together minus the tank (waiting on some petcock parts for chacal) and runs, but I’m getting a ton of smoke out the pipes especially when I rev it and more and more as the bike warms up.

The carbtune was showing me that there’s a little erratic behavior between 12 and 34 as far as vacuum goes.

I only checked Colortune on 1, but but even at 4 turns I couldn’t get away from blue. I tried to make it go yellow so I knew where everything was at and it wasn’t letting me. When I revved the engine I got yellow like normal.

any suggestions to get it dialed in? I’m going to check for vacuum leaks tomorrow.

pics show smoke after a few seconds of shutting the engine off

 

@hogfiddles @XJ550H