Alternative to colortune

Hey guys, I am having a hard time tuning my bike properly. I need to find a good way to tune the mixture screws without a colortune. I am trying to find one, but if anyone has a good way to do it without, that would be awesome. I have dial gauges to balance the carbs, and I was able to get the bike to stop surging, but now it is running rich and has no low end power. When I mess with the mixture screw, I don't see any reaction in the gauges, and I can't hear when each cylinder dies off, so I'm not sure which way to do with my adjustment. I feel like messing with it hoping to come across the correct combo is a crapshoot and I don't know if I would know it when I see it anyway. Anyone with some tips for me?

 

you should put what bike you have in your signature. it would help people diagnose your problem. a lot of these bikes start with the screws 2.5-3 turns out and tune in very small increments from there. you should look up on the forum how many turns out your bike is suggested to have. maybe start at 2.5 and see how it runs and do some plug chops to see if you are lean/rich?

 

Good Call. I fixed it. If its not up yet, 82 750 Seca. Everything I read says 2.5 turns. But when I do that, it runs real poor. Again, biggest problem is I don't know how its supposed to sound

 

Are you anywhere near nw ohio? I have one you could use if you are.

 

No, I'm in Florida... :/

 

So you said you "fixed it." What did you set the mixtures at?

Also, have you wet-verified your float levels? You can't "adjust out" a rich condition if its source isn't the mixture screws.

 

it should sound like a new Toyota
you could hire a piano tuner, they can hear those sorts of things.
can do it with a real sensitive tach, not the one on the bike. a digital one that reads +/- 100rpm will get you close.

 

The person I bought it from tore everything down and rebuilt it per the specs on the manual. The screws are currently set at 3 turns out. I think I found a colortune though. I'll keep you all posted

 

8O

Oh boy.

Some things you just have to do yourself, as you're finding out. Are your valves in spec, or is that another case of taking somebody's word?

 

I appreciate the help Fitz. Don't get me wrong, I want this done right. But if I don't have the right tools and know what I'm looking for, it's irrelevant how far into this I go. So, I want to get the necessary knowledge and told so that I can indeed get it right. That's why I want to know if there is an alternative to the colortune. Either way, I appreciate the insight.

 

So; are the valves in spec?

Because if they're not, you can tune the carbs until you're blue in the face and you're gonna get nowhere.

I'd strongly suggest you check the float levels and ensure your valves are in spec before trying to worry about fine-tuning.

Float levels: http://www.xj4ever.com/setting%20fuel%20levels.pdf

Valve clearances: http://xjbikes.com/Forums/viewtopic/t=14827.html

Part Deux: http://xjbikes.com/Forums/viewtopic/t=29209.html

The best way to "know what you're looking for" is to invest in a service manual. You're going to need it. Just assuming the guy you bought it from actually knew what he was doing won't do.

I'm assuming the knowledge thing is why you're here.

 

Yes sir, knowledge is why I'm here, asking questions. I do have the service manual. I have the full one, the haynes, and a cd version. Overkill I know. The guy I bought it from is a mechanic from my work who is known for his overly meticulous habits. Not saying it's Bible truth, but he knows better what he's doing then I do. I will have to borrow the tools from some guys at work. I went over ask this stuff with him. Valve clearance, float levels, bench sync, the whole spiel. I'm going to see what happens with the colortune and go from there. I might have to rebuild the carbs, but if there is a shot at not having to, I want to explore it. Don't take this as I'm rejecting your input, you have a while lot more knowledge then me. I just don't want to have to jump to a whole tear down if I don't have to.

 

+1 on Fitz's advise -

If you and your friend want to get it "less rich" for now,
Listen to the engine idle, and watch the tach, and turn a Pilot Screw in, slowly, until you see, hear, and feel a cylinder drop out.

Then go out between 1/8 and 3/8 turn. Write it down.

Do the other 3 the same, then, go thru all 4 again, because you get the "feel" for the technique, and the YICS shares some of the intake charge.

Most importantly, test ride for drivability - go a few miles, and then look at the plugs. If they are paper-white, you're too lean (no good!) Shoot for cardboard box brown. This takes multiple rides at slight throttle openings.

 

I third fitz's suggestion... I kept trying to colortune last summer and had no luck getting consistent results. I had wet-set my floats but didn't take the time to do it properly, so when I pulled them to check at the end of last season I realized that they were only 1-2mm off. That was enough to make me waste WEEKS checking plugs, attempting to colortune, etc, eventually giving up. In the end I had to re-do it anyway, and all it would have taken was a half-days work and I would have saved me the headache.

I know how it feels to want to get everything together and go riding, but float levels are definitely not something to skimp out on. Plus, you could make all sorts of stands from stuff you have lying around. My first one I made by putting holes in a thin wooden slat, and screwing it into the bottom of the carbs. However, I would recommend spending $20 and making a PVC stand, it'll last you forever and it makes float setting a hell-of-a-lot easier. It really isn't that bad once you have the process down, but I recommend you do it outside so the fumes don't get to you.

Good luck buddy, I believe!

 

Here we go again; checking your valve clearances is NOT a "whole tear down." It is a simple maintenance procedure that must be performed every 5000 miles.

And it's step 1.




The use of the ColorTune is the final step. In between are float levels and a good solid running vacuum sync; BEFORE you try to adjust the mixtures.

If you're going to try to start at the end rather than the beginning, on the basis of somebody's word, then you're going to find this very frustrating.

 

These bikes are really built great and are fun to ride, when they are acting right. Fitz, many others, and myself would encourage you to do the maintenance and tuning in the order specified. Can't build a house with out first doing the foundation. It is that critical with these bikes. Most of us (me included) who took shortcuts at first only found that we had to go back and do all the things necessary to properly bring all maintenance items into spec and the fine tune. Where in Florida are you?

also to answer almost any question about tuning the carbs...

http://www.xjbikes.com/Forums/viewtopic/t=44642.html

and a great how to...

http://xjbikes.com/Forums/viewtopic/t=2 ... aning.html

 

Fitz, you were right. All the calves were way out of spec. However, I didn't doubt that you knew what you knew your stuff. You obviously do. You have a lot of insight to give. I never said sing the floats is a while teardown. Nor did I intend to imply. I guess what I meant without saying so is that if I was pulling the carbs, it would be to do the whole rebuild. And based on what you keep telling me, should be your suggested starting point too. I mean what's to say they weren't done correctly? If it's silly to take someone's word on properly song the floats, then it's silly to believe the carbs were done correctly from the start. This is supported by your last statement. That's why I wanted to try what was easy and quick to rule out something simple rather then doing, as I started, a full teardown. It seems absolutely absurd to pull the carbs of and spend the time to set the floats, only to put it back together and find out I didn't done the problem. That is the singular reason I wanted to sync and colortune before doing the rebuild.

Either way, valve clearances are in spec now, yet I still have a problem. But without the use of the colortune, I wouldn't have known what the problem was. It seems like I'm facing multiple problems, not the least of which is that the mixture screws don't change anything at all when adjusted, whether turned all the way in or out. Color doesn't change at all, unless I'm not giving it enough time to burn the excess fuel or for the midge to become more rich. I can't imagine that is just the float levels, but I may be wrong.

 

I'm in the Tampa area.

I appreciate everyone's input. I just wanted to find out as best I could what the actual problem was. Is wet setting the floats REALLY the best place to start? I mean if I'm silly for assuming the floats are done right, then I'm more so for not starting with the TRUE foundation. Fitz was right about needing to do the valves, but at the time I asked these questions, all I had were the vacuum gauges, so I wanted to do what I could with what I had. But now that I hit the feeler gauges, actuality had the ability to use the advice I was given.

 

If this hasn't been done do it. 8O

 

you don't want to do something that you might not need to do, i don't blame you a bit.
so here ya go, get a clear hose that fits the carb drains and loosen the screw and drain the carbs one at a time into a nice clean glass jar. if anything comes out that's not gas, your carbs need cleaned.