Tuning issues

[mack]

Ok so although my compression numbers are low, they are coming up. I followed some advise and went ahead and sync'd and colour tuned it today. Went for a ride it still has a stagger in it. Doesn't seem to matter at what rpm, if I'm at a constant it staggers, almost like a miss, but if I throttle up or down it goes away. The bike purrs like a kitten at idle and goes like stink with throttle.
When I colour tuned I got blue then turned the idle mixture screw out till I got a hint of yellow. The sync is good and I checked the pick up coil wires for breaks. They are all good.
I don't have a strobe light so I haven't checked the timing yet and I made a template out of a coat hanger and set all my float heights at 25.7mm. Book says between 24.7 and 26.7 so I went with the mean.
I didn't have any Yamalube on my diaphrams when I took them apart so I didn't use any when I put them back in. No rips though and the carbs were spotless. However I did have an incident with a squirral and the carb parts got mixed up.
I've ordered accel coils in March but they haven't arrived yet.
So opinions please. Float height, ignition coils, air leak?

[Montreux_Blue]

According to Colortune, "Usually a bunsen blue flame is spot on." Just did mine over the weekend with the set of four so I could see all of them at once and was able to see it through the whole rpm range. You might want to re-adjust to "bunsen" blue and then check what each cylinder is doing through the rpm range to see what color they are.

[dbeardslee]

When I colortune I go out until I get full yellow, and then back in till it just turns to bunson blue. Soft and boggy in the lower rpms is usually a sign of a rich condition. Might try half a turn back in on your mixture needles. Also, where are your floats set? Bad or failing coils or high tension wires will sometimes give you a low rpm stutter too. Just some stuff to think about .

[mack]

Hooked

Took him for another ride. (didn't feel like cutting the grass) Don't know if its me or what but if I drove this like BJ and used the throttle and gears only it would be hard to tell it straggers. I pulled up on a guy in a camero and he would speed up to 120 k on the straight and slow to 80 k on the corners. I followed for about six km the drifted to the right to see what was coming and rolled on. Hermes came out of the hole like his ass was on fire and his hair was catching. Geez I'd forgotten what it was like.
So if I have a quarter turn into the yellow it means i'm too rich?(colour tune)

[DGXSER]

Personally, I'd ride it for a little while and check the plugs for color.

[Montreux_Blue]

But if you have a Colortune then you don't have to wait to "read" the plugs. You can see into the combustion chamber to see what colors are going on.

[dbeardslee]

So if I have a quarter turn into the yellow it means i'm too rich?

That would be my guess. You adjust with the colortune, but you verify with the plug color. The thing you have to remember about the colortune is that you're not seeing what's actually going to happen with the stock plugs, as that's not what a colortune is. It takes a little playing around with it before you'll know exactly what it's telling you for a particular type of machine. On mine, if I go about 1/4 into the bunson blue (it changes from yellow to blue, and I go just a tad bit more). If I've diddled with the jets I also make sure I can adjust through the entire range of color - yellow, bunson blue, and white blue (but when I set them I always go out to yellow and then back in). That tends to be a pretty good indication of whether or not you've got the correct mains installed. While it's true that you're only really looking at the slow circuit with the colortune, your mains will affect the slow circuit. For your carbs to function at the top o' their game they need to be clean, and you need to have the proper mains, slide needle position, float height, pilots, mixture and sync. I've found this page to be very helpful when setting up carbs

[cywelchjr]

That would be my guess. You adjust with the colortune, but you verify with the plug color. The thing you have to remember about the colortune is that you're not seeing what's actually going to happen with the stock plugs, as that's not what a colortune is. It takes a little playing around with it before you'll know exactly what it's telling you for a particular type of machine. On mine, if I go about 1/4 into the bunson blue (it changes from yellow to blue, and I go just a tad bit more). If I've diddled with the jets I also make sure I can adjust through the entire range of color - yellow, bunson blue, and white blue (but when I set them I always go out to yellow and then back in). That tends to be a pretty good indication of whether or not you've got the correct mains installed. While it's true that you're only really looking at the slow circuit with the colortune, your mains will affect the slow circuit. For your carbs to function at the top o' their game they need to be clean, and you need to have the proper mains, slide needle position, float height, pilots, mixture and sync. I've found this page to be very helpful when setting up carbs

I can understand that the mains affect the pilot circuit on the 78's and 79's, but unless I'm mistaken, that is not true on the 80 and later carbs since they don't share the main jets. However, I believe that on both the pilot circuit does have some affect through the entire range, as the pilot circuit is always engaged. At least that is my understanding of how these little monsters work (not that I have done anything to mine other than minor adjustments since they work and have worked as long as I have had the bike very well).

[DGXSER]

I have to agree with Doug aka Dbeardslee, the colortune is a good tool to you pretty dang close. But it is not the same spark as the proper NGK or whatever brand plug in that hole. So it gives just a bit different spark.

Now that is not to say you will not be able to hit it good enough with the colortune to be done, but that I would not be surprised if you need to fine tune it a bit when you check plug color either.

As to mains effecting the idle circuit on the 80-81 models, well, I believe it will have an effect. I know on mine, I reassembled one of my needles in the wrong order when putting the slide back together. That cylinder would NOT run right at idle, in fact, if it ran under about 2k rpm it would foul the plug out. But as soon as I took it up over 3k, it cleaned the plug and ran great. Now perhaps that was just holding the needle open when it should have been shut, but it was definitely the main circuit having an effect.

[Montreux_Blue]

Coolest thing about the Colortune is I was able to tune my Dynojet kit in minutes without having to take a test run to guess if it was spot on. I was able to see what it was doing when the mains kicked in and all the way to red-line. 124 main jets, 190 air jets and slide needles set on the third notch from bottom. I'm glad I bought the set of four, makes tuning very quick. I understand that they are not exactly like a stock spark plug since gaps are different etc but it's pretty damn close and the ability to see in the chamber to see the color is priceless.

[XJOK2PLAY]

Hey, Jeremy...
Where did you buy your Colortune at?
What was the cost?

Ya got me interested now...
Thanx.
Bob

PS... Wish things weren't so tight for me right now! I'd love to buy your bobber.... that's a great bike. I've been wanting a second bike that was bare bones... for around town runs. Love the XJ, but it gets a little tiring doing the town running on a fully dressed one.
I do hope you find a buyer for it and it goes to a good home.
Good Luck.

[Montreux_Blue]

I bought the Professional Colortune set (four - 14mm plugs)with the Carbtune Pro which cost 153 UK lbs which converted to $223 US dollars but totally worth it. And I also bought a 90 degree gear drive screw driver off of ebay so that I never have to remove the tank to tune again! I just removed the mounting screw for the octy to move it out of the way and took off the tank mounting bolt and put a 2x4 under the back of it and I had plenty of room to work with. It cut down a lot of the time it would have taken to try different combinations before finding the right one. It took 8 days to arrive from the UK. And to make your money back, just start charging people to tune their bikes like others on here do!

http://www.carbtune.co.uk/index.html

Just click on "Order Shopping Cart", then "Special Offers.....", then "Carbtune Pro, Professional Colortune, Toolpouch." and select the "4 col Carbtune, Toolpouch, Colortune Pro 4 plug", then "14mm" for the plug sizes.

And this is the screwdriver I got.




You can just get the Colortune by itself but I would totally suggest getting the set of four because it's amazing seeing what's happening in all four cylinders at the same time for dialing in a jet kit.

[MrOzz]

Hey, Jeremy...
Where did you buy your Colortune at?
What was the cost?

Ya got me interested now...
Thanx.
Bob

PS... Wish things weren't so tight for me right now! I'd love to buy your bobber.... that's a great bike. I've been wanting a second bike that was bare bones... for around town runs. Love the XJ, but it gets a little tiring doing the town running on a fully dressed one.
I do hope you find a buyer for it and it goes to a good home.
Good Luck.

Bob,

I picked up the single plug one last year on ebay for around $60.00.

Ozz

[mack]

missing

Well took Heremes for a good ride this am. He was missing pretty bad at crusing speed?? 3.5 - 4 k. Real good above that. Brought him home and went back into shop. Re- colour tuned and sync'd. It seemed I was redoing what I'd already done but wound up turning up 1&2 and turning down 3&4. a bit each but it did make a difference. He still stumbles a bit at 1500-2000 but if you roll on the gas he just comes out of the hole very determined should I say. Still haven't had him strobed yet but I got a feeling he's off a couple degree's . The same ones I asked about in the spring when I felt for TDC but the pointer was off a bit. Haven't made up my mind as to weather tobuy one or just take it to the dealer and have him strobe it. I've come this far oin my own. Seems sinful to go to a dealer now. How often do you strobe your timing?, Is it worth buying one?

[dbeardslee]

A stumble in the 1500-2000 rpm range could be an indication of bad ignition coils, or high tension wires. The alternator doesn't put out its full voltage until 2200 rpms (or there abouts), and that can sometimes 'camouflage' a coil problem. At low rpms they may not have enough voltage to fire reliably, but when they get the full 14v to them, they can straighten out and run right. You might try running the primary and secondary resistance tests on your ignition coils. If you're running the stock coils the chances are pretty good that your high tension wires are toast. It's pretty easy to graft new wires into them, though - particularly in the 78-80 model coils.