Help Find A Cure for Crazcnuk's bike?

[3Phase]

Originally posted by Crazcnuk
These are the black plastic floats, and I got the 25mm from one of the other few hundered posts on this.

I know what you mean there.
My bike was sold to me as a 1981. It took a while to find out that it was really a 1980 but I still get '81 stuck in my head now and then.
I read posts and tech tips keeping in mind that a lot of folks here have '78 or '79 bikes and a bunch of them are Specials, not Standards, with a healthy dollop of XJs thrown in to keep it interesting!

Basically, right now it is back running like it used to, no bottom end bobble, good through the mids, and then it runs out of power at about 7k in 4th. 5th has no power up there either, all it does is frop the rpms when you shift, it will not accellerate.

That's actually good that the low end is working, but what do the spark plugs tell you when you run at high RPM and cut the throttle?

I don't know why they would have put 45 pilots in and left the stock mains, that one just baffles me.

Okay, if has stock mains now then it has your old 110s in it and you changed out the 120s you put in there?

Do you have the 42.5 pilots?

I won't know if there has been any change in fuel mileage until I can go somewhere.

Funny part is when I first got it on the road, it would pull right to redline in all gears. I could keep up with Derwat's Special within a length or two.

Only problem is it was getting less than 20mpg at the time.

So, the bike came with stock 110 mains and 45 pilots.
When did the 120s get put in - before or after you were running with Derwat? The reason you bought new needle jets and jet needles is because the old X2 needle jets are worn and ovaled and you're getting crummy mileage.

I can't help you much with needle and jet needle sizing. You'll have to find the correct setting by reading your spark plugs. What I can do is pull out the jet needle sizes from that Hungarian spreadsheet I found so you can get a rough idea of what you're changing with the needles. I have no idea where it came from originally and I still haven't found anything that shows the difference between X2 and Y0 needle jets though, sorry.

Mark	Slots	Length	Dist.1	Dia 1	Dia2	K1	K2	K3	K4	K5	K6	A1	A2	A3

5GL16	1	51.000	3.000	3.000	0.000	16.800	20.800	34.800	0.000	0.000	0.000	1.45	3.00	7.00

5GLZ18	5	50.500	3.000	3.000	0.000	16.300	20.300	34.300	0.000	0.000	0.000	1.45	3.00	7.00

5GZ6	5	52.500	3.000	3.000	0.000	17.200	39.200	0.000	0.000	0.000	0.000	1.45	8.00	0.00

5IZ7	1	51.800	3.000	3.000	0.000	16.800	34.800	0.000	0.000	0.000	0.000	2.15	8.00    0.000

1980 SG = 5GL16
Crazcnuk = 5GLZ18
1978-79 All = 5GZ6
1980 G = 5IZ7


Regards,

Scott

[Crazcnuk]

You'd have to read all the posts, to get teh timeline.


It ran best, with horrible mileage with 110 mains, 45 pilots, and slightly worn needlejets.


I tried 115's and 120's to see if it would help the high end. They did not. The high speed chop looked good on the 120s, but it ran the worst.

Today I put the 115's back in it, reused the old needlejets, as the new ones look to be wrong, but dropped the needles 1 notch.

What I meant about the 45's and 110's was I am not sure why the PO did that. As far as I can tell ALL the carbs close to these all came with 42.5 pilots.

The needles and jets, pilot jet, etc may affect fuel economy, but nothing, so far has been able to make this thing run to redline unless it can throw half the gas out the tailpipe.

Even though it runs smooth in the mid and low range now, I am not sure that it has the power it's supposed to. This one is no neck snapper. It seems good up to about 6k.

[egsols]

reused the old needlejets, as the new ones look to be wrong, but dropped the needles 1 notch.

Were you able to use the new tubes?

I don't recall if you mentioned checking your diaphragm springs or not. Reason I'm thinking that, is if you say the chop shows the 120's are good at the upper rpm but blowing fuel out at all other rpms then perhaps the needles aren't rising enough at WOT. I'm just thinking that if the needles rise normally at mid range then with the 120's you would be rich but, if they dont go high enough at WOT it would appear lean.

Let me know about the tubes, I may have a spare set (originals) to lend you if need be.

[psycoreefer]

If you want to know about emulsion tubes I found a sheet somewhere that described them. It said that the number was the "series" and didn't expand on that but from my deduction it has to do with the number/size of holes in the sides of the tube. The letter/number identifier is the size of the jet - I assume it is the inside but it didn't say that - with letters equal to .05mm and numbers equal to .005mm so X2 to Y0 is .04mm larger inside diameter.

The needles from memory is the first number is the length of the needle, ours should all begin with a 5. The rest had to do with the number of degrees of taper and hight on the needle where the taper starts but I can't remember the details because it didn't make one bit of sense to me.

[psycoreefer]

You mention that the PO up-jetted the pilots and left the mains alone, mine was the same way. The PO had drilled out the pilots - larger then a 50 - mains and everything else stock. I've got 47.5's in it now to make it run decent, with 140 mains.

I haven't been able to figure out why the idle jets need to be so darn big. The funny thing is my problem is at the transition between idle and mains - I have a stumble there where its way to lean. Your having top end problems. I'm starting to suspect my PO cut the springs and so the slide rise to fast creating lean, perhaps your PO put stronger springs in holding the slides down starving it for air at WOT?

I second the suggestion to check your springs - and maybe also the size of the little hole in the slid. I've read about people drilling that hole bigger.

[Crazcnuk]

I checked the springs, but since there aren't any specs for them, not sure what to check them FOR.

In mine there were 2 short springs and 2 longer springs, but the difference between long and short was about 2mm.

The two long ones are exactly the same length and the 2 short ones are exactly the same length. I put the 2 short ones in the center 2 carbs and the long ones in the outer, this time.

The only reason I could think of, for the two lengths, is that instead of putting bigger jets, in the center two carbs, to make them more rich maybe they used quicker acting springs to do the same thing. At this point I have no idea which carbs they were originally as it wasn't something I checked when I took them apart the first few times.

I did not use the new tubes. Until I find out what they are supposed to do, it would just add more confusion. Also, I don't have any 42.5 pilots to try , to see what that would do.

Basically I've spent another couple hundred bucks on this bike and it's changed nothing.

[psycoreefer]

I'd say get some new springs. I'm nearly 100% sure all four springs should be the same length. Did they all feel the same "springyness" or were two stronger then the others?

Yamaha only lists one spring for all the G/H/XJ models and one for E/F models, so I doubt they put in short/long. I looked quickly and bike bandit lists them for like 13 each. A bit steep but local Yamaha dealer says discontinued, but used to list for 5.50. I'd try the dealer first, they may have some or be able to order from the remaining stock in a warehouse someplace.

[Crazcnuk]

I'm not replacing anything else. We are grasping at straws here.

I am not going to make this into a $5,000 POS. It's already the 2nd most expensive bike I've ever owned, and the most trouble.

Unless we con come up with some definitive tests there isn't much more I can do with it.

[psycoreefer]

If the springs all feel about the same "springyness" then why don't you try stretching the short springs to match the longer ones. would be temporary but might let you know your on the right track.

When I do get new springs I'll send you my questionable old ones for the cost of shipping, at least they are all the same.

[dbeardslee]

Craz - I understand your frustration. You had a problem with oil consumption, right? I know the thing that had the biggest payoff for me was redoing the heads and replacing the valve stem seals. It kept oil fouling plugs and would really run like crap even with the carbs setup correctly. Had a LOT of deposits on the back of the valves (probably from oil dripping down and frying) that was disrupting the fuel/air flow, and the sealing surfaces of the valves were pretty bad. Cleaned 'em and lapped 'em, adjusted the valve clearances and put it all back together. After that it would idle all the way down to 200 rpms without cutting out, and will push as far into the red as I want to take it, and no more oil fouled plugs.

Unfortunately that requires new valve cover and head gaskets and stem seals. Cheapest I've been able to find them is partsnmore for $77 in the engine gasket kit. Has everything you need. A few parts, but it's mostly labor.

[Crazcnuk]

The difference from the small springs to the long ones was 2mm. Since they are about 130mm long, I thought it was negligible. Just out of my own sense of proportion I put the short ones on the center carbs and the long ones on the outer.

Right now the bike starts great, runs smooth, purrs right along, as long as I don't want to go over 7k in 4th or 5th gear. I put new plugs in it today, but still have to fix #4 spark plug hole.

There is no bottom end bog now, and it goes right from off idle to 6k with no hesitations.

Tomorrow I am going to take it on a highway run and see how the mileage and oil burning are doing.

[egsols]

Hey Craz,

If I get a chance this weekend I'll pull out my '80 carbs and see what length the springs are in it.

I have two '79s. One I'm riding right know and the other, my original, I parked in '94 but want to get running again.

My old one had a set of '80 carbs on it and they are in pieces right know.

I would be willing to ship you out tubes, pilots, springs, to try out on yours. That way you can see if they are the culprits without throwing extra green at it.

[egsols]

I just had a thought. What size are your float seats? I believe they should be 2.00, the ones I just put in mine are 1.40 but give me enough flow for now. (haven't tried out past 3rd wot) If someone replaced your seats with smaller ones it might be starving the bike at wot.

It's probabley not the case but something else to consider.

[desert1]

Bruces 2 cents

Hey Cray, I put a 79 special engine in my 78' last year....now this motor that I installed had been sitting outside along with the rest of the bike for possibly 10 years...last year this motor was going thru lots of oil I went thru maybe 3 litres in 3000kms and smoked when pulling away from stops......now, this year the motor smokes litely but has burned very little oil......

Marvels Mystery Oil....thats what I added to the oil and gas last year and my thinking is its gradually freed open the rings so that compression has improved.....I know this reads like some hoaky commercial but the engine did improve and I'm up to 33 to 34 MPG
I keep adding it 2 or 3 capfulls to my gas from time to time as well as every other oil change 4 ozs in the oil.....
Bruce

[egsols]

Craz,

Have you checked you case vent? If its plugged you could be building too much pressure which will hold the motor back at top end. I don't know if it could be contributing to oil usage by forcing oil up past the rings, but its just a little thing to check out.