Air/fuel screw location

I'm trying to locate the air/fuel screw location on an xj650 seca? Looked around and couldn't find any info other than it might still be capped? If so then where is it located? The reason I ask is that I believe my bike is running lean,plugs look pretty white to my untrained eye...any thoughts or advice us appreciated as always!

 

Your plugs are good. The YICS engines are tuned to run a little leaner than most, but you could richen the mix up a tad if you want (fuel economy will drop some).
The idle mixture screws are on top of the carbs, up front, next to the enrichment plungers. They may be under brass ar aluminum caps, which will need to be carefully drilled and removed.



Baselne setting is 2.5 turns out from a soft seat.

 

Ok thanks! I found them and they ain't capprd,guess I over looked them.... Talked to Hogfiddles about the plugs as well and he thought they looked lean, I've also been having an issue with revs staying high and sometimes seem to climb on their own when stopped, about 3-4K.... I've checked for vacuum leaks with a few short blast of starter fluid around the carb boots and haven't noticed anything unusual.....did have to adjust my idle speed a bit,it was dropping to about 500-800 at best when warm,needless to stay it kept stalling out if I didn't stay on the throttle...now I have it set to about 1k to just a hair over,is that ok?

 

The factory settting is 1050 RPM, but many of us have it set a bit higher.

I'm not saying the plugs aren't on the lean side, but they aren't horribly lean. The insulators all have a touch of tan, and the ground straps have the color break in the right place.

 

Ok no worries,ive never dealt with air/fuel mixtures before so it's a learning process for me.... Whats your input with it sticking at high rpm?

 

Did you spray around the throttle shaft seals?

It could be a number of things.

Vacuum leak(s), sticky throttle cable, sticky slide(s), enrichment plungers not fully closing, YICS main gallery plug not sealing (this is really uncommon, but worth checking), If the carbs ere ever apart it's possible that the nut on the #3 throttle linkage was put on too tight.

My first line of attack is to remove the choke and throtle cables and then see what the carbs do when working htings by hand.

 

Carbs have been apart and cleaned about a dozen times or so....when is that nut for the number 3 throttle linkage?

 

I'll assume you meant to type where.
The nut is on the #3 carb throttle linkage. It's the only nut in that location. Holds the linkage on to the throttle shaft. You not knowing where it is tells me that you did not tear the carbs down for cleaning. This means that the throttle shaft seals are still original. They are the most likely source for an intermittent vacuum leak, leading to a hanging idle.

 

Yes that's what I meant, and yes the carbs have been torn down and cleaned numerous times by me and others including a local bike shop.... All of that was replaced early on in the rebuild process....I did not personal do that part of it thought, that's why I wasnt sure where it was.....

 

Gee..... I almost wonder if they re-installed they throttle shaft seals cuz they still looked good.----- almost wonder.....

General rule: if YOU didn't tear them down and clean/replace everything YOURSELF..... It didn't get done. (Exception - if HOGFIDDLES tore them down, you know that EVERY single piece got inspected/cleaned/or replaced)

 

... or they may have put the throttle shaft seals in the wrong-way-around.

 

Uh--- I'm not saying that I think they still look good. Let me try to re-do it below so it comes out more righter---
-----
Gee.... I almost---ALMOST--- wonder if "they re-installed the throttle-shaft seals because 'they still looked good' ".
-----
It's about the same mentality as we saw in another thread where "they don't need to be replaced--- they're just dust seals"

Believe you me---I won't go to the t-shafts without replacing them unless I KNOW that they have just recently been replaced... And even then, I'd be reticent to leave them in unless I really REALLY knew the owner would really have just put them in. Which leads to'why do we have to go into them again..? ' , etc....

 

I'm just saying that if they did any work on the carbs at all, they did it wrong.

 

Agreed 100%

 

Most shops don't bust the rack, so unless you saw them apart don't assume shaft seals have been done.

 

Plus, many shops will dunk the whole rack, and not be aware the seals WILL be compromised by the solution

 

Good point !

 

Ok now I'm going to be making a call... Lol! What really sucks for me is that I'm EXTREMELY limited to what I'm allowed to do as far as mechanic work where I live, the land Lord is ok with some thing such as changing a tire,replace a headlight,replace a starter etc. But nothing dealing with any fluids of any type due to damaging the parking lot or fires starting from flammable liquids, which I understand completely...... How much do those seals cost? I did find something a bit startling with a carb boot of when tested it doesn't seem to be a source of a leak...

 

That rubber is probably not leaking there. What you see underneath is the flange that the boot is cast over. Clean it up good and coat it with RTV just to be sure.

 

I don't think that is a big problem on that boot. The part where the rubber is pulling away is fairly unimportant.

I'll say, I'm so happy I paid hogfiddles to rebuild my rack.. totally hassle-free. The airbox boot, on the other hand, were a huge PITA to get back on!

 

We gotta stop replying at the same time like this!

 

Will do! Just got off the phone with the shop and spoke with the girl that worked on cleaning my carbs last and said she did break them down and didn't just dip the whole thing.... Now having not done this myself is there a diagram somewhere I can look at to see which seal y'all are talking about so I can make sure I'm on the same page?

 

IN THE CHURCH OF CLEAN

http://www.yamahapartsnation.com/oemparts/a/yam/500421d3f8700209bc7873ee/carburetor

 

Which number am I looking for?

 

The throttle shaft seals aren't picutured in the diagram. I don't think Yamaha ever sold them separately. The butterfly valve (throttle plate) rides on the throttle shaft, and the seals are on the outer part of the carb body under nylon washers.

 

Unfortunately this is something I wouldn't be allowed to do here....

 

Your inbox is full. I am about an hour from you, and I don't have much space, but if you need to do some work, I have a decent amount of the tools needed to work on these, and a spot we could park the bike in short term.

 

Go ahead an pm me I cleaned it out....

 

Oh, and I don't have a great picture of the throttle shaft seals, but attached shows it in the carb itself, and the side on the shaft. Chacal sells them at a reasonable price. The aftermarket ones I got were an X instead of a < shape, so it looks like they can go in either way, unlike OEM that had to go in oriented a specific direction.

 

What is a reasonable price? And how long of a process is that to do?

 

Well, I am actually finishing that up myself at the moment, so I couldn't give a great estimate. That having been said, I am going to try anyway. Assuming that everything else is clean/good, you still need to remove the carbs, break the rack, remove the shafts, replace the seals, put them back together, sync the butterflys and reinstall. Since the shop said they broke the rack already to clean it, hopefully you don't have to fight to much with stuck screws or anything like that. I work slowly, so I would probably set aside 6 hours to do it, I am sure some of the more experienced guys could do it in less than 2.

 

If you're not cleaning anything, you can replace them all in a couple hours. If you're doing that, replace the fuel supply tube o-rings while you're at it. If you don't, you can simply say "crap..... Now I have to take the rack back off AGAIN, and take it all apart AGAIN--- should have done these when I had it apart for the t-shaft seals.... I can even hear them all snickering and saying I-Told-You-So......aaaagh"

 

Ok so what all do I need to/should I replace? Right now money is tight so I gotta get an estimate first on parts....

 

read the "Church of Clean". It's ALL in there

http://xjbikes.com/forums/threads/in-the-church-of-clean.14692/