New XJ650 owner. Many questions, looking for UNIQUE answers

OK. After posting this, "tech only" thread, I will be posting a general rant/wah wah thread in the appropriate forum.

Picked up an 82 XJ650 Maxim in piss poor shape. I have tried to search and read as much as possible before re-asking questions that have already been answered... but as I'm sure most of you know, the search feature in conjunction with the "back" button isn't the friendliest in the world.

My questions pertain to either the "why's" or to non carb issues, because frankly if I read one more thread about "my bike revs high", or "my idle is off", and see the same "clearance, clean, replace seals, test vacuum, bench sync, running sync, colortune" answer I might vomit. (I swear despite my cynicism, I'm a friendly guy)

1) If I pick up this exhaust, plain and simple. Will I need to rejet? And which jets to I need to alter?

2) Why do the valve clearances get tighter? I would think that as the bike is ridden, the wear on the shims/valves would cause them to get looser. Is it a carbon build up thing?

3) Are these going to be worth a damn at all?

4) Lighting questions... flasher cancel unit... where would I locate this (on the bike)? Does the Cancel unit work if I go all LED? If not Why? Does going LED really save you much power, because the only "always on" lights seem to be the tail and headlights...

Well I have a lot more questions, but I know how these threads can get. Thanks!!!

 

Re: New XJ650 owner. Many questions, looking for UNIQUE ans

1) Maybe, maybe not. It depends on the characteristics of that exhaust and how particular you are about how it runs.

2) The wear isn't at the cam/shim interface. The wear is where the valve seats itself into the head over time - reducing the clearance at the camshaft.

3) <<Shrug>>

4) I don't recall exactly where the canceler is. The issue isn't with the cancel unit, it's with the flasher. LEDs don't draw enough power for the flasher to work. A replacement electronic flasher won't work with the cancel unit.

 

But that is the answer. Which is why it gets repeated.

My bike had a 4-1 and stock jets when I got it. Went to a custom 4-2 and had to rejet the main fuel and shim the needle to get the middle power back.

Chacal has a jet guide in his catalog and that should get you close. How close it up to you.

If I'm remembering right the canceler is under the tank on a frame clip.

MiCarl covered the rest.

 

Re: New XJ650 owner. Many questions, looking for UNIQUE ans

Oh I know. I just don't like when a question and answer series is repeated 100 times. I understand repeats happenning here and there, but it's like there are 1k threads on "my idle is wrong, bike revs high (which mine is doing right now) etc etc" as though that particular bike is going to have a differen answer.

And thank you for your answers!!

It seems so odd that a different flasher unit won't work with the cancel unit. I suppose I'm miles away from makign those changes on the bike anyways as I am still in the "curch of clean"/ YICS vacuum sync phase.

If anyone knows how the cancel unit and flasher work, I may just go ahead and use one of these microcontrollers I have laying around to replace it all with so I can run all LED and such... i'm using the microcontroller to act as an alternate key switch anyways (RFID if anyone's interested in making one, I've had GREAT results).

Also, in my headlight bucket is a black plastic square that has a 4 pin connector and I've no clue as to what it is, what it does, etc. Any words of wisdom?

 

That is your "diode block" it contains diodes belonging to a variety of different circuits, all conveniently clumped into a single point of failure.

If you're in the "church of clean/vacuum sync phase" then you already have your valve clearances in spec? Or, like most of those 1K posts you referred to, have you "glossed over" that particular detail?

One of the reasons that the same answers get repeated over and over is that when people don't like the answer they get, they tend to "grasp at straws" looking for an alternate answer (when there isn't one.)

 

Already did my clearances. A big thank you in Raleigh to Team Powersports and to Fox's in Roxboro for getting my hands on all the shims I needed late in the day on a Sat.

C'mon Fitz, you know me better than that... oh I suppose you don't actually.

I suppose I incorrectly titled my thread here. I am looking to try to ask unique questions, ones I can't seem to either find on the site, or find an answer for in the 20 pages of responses dealing with said issue.


Also, if I were to want to purchas a manometer for syncing carbs, today, like from a store, where would I do that. I obviously made a huge mistake purchasing vacuum gauges from an autoparts store thinking they'd be worth a s**t . nope. I'd really like to find the gauge variety because frankly I don't have a lot of space for a 6' clear tube manometer... unless the BB version works as well as advertised in it's thread.

 

The BB version allows a rank amatuer to quickly comprehend the process, and get the setting into the ballpark, is easy to build and store, and keeps the engine from injesting water.

It should be followed by the 2 tube, or "long loop" method.

3.) The shocks are 12.5 inches, a good length, and have "universal" bushings so they should fit. They are new so they should work.

 

I was never able to find one in the stores, ordered the morgan carbtune from their website, got it pretty quickly considering it shipped from the U.K.... Don't know anything about the BB version...

 

I used ATF. No worry of getting any in the cylinder. It'll just smoke.

If you don't want to store it you could throw it away. The yeard stick and tube one I have costs about $5 to make.

 

The BB sync thread -

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

Even if you botch the bench sync, the BB sync will work, as long as the bike will start and run - I recently used it to help tune my Venture, before switching to my 4-tube, water Manometer, with RickCoMatic baffles.

 

Ref exhaust - down to luck really. Fit it and then see how it runs. Mine has a four into one and runs fine on standard jets (though K&N filter in standard airbox).

Self-cancelling indicators? Why have them - cancel them when you want to by just fitting a new indicator relay (under tank near headstock - one further back is the self-cancelling unit).

If your bike idles too high then try the idle adjuster before anything else, as that is what it's for.

If it still doesn't run right then you might have to just accept that it's down to carburration... though a good, fast run might help things even out.

 

Re: New XJ650 owner. Many questions, looking for UNIQUE ans

The stock flasher has an electrical latch that is controlled by the cancel unit. A flasher from the auto parts store doesn't have the latch mechanism.

 

let me know how those shocks work if you end up getting them, mine ave gone to pot as well and 80 bucks is in the right price range.

pm me cause i may lose this thread, lol

thanks dawg

 

I've put those shocks on my 750 (and I've posted this on several threads asking the EXACT same thing) but they SUCK! They are "dual rate" but the lower coils bind as soon as you sit on the bike, and the suspension ends up way too stiff. It also doesn't help that a whole lot of the spring travel is taken up but the spring-spring interface, maybe a single rate spring would work, but as they are, they aren't worth it.

I rode on them for a couple hundred miles, and was much happier with the progressives I later bought. I haven't ever seen anyone else say they've used those Forsa shocks and liked them (although I've seen the question posed before).

And a little bit of advice. If you do end up having problems getting the bike to run right, don't tell people what not to tell you. Simply state EXACTLY what you have tried, and done to date. On these old, carbuerated bikes, many issues can have similar and interrelated symptoms that make troubleshooting nearly impossible without a good baseline. That advice that "makes you want to vomit" is members attempting to establish a good baseline. Very rarely is there an "answer" when troubleshooting, there are a series of likely conditions and difficulty associated with remeding those conditions that results in a clear path to finding the right answer with the least effort, while catching up on maintenance to head off future issues. And usually, the answer isn't something "broken" it's something "not maintained," and if something IS broken, it's a lot easier to find with all that maintenance out of the way.

 

Manbot,

First, thanks for the advice on those shocks. At $70 that's exactly what I was worried about. You get what you pay for apparently.

Second, I think I've been misunderstood. I don't need any advice on the carbs and clearances and the like. I mean, I do... but it's already on the site, and it is GREAT advice and VERY knowledgeable. The part that makes me want to vomit is the amount of times the exact same advice is given, because the exact same question is asked without anyone trying to find the answers on their own.

It's not too awful when people are having a hard time searching through long confusing threads to find a piece of info they need, but the amount of topics alone that say "new owner, high revving engine, please help" tell me that an honest attempt has not even been made to find the answers.

That is why I've read every carb thread I could get my hands on before I started asking the same exact questions over and over. And I apologize in advance if I make the mistake myself.

about the flasher canceller... when does it cancel then? If I am going to emulate this using a microcontroller, I'd love to know what I'm emulating. As in, does it cancel after a certain amount of time, tilt switch?

 

It's a distance thing. There is a reed switch in the speedo and a timer in the auto cancel if I'm remembering the wire diagram right.

 

If memory servers it's 150 feet or 10 seconds. Whichever happens first.

 

MiCarl, I have a basic flasher relay on my bike which works just fine for manual operation. I just disconnected the self-cancel relay from the circuit.

 

ooooh THAT is what that reed switch is for... hmm that piques my interest into connecting it to my uC. Thanks guys. Always good info here. Anybody have the flasher, and cancel unit model numbers? Possibly datasheets?

About to get my nerd on. But for today... somebody finally gets to do a running sync...

it's me.

 

Just out of curiosity has anyone ever drawn up a diagram that explains why the valves get tighter as they wear instead of loosen? I've seen it explained many times on many threads but I don't recall ever seeing a picture.

Hmmm... maybe I know what I'll be doing later.

 

As the valve seat in the head gets bashed about it wears (steel Vs alloy), therefore the valve moves further into the valve pocket in the head over time. Consequently the valve stem moves closer to the cam, with the shim filling the space in-between. Thus the clearances tighten rather than open. Remember, these measurements are very, very tiny.

I too thought the opposite until someone (on this site as it happens - probably Fitz) explained it to me.

Hope this answers your question. Nige

 

Re: New XJ650 owner. Many questions, looking for UNIQUE ans

Nige, that is a very good explanation of valve wear. I understand what is going on but I though a picture is worth a thousand words and it might help show others why the valves tighten up instead of loosening as many people think they do. I think I have just volunteered myself to draw (or find) something and get it posted.

 

Truth be told, EVENTALLY they will stop "bedding in" and valve train wear will become an issue; but not until they've been adjusted a few times during the "pounding in" process. Once a motor that has had the valves properly attended to hits 30K or more miles, some of them may actually start to show a slight "loosening."

But only after they've been adjusted to compensate for the bedding in, and more than once.

We generally deal with lower-mileage bikes whose valves have been completely neglected, which is why they're invariably too tight.

 

Ever see the valves rotate while running??

BMW at 14,000 RPM

and the springs rotate??

yes they do