I have a 2006 500HO and what I need is how do I know when the piston is on the compression stroke. I've got around 80 hours on it after the first dealer maintenance. I figure i'ts time and I want to do it myself. Thanks guys.

I dont think you have to adjust the valves just torque the rocker arms to 27 ft-lb

Mornin ivplay
The valves are adjusted to 006 and you do the front 2 at the same time, You don't have to remove the gas tank like the book tells you to, You just need this setup. I think it is a 8mm or you can use a 5/16. It's no biggie, The only hard one to get to is the top left one. But you can get to em all from the right side.

This message has been edited. Last edited by: hobbles,

You don't have to use the compression stroke way, just line up the timing mark, A book will tell/show you it all. If your gonna get a book, get one from Polaris not an after market one,

When preparing to adjust valve lash remove the spark plug so the engine can be rotated easily, it will also stay where you set it better. Make sure the cam lobe (for the valves you are adjusting) is on the opposite side (180*) from the rocker arm, assuring that the valves are completely closed.

Remove spark plug(s).

Stick finger in spark plug hole.

Rotate crankshaft in direction of normal rotation.

When you feel air discharging from spark plug hole, you are on the compression stroke.

On ANY cylinder of ANY four-stroke engine, at top-dead-center (TDC) after the compression stroke, ALL valves are COMPLETELY closed.

That's the point for valve-lash adjustment.

There is a timing mark (T) if I remember correctly on the flywheel that you can see from the timing inspection hole. There is a bolt on the right side crankcase cover next to the pull starter, when you remove it you will be able to see the flywheel. With the valve cover removed, use the pull starter to turn the engine over slowly and watch as the cam actuates the rocker arms. After the intake valves open AND close, pull the starter rope VERY slowly and watch for the timing mark at the same time. When the mark is perfectly lined up with the arrow, then you have exactly Top Dead Center.

Good luck!

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Originally posted by jaxnjil:

quote:

Stick finger in spark plug hole

the problem with this is if yoou dont get a realy good seal with your finger you cant realy tell if piston is coming up on compression or exhaust

Actually, jaxnjil; air rushing from the cylinder on the compression stroke isn't at all subtle, when the engine is pulled through by hand . . .

Try it!

Very little airflow through the spark plug hole occurs during the exhaust stroke, because 1) the exhaust valve cross-section is much greater than that of the spark plug hole, and 2) the exhaust valve begins opening BEFORE bottom dead center prior to the exhaust stroke, and remains open during part of the intake stroke (the amount depending upon the valve duration of the engine).

By contrast, all valves are sealed during the the compression stroke, ejecting the cylinder's volume at the point of valve closure entirely through the spark plug hole . . .

In my experience, the compression stroke is decisively detected by the "finger in the spark plug hole" method; YMMV!

This message has been edited. Last edited by: Tree Farmer,

"YMMV" means, "your mileage may vary." That is, your experience, or your perception, may be different from mine, jaxnjil.

Also, humbly and modestly, I think indoctrinating a "novice" with the information ALL valves are COMPLETELY CLOSED at TDC of the compression stroke may be useful, now and always. Your contradiction welcomed.

I don't deny being argumentative by nature; however, my suggestion for finding the compression stroke was offered as a constructive response to the question posed in the initial post on this thread.

I do NOT argue the method I suggest is "better" than one you recommend; I only report I've used it successfully on a wide variety of engines over many years. No doubt, your cork method works fine, provided a cork of usable diameter and length is in the toolbox or the shop.

While I don't find a fine distinction between the exhaust stroke and the compression stroke when using the method myself (seems pretty clear which is which, to me), your point about possible ambiguity is noted.

And, thank you for your judgmental literary criticism of my posts--also noted!

May I PM draft posts to you for editing and approval before posting?

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Just messin' with you, jaxnjil!

Not related to finding the compression stroke, exactly, but . . . to the use of an empty spark plug hole for tuning purposes:

In the old days, some British bikes were timed, based upon the amount of protrusion of a rod poked down the spark plug hole . . . the rod (calibrated with measuring marks) was inserted in the spark plug hole, the engine rotated, and the piston crown pushed the rod out the top, proportional to the crankshaft revolution; timing was effected based upon the correspondence of the exposed rod length to crankshaft rotation relative to TDC.

Off-topic content acknowledged; however, generally related to tuning with information obtained through the spark plug hole.

This message has been edited. Last edited by: Tree Farmer,

Mornin ivplay

Bob O said it better then I did, That's how you want to do it. It's easy and it's the right way,
You'll do fine...

Thanks for all the info guys. I started to buy an after market manuel but i will buy the polaris manuel. What is the difference between the manuels?

Mornin ivplay
The stock manual covers things better and gives more info, And that's what you need. It also cost more (bout $20 more) I bought the after market one for $30 delivered and it was for the 06 sportsman but I didn't like it. So I gave it away and got the one from Polaris, That one I like, Besides, the the young man that worked on mine at the shop didn't look like no rocket scientist and I figured if he could fix my quad with the book, Then that's the one I better get.

my goodness tree you must be my age, i didn't think anyone remembered that old brit. tuning method.....stroker

quote:

Originally posted by stroker:
my goodness tree you must be my age, i didn't think anyone remembered that old brit. tuning method.....stroker

I imagine I'm much older than even YOU, stroker!

Not much glory in my "seniority," and senility IS cruel.

Only, . . . hey; where am I?

Hey guys is that .006 mentioned a go and no go on .007. I have 3200 on my 500 and haven't adj the valves yet. Thanks Mtnbum

that would be correct on the go-nogo deal. i have played with my valve settings a little bit and left them at .004 int and .008 exhaust. this would alter the valve timing ever so little, but the engine feels good at those settings......stroker

quote:

Originally posted by hobbles:
You don't have to use the compression stroke way, just line up the timing mark, . . .

The "timing mark" lines up TWICE, during each four-stroke cycle, hobbles--once, between the compression and power stroke; and, once between the exhaust and intake stroke.

The former's the one where valve clearance should be adjusted; thus, finding the compression stroke (by whatever means) remains critical.

Nothing wrong with manuals, and I recommend 'em when available, but--without any manuals, in total darkeness, the exact region of rotation for adjusting valves can be determined on any four-stroke engine anywhere in the world.

First, determine the initiation of the compression stroke, by any valid technique; then, rotate the engine to the piston top-dead-center position.

If there are timing marks (index and witness mark) you can feel, line 'em up; if not, stick a wire or something down the spark plug hole and feel for the maximum excursion of the piston. (Of course, if you have light, you can line existing timing marks up visually; but if its dark, or if there are no timing marks, you can still find top-dead-center.)

Must you be EXACTLY at top-dead-center to adjust valve lash accurately? No, not really; although the exact point removes doubt. A short sector of cam profile about the top-dead-cener position is CIRCULAR in cross-section, the radius of the lobe doesn't change in this region of rotation; any point on that segment with contact by the cam by the follower will allow precise and correct valve clearance setting.

I do NOT say, "We don't need any stinkin' manuals," only, understanding some engine principles makes one less dependent upon them. Manuals remain useful aids and tools in themselves.

---------------

WARNING: Boring anecdote follows!

An American once went to Africa, serving as a "mercenary" in the service of a losing side; rebels against a Soviet-client state.

Anyway, this guy was captured, tried, convicted, and sentenced to prison in the "Darkest Africa Hilton."

His job, during his confinement, was maintaining and repairing the obsolete-technology ex-Soviet motor vehicles in a motor pool; for other "senior citizens" who recognize what I'm talking about, vehicles with "points, coil and condenser" ignitions.

So, few, if any manuals; and--if present written in an undecipherable foreign language. Cryptic markings on the equipment . . . no knowledgeable technical personnel among his captors . . .

Anyhow, this erstwhile "prisoner of war" served out his time, tuning and repairing the obsolescent-technology Soviet equipment in a motor pool, avoiding the fate of having his earthly remains decomposing, enriching the soil of the African countryside . . .

How did he accomplish this "gainful employment?" By applying basic internal-combustion engine principles, learned in his previous life. (The prisoner served his time, was released, and returned to the US.)

MORAL OF THE STORY: Don't expect one; except maybe--serving as a mercenary in Africa for a shaky would-be regime may be hazardous to one's health; although . . . they may be hiring, now!

quote:

Must you be EXACTLY at top-dead-center to adjust valve lash accurately? [i]No, not really;[/i] although the exact point removes doubt. A short sector of cam profile about the top-dead-cener position is CIRCULAR in cross-section, the radius of the lobe doesn't change in this region of rotation; any point on that segment with contact by the cam by the follower will allow precise and correct valve clearance setting.

And as I had posted before (assumeing you have the rocker cover off) to perform the valve adjustment, observe the cam lobes and make sure the (lift) side of the lobe is 180* from the rocker insuring the valve/s are completely closed. Nice story Tree Farmer, I can relate to that, from working on very old fleet equipment (40's-70's) and the repair manuals (if any) were all torn up and half there, you just have to apply what you know and hope for a successful outcome.
"Use common sence, and pay attention to the details"

Being at TDC isn't really necessary. The main thing you are trying to accomplish it to adjust the valve clearance when the lifter or rocker is on the base circle of the cam lobe and isn't on the "ramp". You should be able to adjust your exhaust valve then the intake valve is closing and adjust the intake valve when the exhaust valve is opening... FWIW.

cajun, thats the way to get correct settings on long duration, hi lift camshafts, but as you say works perfect on stock cams as well, good tip......stroker