I need a reality check.

[Flyingw]

On the 185S motor, when installing the CAM, could someone please verify that the CAM lobes point down when timing the motor. I have the factory manual and the Clymer manual and neither mention CAM position when setting up the motor. I'm pretty certain the lobes go down so the rockers are not putting any pressure on the valves but I'm a bit tired and punchy and I don't want to put it in 180 off.

[shortline10]

Yes the cam lobes are down , crank shaft keyway and camshaft sprocket 12-o'clock position and piston TDC . I don't even fuss with the timing marks on the flywheel .

[Keith Salyer]

You have your clock set wrong, you work day shift , not graveyards, Lol

[Flyingw]

Thanks Shortline, that's what I needed to know and Keith, I am a habitual night owl. I take after my parents.

[tri again]

VERY common question.
Repair manuals are like anatomy books.
They all seem to copy each other's mistakes and omissions.

[Keith Salyer]

Lol, I understand. My mother was that way. Dad woke up early, Mom the night owl. I'm at my best 3-11

[Flyingw]

Thanks for the help guys. The trike is complete and back home. It busted off on the second pull. It turned out great and runs like a champ so now its on to Keith's Tecate stuff.

[oscarmayer]

nice! so is that for your wife?

[Flyingw]

No it was for a fellow 3wheeler hottie. She brought it to me and said "Just make it run". Well, I did that in a long about way. My wife doesn't ride. Not her thing but that's ok..

[oscarmayer]

LOL I get he feeling your wife is gonna be jealous now. ;)
that hottie single? LOL I sound like an Inet perv.
that's what happens when you get separated. LOL

[Flyingw]

Naw, its all good. The hottie is married and we ride together.

[onformula1]

Very nice, is that a 1983-84 Honda 250r aftermarket desert tank?

[Flyingw]

no its an aftermarket 185/200 plastic tank. Kinda funky I agree but its better than a steel one.

[tri again]

Thanks for the help guys. The trike is complete and back home. It busted off on the second pull. It turned out great and runs like a champ so now its on to Keith's Tecate stuff.

You're my (our) hero.
#1 is happy wife.

#2 is happy wife.
# 3 is, you guessed, a happy wife.

[oscarmayer]

That is awesome man. Glad things work out. It looks really good and she is is lucky to have you as a friend. Hottie's hubby is lucky to have a girl like her who rides and is a hottie. ;).

My next girl requirements.
1- ride quads, trikes or bikes

Hahaha I wish right!


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[wonderboy]

Hey FlyingW!

Humor me for just a minute... then tell me if I'm full of it.

I don't think it matters if it goes in lobes up or down (180 degrees out).

Here is why: The crank goes around twice for every one time of the cam. Reducing this a bit, one turn of the crank gives you 1/2 rev of the cam. So, if the piston is at TDC and the cam is installed lobes up, just turn the crank 1 full rev back to TDC and the cam is now lobes down. You are exactly where you would be if you installed it lobes down in the first place.

I think this is why the manual doesn't specify. I don't think it matters.

Let me know if I'm full of it or if I neglected something important...

:)

[The_Steve_Man]

Is that Lisa's new ride?

[oscarmayer]

Wonder boy. It matters. Where is why. If the cam is 180 out it could cause piston to valve contact. It would also not let the firing operate correctly causing it to try to fire on the exhaust stroke instead of intake. Timing makes or breaks a motor. It is extremely critical. I have seen a 50k race motor destroyed when attempted first start over being 1 tooth off on a belt.




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[Flyingw]

I agree, it does matter because if I were to install the CAM with the lobes up, I think I would have a difficult time even getting the CAM in because of the rocker arms. The rocker arms would need to be unloaded to adjust the valves. The same applies to any overhead CAM engine when setting it up for time and valve adjustment. What Shortline told me was correct. CAM lobes down, timing mark on the CAM sprocket up at 12 oclock, crank at TDC with the keyway up at 12 oclock. I think why the book doesn't say that specifically is the fact that the manuals were written for seasoned mechanics and there are assumptions in the books like CAM position. If Honda wrote the books for dummy mechanics like me then each step would be spelled out.

[Flyingw]

Yes Steve, that is Lisa's camp ground/river cruiser. She did have an issue with the pull start rope breaking when she got it home. That was a rope I got from my neighbor for his snow mobile because the delivery date for the rope I ordered was over a week out so I put that rope in and wouldn't you know, the next day the rope I ordered showed up. No big, I went out to Weatherford yesterday and put a brand new rope in while Lee and Lisa were at work.

[jb2wheels]

I'm with you - we can't put a cam in a 4 stroke "180 out" 0 = 180 = 360 ...

If the cam is "180 out" - for example pointing up when the crank is up but you want the cam to point down when the crank is up, leave everything connected and spin the crank around once and the cam will be spot on. I promise. With no engine damage.

With the crank at 0, the cam is either going to be at it's starting point or 180 degrees away from it's starting point. As long as ignition spark event is driven off the cam, you're golden.
And in a lot of causes, 4 strokes fire on both the "squeeze" and "blow" stroke just because it's easier to crank trigger the firing event. Wasted spark.

You can put a distributor in 180 out. Too easily I might add...

You can put a cam in anything from 1 to 179 or 181 to 359 degrees off and maybe ruin an engine depending on how far off it is, but a cam can't be 180 out.

Like Jim says, in this case, it sounds best to put the cam in lobes down for installation and initial valve adjustment. That's different.



Hey FlyingW!

Humor me for just a minute... then tell me if I'm full of it.

I don't think it matters if it goes in lobes up or down (180 degrees out).

Here is why: The crank goes around twice for every one time of the cam. Reducing this a bit, one turn of the crank gives you 1/2 rev of the cam. So, if the piston is at TDC and the cam is installed lobes up, just turn the crank 1 full rev back to TDC and the cam is now lobes down. You are exactly where you would be if you installed it lobes down in the first place.

I think this is why the manual doesn't specify. I don't think it matters.

Let me know if I'm full of it or if I neglected something important...

:)

[The_Steve_Man]

Jim your one hell of a guy!

[Flyingw]

Thanks Steve but Lisa asked and I needed something to do so it worked out.

[wonderboy]

Ok, so the rocker arms are in the way preventing you from installing lobes up. That is the gotcha detail I didn't know about. However, the cam timing will be perfectly correct if you were able to install it the other way around.

There is a lot of misconception about timing the cam to the crank. With the cam out of the picture, the bottom end has no idea if it is at top dead center of the compression stroke or TDC of the exhaust stroke. The cam decides when these events happen as well as ignition. There are two valid orientations of the cam 180 degrees apart (installation difficulties aside) with the piston at TDC.

At any rate, installation procedures dictate lobes down, so there is no arguing that. However, on other machines where the rocker arms are installed after the cam it wouldn't matter.

[Keith Salyer]

Lol, I second that, Jim is one hellova guy with mad wrenching skills. Also sort of godlike being able to resurrect the dead like he does.

[Flyingw]

Its more like.... I have issues.... and I'm only hearing 37 voices these days instead of the 64 I heard last week.