Won't Start at all...

qferret · Posted: May 27, 2006, 3:34 pm Post subject: Won't Start at all...

Hey folks,

Been a couple of forevers since I've posted. (Live in Minnesota, garage not heated) LOL

Still fighting with getting my XS 650 running decent.

The "passenger" side (I can never remember if it's right while eyou're sitting on it, or left while you're looking at it from the front) still "drifts" 3/4 inch or so on the timing mark. The other side is perfect. I have installed a Boyer-Brandsen ignition with no difference. I would assume the problem lies in the valve train? (as there is only one "coil" now...parallel pistons...etc)

I'm heading back out to the garage now to putz around with it, but any advice would be appreciated. I'm almost to the point of moving it to the back of the garage for a few years and buying one that runs. (Don't tell my wife) LOL

qferret · Posted: May 28, 2006, 5:37 pm Post subject: Re: Won't Start at all...

OK....

I pulled the exhaust pipes to be sure one wasn't clogged with carbon and causing me grief. Still nothing.

I sprayed a bit of ether in the exhaust ports and cranked it over. Twisted Evil

The side that seems to be giving me the timing troubles started on fire Shocked

After blowing the flame out (wasn't an inferno or anything) I did it again to be sure it was JUST that side that popped a flame. Same result.

Am I sucking in through the exhaust and out through the intake on that side?
If so, how the heck is that possible for ONE piston on a parallel 2 cylinder? Question

Going to dig out the feeler gauges again, though I adjusted the valve lash last time I put it back together...

I'm hoping if I keep posting progress (or the lack thereof), I'll eventually post something that will cause someone to say "Look idiot, if it did that, you obviously need to...yada yada yada" LOL

qferret · Posted: May 29, 2006, 10:51 am Post subject: Re: Won't Start at all...

grrr...intake valve on that side is stuck open. That explains the exhaust side flame,but would that mess with the timing too?

Will post any new results after getting the valve unstuck.

qferret · Posted: May 29, 2006, 4:06 pm Post subject: Re: Won't Start at all...

wth?

The instructions I have for adjusting valve clearance say to go to tdc after the intake valve opens, then closes.

I can adjust the exhaust valve clearance (.15 mm) but to adjust the intake on either cylinder to factory specs (.06 mm) I have to screw the adjuster down so far that the locknut doesn't even thread all the way on. Also, when I adjust it like that, the intake binds when I start to turn it over...

Am I drinking too much beer while I'm working on it, following BS instructions, or looking at getting a new cam?

I'd swear it looked OK last time I adjusted in this way, but now I wonder...did I get sidetracked after checking the exhaust side?
(It has been 6 months since I played around with it) Wink

Also, on a parallel twin, are both cylinders on the same cycle at the same time?

grizld1 · Posted: May 29, 2006, 6:02 pm Post subject: Re: Won't Start at all...

The Yam 650 is a 360 degree parallel twin, meaning that the pistons travel together and fire alternately (while one's on the power stroke, the other's on the intake stroke). To achieve this, the cam lobes for the two cylinders are positioned 180 apart on the camshaft, and the shaft turns at 1/2 crank speed.

It sounds as though you have internal issues in the valve train. I just got through degreeing a new Shell cam; like many performance cams, that one's checked (not run!) with all valve lash removed. My valves, adjustors and rockers are stock. There was no problem with the adjustors or with binding, even run down that close.

grizld1 · Posted: May 29, 2006, 6:02 pm Post subject: Re: Won't Start at all...

Oops! entered this twice somehow, and can only edit; can't get the delete button.

qferret · Posted: May 29, 2006, 7:17 pm Post subject: Re: Won't Start at all...

OK, so just to recap & be sure I'm doing it right:

1.Intake valve goes down.
2. Intake valve comes up.
3. Engine gets to tdc.
4. set clearance on both intake and exhaust on that side.
5. repeat for other cylinder.

Static timing:

groove on top, dot to the rear while pistons are at tdc

When the valve "binds", I think the spring is fully compressed. Assuming the above directions are correct, what could possibly be the issue. (Besides the springs & valves being too short)

btw...thanks for the help grizld1...glad to see you're still here. Wink

kingwj · Posted: May 30, 2006, 6:45 am Post subject: Re: Won't Start at all...

I always use exhaust valve closing, intake valve beginning to open (overlap) adjust the other cylinder. That way you know the opposite cylinder is on the root of the cam.

grizld1 · Posted: May 30, 2006, 7:26 am Post subject: Re: Won't Start at all...

You're correct on cam installation; but be sure the groove is aligned exactly with a line through the camshaft and crankshaft centers with the slack out of the front run of the cam chain: in the 447 engines the cam sprocket has 36 teeth and turns at 1/2 crank speed; (360/36)x2=20 degrees of crank rotation per tooth. Cam timing error won't cause the valve lash and binding problems you're describing, however. I'd suspect valve damage; you say one intake's stuck open, and of course that could produce exactly the adjustment and binding issue you're describing; valve stem doesn't rise all the way, tappet's run way down to meet it, bind occurs; but you say the intake adjustors do the same thing on both sides. Sometimes it's best just to get in there and have a look.

Wulf · Posted: June 1, 2006, 6:14 pm Post subject: Re: Won't Start at all...

You may have a bent valve or excessivly worn valve guide causing the valve to bind. Just something to think about.
Wulf

qferret · Posted: June 1, 2006, 6:27 pm Post subject: Re: Won't Start at all...

I've got a few things to take care of before I can hit the garage, but I'll post pictures later.....worth 1,000 words (would probably be 20 words if I knew what I was talking about) Wink

qferret · Posted: June 1, 2006, 7:58 pm Post subject: Re: Won't Start at all...

I followed kingwj's advice on how to set up the motor in preparation. No difference.

The picture is a little tough to see the gap, but if you magnify it, the black space is about the right width. The valve is fully closed, and if I tighten the adjuster down, the valve isn't binding, the spring is getting fully compressed preventing the camshaft from going further. (by hand of course)

The ONLY thing I can think of is that the intake rockers are on the flat spots on the sides of the cam lobes when the pistons are at tdc. the rotor mark is actually tdc, I checked with the screwdriver in the plug hole trick. I'm going to "play" with the static timing position a bit & see what I can come up with. It's entirely possible that its 1 tooth off or something. (the motor is currently tilted, making it tough to judge)

Thanks all for the advice so far, any more is still appreciated.

btw, if any of you haven't been there, 650wiki.org has a nice start on documentation. (The LED ideas are good). I'm hoping to have something worth contributing at some point.

grizld1 · Posted: June 2, 2006, 9:03 pm Post subject: Re: Won't Start at all...

When you check cam timing, try jamming a piece of tapered dowel (I use piece of a bamboo barbeque skewer) into the hole in the ignition side of the crank shaft, and tie a piece of cord, fishing line, etc. to it. Pull the line taut, line it up with the camshaft center, and sight the cam groove with it. Be sure the cam chain adjustor's tensioned; that takes the slack out of the front run of the chain.

kingwj · Posted: June 3, 2006, 8:58 am Post subject: Re: Won't Start at all...

Are you sure the valve is bottoming out? The cam lift, rocker ratio, valve spring length are such that it should be difficult if not impossible to bottom the valve. I would wager you are off on your cam timing and the valve is touching the piston.

qferret · Posted: June 3, 2006, 9:32 am Post subject: Re: Won't Start at all...

Unbelievable.....

Both intake valves are slightly bent. This project is turning into a nightmare, b ut you get what you pay for & I got 2 bikes for $0 LOL

I'll post back after fixing this issue, although I'm sure the timing drift will still be there.

grizld1 · Posted: June 3, 2006, 7:09 pm Post subject: Re: Won't Start at all...

Nightmare? Nah, just par for the course. Bikes don't come free-to-cheap unless Og the Cavewrench has screwed 'em up first. Erratic valve action could very well cause erratic ignition--sometimes the fuel charge is there more-or-less on time, sometimes not? Your electronic ignition won't work right on one side and squirrely on the other--it hits every 360 or not, regardless. Bad cam or crank bearings would cause the same wandering on both cylinders. You might want to make sure that right-side connecting rod's in good shape while you're in there, with no up-and-down slop at the big or small end.

qferret · Posted: June 4, 2006, 3:17 pm Post subject: Re: Won't Start at all...

Progress!!

I pulled the intake valves out of the other motor I have. They operate freely now. (The valve guides in that head are shot, or I'd have just switched heads)

If I use ether, the bike sputters a bit but never quite catches. According to my 9 year old, the timing marks line up on both cylinders now. (starter slips again, so I can't check it myself) I rebuilt the carbs and set the needles at the starting point, I may try playing with those a bit to see if I can get it to catch & run.

qferret · Posted: June 4, 2006, 4:25 pm Post subject: Re: Won't Start at all...

OK... still won't start, but....

I disconnect all of the unecessary wires and hook up jumper cables, it comes damn close.

About the only electrical pieces that haven't been swapped are the rectifier and regulator. Any guesses?

grizld1 · Posted: June 4, 2006, 8:26 pm Post subject: Re: Won't Start at all...

No guesses on electrical parts--that gets expensive! First off, with an electronic iggy you need plug caps with a minimum 5K Ohm resistors. Check what you have with a multitester. Next, which Boyer do you have--the new style with the itty-bitty 0.6 Ohm proprietary coil (Micro Power) or the old style Micro Digital? If it's the Micro Digital, you need a coil with primary impedance of 4.5 to 5 Ohms to work well.

The Boyer needs quite a bit of power to run well. You might want to double-check connectors and make sure they're clean and tight. I always cut the Boyer crimp-fit connectors off and solder on my own. As far as checking the charging system goes, follow the book. There aren't any short-cuts. If you're using an analogue multitester, be sure it's one that has a lowest Ohm scale no higher than RX10.

kingwj · Posted: June 4, 2006, 9:47 pm Post subject: Re: Won't Start at all...

did you check compression after the head work? just curious, did the valves touch the pistons? Any theories on why they were bent? that is not natural.

qferret · Posted: June 6, 2006, 8:32 am Post subject: Re: Won't Start at all...

No clue why they were bent. I'd have to ask "Og" Wink

At any rate, the "engine" issues seem to be cleared up now. Thanks all for reading my ramblings.

Now I'll start chasing electrical gremlins (Not sure I want to start that on 6.6.06 though) LOL

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