Kicking Back!

My MkII 850 is kicking back so bad I'm scared to go near it now. I have a strange situation where my rotor has no actual timing marks, someone before me has punched some in, but there's 3 to choose from!? Recently I pulled it out and put a friends rotor in and we set the timing with that in there. We put new plugs in at the same time and I rode it for a month just fine... then a couple of weeks ago it started backfiring and missing on a run, and then ever since it's been kicking back when I'm trying to start it. It did it so bad today I have a decent limp tonight! And I didn't even get it started.

1. Should I just buy a new rotor?

2. Why would it have run fine for a while and then gotten so rough all of a sudden? Can timing go 'out' that quickly?

I don't have a strobe so can't actually check the timing at the moment, but even if I did I'm not sure what the point is given the rotor has all different marks on it.

I'm a bit of an amatuer sorry, but I'm comitted to getting my head around this bike because I fuckin love riding it! Any help very greatly appreciated.

HFOS,

Timing, check with a timing light etc etc, what is happening is the spark is going in too early.

If you want an easy fix, pull the plugs, take off the timing cover, spin the engine, see which way it turns on the end of the cam ( which should be counter clock wise CCW), adjust the timing so the spark goes in a little later, perhaps move the disc 3 or 4 degrees CCW, and try to kick it again.

Points ignition or leccy version. ?

Points - checked that your auto advance isn't stuck advanced. ?

Checked your battery voltage if electronic ignition ?
No 1 thing to check if they suddenly change or start playing up.

Oh yeah sorry, it's electric, a Boyer.

Really the battery? Will check it out. I haven't checked the battery for ages!

Headfullofsnakes said:

1. Should I just buy a new rotor?

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Buy yourself a strobe first. The fact that the rotor has no apparent timing marks is odd, is there a number on the rotor? If the rotor magnetism is still strong then the problem may not be the rotor, as Rohan suggested, the battery would be the first thing to check, also the wiring and connectors to the Boyer pickup and wiring connections to the pickup plate.

Headfullofsnakes said:

I don't have a strobe so can't actually check the timing at the moment, but even if I did I'm not sure what the point is given the rotor has all different marks on it.

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You can't really check a Boyer electronic ignition without a strobe. The correct timing position can be found with a simple degree disc and a piston stop. More info can be given on how to do that that if required.

I'll go buy a strobe I think.

'll go buy a strobe I think.

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Good job, the cheaper the better ( believe it or not )

A strobe will do you no good without a CREDIBLE timing mark on the alternator rotor.

Verify your battery has a proper charge and will hold it.

Borrow your friend's rotor, re-time the bike accurately.

After you're done, rotate the engine till you see the white mark on the ignition rotor perfectly centered in the little CCW window.

(You shoul have a cursory look at both rotors side-by-side, referencing the keyway, to get an idea as to which mark is the correct one)

Swap rotors and verify where the timing pointer in the primary cover is pointing. Make a permanent, recognizable mark in alignment there.

Next time, you can check with your own rotor and be fairly sure of accuracy.

(The rotor is an old model, as used on earlier models that didn't have a timing window)

Headfullofsnakes said:

2. Why would it have run fine for a while and then gotten so rough all of a sudden? Can timing go 'out' that quickly?

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No, but batteries can.

It won't help to try and time the bike if the battery is weak.

First things first.

Good advice coming in here. Yes make sure the battery is up. Yes get your hands on a timing light. You can use a degree wheel to verify the mark on the rotor, or in you case put one on. There is a downloadable, printable degree wheel in the tech section, or you can buy one.

I did not invent this process, but learned it here in this forum. Attach the degree wheel to the end of the crank, at the alternator nut. I actually used the drum sander out of my Dremel tool, and used a bolt through it to expand it out to fit the inside of the alternator nut and thus had a threaded rod to attach my degree wheel. Others have used magnets or whatever other kind of trickery they had on hand to center the wheel on the crank end.

You need a piston stop, I made mine from an old spark plug with a brass bolt sticking through where the porcelain once was. Rounded head down so as not to mark up my piston. It is adjustable by a nut on each side of the spark plug base.

Then rig up a pointer so that as the degree wheel spins on the crank you can see it to index it. Put in your stop, rotate either direction until you GENTLY come up to the stop. Note the reading on the degree wheel. Rotate the other direction until you come up to the stop. Note the reading on the degree wheel. They will not be the same, so you adjust the wheel by half the difference and keep rotating back and forth until you have adjusted your degree wheel on the crank such that it stops at the same number of degrees before and after TDC.

After you have acheived this you can then carefully turn the motor until the degree wheel shows 28 degrees (or whatever is considered correct for the Boyer) BTDC. Don't move anything! You can now put on your primary cover and check to see if there is a mark showing through the port and where it may line up with the timing plate.

This process is often necessary regardless of your rotor as timing plates may or may not be accurate.

Russ

I guess I should clarify that my comments were made ASSUMING (stupid, I know) that the timing was originally correct (he stated it was running great); electronic ignitions do not wander off-time unless the rotor or stator are loose.

grandpaul said:

I guess I should clarify that my comments were made ASSUMING (stupid, I know) that the timing was originally correct (he stated it was running great); electronic ignitions do not wander off-time unless the rotor or stator are loose.

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Or the battery is low?

swooshdave said:

grandpaul said:

I guess I should clarify that my comments were made ASSUMING (stupid, I know) that the timing was originally correct (he stated it was running great); electronic ignitions do not wander off-time unless the rotor or stator are loose.

Click to expand...

Or the battery is low?

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My comment related to confirming the timing mark on the rotor.

I, too, believe the battery is low; I replied to that issue in my first post.

Josh Cox said:

'll go buy a strobe I think.

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Good job, the cheaper the better ( believe it or not )

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No they 'aint, they can't keep up as the revs rise been there done and got the bloody scars.

Cash

I would get one that at least plugs into a battery, you'll get a better light out of it. Then when you get it, you need to get it started to use it, catch-22? Use a separate battery, like your car battery, with it, not the bike battery.

Dave
69S

Ok so I chucked a new battery in and she's going sweet and hasn't kicked back at all yet. So that's good news.

I have discovered my rotor needs to be spaced out more too. It's sitting a too far in on the shaft, so not getting full coverage in the stator (if that makes sense!?).

I'm assuming this might be partly why I was running my battery low???

Partially short rotor interface shouldn't affect charging much. In some cases you can shim rotor and/or stator to get it better without bumping up against the cover.

Get a timing disc and a TDC tool and make your own marks on the rotor and stator. This is a good thing to do anyways as factory timing marks can be a long ways off. Mine are off by 5 degrees! And as other have mentioned you will also need a strobe to do the final timing. Once you find 31 BTDC with the degree wheel, set the static timing via the hole on the Boyer plate lined up with the magnet. This should get you pretty close. Close enough to run for sure. In terms of kicking these bikes over, you cannot hesitate at all or the kickstart lever will get you! You need to really put some weight behind it and kick it through with authority. Otherwise, you will see kickback, even with perfect timing.

tpeever said:

In terms of kicking these bikes over, you cannot hesitate at all or the kickstart lever will get you! You need to really put some weight behind it and kick it through with authority. Otherwise, you will see kickback, even with perfect timing.

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Unless you have a Tri-Spark that is.

I'll repeat, it's not likely that the timing has "wandered off" (unless headfullofsnakes finds the ignition rotor or stator loose); he stated it had been running great before the battery issue.

So, there is no need to re-static time the ignition (especially since he already stated the battery replacement corrected the kickback issue).

Now, if you find it's running as near perfect as you believe it needs to be, (should start up easily, idle well at about 1,000 RPM, and top 100 without too much drama, climbing right up there fairly smoothly with no pinging or knocking), you can slowly rotate the engine using the rear tire with the tranny shifted up to 3rd or 4th gear; turn it 'till the ignition rotor's white dot appears in the CCW timing hole of the ignition stator. Now, re-check where your timing mark is on the alternator rotor in relation to the pointer needle. That is your future timing reference point. Mark it well so as not to confuse it with any other mark.

If you have the inclination to proceed further, do the whole degree wheel process.