MZ/MuZ Riders

basser23 wrote:I've been watching this thread for awhile now and I HAVE seen a plug test good out of the cylinder,and not fire with compression! Stupid question...has the plug been changed for a known good one?

Yes and no ... the new copper plug produced much less impressive spark ... I still tried it a few times ... then the old iridium plug is in it now ...
I also ran the plugs out of the GS500 last year, the GS runs good with those plugs.

Cool.
Srinath.

Does the press on type compression tester fit the skorp ... I am not getting a good seal ... or its got 0 compression ... no its squelching air around my hands and not into the tester ...
Cool.
Srinath.

Screw in type as far as I know is the most accurate...if you've got no compression,no start....or even low compression nostart.....we know this....

basser23 wrote:Screw in type as far as I know is the most accurate...if you've got no compression,no start....or even low compression nostart.....we know this....

i would guess if you put the plug back in and put your finger over the engine breather hole and crank the engine , if the pistons leaking you will feel it through the engine to the breather as built up back pressure,,

It acually sucks my hand if I keep it over the intake ...
I have ordered the screw on adapter ...

Cool.
Srinath.

I think you're wasting your time with a compression tester, these engines have an auto decompressor so you won't get a reading.

Make sure your valve clearances are bang on. Tight valves (with little or no clearance) will become even tighter as the engine warms up.

Try removing the drain screw from the side of the left hand carb float bowl to drain it, then turn on the fuel tap and check that you've got a good flow.

My Baggy was a bitch to start after it's been stood for a few days as the fuel in the float bowl goes stale quickly, I now turn the fuel tap off and let the bike run till it cuts out so the carbs are dry before I park it up for any length of time.

Not sure if it could cause the problem you have but the voltage regulators have a spotty reputation if memory serves me correctly.

Chalks wrote:I think you're wasting your time with a compression tester, these engines have an auto decompressor so you won't get a reading.

Make sure your valve clearances are bang on. Tight valves (with little or no clearance) will become even tighter as the engine warms up.

Try removing the drain screw from the side of the left hand carb float bowl to drain it, then turn on the fuel tap and check that you've got a good flow.

My Baggy was a bitch to start after it's been stood for a few days as the fuel in the float bowl goes stale quickly, I now turn the fuel tap off and let the bike run till it cuts out so the carbs are dry before I park it up for any length of time.

Its stood forever ... cos the bloody thing isn't starting ... But it has fresh fuel, I keep emptying the tank etc and then put the fuel if its more than a week or so old, I put it in my car.

Where is the auto decompressor ... I didn't know that ...
The timing has to be off then, the auto decompressor makes compression irrelevant essentially.
Cool.
Srinath.

How does the decompressor work in this thing ?
OIl pressure ?
Electric ?
Cable ???

Cool.
Srinath.

The fuel in the float bowl goes stale quickly not the fuel in the tank.

Try this for how the decompressor works:

http://www.youtube.com/watch?v=vU0QPhhpJ-E

http://www.youtube.com/watch?v=-oiGt3d9j7A - 600 Yam

OK So with the decompressor if I get say 60-70 psi Its about the best it can show - is that about right ?
I am thinking 1/2 the possible best ... and 120 I am guessing is the best ...

OK other than that, I need to exactly time the spark - I will get into the rotor in a few days and make sure its not "walked".

Cool.
Srinath.

Ok, What happened ?
Just wondered, What ever happened with your 660 ?

I have to get back to it ... hopefully in a week or so. Too much other projects etc.
Cool.
Srinath.

Swapped parts from the running skorpion. Igntion coil, carbs, ignitor box, the next thing to try is the left side crank sensor or maybe I'll swap the whole cover across.
Lets see, I am at my wits end.
Cool.
Srinath.

Srinath wrote:OK So with the decompressor if I get say 60-70 psi Its about the best it can show - is that about right ?
I am thinking 1/2 the possible best ... and 120 I am guessing is the best ...

OK other than that, I need to exactly time the spark - I will get into the rotor in a few days and make sure its not "walked".

Cool.
Srinath.

I don't think you can make any assumptions about how much compression to expect with an operational decompressor.

The flywheel cannot "walk" as far as I know, unless someone installed it without the key or the key broke. It is almost impossible to get off without the right tool once installed correctly since the shaft and flywheel are tapered, so slippage wouldn't be expected without a major fail of an install.