Skorpion Tour engine rattle

[sandberg]

Oh, by the way, if any of you find yourself in the Atlanta area you are welcome to come on by and take the bike for a spin.

[hb7]

It makes the noise at ~3000-4000 rpm...
Only under load ? or can you rev it and hear it in neutral ?

Take a cassette player with a built in mic and tape it to the bike near the motor (like the space betwen the starter and the carbs) use newspaper for heat insulation. 2 minutes of
recording is enough...

Import audio with your computer and compress into an mp3...

[sandberg]

The noise is only under acceleration/load. Nothing at any other time. Bike rides nicely otherwise.

Do you still have a tape recorder? I only have a digital camera that can collect sound as an MPEG. Not sure if I want to tie that one down there or not. Maybe duct tape?

[hb7]

Mpeg will work with audio....I would offer to help, but I'm in California.

Wrap it up and tape it down for 5 minutes or less....if the noise is only under load, maybe it's a transmission issue like a chipped gear....

[Bill Jurgenson]

The noise is only under acceleration/load.

Why didn't you say that to start with?
Seems pretty obvious that the gears are pitted.

Another case of what I have been talking about:
low rev "thumper-style" riding on this (or any other) modern single.

It ist getting tiring: the xtz engined bikes (MZ, SZR, xtz, Aprilia) are not thumpers and cannot bear such treatment.

Due to the abnormally large jump from 1st to 2nd in the xtz cluster (unlike the much better szr cluster) 2nd gear gets too much load at low rpm.
You have to either winds out 1st far enuf for 2nd to be above 3500 when shifted or be VERY ginger with the right hand, a daunting proposition with the stock CV carb, if not to say virtually impossible.
see many back postings.

[whysub01]

My Skorpion had a similar ratlle-like the engine was pinking badly under load, but not at all times nor in all gears. It was really worrying for a while, as I thought it was going to seize at any moment. I spent hours resetting the carb, checking the valves, checking oil level and the oil pump, etc.

Turned out to be nothing more than the rubber chain guide on top of the swing arm had worn through in a couple of places (hardly noticeble at first glance) , and the chain was slapping on top of the swing arm, hence the metallic "pinking" sound.

A new rubber and the bike was perfectly quiet again. Worth a try.

[sandberg]

I have checked all the possible engine problems and could not find anything. Then I looked at the chain area and you might be right. The rubber is worn through and the chain needs adjusting. So now I will order a rubber chain protector from Bikeworx and adjust the chain. I will let you know if that was the cure.

By the way, how many miles do you get from a chain on a Skorpion model. I have just over 12k miles on mine. When you replace it, do you get an open chain with a removable link or is it an endless chain? My other bike is a BMW twin which explains my ignorance.

[hb7]

21k on the CZ OE chain....with a chain oiler.
Rivet link is the OE way.

[Bill Jurgenson]

for the Skorpion, OEM is an endless chain and that is nonsense!!
Rivet link is fine IF you have the tool for your particular chain.
I use a clip link on most of my stuff and a rivet link on my street Skorpion, but I have the DID tool. I use only DID chains...

b

[keithcross]

Like Bill, I use a spring clip type link on my Baggi which is used in all types of conditions, from summer roads to green lanes, in summer and winter (in the UK we use olts of road salt in winter ).
I have used all types of chain (the Baggi has 65000+kms) and find most wear out at about 10-12000 kms. Maybe the Baggi is harder on chains than the road models as it has a lot more suspension movement and therefore slack in the chain (MZ recommend 75mm slack on the side stand).
I also use a scott oiler. The original chain lasted 7500kms before it snapped (doing a wheelie, so fair enough I suppose).
Still the bike is still a brilliant bike to ride, although I have now retired it from day to day use.
I now use an Aprillia Pegaso Strada for my daily commute. Even though this bike has a similar engiine to the MZ (as fitted to Yamaha's XT660X, XT660R and MT03 models) the bike isnt as nice to ride in many ways.
Main differences when riding the 2 bikes,apart from teh obvious ones due to riding position are
The MZ certainly handles better in the turns.
The Aprilia has a freeer revving motor (pick up through the revs seems a lot quicker).
The Aprilia has fuel injection. This system seems to give a snatchier ride, with some dead spots. This is apperently a known problem on both Yamaha and Aprilia forums.
The Aprilia has a better front brake, although I intend to upgrade the MZ's one day.

Keith
When riding for pleasure the MZ is a lot nicer bike to ride.

[hb7]

I just lost my first chain clip on the MZ.....fortunately I regularly check to see that it is there, and there it was gone. I have 12.5k miles on that XSO RK chain. Safety wire doesn't last, and I haven't tried the blue silicone on the clip from the F650 chain gang boards. Losing a clip is very bad....

I think rivet links are now the only way to go....

[sandberg]

Well I finally got around to replacing the chain guard and adjusting the chain and IT IS FIXED! Thanks to Whysub01 for his insight to this problem. I almost thought about selling the bike out of fear the engine had a serious problem. Funny that the noise only occured sometimes around the 3-4 k rpm in 3rd and 4th gears. Anyway I am happy again that I don't have to tear the engine apart.

Now, next question. I noticed that my tachometer is getting a little erratic. I thought that electronic tachs were free from problems like that. Any ideas?

[basser23]

Good you have that sorted..I had the same problem..
Tachs on these bikes always are a bit erratic...at least mine is too..
I am now considering an electronic unit from Acewell to replace all
the insturments. look up "Electrosport " on the web if you are in the US.
or Acewell instruments...
Chip

[DAVID THOMPSON]

the tach on my rt125 is also sick..
when you first start the bike it does not work ..after about 2 to 5 min
it starts working . i live in a very humid river valley.

the heat from dial lamp drys it out then it works

[keithcross]

Good you have that sorted..I had the same problem..
Tachs on these bikes always are a bit erratic...at least mine is too..
I am now considering an electronic unit from Acewell to replace all
the insturments. look up "Electrosport " on the web if you are in the US.
or Acewell instruments...
Chip

I have one of these fitted and it works real well. The revcounter cable can be connected directly to the ECU unit, one of the connections is marked for this (tach I think).
It is also possible to fit the tempreture sender. To the left/rear/bottom of the cylinder there is a lug on the cylinder that is tapped M6. This can be re-tapped in the size required fo the sender unit supplied.
A picture of the unit is here.
http://www.mzriders.com/mz/album_pic.php?pic_id=193
The second unit was fitted as a stop gap between the Acewell unit and the standard speedo to keep a record of milage etc.

Keith