660 Scorpion misfiring above 3000RPM

[Kraut]

Hi there,

I am new to the board and to MZ and have already a problem: This 2001 Scorpion Traveller has only 4500 miles on the clock and is very clean. However, shortly after purchasing the bike, it began to misfire and bog above 3000RPM. I checked the carb., fuel and supply, spark plug (which seemed fouled so I replaced it). No success. I then checked your forum and found that there might be some issues with the harness, connectors or ignition module. I am at a point where I checked most components and like to try a new ignition module. I just can't seem to locate a module here in the US and the Yamaha dealers a helpless. The part number is 4MY-82305-00, orange lable, big J, also has the number 131800-6150 on it.
Any hints to find a new unit or what Yamaha part number could cross-over are appreciated.

Thank you,

Marc

[Skorpion660]

This may help there's a hidden filter, note cautions about removing pin etc.

http://www.mzriders.com/viewtopic.php?f=3&t=4705&p=24870&hilit=carb+filter+hidden#p24870

[Kraut]

When I had the carb. remove, I did check the "hidden" filter screen and cleaned it as well. I just replaced the main relay per David's suggestion and came back from a road test with the same result
It amost seems that the rev-limiter sets in too early in times and intermittenly.

Marc

[Anders]

Have you tried to eliminate the sidestand switch?

[billr]

I ran into similar issues with my Traveller. Running along just fine and suddenly drop in power and surging.
Strong spark, new plug, went through the carbs (I'm one of the "fumble fingers" that managed to break the float support... )...my screen was filthy.
Everything was cleaned up, but it would still cut out and act like it was starving for fuel.
Seemed to run fine with a full tank, but around half full...
Replaced the gas shut-off valve with a new Acerbis part and all is well.
Good luck, hope you find the problem.
Bill R

[Kraut]

Well, spent some time with the 660 today again. By-passed the safety switches by grounding the green wire at the main relay. Same issue of cutting out above 3000RPM up to about 5500RPM. Sprayed the ignition coil and wires with water to see if there is a crack in the isolation. No issue found. The fuel petcock is working fine and delivering plenty of fuel. Unless there is another shut-off valve in the carb., I don't see fuel to be an issue. Are the ignition modules known to go bad? It's hard to test the spark at that high of RPM just riding on the streets. Does anybody know of a good MZ parts source here in the US? I tried Mr.Scooter in CA to get me a P&A on a new module.
Once again here is what I have done so far:
* Drained and filled fuel tank.
* Cleaned carb and filter
* Replaced spark plug
* Removed vacuum system for EVAP
* Replaced main relay

[OLDMTNCARVER]

Marc,

Could it be a ventilation or vacuum line issue?
I've read something about some members have had a problem with the tanks vent line clogging enough to cause the tank to expand in hot temperatures. I'm wondering if this might also cause a fuel flow problem...

Another thought, might it be the emissions canister not venting? Helped a rider with a '91 GSXR 1100 that had tipped over. The canister filled with fuel and not much above idle it would die out... unhooked the canister, all good.

Finally, have read posts that mention a fuel pump, beyond that, some talk of "ditching it".
Search fuel pump, see what you come up with and might it be a bypass the pump solution...

Regards,
Robert

[droy]

Marc,

PM'ed you regarding the ignition module

Doug in NJ

[edfmaniac]

You could also change the setting on the secondary carb delay screw to see if the problem coincides with the opening of that carb. Screw it in to make it open sooner in the throttle curve and out for later.

[Ratbag]

check the coil mount hasnt broken, there are 2 rubber mounted bolts to frame right side under the tank. 1 mount had broken away and it was pulling the small spade connector slightlty, causing my missfire. Now because I live about 12,000 miles from the UK I had to think of some OZ ingenuity to get it going. I used a 6mm piece of reinforced hose(cut to length) as the mount and a slightly longer bolt(and nut) to go through the hose and coil mount. Tightened it all up and no more cutouts!

[DAVID THOMPSON]

spade lugs were loose on my coil once
just a pure accident i spotted it quickly...

i have noticed that the spades on all 3 of my mz bikes seem to not stay tight

in fact i have gone to soldering them on where there connected on the rt125
i remove the spade and just solder them to the connection point
in some places i have used Anderson power pole connectors

direct soldering makes it hard to work on later ..but has brought the its dead and has to be hauled home drill to a stop

dave
power pole picture
i use them to replace connector plugs that have died on bikes and cars
best to solder the wires on the lugs as the wrong crimp tool can mess them up
if soldered they can be taken apart and reused. there not cheap but nothing is cheap any more
if there is a good HAM RADIO STORE in your town they most often stock them
i get mine from this company when they show up at a ham flea market every year
they bring a huge table of all kinds of radio connectors
http://www.pl-259.com/