bike cutting out

[robert mack]

hi

had the bike cut out on me today 4 times!. as soon as i stopped and hit the starter button she started no problem.

theres no rattling or anything like that. it was as if i had hit the kill switch. it just died. still had electrics but now my main beam flasher button has stopped working.

anyone got any thoughts?

[DAVID THOMPSON]

one of my things to check is relay 19
it is on most newer mz bikes and controls power to most every thing
put the words relay relay in the search box above right with no space between them
and then click on Jump to post lower right of page
and read about it
dave

this relay has a green wire going to it grounding the lug at the green wire bypasses all the safety cutouts
like sidestand and kill button on the handle bar and my even make bike still run with the key off ??
have been busy of late and still on a learning curve of all things about this relay
the one thing i do know is it has been the source of most of my electrical problems on my rt125
connect red/black to red/white at the relay will bypass the relay but you will probably have to take out the jumper to kill the bike and again no safety cutouts

[robert mack]

hi david

thats for the reply, found the relay and have a new one coming tomorrow. better to be safe than sorry.

[DAVID THOMPSON]

LET US ALL KNOW IF THIS FIXES THE PROBLEM
dave

[robert mack]

hmmmm fitted new relay.

engine does not sound ok with new relay, at idle speed the brake light does not come on when you pull the front??. will be taking her out tonite so will keep you updated.

[robert mack]

update

went out on bike for fuel, got there ok however, cut out twice on the way home so im stumped!!!.

changed the relay, spark and oil and still dying on me. just realised that it only started cutting out after i changed the headlight bulb. it had a 35w candle bulb but i changed it to the factory 65w halogen.

[DAVID THOMPSON]

did i see you mention checking fuel for dirt or water some where in there
dave

[robert mack]

check filter, cleaned carb.
anything over 7 1/2k revs and it cuts out

[DAVID THOMPSON]

if it is a 660 that may be rev limit of your cdi box
i have had a bunch of bikes and my rt125 is the only thing i have had that will sing
a song at 10,000 rpm couple hondas went that high but in a short while the piston tops
made love to the head
dave

[robert mack]

ita an rt125 david.as soon as its warmed up, no matter what gear im in, as soon as it hits 7 1/2k the engine cuts out.
think i will need to put it into a garage

[DAVID THOMPSON]

try a new plug and clean that fuel system again including the tank and shut off valve screen
i got a load of bad gas on a trip and had to haul the bike home about 50 miles
and it took 3 carb and tank cleans before it ran right
what a pain

also check the area around the air intake under the seat it is not a shop rag storage area
that thing needs air and anything in the area slows down the flow
dave

[robert mack]

hi david

tried all your suggestions and still the same.i think i need to write to mz themselves(if they are still running) and ask them.
it must be some sort of trip/kill switch in the engine thats been triggered.

all the best

robert

[djsbriscoe]

Hi,
Have you considered that it might have a restricted CDI box fitted as described in this page from the workshop manual

[img]

80kmVariant.jpg

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If so, the cdi box would be listed in the parts book and on Grahams website so that you can confirm if it is or isn't the standard box.

David.

[robert mack]

hi mate

its not a restricted one im afraid. i phoned the scottish mz dealer and spoke to him, totally stripped the carb and i mean totally lol so im off to put it back together and see if that helps.

all the best

robert

[DAVID THOMPSON]

the things you say its doing seem to me to be what mine always did
its starving for gas that will burn or air to burn it with and the saxon tour did same with a pinched or kinked fuel line ..it just stopped revving at 4200 udm /rpm
dave