Got a mate, with a few problems with his bike and wondering if anyone can help me, to help him

My Montesa 4RT will start but won't run.

Once started it runs for only a couple of seconds then stops.

It will re-start but same thing again.

Bike has recently had a brand new stator, new throttle body and condenser.

I've tried new plug, all connections etc.

Anyone ever had this before or suggest what to check next.

Thanks

Edited April 11, 20179 yr by johnnyboxer

Only when the s/arm had rubbed through the loom behind the engine.

bad earth?

He's checked the loom and earth, but will do it all again

How about the bank angle sensor?

Dodgy connection to the plug cap

Edited April 11, 20179 yr by jrsunt

How did it all start originally

sounds like we are starting halfway through the story 

the more Info the better .

can he swap the tank and fuel pump?

was it a new throttle body with the ECU or a second hand one?..... I had starting problems that were compounded by fitting a duff used throttle body in the belief that it was good.

If you have the old condenser, strip back the wiring and check that you don't have 'black wire' corrosion in the wires. If you do, check the loom side wiring as the corrosion will travel up into the loom and you wont get the a good voltage into the loom from the condenser. If there is corrosion the two wires are approx. 10" long from the plug before they join into the loom via 'crimp' connectors. The loom will come out with removing the throttle body , tank and airbox. This should allow you to remove it with a bit of fiddling and its easier to remover the fan relay with the loom rather than try and disconnect it on the bike.

Try connecting a 12v battery directly to the pump in order to power it up independent of the bike condenser/voltage system. If the bike runs I would suggest you have a bad connection/corrosion on the loom side of the condenser electrical plug, a bad connection on the fuel pump connector or as in my case also a duff ecu. 

With the fuel pump disconnected,  connect a voltage meter to the loom side of the fuel pump black 2pin connector and kick it over, the first kick should show approx. 9v then 12.5v plus on the second kick. The voltage increases as the condenser (which is just a capacitor/battery) charges and discharges into the electrical system. If its lower than this I would suspect corrosion/bad connection on the condenser connector/loom wires.

Apart from the earth on the coil, all other earth wires are fed into a common yellow block under the tank just behind the head stock. If you unclip the top of the plug you can lift out the connector rail for all the earth connectors and check for corrosion.

 

good luck

Plenty of good info in the post above. As jr sunt said eliminate the bank sensor, if its not the cause now it will play up down the line ( well all 4 of mine have) so may as well do it whilst your searching for the problem.  Good luck.

to link out the bank angle sensor link the two outside connectors on the loom side plug.....if you just remove it the bike wont start !

I had a fueling issue with my 09, it would sputter a couple of times but never run much as you described in the origninal post.  What I ended up finding was that the metal sump under the fuel pump had corroded and plugged the fuel filter and damaged the fuel pump.  I was able to swap out the tank and injector from a new bike and mine fired up right away so I then knew where to look.....

Thanks, all great info 

He can read the thread (he can't log in to TC, but I'll get him to contact Andy to reset his username tonight) and will reply later

It seemed to start with the bike (bought used, but hardly used) which had a PTB fitted and when fitted with the stock TB it resolved it but has now returned to being problematic

Fuel pump seems to be worth a look 

Often the simple things can cause issues like this.  

Have you turned in the tick over (idle) adjustment screw? the 4RT is suppose to idle at around 1800 to 1900 RPM's and the first thing you should check if it starts but doesn't stay running is that setting.  much lower than around 1700 and they will just stop running like you described.  And a brand new throttle body will often need this setting adjusted different than how it came.

Best of luck. 

Edited April 12, 20179 yr by jonnyc21

Glad you can logon to this thread

Some time ago there was  a thread running about throttle bodies going past   The lock stop, which was fixed by a simple washer. Perhaps you're unlucky enough to have broken 2.  

 

Hi JR. the TB appears to be opening and closing ok ! Is there any other way of checking the lock stop that you mentioned ? Thanks. 

I don't know, I've had a quick search but can't find it. I'll try again