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Hello all

Help please

Can anyone advise please?

Just got a 1991 750 fm model (single sided swinging arm).    Very original and just 27k miles with some history

The bike runs but cuts out after a few minutes and then takes an age to Re start

I have heard that regulators can be a problem as can fuel pump.   Any suggestions would
Be much appreciated 

Also.    The bike has original exhaust system but the collector box is blowing.     Does anyone have a spare to buy please?    Or is there anything else I could adapt?   Thanks

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Sounds like some form of thermal issue - dies when the engine warms up?

 

Does the bike cut out instantly or does it cough splutter then dies? This could separate a fuel/carby issue from ignition/electrical fault!

 

If you are able to crank the bike over at good speed then your battery is probably ok. Get your engine running and measure your battery voltage to determine the status of your charging system.

 

There are a number of issues that could cause your fault, faulty kill switch, Ignition module, sidestand switch, neutral switch, fuel pump, ignition switch, poor wiring connection somewhere, just to name a few!

 

Have a good look at the Starter Relay 4P connector the relay also houses your Main 30amp Fuse, the connector and fuse can suffer from high resistance contact and heat stress. Have a close look at the state of the main fuse leg connections and the connections for the Red/White and Red wires at the Starter Relay.

 

Check the Ignition Pulse Generator coils they can become intermittent with heat.

 

Try running the bike in your garage, try and identify what fails when the bike cuts out. Flex your wiring harness, make sure your fuel pump is working or not, check out the state of your Sidestand switch, neutral switch, kill switch and their wiring. Flex the wiring to your Ignition Control Module does this induce the fault? Check ignition switch and its wiring.

 

Do you have the Service Manual? You can download it from the forum.

 

Need more feedback on your issue. I've never owned a non fuel injected VFR so just firing off a few ideas for you.

 

Good Luck.

 

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There's 2 potential areas that may be causing this: fuel & ignition. Through series of tests which we'll walk you through, we'll narrow down what is at fault.

 

 

Is it consistent amount of time from when you start it to when it dies? 2-min & 31-sec? 5-min & 17-sec?

If you let bike sit for 10-15 minutes after it cuts out, does it start up just fine again?

 

Do you have voltmeter?
Do you have vacuum-gauge/pump?

 

Electrite-Digital-Multimeter-6317236_2.jpg.02c21a1a82c6ee9e3b5386697c8ce406.jpgkartel-manual-hand-vacuum-pump-with-vacuum-gauge.jpg.21218bb0b9c75e9d579edc5e452a5ca0.jpg

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