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Took my TV175 out last week for a spin and a few miles from home it started to splutter like it was running out of fuel. I quickly switched it over to reserve but it eventually conked out.

I left it a few minutes and I eventually got it started it spluttered a few minutes then ran ok. 100 metres down the road it conked out again. Got it started and got it home.

Thought it might be a dodgy fuel tap. Checked both reserve and on both working fine.

Fuel level in the tank was almost full too.

Started it mid week and took it around the block and was fine, thought it may be dirty fuel or something.

Got ready today and took it for a spin. Again about 10 miles in to the ride, started spluttering again, flipped it over to reserve but still died.

Checked the carb everything looked ok, noticed the fuel in the fuel pipe was bubbling with a big air gap. Switched it over to res,off and on no difference.

Broke down 10 times on the way home same symptoms. Like a fuel starvation.

Got it home and took the carb off thinking it could be a sticky float, but no, everything working fine and clean. Fuel tap is working fine.

Put it all back together again and the revs seem to be racing a bit on tickover but apart from that all good. Took it round the block seems OK. But clutch is now slipping a bit, might be unrelated but not sure.


Any ideas anyone?


It's a sx200 Spanish motor with standard air filter and a 25mm phbl Dellorto.

have you checked the breather in the petrol cap isn't blocked?

No I haven't, I will check.

Kristof Lammy pie wrote:No I haven't, I will check.

My first thoughts too!

Checked the cap, it appears clear. I will replace it though

Has anyone drilled a hole in the cap to make sure it breaths?

If it's still on points ignition it could be the condenser breaking down. It can feel like fuel starvation.
Paul.

No its on 12v

Take the 2nd green (one from loom) off the CDI and see if it makes any difference. An ignition or ignition switch failure will give similar symptoms. Taking off the loom's green bypasses the ignition/kill switch and can cure it, although you will no longer be able to turn the ignition off with the key. Also typical of the LT coil failing on the stator. Could be one of a number of things

Could be the LT coil on the stator. Had a similar problem once. To test it, unplug the connections from the CDI, and connect a multimeter on the ohms scale between the white wire from the stator and a good earth on the frame. The reading should be 0 ohms. Then check between the green wire and the white wire, it should measure a value of about 480ohms. Then to check the pick up, connect the tester between the red wire and the white wire, it should measure an ohms value of about 110ohms. if it is vastly different, report on here.


Paul

Will check the CDI and rectifier check, but just wondering why the fuel would have an airlock and be bubbling?

Have you checked the fuel rate out of the tank/tap ?

Might be worth timing it to see if your getting a slow fill rate.

It's a brand new fast flow tap that works perfectly.

Where do you have the fuel line positioned? It's not getting hot by any chance is it?
Paul.

Rectifier is only for the lighting circuit and has no effect on ignition. You may often see what appears to be an air lock but it's not and it's not unusual.

Scooter Paul wrote:Where do you have the fuel line positioned? It's not getting hot by any chance is it?
Paul.

Iits just in a small loop from the tap to the carb. The only thing I could change is the angle of the carb pipe so the fuel tube doesn't have to go up slightly.

Kris - re the fuel - have you measured the flow rate ? Is it a fast flow tap?

Sorry should have read earlier post.

Kris -- I had a similar problem, bike would start spluttering and running like shit at the same spot on my running in route. I checked the flow from the tank and it was an absolute trickle. Changed to a cam lam fast flow tap and all good -- it would run OK for a period or till I tried to open her up and either maxed out like it had a flat spot or start spluttering.

I will check the flow rate again and report back.

The fast flow tap I fitted was from Allstyles.

Just tested it. It filled a 620ml drinks bottles in 1 minute .15 sec

On reserve and the petrol cap off its 59 seconds.

it could be lots of things Kris its difficult to diagnose an intermittent fault via the internet
You've clearly checked all the obvious things and drawn a blank. (I take it you have replaced your spark plug ?)
My feeling is its an electrical issue because if it were fuel related it would cut out and stay that way until the fuel flow was reinstated.

I had the exact same symptoms coming home from the MOT last year. it started to cut out and sounded just like a fuel starvation problem.
it turned out to be an electrical short on the cable between the junction box and the HT coil ,rubbing on the top of the mudguard.! it took some finding because it was intermittent . One minute it would start and run the next it would cut out and refuse to start for ages.

i'd check your entire ignition circuit from the green stator coil out of the magneto housing to the coil and then to the spark plug