Euro Breakdown Symptoms

[Paul_from_Thornbury]

Yes new needle and float valve, 300.

[nastro azzurro]

As I’ve said; been through all that, changed carb and all was good and has been ever since.
Don’t quite understand why you’re going to all that trouble without ruling out the carb? I get a new carb is £200 but if you work out the hours you’ve spent (I know it’s your own time) @ say £50 an hour for most professional outfits it’s negligible surely?
Nevertheless, good luck.

[Leotech]

A pal had a very similar issue and it was the MB fuel lever rod extender thing he sells with the extra holes in if your rod is too short. There was so much wobble on the extra pins that when fuel was at on it was only half on and similar when he put it on reserve.

It would run great at lower speeds but then start to misfire and die if he gave it some throttle.

[Paul_from_Thornbury]

Typically started first thing this morning, so I drained tank and fitted a new rebuilt fuel tap, and new continuous fuel pipe. I had a clear pipe with a quick disconnect in the line as it was easier to remove pipe via the QD when taking carb off as the pipe connection on the VHSH is so tight. It ran fine, even using the last litre of fuel and onto reserve with no issues.
Despite this I have also replaced the Scootronics DC Coil/CDI, changed HT lead and HT cap.
I’ve also disconnected the green wire to cut out button. Also removed the MB filler cap/dipstick and put original cap back on.
I shall run in this configuration and see how it does, it seems fine. Running around the neighbourhood, not too far from home in case it’s a push home.
I’ve tried on internal and external pick ups and it’s fine on both.
Now the ignition circuit is at its simplest. I don’t use the LT coil on stator. The Scootronics gear is fed direct from by battery. I have choice of two pick ups.
Fuel delivery has been totally changed.
I’ve a new float for VHSH coming in the post just in case.
New carbs are available at local scooter place in Helsinki if necessary.
Fingers crossed, touch wood etc etc…

[Adam_Winstone]

So, unless I have missed something posted, this would appear to be a contaminated fuel issue, which was virtually the first comment posted, the easiest and cheapest thing to check and resolve. It was also the most obvious as it happened after adding fuel from a Jerry can and repeats the issue when run on reserve, which always indicates the very common occurrence of sucking water through from the bottom of the tank when going onto reserve.

NB: Fuel contaminated with diesel gives issues in both the ON and reserve positions.

I've posted the story before but a pal spent roughly £1000 on engine components, rebuilds and van hire before believing me that the issue was likely from the small amount of new fuel that he used to top up from his Jerry can. After all of his expenditure and effort a change of fuel cured it instantly.

Good to hear that it may now be resolved.

[Paul_from_Thornbury]

Adam_Winstone, see post from July 23rd, fuel drained and fresh fuel added. Same problem.
My last changes prior to your post show that the fuel I drained was to change the tap, this was that fresh fuel, just in case the tap had an issue. The tap I removed looked ok on inspection and has now gone back into my spares pack I carry.
The other changes I made the other day are to replace the Scootronics CDI/Coil, HT lead and HT Cap.
I am currently running with green wire to cut out button disconnected.
Currently I have run about 150km in last few days, going on to reserve twice, getting the engine nice and hot and running up to max revs, around 8000rpm, with no issues so far.
I know the mass changes I made are not ideal, but the fault wasn’t one that occurred the moment I started and rode up the road. It tended to happen when hot and after about 50-80mm if riding.
I’m hoping the fault is found. The removed parts are in a box marked suspect and I’ve ordered new as spares.

[Adam_Winstone]

Whilst it would be nice to know exactly what the cause was, I'm glad to hear that all appears to now be working ok, which is the main thing. Long may that continue.

Fingers crossed. Happy and safe riding.

Adam

[Paul_from_Thornbury]

After all of the above the problem re-arose on way to Swedish Scooter Rally on Gotland. I finally made it but on the Rideout on Saturday it was virtually unrideable.
I returned to the site and set about the wiring. It’s pretty simple on my set up, wire direct from battery to CDI with a switch in between.
External and Internal pick ups to CDI via a selector switch.
All these seemed ok, but I tidied up a few other connections on the DC stator connections for DC supply to scooter.
But…. The killer was my earth strap was loose in the earthing ring attached to the mag housing.
I have the MB mag flange wiring set up with a spade available to earth, it’s been on my to do list, so fitted a new earth strap.
That’s has totally transformed the ride, this shows it’s been a longer standing issue than the Euro.
The engine is quieter, smoother, more responsive, more economical, so that earth has been messing with the combustion process for ages.
So lesson learned there.

[Adam_Winstone]

Glad that you seem to have it sorted.