Re: Mototrans 250 Scrambler restoration: she's a runner!

[Ventodue]

As Colin, Al. FWIW, I use TT100s (! Yes, they still exist ...) on my 450.

[A.I.M]

Thanks Colin & Craig, that's useful guidance. I did try DVLA last year, and they responded much faster than I had anticipated, but they would not complete the procedure until I could provide a picture of the bike in complete condition.

[A.I.M]

Having just fitted new tyres to both front and rear wheels, I was struggling to get the cush drive and sprocket carrier flange to fit back into the rear wheel. On further inspection I discovered that the flange is cracked and needs to be replaced - and I can't understand how I missed this before, but the casting is clearly now brittle. However none of the usual excellent sources of spares appear to have these in stock. Can anyone suggest where I could try to source a replacement? I would prefer new rather than used... but never say never.
Also just received the engine back from (a veeeeerrrryyy long) overhaul, minus a seized-solid auto advance unit, so contemplating taking the opportunity to upgrade to electronic ignition.
Thanks,
Al

[Duccout]

Hi Al,

I see that you are in the Pyrenees (one of my favourite places) so not far from Spain; there are loads of spares around in Spain and there are two Gumtree type sites that I know of - Milanuncios and Todocoleccion where used parts can be found. The only place that might have new ones is Old Racing Spare Parts.There is also a Spanish supplier called Andreas Wolff who sells on these sites.

Colin.

[Ventodue]

Also try:

Recambiosducati.com. This is Miguel Angel Moreno.

Recambiousado.com. This is Jesus Lloriente Guzman.

A sprocket carrier is a "porta corona", btw

[A.I.M]

Yet again (both sets of) your advice hit the spot and I have ordered a replacement - thanks ! It all takes me one step closer to getting on the road

[A.I.M]

It's been about a year and a half since my last update:
- My scrambler has been technically ready to go for the last 12 months or so, and it was starting, running and revving well in the garage with no load on the engine. Not road-tested though.

Rebuilt2a.jpg

Rebuilt4a.jpg

- I have just completed the very onerous cross-country administrative procedures in both UK and France to allow the bike to be used on the road and I have the French number plates and insurance. At last I am allowed to use it on the road
- And now the engine won't run!
> I can get it to start but I can't keep it running for more than about 15-20 seconds.
> I have checked and changed the fuel (with upper cylinder lubricant at 1/1000).
> I have checked for dirt/debris in the (new Amal 627) carburettor, tank, fuel filters and pipes - all spotless.
> The ignition (Sachse) seems fine since the engine does start.
> The battery is fully charged
> The engine has not run hot enough nor long enough to assess plug condition (NGK BR6HIX).
> Same symptoms with petrol cap open, so there's no vacuum developing in the tank.
> I'm kicking it over and getting it to start with full choke. I've tried at lesser and no choke positions but in those cases it doesn't start at all. I've also tried with and without throttle, it seems better with no throttle.

I am struggling to work out what could be causing this. I would be extremely grateful for suggestions how to resolve this so I can move on to road-testing and shakedown of the bike, I'm itching to get her out on the road!

[Duccout]

Hi Al,

Bummer. Bike looks great, well done. I would hazard a guess that the problem is with the carb, most likely caused by gum from standing a long time. It could be ignition related, which would manifest itself when you try to open the throttle and the spark would fail, but the symptoms you describe are classic blockage in the carb, and I would guess at a blocked pilot jet. The fact that it will only run with the choke confirmes this. What about the tickler? If you flood the carb really well does it run for longer? Do you have the old carb still available? You could bolt this on and see if the problem is still there.

I know that It is obvious, but look for the obvious! Loose wires, loose battery connection, short, anything that could have come loose. I once had a problem with my 750 Ducati when it would cut out when pulling away, which was not very safe! I checked everything, to no avail, then one day I found that the clutch cable had chafed against one of the coil terminals and was shorting out as I released the clutch.

Cheers,

Colin

[A.I.M]

Thanks, Colin
I do still have the old carb, but it's not in the best of condition. I might try swapping over some of the internals from one to the other to try to help fault-finding, but the pilot jet in the new one is a bush rather than the removable pilot jet used in the Spanish version, so I can't change that out without buying a replacement (that might be possible as I'm only a couple of hours from Barcelona).

Electrics/electronics is really not my strong suit, so I might have to find a specialist to help if the carb is not the source of the problem....

Much appreciated
Al

[Duccout]

Hi Al,

My first port of call would be the pilot bush, if you have a compressor give it a blast of air, if not a piece of copper wire pushed through it and then a blow from your mouth should ensure that it is clear. Are you sure that there is not a pilot jet fitted? I recently bought a new 27mm Amal from Burlen and that has a pilot jet fitted.

Cheers,

Colin