Probably been asked a million times before.......

[Laverda Dave]

I know this may have been asked a million times before but after searching the carb threads I cannot find the answer I need. Here goes..... Does anyone know of position of the carb needles, Mr Haynes advises the third grove, I've done this but the bike is still a pig to start. I've got the carbs off for the third time now and going through them again.  History is they were stripped, ultrasonically cleaned, vapour blasted, new jets, gaskets, needles etc (Keyser kit) and carefully re-assembled. I even made a custom 21mm float height gauge as advised by Chris  . To-date I have started the bike 3 times and every time its a nightmare, it just doesn't want to run, three of the headers have begun to yellow just through trying to set the carbs up, I haven't been on the road yet! The exhaust is a DS item and I'm aware of the potential for more fun and games regarding the back pressure 
I'm going back to basics now, stripping the carbs again and using some carb cleaner to flush them out.
Any help or advice appreciated at this stage, I just want to get it MOT'd before winter!

[hairygit]

With an aftermarket exhaust, it will almost certainly not run properly on standard jets/ needle settings. Are you running stock airbox/ filter? What make is the exhaust?

Sent from my X6pro using Tapatalk

[Nurse Julie]

Mine are set on groove 3, original exhaust, stock air box etc.

[Laverda Dave]

Thanks Julie.  Hairy, It's a DS item and everything else is stock.
I've just reset the floats again at 21mm and blown everything out. I've lapped the valves using solvol.
I'll try and set in up in the morning, lucky I'm on a week's holiday 

[Nurse Julie]

It may be worth you talking to Paul Gledhill. He has a DSS exhaust and had a load of trouble getting the bike running right but, I know he did resolve it.......but I don't know how   

[paul G]

It may be worth you talking to Paul Gledhill. He has a DSS exhaust and had a load of trouble getting the bike running right but, I know he did resolve it.......but I don't know how   

😬😬 Laverda PM me and I will let you have my mobile number.
It would take ages to do it on the forum.
Mine was the same running weak and would not Rev.
If you have changed the valves and they are not genuine then the 21mm may not be the correct setting. I suppose it depends on the springs in the needle valves.
I also ended up doing the settings with the carbs on their side so the pressure was taken of the valves.
Regards,

[Laverda Dave]

OK Paul, I'll PM you tomorrow, I'm sure you'll have the answers  . 
I've set the floats with the carbs on their side, letting them soak a bit tonight with some carb cleaner in the drillings just in case.  I'm going to re-check the ignition again in case its slipped (its a brand new Boyer). I'll put the carbs back on tomorrow after I've err....... taken the Morini  for its MOT and collected the respoked wheels for the CB250RS rebuild.
Dave

[Laverda Dave]

Hi Paul,

I haven't forgotten  .  I thought I'd get the carbs back on before I PM you.  I re-assembled them (how many times now...... ) after checking the float heights again, 21mm spot on, I checked them again the next day, still 21mm, they hadn't shrunk overnight and I put them back on.  I rigged up the fuel line and...................they pissed petrol out of three of the overflow pipes  .  At that low point I turned my attention to the CB250RS rebuild.
I've just got home from work and will go into the man cave this evening to take them off again and have another go, I'll PM you when its something positive and I've hidden the box of matches.............

[Nurse Julie]

I'm sure you have checked but are all the O rings fitting as they should do?. The reason I ask is that I know someone who had their carbs vapour blasted and because it takes off the surface of the metal, the O rings didn't fit snug any more.

[Laverda Dave]

Hi Julie, They all appear to be OK, nothing loose or over tight. All the needles, jets, o-rings and gaskets etc are new Keyster items.
My only concern is the fuel inlet valves, I've seen these with Viton seals in the past and mine are just plain steel. I cant see how these form a good seal against the brass seat without letting fuel by. Looking through a magnifying glass the steel needle tip appears to be rough.  I tried using autosol to lap the two together to make a better seal but the valve sits so far into the brass seat I cant hold it to spin it!
Keyster must have sold enough of these kits in the past so they can't be that bad unless I have a rouge kit?

I've been in the garage this evening, I've put the carbs back on the bike after another check and careful setting up and will try and start it tomorrow morning and see what happens.

[Nurse Julie]

Do yours not look like this then Dave?

[Laverda Dave]

Yes it does Julie, I have four of those incontinent little swines 

[Nurse Julie]

So which part of yours has the steel bit with no O ring?

[Laverda Dave]

The needle itself, the bit with the cone, my old 400/4 had a very small viton seal on the cone and this pressed against the brass seat, no leaks at all.  I don't know if they were original (it was a F2 and the first 400 I restored in the mid 80's. I had to sell it straight after due to the mortgage rate going up to 15% at the time!).  I thought that's what I'd get in the Keyster kit. I looked at using the old ones from the carbs but they were seriously mangled, the needles had no spring in them at all, they were stuck solid.

[Nurse Julie]

Maybe you have got a dodgy Keyster kit. I have never used that type, I always use the Cruzinimage kits and I have never had any problems at all. Very frustrating for you though.