Dellorto flaw

[Deleted member 12676]

Looking at mine again I see a small (.65mm dia.) hole that is uncovered just as the slide begins to be opened. So I am going to JBWeld shut the additional hole I had drilled and open that bottom most hole to .72mm diameter to see what happens. Drilling out an existing hole is easier than starting a new hole.

 

[lazylightning@mail.r]

Mine had no such hole at the bottom that is uncovered just as the slide opens. The first hole was quite a ways up there. After I drilled the extra hole at the bottom of the column, things got much much better....

 

[Deleted member 12676]

Look again. It's forward of the column and below the lowest visible part of it. Not easy to see unless you are looking for it which is why I missed it.

 

[Old Bob]

All this thread amounts to is manufacturer bashing.

 

[Deleted member 12676]

All I've done is report a problem and a fix. No bashing going on here. If anyone wants a Dellorto then buy one, fine with me. I'm confident I'll eventually get mine dialed in.

 

[Deleted member 12676]

Lightning, here is a photo showing the 3rd hole. Sorry that its not more clear. Old camera thats not good at close shots. I had to add black dots to accentuate the holes which came out fuzzy.

 

[lazylightning@mail.r]

Lightning, here is a photo showing the 3rd hole. Sorry that its not more clear. Old camera thats not good at close shots. I had to add black dots to accentuate the holes which came out fuzzy.View attachment 47725

Hi Jaguar!

Thanks for the photo! Yes, I see it now. It's not in the column but in the carb body just under the place where the column comes in. Now I remember reading that when some guys remove the brass column ( you have to read up really well to learn the trick to it) for boring out the venturi, they have a problem getting the column back in just right so that the little hole in the column that is inside of the carb body (and not visible) to line up just right with the little hole in the carb body. Thus they also have a problem getting it to idle. What can I say? After I added the hole, it idles without racing. It helped I think.
So as I understand this is a problem only with the SHA type carbuerator. The other models of Dellorto don't use the column? I'm fine with this carb. I'm happy about it. My problem lies in other things.

Paul

 

[Fabian]

If some people insist on messing around with float style carburettors then this system might be for them, because the idle jetting can be set to personal preference, even though it compromises the top end.
The top end can be compensated for by the bypass system as well as giving the possibility to feed in a multi-fuel combination on top of pump grade fuel.

Do a Google search for: "Adjustable Main Jet" + motorized

 

[lazylightning@mail.r]

I read somewhere that some race their motored bikes on alchohol and nitrmethane mix. Just have to change some seals and fuel line parts.

I also read that the power for nitromethane enriched fuels is increased by adding a tiny bit of hydrazine in racing model planes and cars and stuff. This practice creates a highly unstable mix and any respectable model club does not allow anyone to use such mixes! ;-)