VOR 503 - fuel starvation?

[Johnny Wishbone]

Hi all, after stripping and rebuilding the carb (Dellorto VHSB 38) on my VOR I can't get the bike to start at all. I have set the idle mixture to the factory setting but it doesn't seem like I'm getting any fuel flow through the carb. I have checked the float bowl and have fuel there ok. I'm not familiar with this carb at all - are there any settings I've missed, idle jet, starter jet etc...

?

thanks guys!

[Wayward Son]

checked valve clearance?spark?

[Johnny Wishbone]

Sure have Eddie - clearances are good, getting a good spark too. When I got the bike it was a b*tch to start so I stripped it. The carb was filthy so I took it all apart and left it all soaking in carb cleaner. I recently reassembled the bike and found that the stator was out of alignment so that was probably the main reason why the bike was so hard to start in the first place.

Now though it won't fire up at all - not even a backfire (which it used to do right before it started). I have set the idle speed screw and mixture screws to their factory settings but still no luck. Is there any adjustment on any of the jets or on the atomizer or anything?

[Johnny Wishbone]

Just a quick question - I want to make sure this makes sense before I go adjusting anything else ?

When I stripped the carb initially I noticed that the two float arms coming off the fuel valve weren't at the same height, there was a difference of about 1mm between them. When I checked for information on the correct float height I couldn't find anything specifically for the VHSB38 but I did find info for a similar Dellorto carb (dunno which one) but it said that most Dellortos are setup with the float arms level with the float chamber deck on the carb body. Both float arms were a couple of mm off (richer) this mark so I adjusted them accordingly so they are now both parallel to the bowl deck.

Since I put the carb back in the bike I seem to be getting complete fuel starvation so my question is this - since the starter jet is positioned a lot higher up in the float chamber is it reasonable to assume that I have set the float heights too low (too lean) so that now the fuel level in the float chamber isn't sufficiently high to actually feed the starter jet??

The bike was a total ba*tard to start in the first place and when I looked at the stator it seemed to be quite a long way off position. I am now also thinking that (even though the bike seems to be running rich further up in the rev range) the float heights weren't high (rich) enough and that the starter jet was barely able to draw fuel up into it thus making the bike even harder to start. The bike wouldn't idle particularly well and would cut out if left idling. It would also cut out if the choke was turned off - you could only turn the choke off after about 15 minutes of riding.

Now since I have adjusted the floats heights back down (leaner) the starter jet isn't able to draw any fuel so it will never start with the current float settings. Flying Bob told me that the float heights should be set at 11.5mm - when I checked that against the deck it seemed to go against the earlier setting I had read of being parallel to the deck - sorry Bob!! I should have listened to you

Anyway, just thought I run my theory past you guys before I made any adjustments tonight. I will set it at 11.5mm and give it a kick ?

J.

[Wayward Son]

its possible its low float level,but it would have to be really low.

no spark plug of course?

[Johnny Wishbone]

Hi Eddie, what do you mean by "no spark plug?"?

Well, I tried it again last night and still nothing ? I set the float heights to 11.5mm and kicked until I was blue in the face... nothing... ?

I took the carb back out and blew the starter circuit and air jet out again, still nothing....