at least they are all nice and cheap....they can always come in handy later if you need them

Benny,

You were spot on with the 180 air jet. The pilot jets could also do with a little smaller size.

I've just realised that the vacuum ports on the carbs (to provide vacuum for the timing advance) have been left open, I've got a feeling these affect the engine more than I had imagined.

At the moment all I can get from people is baseline jetting. It's a matter of trying out different combinations.

Chris, Ok that makes sense, you will be loosing valuable vacuum needed to draw fuel for the idle cct. Also I had forgotten that your carbs have a vacuum port for ignition timing advance. I will take a stab and make a guess that these vacumm ports [for the ignition timing] account for why the idle jet size for the left and right carb barrels differ. If you plug the vacuum ports on the carb, i would be inclined to then fit matching idle jet sizes for each barrel.

Quote:

Yes you are correct. the idle jet [IMO] has the largest influence on your tune, especially on a street as most of your driving will be in the idle and progresssion ccts. In terms of percentage, your engine will rarely see WOT [main cct].

cheers
benny

I had it running okay this morning on idle (with the vacuum references blocked), but it died a little when coming off the throttle. So I pulled the carbs to;

> Clean all the jets.

> Reset the float level.

> Confirmed a good seal on the starter disc.

> Checked for possible air leaks around manifold.

> Cleaned & checked pilot screw tips.

> Cleaned & checked bypass vessels.

> Capped and sealed vacuum reference lines.

So basically I put them back together and still have the same issues, I can;t even get it back to the good idle. Could this all be due to jetting? I'm still getting backfires through the carbs.

I actually thought it could have been cam overlap but decided this couldn't be the case as the backfires were mostly around one barrel on each carb so I'm thinking maybe my tappets and timing is still out.....

What a pain, first the bike carbs and now these!

Okay, so it turns out the accelerator pumps weren't quite working as much as they should have so I've now set them to deliver the most they can on both carbs. That seems to have cleared up some of the spluttering.

I installed some 140 mains and 70 pilot jets but I'm sill getting a lot of bogging down low, I'm convinced it still has something to do with the primary circuit.

Tomorrow I'm going for bigger pilot jets again.

Does anyone else run these types of carbs or have any suggestions to the jetting arrangement?

Hey Chris,

take a look at this page, it has tuning stuff for Mikuni's as fitted to the Toyota 2TG etc. Hopefully some good stuff for you there..

Toyota Solex tuning info

Yeah Dean, thanks I have a hard copy of that already.

Those tests involve equipment that I don't have access to, if I did I wouldn't have written this. Basically I'm road testing and balancing using a synchronizer.

Was just hoping that someone could confirm their jetting specs up against mine so I at least knew if it were a simple matter of fine tuning or some mechanical malfunction within the carb(s) itself. At the moment all the manuals have several suggestions for troubleshooting and they basically point to everything from dirty throttle valves to too small or too large a main jet.

So yeah basically if someone could confirm my jets being in the same range as theirs, that would at least narrow down the scope or work to rectify the spluttering/bogging issue.

soldering iron and a set of machinist drill bits is wat you need then you can resize any jet to any size.trust me saves time and money.

Normally you should only need to balance one carb body against the other and then balance shouldn't change regardless of jetting changes.
So to me it is all a jetting issue (guess you already knew that tho!). Backfiring or spitting under accel usually indicates leanness, a rich mix will normally feel "heavy" as it revs.
Just throwing it out there but are the throttle plates around the right way? Some have a groove on the edge that should pass across the progression holes as they crack open, I have seen them inserted backwards before..

EDIT: Wurzel has my carb book which gives basic starting points for weber/dellorto carbs but I can't see them being that different for a Solex, I mean you are still trying to put the same amount of fuel in per cylinder regardless of carb type? Anyway I don't have it on me so can't tell you what it would be for your motor sorry, maybe contact Wurzel?

@ Greendog

Yeah I got some POS cheapy eBay bits. I'm not sure how well it would drill though, I mean how do you ensure that the bit stays central as you drill? or does it not matter?

I opened up the pilots with one bit but I obviously opened them up too much, so when the throttle valves were opened (minimally) and as they incorporated or activated the bypass (to go from supplying the pilot screw to supplying the cylinder itself) all the engine did was run but not really respond, too much fuel.

So I'm hoping that maybe 75 - 80 pilots will help things along.

Not sure about cheaper. If you think about it, with those tiny drill bits you'd need a micro/mini chuck to accommodate them so I'm not sure that that is cheaper. Either way the bits I had would work well if I had a decent chuck.