Idle Problem

[camport]

Hey

 

I've got a 5k with a few bits and pieces done, had a pair of 40mm solex sidedrafts on until one of them became unusable.

 

Was looking for another pair of sidedrafts for a while and must have been the worst time because it took me 2 months and had to get some from the other side of the world.

 

Got a similar pair of 40mm solex sidedrafts. I have put the jets, air correctors and emulsion tubes from my old set into my new set just because they seemed to run okish at least and I can always get them tuned.

 

After having a problem with the car idling high once motor turned on (2000rpm - 3000rpm) put it down to a balance issue with the linkages.

 

They appear to be balanced now because once the car is turned on the idle is 1000rpm (although this is with the idle screw backed completely off) on the throttle linkages so I don't know how normal that is..

 

BUT - now after 10 -15 seconds of having the motor running the revs rise to 2000rpm all of a sudden.

 

I was thinking an air leak? After searching online I read to spray wd-40 around the intake manifold and carb manifold and around vaccum hoses etc which I have done but have found no change in the pitch or running of the motor so I'm not even sure if there are any leaks.

 

Kind of hit a brick wall with this one.. can anyone offer any advice?

[philbey]

Not sure about the solexes, I'm running Dellortos, but firstly, are they balanced? Have you put gauges on them and adjusted them accordingly?

 

Secondly, fiddle with the idle screw a little.

 

Thirdly, if you actually want to get proper performance out of these carbs then you have to get them on the dyno. I got my car running, driving etc, fiddled with settings and so on, but always had minor issues like yours. Dyno netted me a 50% increase in power!

Edited November 3, 2009 by philbey

[silverra23]

Check this link out on toymods

 

http://www.toymods.net//forums/showthread.php?t=15622

 

not sure if you need to be a member or not to read it.

 

lots of good information on what goes wrong with solex carbies. loose venturis are apparently very common.

[camport]

Check this link out on toymods

 

http://www.toymods.net//forums/showthread.php?t=15622

 

not sure if you need to be a member or not to read it.

 

lots of good information on what goes wrong with solex carbies. loose venturis are apparently very common.

 

Thanks I'll have a read^

 

re : 1st reply - Yeah I'm pretty sure they're balanced, the rpm increase is 10 seconds after the motor is turned on not straight away. I will get them dyno tuned but I just need to get it idling better so I can drive it to the shop.

 

I'm just running out of things to fiddle with, as I said the idle screwed is backed fully off.

 

Oh I should have mentioned - The idle mixture screws do NOTHING whether they are fully in, seated or fully out... usually they should be making quite a change if they are played with..

 

 

Thanks

[camport]

Doesn't seem to be anything mentiond in that thread ie loose venturis.

 

I would post a thread there but i've been waiting days for my account to be enabled don't think it's going to happen..

 

Still looking for an answer :y:

[silverra23]

The size of the Toymods forum means that it takes a little while to get approved.

 

They also don't approve you if you didn't answer all the questions and fill it out properly.

[altezzaclub]

Float levels as they should be & no invisible bits of hair under the float seat??

 

I wondered if it overfills the float chamber, which is why it takes 10seconds before it speeds up, and that would also explain why the mixture screws do nothing.

[camport]

Float levels as they should be & no invisible bits of hair under the float seat??

 

I wondered if it overfills the float chamber, which is why it takes 10seconds before it speeds up, and that would also explain why the mixture screws do nothing.

 

Thanks for all the replies.

 

Could you explain to me how to go about checking this? I'm still learning about carbs it's going good so far, good things to know about..

[TRD ke70]

if you have had the tops of the carb's, did you line the choke disc's back up.

 

if you don't line them up properly, the chokes will be stuck on.

Edited November 9, 2009 by TRD ke70

[altezzaclub]

You wll need a Solex manual or a webpage that talks about float level.

 

For Webers you take the top off, invert it and meause from the "top" (now bottom) of the float to the lid. Whie its open you take out the float shaft and make sure there is no fine hair or fibre around the float valve or its seat.

[camport]

if you have had the tops of the carb's, did you line the choke disc's back up.

 

if you don't line them up properly, the chokes will be stuck on.

 

Yeah that's what I thought too, is there any way to tell they're stuck on?

 

Here's two pics of the choke setup one with the tops on and off.

 

 

 

When the chokes ( in pic 1 ) are pulled back the idle drops significantly to stall.

 

As you can see in pic 2 the choke plate thing, the holes are lining up. Is that how it's meant to be?

 

I changed them around and assembled them so they werent so they would effectively open it the chokes were pulled, but the car wouldn't start..

 

 

p.s ignore the rtv its temporary

Edited November 14, 2009 by camport

[Felix]

I found this Mikuni PHH manual.

 

Looks like your carbs are a bit different, but that manual gives an explanation of how the starter disks work. Hopefully it can be of some use.

[TRD ke70]

sorry mate, it's been a while since i have done one, can't really remember.

 

One other thing though, are you going to be using insulating blocks between the manifold and the carbs?

It can also make a huge difference to how the carbs work.

Edited November 14, 2009 by TRD ke70

[camport]

sorry mate, it's been a while since i have done one, can't really remember.

 

One other thing though, are you going to be using insulating blocks between the manifold and the carbs?

It can also make a huge difference to how the carbs work.

 

What are insulating blocks?

[crunchie]

Not sure if this helps but its an oldschoool trick to check the state of the carbies.

 

Sounds funny but get a garden hose about 600mm long, put 1 end at the throat

of the carby, listen into the other end. Every throat should sound the same.

You wil hear a sort of dok dok dok sound.

 

The mixture ratio actually affects the sound the valves make when they open

and close and you can hear it through the throat and the hose.

 

If you are feeling keen try a home tune yourself using the hose, play around

with the mixture screws. Wind them all in, then out say 2 / 2.5 turns and fine

tune by sound.

Works a treat on twin 48mm S/D Webbers (3TG motor)