Si 24/24 carb

[cb]

I suspect my 24/24 carb maybe warped slightly. The reason I think this is, over the last few months I have had to replace gaskets due to fuel/oil splashing over back wheel. I replace gaskets, torque the carb down, no fuel/oil splash for a while, then re appears. Also, occassionally the throttle seems to stick when in idle, the revs race slightly as if the throttle slide has stuck slightyly open, only just noticable though. Is it worth skimming the bottom of the carb, or should I replace whole carb?

Thanks in advance

[vespasco]

Its worth lapping the carb yes but first check the slide moves freely in the carb. Its possible the groove where the slide goes has been nipped up by the carb bolts being over torqued. Pull the slide at the point where the throttle cable attaches to it and see if it snaps back, or gets stuck!

A warped carb would give similar symptoms but its also worth checking the head is torqued up too while youre tinkering.

[henri]

a 2nd to the above answers , lap it n use a good quality gasket n grey silicone sealant aswell, belts n braces , if you decide to swap carbs ,i'd stick your present jets in the new one or replace the new 1's with genuine dellortto jets.the new spaco's dont have genuine dell' jets in an the quality is variable . H

[cb]

I have looked at the carb, looking down at the slide it remains slightly open when throttle off. Is that normal? The other carb I have, the slide is completely shut.

[vespasco]

If the carb is on the bench (i.e. - with no tension from throttle cable holding it open) and it doesnt spring close then its possible the groove for the slide is buckled.
(Slacken off the idle screw so its not stopping the slid too).

[cb]

Thank you for the advice.

[cb]

Sorry, this maybe a daft question but, how do you tell the difference if the carb is a spaco? I have read some detrimental things about spaco carbs. I have another carb, the only difference I can see is the mixture screw (back of the carb), on the new one this has a bolt head, the one currently on the bike is a screwdriver head. Does a bolt head mean its a spaco?

[henri]

some have screw heads ,mostly older , an some 8mm hex heads , more modern 1's , an as gaz says it will be named on a plaque up by where throttle/slide rod goes in, wether it says dellorto or spaco chances are it was made by spaco who manufactre all dell' carbs an have for years . the slagging of spaco's is mostly based on there crap jets , an "italian" snobbery , H

[cb]

There is no spaco name on the carb anywhere..

[vespasco]

I dont think theres anything wrong with spaco carbs. If you buy one direct from dellorto, it will be a spaco carb body, with a few dellorto bits such as jets, slide and float bowl top (the round bit that says dellorto (probably))!
The spaco (and non branded) jets have been questionable.
Likely the carb will be stamped either dellorto, spaco,or have what looks like a chunk missing where this stamp usually is which i think is the old style dellorto carb, which is likely to have a coarser thread on the idle mix adjuster when compared to your 'new' carb with hex head head, fine thread idle mix adjuster screw.

You can also sometimes tell if your slide is catching in a warped carb body 'groove'... Look for marks, or use a marker pen, on the edges of the slide, to help locate any places where the slide rubs/catches.

Later carbs have a notch cut out on top of the carb where the bolt goes through, to prevent over torquing of the bolt/sleeve nut, where it warps the slide groove/channel.

[cb]

Thanks.

[henri]

no name next to the plaque saying 24/24d , usually means early carb as does the slot headed mix-screw , as ive always seen spaco cast in spaco carbs ,even the ones made for dell', an even jetex marked the few pattern/copy carbs they made , so could be a dell' thats had its float bowl top changed as thats usually cast with dell's name . H

[mickymidas]

Just to add another equation into the mix......are you sure you have the correct mixer screw in ?.....P range and T5 are slightly different ....My Rally /P200 would not tick over / run properly until I found that the wrong mix screw was in, and also leaked down rear of casing......T5 has 0.5mm point where P range has 0.2mm point I think.

[henri]

aswell p200 , an 125/150's also have different sized ends to the screws , just to make life interesting i guess , H

[shaunpx]

I had similar problems with a Si 24/24 crab on my px200e the fuel leak was due to the float needle seat leaking and coming out the overflow and the sticking slide was due to the linkage that's on top of the auto lube wasn't fully going back to the closed position... to check the float seat disconnect the float housing from the carb hold the float up so its closed and switch on the fuel tap to see if it leaks... to free the linkage I sprayed it with silicon spray and kept moving it back and forth also slightly bent it back a bit which seems to have cured the problem

[cb]

Cheers for all the advise, I will be taking it apart the coming weekend. Waiting for a gasket set and bits for a carb rebuild. I will be stripping down the old one to b*st**dize it.

[bigd]

Cb you might find something in this from when I had a carb leak problem.

vespa.proboards.com/thread/4389/carb-box-leak?page=1&scrollTo=30898

[cb]

Cheers bigd