Cracks on the air cleaner box duct (question from newbie)

[zioclive]

Dear friends, I had a leak from the overflow tube of a carburetor (the bike is a z1r) .
I've noticed a considerable big crack on the air box duct of the leaking carburetor.
On the redline cicle site ( http://www.redlinecycle.com/Carb%20-%20 ... 0seat.html ) I,ve read that a crak on the standpipe could cause an intermitent leak from the carburetor's overflow tube .

Do you confirm this ?
Please could someone try to explain me why the two things are related ?

Many thanks
Fabio

[Garn 1]

Fabio, I don't think the two things are related.

Firstly, that crack/split in the air box duct may cause a little erratic running, as it is sucking air.. not too serious on this side of the carbs!

The crack in the stand pipe is a common problem, as it slowly drains the two connecting bowls, when bike is standing. Also, this problem is very hard to detect. You can often change float level cut-off needles, unnecessarily, by mistaking this problem. The crack is a longitudinal crack, usually travelling the full length of the standing pipe (that's the pipe that pokes up the bottom of the float bowl). You can carefully solder the crack. I have heard of using heat-shrink tube over the pipe!
RegardZ

[zioclive]

Thanks for amswering Garn 1 .
My mistake (one of the many ) has been thinking that the standing pipe and the air box ducts were the same things .

Anyway I will glue the crack in the airbox duct just to avoid dirty air to enter into the carb.

Then I will look at the standing pipe , using heat-shrink tube over the pipe seem a good idea but I wonder if the fuel could melt it ....

[kev edwards]

if the shrink tube is made from hdpe it will not melt if its some sort of pvc it will melt , so probably best to source new stand pipes , better safe than sorry. good luck .

[Garn 1]

That stand-pipe in the float-bowl may be difficult to retract to fit a replacement... I have not yet worked out if it part and parcel of nipple on the outside which carries the overflow tube.

I think most heat-shrink is impervious to fuel. Trouble may be in effecting a seal where crack enters the bottom of the float-bowl. Maybe a little glue!

Regardz