Downjetted and now Maxi wouldn't start this AM

Jeff Woodin /

So yesterday afternoon after riding home from work I decided to clean the carb and downjet. This was my first time working on a carb. at all so please excuse my noobness. It's a stock Maxi with a Dellorto 14.12 SHA. Also, I recently de-rusted and cleaned the gas tank, which was pretty bad.

So the carb was in fact pretty dirty. My decision to downjet came from some signs that the bike was running rich. I had some other symptoms that were probably related to the carb being dirty - there was a bunch of rusty sediment in the bowl.

Anyway, I cleaned it and went from a 60 to a 58 jet. Put it back together, started it up and it ran great. Rode around town, seemed just as powerful as before, etc. However, I couldn't really get it to run this morning. It would start up, but want to die out when I revved it up. I had to give up and drive to work. I'm just wondering if going down 2 jet sizes could be enough of a change to cause this.

Since it ran fine yesterday afternoon, the only thing I can think is that the 58 isn't delivering enough fuel when the engine isn't warmed up and it was also cooler this morning (about 60 degrees vs. 75 yesterday pm.) In my noob mind 60 to 58 doesn't seem like a big change but maybe it is? I guess my next step is to take the carb off and maybe try a 59 or just even go back to the 60. Thanks for any input.

Re: Downjetted and now Maxi wouldn't start this AM

your jetting has nothing to do with it. that is my opinion. However. try starting the bike full throttle. you might need to readjust your needle (did you move it?)

Re: Downjetted and now Maxi wouldn't start this AM

Jeff Woodin /

I didn't move the needle, just sprayed things down in general with carb cleaner. Would it normally need to be adjusted if one is down jetting? It just seems strange that it ran fine yesterday and then not this morning.

Re: Downjetted and now Maxi wouldn't start this AM

K Olena,

You do realize SHA carbs don't have a needle?

Jeff,

I would make sure that your float needle is seating correctly and the rubber tip is in good condition. Also check your float level. Those SHAs sometimes don't wanna seal right too. Put a O-ring in between the intake and carb to eliminate that possibility.

Re: Downjetted and now Maxi wouldn't start this AM

Jeff Woodin /

Thanks, do you have any idea what the float height is supposed to be in this carb? How can I tell if the float needle is seating correctly? I guess I didn't really take a close look at this first time taking it apart...

Re: Downjetted and now Maxi wouldn't start this AM

From the wiki,

A properly set float will be parallel to the base of the carb body when it is held upside down w/o the float bowl on.

For the float needle just check that the rubber on the tip is still in good condition.

Re: Downjetted and now Maxi wouldn't start this AM

Jeff Woodin /

OK - thanks, can you forward me the wiki page that has that info? I can't find it by searching.

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