we were going to do an LAX-CRB trio and it has a stop in Tokyo and Singapore so now decided to fly from LAX, do a week in Tokyo, fly to Colombo for a week in Sri Lanka and then home to LAX

Any thought on the best site to go in to book multi city stops? Or if it’s worth Calling the airline for a long stopover (Singapore air)

I would research at skyscanner.com. Then I would call the airline that looks like the best bet. You could also look at airtreks but they mostly deal in trips with more stops.

Use ITA and Google flights - http://matrix.itasoftware.com/ - to see what the costs look like for various carriers. I just checked on Singapore's fares and it looks like with most of Singapore's economy fare classes a stopover (you're allowed up to three in each direction) will cost $50 over the base fare. So just use the "multi-city" function on Singapore's website and see what you get.

I also assume you meant CMB, not CRB; CRB is a place in the Australian outback.

yup, was winging the code

thanks guys - I use skyscanner as my go to so will stick and also just try calling singapore. While looking last night we found the multi-city for $1009 a ticket!!!! By the time we'd discussed and gone through to payment it had jumped up by $300, absolutely kicking myself