Curvy carb setup.

[nutzboutbikes]

I just wanted to post my finding's and so that it may help other Curvy owners trying to diagnose the same problem I had.

The story, my bike has felt like it has been lacking/bogging at little to part throttle for while and after doing a track day at Snetterton yesterday I thought some thing has to be done, so today I headed out to the bike and was determined to get to the bottom of it!.

I thought it has to be a fuel/carb problem by the way the bike felt so firstly I checked for leaks and none were found, next set the a/f screws dead on 2 1/2 outs as per Haynes and what I had also read on the internet, next up balanced the carbs did this and thought that sounds better so started buttoning her back up, as the air box went back on I thought that sounds bad again so out of curiosity I would just check to make sure all was good with the work I had just carried out, to my surprise I found that when the air box is refitted the air flow to the back carb changes and the carbtune showed it to increase!! :confused:, I had no idea why and still can't figure it out but ah ha I thought gotcha could this be the problem?.

It was at this point I remembered I had posted on a thread just the other day the front carb a/f screw was set at 1/4 of a turn out when I removed them for cleaning, so my next step was to wind the front a/f screw in to 1/2 a turn I allowed 1/4 of a turn for the slip exhaust and when I started her up she sounded sweet again the problem sorted, at last!. :grin:

[johnnyrod]

You've totally lost me. What are the mixture screws set on now? And did you check the float heights before you started?

[nutzboutbikes]

Front a/f screw now set at 1/2 turn out.
Rear a/f screw set at 2 an 1/2 turns out.
Float heights are 7mm.

[johnnyrod]

1/2 a turn? I would take the screw right out and check the needle isn't broken off the end of it

[nutzboutbikes]

When I got the bike it had sat for some time so I had the carbs off for cleaning, during stripping them down I noted the front carb only had 1/4 of a turn!, the bike had never been taken apart before so that must of been how it came from Suzuki!, I checked and cleaned every thing and all was fine, the only thing I changed was setting both a/f screws at 2 1/2 turns.

The bike is running better than ever now so I guess Suzuki set the a/f screws this way to compensate for when the air box is refitted as the vacuum in the rear cylinder shots up!!, as said I cant figure out why the airbox has this affect but it does.

[johnnyrod]

Something odd is going on I think. For a while before I had the carbs set up on mine to match the pipe, it would run lean, and the only way to balance the carbs without the gauge needles fluttering would be to take the tagnut off the left side of the airbox and refit the airbox, so it would run less lean but allow access to the adjuster. Now it's runnign right (in terms of mixture) the needles don't flutter any more, an I can balance it without the airbox as normal (for these bikes). There is no difference I've ever seen. Maybe it's not so much you have a restriction in one as a lack of restriction (leak) in the other, when the airbox goes back on?

[nutzboutbikes]

It's sure is an odd one.
I sprayed carb cleaner around all the joints and its all tight and leak free.
It runs great now loads of power, no flat spots or snatchy throttle response, so I am going to leave it as is.