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-   -   Carb issues (http://forums.sv650.org/showthread.php?t=239054)

Spiral 25-04-21 03:50 PM

Carb issues
 
Having put a slip on on my curvy it's not happy at low revs.I took the carbs off to get to the mixture screws to get them to 3 turns out.....

However the 21 year old screws are absolutely solid on both carbs, I even cur deeper notches in the screws to get better purchase but they aren't going anywhere :mad:

Has anyone got any tips to free the *@@*### things, or would putting bigger pilot jets in get around this (currently 17.5s) ?

Failing this has anyone got a pair of carbs that everything works on / is free ?

Getting to be a bit of a money pit this bike :pale:

graham04 26-04-21 08:22 AM

Re: Carb issues
 
Got one stuck on my 600 Monster, possibly an age thing. Soaked the slow jet for a day in wd40, then carefully drilled with a small left hand drill bit. Came out after going up one size. It would be easier if you have at least one jet in your hand to see how deep you can go.

Spiral 26-04-21 04:24 PM

Re: Carb issues
 
Quote:

Originally Posted by graham04 (Post 3127655)
Got one stuck on my 600 Monster, possibly an age thing. Soaked the slow jet for a day in wd40, then carefully drilled with a small left hand drill bit. Came out after going up one size. It would be easier if you have at least one jet in your hand to see how deep you can go.

Thanks for the input, I'll get a set of left hand drill bits & try my luck.

johnnyrod 26-04-21 08:00 PM

Re: Carb issues
 
If it's running lean then tweaking the idle mixture is only a sticking plaster, it'll be running lean all over, especially at higher rpm. If you don't want to fork out for dyno time to set it up properly you could go up on the main jet, and also raise the needle by a clip or maybe half a clip (move the shim) to deal with midrange.

Spiral 27-04-21 04:36 PM

Re: Carb issues
 
Quote:

Originally Posted by johnnyrod (Post 3127677)
If it's running lean then tweaking the idle mixture is only a sticking plaster, it'll be running lean all over, especially at higher rpm. If you don't want to fork out for dyno time to set it up properly you could go up on the main jet, and also raise the needle by a clip or maybe half a clip (move the shim) to deal with midrange.

I'm going to up both jets & raise the needle, I think it only needs a small changes so I'm going to try a 20 pilot, (up from 17.5) and a 142.5 main (up from 137.5). It'll give me a starting point before I do the cam swap, probably in the summer when I get some time off work.

I live in a bit of rural backwater & don't think there are any dynos, but they probably are a bit OTT for a £600 motorbike anyway !

johnnyrod 28-04-21 05:26 PM

Re: Carb issues
 
I wouldn't bother changing the pilot, you haven't modified enough to need it. You'll most likely need to adjust the needle position though.

Spiral 28-04-21 05:45 PM

Re: Carb issues
 
Quote:

Originally Posted by johnnyrod (Post 3127718)
I wouldn't bother changing the pilot, you haven't modified enough to need it. You'll most likely need to adjust the needle position though.

It's popping & running erratically at low revs & the mixture screws are seized on both carbs, so it's worth trying it before getting replacement carbs, plus I'll be doing the "cam swap" before too long as well.

johnnyrod 29-04-21 05:57 PM

Re: Carb issues
 
You won't need to adjust anything on the carbs for the cam swap

Spiral 01-05-21 01:30 PM

Re: Carb issues
 
Well I just got the carbs back on after changing the pilot jet to a 20 & the main to a 142.5 & cranked it.

For the first time it started easily, it didn't pop & bang, and most of all it didn't need the choke on for 7 or 8 minutes until the motor was hot either.

I've never had a fourstroke anything with a manual choke need as much choke & warming up as this SV did, and it was erratic for the first few mins riding after the warm up too, hoping to find that cured as well when I get some time & dry roads to take it out for a ride.

johnnyrod 01-05-21 05:36 PM

Re: Carb issues
 
That sounded more like you had a blocked pilot jet or other lean running issues at idle TBH but yeah if it's rich now it'll start fine cold, maybe less easy when hot


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