carb issues

[Tonyxs11]

im having a bit of a problem getting my 79 SF to run right at idle, running rich. the mixture screws are missing the springs but comparing the screws to new ones it looks like mine are the wrong ones.
mine taper off but at the last 5mm or so theirs a steel straight pin sticking out the end ???? but looking at OEM ones they taper off to the very end. looks like someone has been messing with them

this is a factory one, p.n. 2A2-14923-00

[bikerphil]

That one in the pic is for the early type carbs, the late type have the type with the flat tip. Post a pic of your carbs and we'll help identify which type they are.

[Tonyxs11]

Im pretty sure they are the right carbs for a 79.



this is the mixture screw in them

[bikerphil]

Yep, you have the correct early type carbs that use the pointy type mixture screws. Many times, people overtighten the screws and the tips get stuck and break off in the carb body. Then, when they try to remove them, they booger up the hole and it becomes enlarged. Maybe that was the reasoning for using the peg tip mixture screw. Or they just didn't know any better. Just a thought.

That screw in the pic isn't even correct for the late type carbs, totally different.

The tap thread size for the correct mixture screws is M5X0.5 in case you need to clean up the threads in the carb body.

[Tonyxs11]

Yep, you have the correct early type carbs that use the pointy type mixture screws. Many times, people overtighten the screws and the tips get stuck and break off in the carb body. Then, when they try to remove them, they booger up the hole and it becomes enlarged. Maybe that was the reasoning for using the peg tip mixture screw. Or they just didn't know any better. Just a thought.

That screw in the pic isn't even correct for the late type carbs, totally different.

The tap thread size for the correct mixture screws is M5X0.5 in case you need to clean up the threads in the carb body.

yeah cheers Phil just what i was thinking !!!! will have to spend more money on a set on mixture screws

[normalthom]

I wish I had you guys skill set. My 1981 MNS is in the shop now getting the carbs rebuilt, and the price (so far) is over $900.

[Tonyxs11]

I wish I had you guys skill set. My 1981 MNS is in the shop now getting the carbs rebuilt, and the price (so far) is over $900.

i was a bike mechanic for many years which helps

[Rasputin]

I wish I had you guys skill set. My 1981 MNS is in the shop now getting the carbs rebuilt, and the price (so far) is over $900.

And that is exactly the reason so many of us learned to do it ourselves! It is not that hard and there is always helpful advice here so do not be afraid to save your bucks and learn something new. Yes it does take time and patience but so does earning a thousand bucks to hand over to someone who does not get it right.

[oldyam80sg]

1000% agree Rasputin!

[cajun31]

I wish I had you guys skill set. My 1981 MNS is in the shop now getting the carbs rebuilt, and the price (so far) is over $900.

Before spending that kind of money you would have been better off just asking if someone on this site would have been willing to have a go at them for you. If you plan to keep the bike you should try to work on the bike yourself. Most shops do not have mechanics that know how to work on these old bikes. Mind you there probably are a few left out there but they are getting more and more rare with each passing year.

[Tonyxs11]

mixture screws turned up today, should make a difference !!!

[JonnyO]

I wish I had you guys skill set. My 1981 MNS is in the shop now getting the carbs rebuilt, and the price (so far) is over $900.

Oh boy...at that price I think it's worth enlisting the aide of my mechanic buddies. Take pictures-ask questions-read manual.
But hey, what do I know?
( I know I need mine rebuilt and the petcocks, too.