Jetting Help

[thatkid]

Have you done a compression test? All 4 plugs removed, then test all 4 cylinders

Did you put an airline through the pilot jets? Especially #3. With the brass jets removed, remove the mixture screw, its spring, washer and o-ring, also blow out the jet and mixture screw galleries in the carb body.

You make no mention of either.

[yamaboy]

Have you done a compression test? All 4 plugs removed, then test all 4 cylinders

Did you put an airline through the pilot jets? Especially #3. With the brass jets removed, remove the mixture screw, its spring, washer and o-ring, also blow out the jet and mixture screw galleries in the carb body.

You make no mention of either.

I haven't done a compression test yet because I only have a car tester and I need a smaller fitting which will accomodate the bike's smaller plug holes. If not i'm going to purchase a bike compression tester soon.

As for the pilot screw , right? I have not messed with it for the fear that I'll mess up the turn settings.Turns out that there is nothing to mess . Please correct me if i'm wrong. I'll make sure to unscrew it and run air,carb cleaner and a fishing ling/thin metal line. I have removed the mixture screw and ran a thin metal line but no air so that will definetly be something that I need to do.

Appreciate your help!

[thatkid]

Remember to also remove the pilot air jets, and clear those.

[yamaboy]

Remember to also remove the pilot air jets, and clear those.

You my friend are a genius!

The damn air jet screw for #3 was plugged big time. I ended up replacing it with a spare one so I'll see what happens when I put my carbs back on. I've also re-cleaned the pilot,main jets with their passages as well as the mixture screw port. I've also ordered new gaskets for the carbs ..#3 looks a bit worn.(gasket for the jet "holder" and one that emulsion tube goes into)

I'll keep you updated

[thatkid]

Well lets hope that blockage was the cause of the #3 mixture screw refusing to comply with instructions

As for genius I wish. Basically it's only educated guess work. Always remember before cleaning any Jet remove it from the carb body, otherwise any obstruction will only get pushed further into the carb, and if possible clear any carb galleries with an airline.

It's a pleasure working with you.

Mal

[yamaboy]

Well lets hope that blockage was the cause of the #3 mixture screw refusing to comply with instructions

As for genius I wish. Basically it's only educated guess work. Always remember before cleaning any Jet remove it from the carb body, otherwise any obstruction will only get pushed further into the carb, and if possible clear any carb galleries with an airline.

It's a pleasure working with you.

Mal

Looks like the issue has been fixed and all 4 cylinders are running around the same temperature(380~450).#3 which was running at 170 degrees has returned to normal. #1 is running a bit cooler but I think everything should be great once I change the carb gaskets aswell as the emulsion tubes..Factory Pro told me they are backordered and will take about another month before they ship...Have already waited 1 month and a half

As of right now , I'm running a 110 main jet , stock pilot jet , 3rd clip on the needle ,23mm on the floats and 3 turns out on the idle screws. I have also performed another sync and all I can say is WOW! It screams at higher RPMS and idles well. I'll need to read the plugs for more info.

I never thought a carb retard like me would get this stuff so THANKS guys. I couldn't have done it without your help.

I'll keep you updated once I get new gaskets,float valves, and emulsion tubes

[yamaha_george]

I haven't done a compression test yet because I only have a car tester and I need a smaller fitting which will accomodate the bike's smaller plug holes. If not i'm going to purchase a bike compression tester soon.

As for the pilot screw , right? I have not messed with it for the fear that I'll mess up the turn settings.Turns out that there is nothing to mess . Please correct me if i'm wrong. I'll make sure to unscrew it and run air,carb cleaner and a fishing ling/thin metal line. ave removed them mixture screw and ran a thin metal line but no air so that will definetly be something that I need to do.

Appreciate your help!

Anyone reading this NEVER put a metal object thro any jet. Jets are not that accurate to start with **
shoving metal will at best scratch the hole & a worst gouge the hole in the jet moving it up a size!

** http://www.saltmine.org.uk/martin/jet_sizing.html

This URL has PDF 's you can download & print off for reference

[yamaboy]

I haven't done a compression test yet because I only have a car tester and I need a smaller fitting which will accomodate the bike's smaller plug holes. If not i'm going to purchase a bike compression tester soon.

As for the pilot screw , right? I have not messed with it for the fear that I'll mess up the turn settings.Turns out that there is nothing to mess . Please correct me if i'm wrong. I'll make sure to unscrew it and run air,carb cleaner and a fishing ling/thin metal line. ave removed them mixture screw and ran a thin metal line but no air so that will definetly be something that I need to do.

Appreciate your help!

Anyone reading this NEVER put a metal object thro any jet. Jets are not that accurate to start with **
shoving metal will at best scratch the hole & a worst gouge the hole in the jet moving it up a size!

** http://www.saltmine.org.uk/martin/jet_sizing.html

This URL has PDF 's you can download & print off for reference

The metal line that I've used was really thin and smaller then the jet hole. About the size of the pilot air screw hole. Anyways , I do agree that it's not a good idea...Scratches are probably at the microscopic level

[yamaha_george]

[

Anyone reading this NEVER put a metal object thro any jet. Jets are not that accurate to start with **
shoving metal will at best scratch the hole & a worst gouge the hole in the jet moving it up a size!

** http://www.saltmine.org.uk/martin/jet_sizing.html

This URL has PDF 's you can download & print off for reference

The metal line that I've used was really thin and smaller then the jet hole. About the size of the pilot air screw hole. Anyways , I do agree that it's not a good idea...Scratches are probably at the microscopic level

If you read the article you will see that the jet sizes are NOT very accurate to start with a series of even micro scopic scratches could take the flow level to the next bigger size and alter the ability of matching the carbs which if you follow the article is already a difficult task without complicating it more by poor engineering practices.

I have seen a so called tuning pro take a a set of O/A welding tip cleaning wires to a customers set of carbs he wondered why I picked up my carbs with their flow tested jets and left HURRIEDLY .

[thatkid]

Anyone reading this NEVER put a metal object thro any jet. Jets are not that accurate to start with **
shoving metal will at best scratch the hole & a worst gouge the hole in the jet moving it up a size!

** http://www.saltmine.org.uk/martin/jet_sizing.html

This URL has PDF 's you can download & print off for reference

Well spotted, personally I've never used any implement to clear Jets, only Carb cleaner or other solvents. Never even thought of the consequences metal objects would cause. Thanks for pointing that out.

[yamaboy]

Anyone reading this NEVER put a metal object thro any jet. Jets are not that accurate to start with **
shoving metal will at best scratch the hole & a worst gouge the hole in the jet moving it up a size!

** http://www.saltmine.org.uk/martin/jet_sizing.html

This URL has PDF 's you can download & print off for reference

Well spotted, personally I've never used any implement to clear Jets, only Carb cleaner or other solvents. Never even thought of the consequences metal objects would cause. Thanks for pointing that out.

I guess it's a good indication that the plugged jets need to be changed If just air and carb cleaner doesn't clear them up. I was surprized how plugged the pilot air screw was and could not clear it with anything.

[thatkid]

Did you check the replacement "Pilot Air Jet" size? there's different sizes namely Cali carbs.

Out of interest for me. I recalled your carb tool thread, was the wrong float needle in #3 carb? that would account for a PO compensating for poor idle mixture, and probably setting the wrong float hight on that #3 carb to compensate for the real undiscovered issue.

Since you set the float heights correctly that would also explain why the same issue returned?

Just curious, I could be way off the mark.

[yamaboy]

Did you check the replacement "Pilot Air Jet" size? there's different sizes namely Cali carbs.

Out of interest for me. I recalled your carb tool thread, was the wrong float needle in #3 carb? that would account for a PO compensating for poor idle mixture, and probably setting the wrong float hight on that #3 carb to compensate for the real undiscovered issue.

Since you set the float heights correctly that would also explain why the same issue returned?

Just curious, I could be way off the mark.

I did not check the pilot air jet size..darn thing is so small that all of them looked the same to me..
I just got a carb gasket set so I'll check that once I pull them out again. Good catch!

All of the needle "jets" if you are referring to them had the same setting(2nd clip then switched to 3rd clip). Brand new from Factory.. If you are wondering about the floats plastic holder(one with the float valve in it) , it was not seated all the way in its place. Of course the carb case pushed it in its place like you said, once I tightened the 4 screws. I have also flipped the #3 float into #4 and rechecked height(23mm)

Just glad it fixed the issue but It was definetly the pilot air screw and possibly the mixture screw passage being restricted..

Also curious.. Have you checked your headers temperature with an IR gun? Is 450F optimal?

[thatkid]

As far as i know, if all headers are near/close to the same temp. Then all is fine.

Yes I've checked mine 2 @ 410ish 1 @ 380 1 @ 260. I have my spare carbs fitted, and im leaving them on for now (it ran okish before). I want to identify any difference with my cut down airbox. Not to bothered with idle mixture at the mo.

Im in the process of servicing the originals. Float heights were all 20mm, cant remember who pointed me to get a float height tool I've already used it 8 times 4 carbs, all measured then adjusted to the correct height thats 8 times right? OOOH i feel special . <<< snarky

[yamaha_george]

As far as i know, if all headers are near/close to the same temp. Then all is fine.

Yes I've checked mine 2 @ 410ish 1 @ 380 1 @ 260. I have my spare carbs fitted, and im leaving them on for now (it ran okish before). I want to identify any difference with my cut down airbox. Not to bothered with idle mixture at the mo.

Im in the process of servicing the originals. Float heights were all 20mm, cant remember who pointed me to get a float height tool I've already used it 8 times 4 carbs, all measured then adjusted to the correct height thats 8 times right? OOOH i feel special . <<< snarky

`

M,
that 20mm rang bells are you sure that is the correct height ? seems a trifle low I thought 23mm was closer to the "book" yes i know that carbs differ but that is quite a bit.

Those pipe temp have way too much difference I try to work within a 40 degree spread.
Glad you like playing with your tool (english humour at work )