collapse

www.dimecitycycles.com


www.restocycle.com

www.CITYLIMITMOTO.com

www.jadusmotorcycleparts.com

www.bisonmotorsports.com

www.speedmotoco.com

www.cognitomoto.com

www.townmoto.com

www.sparckmoto.com

www.Moto-Madness.com

www.pistonsociety.com

www.steeltowngarage.com

QUESTIONS ABOUT THE SITE? TROUBLE REGISTERING? ADMIN@DOTHETON.COM

Author Topic: My Suzi T500 Project *New Video*  (Read 177548 times)

Offline cxman

  • DTT SUPPORTER
  • *
  • Posts: 2301
Re: My Suzi T500 Project *New Video*
« Reply #1230 on: Mar 09, 2017, 20:44:13 »
measure the slides if they are both really 2.5 or teh same measurement from slide top to bottom of cut away

check the slide is not hung up in the bore and is not resting on the jet needle

if all that is ok check the carb part numbers i have seen this issue before when a carb was bored to a bigger size and they never undercut the carb floor groove that

the slide rests in

1978 CX650 Super Deluxe
1979 XS1100 Special
1980 XS650
1980 cx500  The Beast
1983 GL650 i
1983 cx650 Custom
1973 CB450
1973 cb750
1980 cb750
1981 cb650
1982 cb900 c
1977  gl1000
1976 gl1000 LTD
 1983 GL1100 Nekid
and a bunch of others

Offline 50gary

  • Posts: 585
  • Under the Limelight
Re: My Suzi T500 Project *New Video*
« Reply #1231 on: Mar 09, 2017, 21:10:23 »
An easy way to measure the cut is to put the slides on a surface table (towards the edge) and use your metric drill index as a "pin" to find the exact size cut.  Verify and go from there.
   Cheers, 50gary
Short track speedskating, cycling, guitars, motorcycles, juggling dynamite. I was born to laugh at Tornadoes.

Offline teazer

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 8161
Re: My Suzi T500 Project *New Video*
« Reply #1232 on: Mar 09, 2017, 21:16:35 »
Or do as I suggested and put them toe to toe on the kitchen table/office desk/ measuring marble slab and see if there's a difference - not as sophisticated but quick and easy to see if they are the same or not.

Offline clem

  • DTT BOTM WINNER
  • *
  • Posts: 1405
  • static fluff
Re: My Suzi T500 Project *New Video*
« Reply #1233 on: Mar 09, 2017, 23:44:41 »
I think it's usually the fact that the slides get installed backwards as opposed to switching them between carbs.
John are these new? If not did you clean out the air jets?

Sent from my SAMSUNG-SM-G920A using DO THE TON mobile app

"After every war there are soldiers who refuse to surrender. To this day there are still thousands who cling to their 30+ year old motorcycles, thinking that the war is still on, refusing to concede that the four-strokes have won"

1972 DS7 http://www.dotheton.com/forum/index.php?topic=45886.msg505995#msg505995
1983 CB550sc bobber http://www.dotheton.com/forum/index.php?topic=30599.30

Offline johnu

  • DTT BOTM WINNER
  • *
  • Posts: 1441
Re: My Suzi T500 Project *New Video*
« Reply #1234 on: Mar 10, 2017, 10:55:49 »
Ok guys thanks for all the suggestions but a bit of a false alarm 8)  I feel a bit supid now for not messing with them a bit more but for whatever reason after playing around with them for a little bit they both go down completely to the same level.  Not really sure what caused it in the first place though ???  I marked the slides to the carbs and the carbs were brand new a couple of years ago when I built the bike.
Clem are the air jets the air screws?  It is strange that adjusting the air screws didn't change a thing.  I am going to hopefully try running it again today and I will give it a run around the block to get a better idea of what it is doing.

Offline Ply318ci

  • Posts: 280
My Suzi T500 Project *New Video*
« Reply #1235 on: Mar 10, 2017, 13:26:02 »
May or may not be helpful but when I had my RD350 I had the same problem turns out the carbs were just dirty and a through deep deep clean solved the problem.

Number 11 specifically was totally gummed up.



Sent from my iPhone using Tapatalk
« Last Edit: Mar 10, 2017, 13:27:44 by Ply318ci »

Offline clem

  • DTT BOTM WINNER
  • *
  • Posts: 1405
  • static fluff
Re: My Suzi T500 Project *New Video*
« Reply #1236 on: Mar 10, 2017, 14:18:19 »
I was referring to number 28 in that diagram. On the stock RD carbs they are behind a brass ball. Doesn't look like yours have that brass ball.

Sent from my SAMSUNG-SM-G920A using DO THE TON mobile app

"After every war there are soldiers who refuse to surrender. To this day there are still thousands who cling to their 30+ year old motorcycles, thinking that the war is still on, refusing to concede that the four-strokes have won"

1972 DS7 http://www.dotheton.com/forum/index.php?topic=45886.msg505995#msg505995
1983 CB550sc bobber http://www.dotheton.com/forum/index.php?topic=30599.30

Offline jpmobius

  • DTT BOTM WINNER
  • *
  • Posts: 1058
  • where does this go?
Re: My Suzi T500 Project *New Video*
« Reply #1237 on: Mar 10, 2017, 20:38:36 »
#28 is an air jet.  It functions exactly like #29, the pilot air screw except that it provides a fixed amount of air depending on the jet size instead of being a variable metering needle.  Stock RD carbs do indeed have this jet, but it is permanently made into the carb body.  It is not behind a ball on the 350 carbs.   It can be changed by drilling and tapping the bore it is in and using standard Mikuni air jets. The ball at 7:00 0-clock is just to block off the bore for the pilot air after it is drilled at the factory.  I have never had to remove it to adequately clean this air passageway - it only has air traveling through it so stays quite clean - of course you have to check it anyway with a jet of carb cleaner.  It is very important to understand the function of these two parts - the fixed size air jet and the needle if you want to be successful at properly cleaning the carb and getting it to perform correctly.  The air jet supplies air to the main fuel system and interacts with the main jet and emulsion tube (#11).  It functions like the pilot air screw/needle in that is supplies air to the main fuel supply like the needle supplies air to the pilot fuel supply.  If you look at the carbs construction, you will see that the horizontal bore for the air jet intersects the vertical bore for the emulsion tube.  Fuel gets sucked up into center of the emulsion tube through the main fuel jet #36, but before it gets to the top and enters the main bore of the carb, it gets mixed with the air supplied by the air jet inside the emulsion tube.  So if the jet is incorrectly sized or any part of the emulsion tube, its bore, the passageway for the air jet or the jet itself is dirty or damaged, the fuel mixture will be wrong.  The pilot system is the same. Air is supplied by the pilot metering needle.  The pilot system gets an adjustable air supply because the fuel/air needed at idly is so tiny that just a hair inaccuracy will screw up the idle and it would be too fussy to fit a fixed jet.  Anyway, the air from the needle goes to the pilot emulsion tube where it gets mixed with the fuel supplied by the pilot jet.  The pilot system and the main system are completely separate from each other and share no internal passageways or components.  You do not see a pilot emulsion tube in the exploded view because the tube is actually part of the pilot jet itself.  The pilot jet is just the size of the hole bored into the end of the jet.  The tubular part with all the little holes bored in it is the pilot emulsion tube.  Fuel gets sucked up through the jet in the end, and air from the needle gets sucked into all those little holes and mixes with the fuel before it ever goes into the main bore of the carb.  So when you take the carb apart to clean it, you have to remove the pilot jet with its made on emulsion tube and make sure all the little holes are clean, that the bore or well that it goes into is clean and that the passageway from the needle to the well is clean.  If you look at the pilot jet, you will see that the end that goes into the carb body first has a taper.  That taper seats to a mating taper in the body, so air in the well surrounding the pilot jet emulsion tube can't leak past the joint - all the air must go through all the little holes and mix with the fuel.  Once you understand this, it is easy to follow the paths of the air, fuel, and air/fuel mix and make sure the passageways are clean.  On most Mikuni VM carbs, the air for the pilot system is supplied by the bore at 8:00 o-clock. Often you can see the tip of the needle through this bore.  The air for the main system is at 6:00 o-clock.  If the carb is clean and disassembled, you should be able to shine a bright light into the emulsion tube bore - straight up from the bottom - and see the light through the main air jet - it is a tiny hole!
« Last Edit: Mar 10, 2017, 20:45:49 by jpmobius »
Mobius


On a long enough timeline, the survival rate for everyone drops to zero.

RD350 Yamaha build  http://www.dotheton.com/forum/index.php?topic=66498.0

Offline johnu

  • DTT BOTM WINNER
  • *
  • Posts: 1441
Re: My Suzi T500 Project *New Video*
« Reply #1238 on: Mar 10, 2017, 21:04:28 »
#28 is an air jet.  It functions exactly like #29, the pilot air screw except that it provides a fixed amount of air depending on the jet size instead of being a variable metering needle.  Stock RD carbs do indeed have this jet, but it is permanently made into the carb body.  It is not behind a ball on the 350 carbs.   It can be changed by drilling and tapping the bore it is in and using standard Mikuni air jets. The ball at 7:00 0-clock is just to block off the bore for the pilot air after it is drilled at the factory.  I have never had to remove it to adequately clean this air passageway - it only has air traveling through it so stays quite clean - of course you have to check it anyway with a jet of carb cleaner.  It is very important to understand the function of these two parts - the fixed size air jet and the needle if you want to be successful at properly cleaning the carb and getting it to perform correctly.  The air jet supplies air to the main fuel system and interacts with the main jet and emulsion tube (#11).  It functions like the pilot air screw/needle in that is supplies air to the main fuel supply like the needle supplies air to the pilot fuel supply.  If you look at the carbs construction, you will see that the horizontal bore for the air jet intersects the vertical bore for the emulsion tube.  Fuel gets sucked up into center of the emulsion tube through the main fuel jet #36, but before it gets to the top and enters the main bore of the carb, it gets mixed with the air supplied by the air jet inside the emulsion tube.  So if the jet is incorrectly sized or any part of the emulsion tube, its bore, the passageway for the air jet or the jet itself is dirty or damaged, the fuel mixture will be wrong.  The pilot system is the same. Air is supplied by the pilot metering needle.  The pilot system gets an adjustable air supply because the fuel/air needed at idly is so tiny that just a hair inaccuracy will screw up the idle and it would be too fussy to fit a fixed jet.  Anyway, the air from the needle goes to the pilot emulsion tube where it gets mixed with the fuel supplied by the pilot jet.  The pilot system and the main system are completely separate from each other and share no internal passageways or components.  You do not see a pilot emulsion tube in the exploded view because the tube is actually part of the pilot jet itself.  The pilot jet is just the size of the hole bored into the end of the jet.  The tubular part with all the little holes bored in it is the pilot emulsion tube.  Fuel gets sucked up through the jet in the end, and air from the needle gets sucked into all those little holes and mixes with the fuel before it ever goes into the main bore of the carb.  So when you take the carb apart to clean it, you have to remove the pilot jet with its made on emulsion tube and make sure all the little holes are clean, that the bore or well that it goes into is clean and that the passageway from the needle to the well is clean.  If you look at the pilot jet, you will see that the end that goes into the carb body first has a taper.  That taper seats to a mating taper in the body, so air in the well surrounding the pilot jet emulsion tube can't leak past the joint - all the air must go through all the little holes and mix with the fuel.  Once you understand this, it is easy to follow the paths of the air, fuel, and air/fuel mix and make sure the passageways are clean.  On most Mikuni VM carbs, the air for the pilot system is supplied by the bore at 8:00 o-clock. Often you can see the tip of the needle through this bore.  The air for the main system is at 6:00 o-clock.  If the carb is clean and disassembled, you should be able to shine a bright light into the emulsion tube bore - straight up from the bottom - and see the light through the main air jet - it is a tiny hole!

Thank you for the explaination, it is much appreciated.  I hope to have some time tomorrow to work on the carbs.

Offline teazer

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 8161
Re: My Suzi T500 Project *New Video*
« Reply #1239 on: Mar 10, 2017, 23:51:54 »
Nice explanation Mobius. 

In general, if the slow speed jetting is non responsive to changes in the slow speed air screw, it means that the mixture is too rich or too lean to respond.

Main jet air jet is typically 2.0mm on a VM34 carb for a two stroke and rarely needs to be changed. The air jet changes the rate at which fueling changes with revs. So for the same sized main jet, a larger air jet will be much leaner at high revs than a smaller air jet but that difference is only at high revs.  At lower revs it makes little or no difference.  And yes, that's a variable with air speed where most of the time we are talking about different throttle openings.  Adds a whole new dimension.......
« Last Edit: Mar 11, 2017, 20:35:11 by teazer »