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Author Topic: My Suzi T500 Project *New Video*  (Read 133655 times)

Offline HollywoodMX

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Re: Re: My Suzi T500 Project (Finished Video & Pics!)
« Reply #1050 on: Jan 25, 2014, 02:09:39 »
Just weighed each end today 158lb rear and 161lb front so it adds up to 319lb not sure how accurate that is!  I was sure it was lighter than that, my KTM is 228lb and it doesn't feel a lot different ot the Suzuki.  Must be the weight is higher up on the KTM :)

It's probably close enough.. Lol.  Where the weight is is carried makes a big difference an interferes with Human estimating.  The Buell carries it's gas in the frame and the oil in the swingarm then the exhaust under the engine.  It feels like 325 but still is 395 with the overweight v twin.
TR1 Build thread: http://www.dotheton.com/forum/index.php?topic=54733.0
Xv920 Tracker thread: http://www.dotheton.com/forum/index.php?topic=59754.15

77 KZ1075 Supercharged - 81 Yamaha XV920rh (x2) - 06 YZ250 highly modified - 08 Hyabusa

"I live my life a 1/4 beer at a time"

Offline clem

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Re: My Suzi T500 Project (Finished Video & Pics!)
« Reply #1051 on: Jan 25, 2014, 11:01:38 »
If I am correct, that's over 100 lbs of weight loss!
"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 Walms

  • Posts: 397
My Suzi T500 Project (Finished Video & Pics!)
« Reply #1052 on: Jan 25, 2014, 13:56:50 »
70 lbs less than my 500... ;)

Offline johnu

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Re: My Suzi T500 Project (Finished Video & Pics!)
« Reply #1053 on: Jan 31, 2014, 17:46:53 »
Finally picked up my pilot jets this week :)  Tried the 45's first and it still ran about the same, idle was high though when I started it.  So I put the 25's in and I had to turn the idle up when it started, it ran quite a bit better (with air srew 1.5 turns out).  So next I played with the air screw but it is still very difficult to detect any change in the way the engine is running, it didn't stall or rev up no matter which way I turned the screws.  So I set them at half a turn out and rode it and this made it run worse.  Then I set them at 2.5 turns out and that made it run better than any other setting so far.  It is still not wanting to pull cleanly when you first pull away then suddenly it takes off.  What should I do next to clean it up even more?

Offline Walms

  • Posts: 397
My Suzi T500 Project (Finished Video & Pics!)
« Reply #1054 on: Jan 31, 2014, 19:22:21 »
Check to make sure your coils and motor are grounded well to the iggy.
I had a suspect ground to my coils and the bike would idle fine putt around ok but as soon as the pipe started building pressure, it would fizzle out.

Offline johnu

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Re: My Suzi T500 Project (Finished Video & Pics!)
« Reply #1055 on: Jan 31, 2014, 19:27:36 »
Check to make sure your coils and motor are grounded well to the iggy.
I had a suspect ground to my coils and the bike would idle fine putt around ok but as soon as the pipe started building pressure, it would fizzle out.

I will check but they should be ok as I sanded paint off all of the ground points when I built everything up :)  I think I am going to go down one lower on the pilot jet to a 22.5 and see if that makes it better.  I really think that's the right direction, must be worth a try anyway ;D
« Last Edit: Jan 31, 2014, 19:33:16 by johnu »

Offline cobraace2

  • Posts: 259
Re: My Suzi T500 Project (Finished Video & Pics!)
« Reply #1056 on: Feb 01, 2014, 15:00:16 »
Finally picked up my pilot jets this week :)  Tried the 45's first and it still ran about the same, idle was high though when I started it.  So I put the 25's in and I had to turn the idle up when it started, it ran quite a bit better (with air srew 1.5 turns out).  So next I played with the air screw but it is still very difficult to detect any change in the way the engine is running, it didn't stall or rev up no matter which way I turned the screws.  So I set them at half a turn out and rode it and this made it run worse.  Then I set them at 2.5 turns out and that made it run better than any other setting so far.  It is still not wanting to pull cleanly when you first pull away then suddenly it takes off.  What should I do next to clean it up even more?

Ok John how does it run  above 4000 rpm. If it runs good  maybe you should talk to Eric about how wild he got on the porting ;D As you start to port any 2stroke you start to loose drive ability down low  :(  that's why a lot of guys install reeds to get some of that back

Offline HollywoodMX

  • Posts: 766
Re: Re: My Suzi T500 Project (Finished Video & Pics!)
« Reply #1057 on: Feb 03, 2014, 03:51:46 »
Finally picked up my pilot jets this week :)  Tried the 45's first and it still ran about the same, idle was high though when I started it.  So I put the 25's in and I had to turn the idle up when it started, it ran quite a bit better (with air srew 1.5 turns out).  So next I played with the air screw but it is still very difficult to detect any change in the way the engine is running, it didn't stall or rev up no matter which way I turned the screws.  So I set them at half a turn out and rode it and this made it run worse.  Then I set them at 2.5 turns out and that made it run better than any other setting so far.  It is still not wanting to pull cleanly when you first pull away then suddenly it takes off.  What should I do next to clean it up even more?

You have a good selection of jets to at least point you in the right direction. I'm leaning to what the cobra is saying. The porting must be interfering with things.

I have an idea. Can you make custom washers that sit between your pods and your carbs. Your goal is to create more pressure by restricting the airflow. A easy trick is to cut the tops off a soda can. With the drink tab fully removed pointed towards the floor. That make sense?

Try that and try your range of pilot jets to see if they start providing you a direction.

Also are you sure you absolutely sure you have no vacuum leaks? Have you done the spray test?
TR1 Build thread: http://www.dotheton.com/forum/index.php?topic=54733.0
Xv920 Tracker thread: http://www.dotheton.com/forum/index.php?topic=59754.15

77 KZ1075 Supercharged - 81 Yamaha XV920rh (x2) - 06 YZ250 highly modified - 08 Hyabusa

"I live my life a 1/4 beer at a time"

Offline Walms

  • Posts: 397
My Suzi T500 Project (Finished Video & Pics!)
« Reply #1058 on: Feb 03, 2014, 08:59:54 »
I don't see how restricting the intake makes sense?
Was the motor ported by someone who knows what he's doing? To suspect its the porting at this point would make me a bit concerned.
Was the combustion chamber cut to bring the compression back after raising the ports?
If it were me, I'd want to know the port timing and compression before even starting the bike.

Offline jpmobius

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Re: My Suzi T500 Project (Finished Video & Pics!)
« Reply #1059 on: Feb 03, 2014, 09:21:37 »
John, Fantastic build.  Really like the pipes.  From everything you have reported so far, you have been and still are rich on the pilots.  Have to admit, seems odd as you are pretty small now.  Couple of things.  Are you still running your vent lines and can?  Remove this if so, at least until you get it sorted.  Also, where are the jets from?  Get some authentic Mikuni jets if yours are not the real McCoy.  Some replicas can be way off.  Otherwise, go through and re check all the obvious stuff for leaks and proper assembly.  If you have not had the carbs apart completely, maybe you should just to be sure the is no restriction in the pilot air system.  Also, check the emulsion tube style.  If it is solid, you may want to consider going to the alternative type with the vertical columns of holes.  Down the road though, as you should get it closer first.  Lastly, there is absolutely no question as to how profoundly the pipes and porting can afflict the low end.  I recall a drag motor I built a long time ago much like yours.  Big carbs, very heavy porting on a piston port motor, and pipes aimed at max power and high rpm.  Wicked power (10's on an AC 350), but absolutely no idle below 2500rpm.  VERY hard to start with the kick, but easy if you got the motor to spin up to 2500!  At Idle, you would have fuel dripping off your hand if you held it near the intake.  This thing was as lean as I could get the low speed circuit, but the tuning made the reverse air flow through the carbs so bad at low revs that it was essentially double and triple dipping the low speed system and making it super rich a low speed revs.  I remember similar no effect on the air screws like you are having.  You could actually see a fog hanging in front of the carbs at "idle"!  Looks like your situation is far less severe, but there may be only so much you can do.  There is a reason for restrictive reed valves!  At the end of the day, looks like you have had definite improvement going leaner.  Needing 2 1/2 turns out of air to see effect means you are still too rich, or there is something besides jetting making it so.  One last thing.  Forget all the carb tuning except for the mains until you are happy with them.  Get the mains right first, as they (like all the other parts) do in fact effect the entire rev range to some degree.  If the mains are rich, it may seem to run pretty good because the lower revs are so awful.  Forget that.  Get the wide open very close first.  There is no sense in compounding the much more difficult low end and drivability tuning on a two stroke!

best
Mobius


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Offline johnu

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Re: My Suzi T500 Project (Finished Video & Pics!)
« Reply #1060 on: Feb 03, 2014, 18:19:52 »
First of all thanks as always for all the comments and suggestions, really appreciate it :)

To address the porting work first: Eric from sundial motorsports is well respected for his work tuning T500's, he has many years of doing this under his belt.  My requirement from Eric was that I would end up at around 55hp with all of the engine mods, I told him I wasn't too bothered about the bottom end but he insisted that he port it so that it would have good power all through the rev range.  This was corroborated by a member on here that did the calculations for my pipes, he told me that the porting specs on my cylinders is not real crazy.  The pipes were also not designed for power all in the high rpm range, they should work well at low rpm as well as up higher.

I raced two strokes for many years and I know the basics about how they run and how one thing will effect another but unfortunately I never really paid much attention to the carburation, I had a tuner that worked with me on that.  I guess what I am saying is that I can tell by feel that this is most likely not a porting issue but a jetting issue.

Anyway I will do a plug chop at full throttle to check where I'm at on the main jet.  My carbs are brand new and I have had them totally apart and there are no obvious issues.  All the jets I've used have been genuine Mikunis.

Again keep the comments coming I am glad there are people interested in this it is a big help!

Offline clem

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Re: My Suzi T500 Project (Finished Video & Pics!)
« Reply #1061 on: Feb 03, 2014, 23:07:44 »
John I wanted to give you props on the pipes. As I found out gas welding 22ga. is very tough!
"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 Walms

  • Posts: 397
My Suzi T500 Project (Finished Video & Pics!)
« Reply #1062 on: Feb 04, 2014, 00:10:36 »
One sure fire way to know if you are running lean on the idle circuit is by wicking the throttle quickly in neutral, if you get any bog before it picks up, it's lean.

Offline johnu

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Re: My Suzi T500 Project (Finished Video & Pics!)
« Reply #1063 on: Feb 04, 2014, 00:52:36 »
John I wanted to give you props on the pipes. As I found out gas welding 22ga. is very tough!

Haha thanks, gas welding 22g mild steel is a piece of cake compared to gas welding aluminum tanks :)

Offline HollywoodMX

  • Posts: 766
Re: Re: My Suzi T500 Project (Finished Video & Pics!)
« Reply #1064 on: Feb 04, 2014, 03:51:51 »
First of all thanks as always for all the comments and suggestions, really appreciate it :)

To address the porting work first: Eric from sundial motorsports is well respected for his work tuning T500's, he has many years of doing this under his belt.  My requirement from Eric was that I would end up at around 55hp with all of the engine mods, I told him I wasn't too bothered about the bottom end but he insisted that he port it so that it would have good power all through the rev range.  This was corroborated by a member on here that did the calculations for my pipes, he told me that the porting specs on my cylinders is not real crazy.  The pipes were also not designed for power all in the high rpm range, they should work well at low rpm as well as up higher.

I raced two strokes for many years and I know the basics about how they run and how one thing will effect another but unfortunately I never really paid much attention to the carburation, I had a tuner that worked with me on that.  I guess what I am saying is that I can tell by feel that this is most likely not a porting issue but a jetting issue.

Anyway I will do a plug chop at full throttle to check where I'm at on the main jet.  My carbs are brand new and I have had them totally apart and there are no obvious issues.  All the jets I've used have been genuine Mikunis.

Again keep the comments coming I am glad there are people interested in this it is a big help!

Oh I was not saying it's a porting issue. I should have been more clear I was leaning that the porting is causing a jetting issue due to change in velocity of air coming through the carbs this compounds when you Ditch the factory air box for pods as well (some bikes worse than others).

The reason for the pop can top test is to increase your low volume low pressure at idle to a higher pressure.
Switching to focusing on the main might help in this drastic situation but if you are going to that, you might as well tune the needle in the same direction as the main. Meaning if leaning the main 1 size produces postive results I would lean the needle next and ping pong the two.

How much lower do the pilot sizes go? 25 sounds really small. What was stock again?
TR1 Build thread: http://www.dotheton.com/forum/index.php?topic=54733.0
Xv920 Tracker thread: http://www.dotheton.com/forum/index.php?topic=59754.15

77 KZ1075 Supercharged - 81 Yamaha XV920rh (x2) - 06 YZ250 highly modified - 08 Hyabusa

"I live my life a 1/4 beer at a time"