T500 Cylinders Early vs Late

TLRam1 · Post by **TLRam1** » Sun Sep 13, 2009 8:35 pm

Referring to the bike Kevin bought.

Kevin and I are trying to determine if these are the early model cylinders where the 150 mains were used, how do you tell by the intakes?

muzza · Post by **muzza** » Mon Sep 14, 2009 5:55 am

the later model cylinders have an intake bridge cast into the cylinder.

TLRam1 · Post by **TLRam1** » Mon Sep 14, 2009 9:46 am

muzza wrote:the later model cylinders have an intake bridge cast into the cylinder.

Kevin sent this to me in an email, does this help?

When I stick my finger into the intake port I can feel what appears to be a small "bridge" right up against the piston. It runs vertically, in line with the piston rod. If a picture is needed I'm sure I can get one, but will wait until the daylight is more favorable.

jkevinlilly · Post by **jkevinlilly** » Mon Sep 14, 2009 10:41 am

I just sent you guys a picture of the intake. From Muzza'a description they are not the early model.

Kevin

TLRam1 · Post by **TLRam1** » Mon Sep 14, 2009 6:08 pm

Here is the best photo Kevin could take, what can you tell us by this?

jkevinlilly · Post by **jkevinlilly** » Mon Sep 14, 2009 6:22 pm

Sorry for the poor quality pics guys, but the way cheap digital cameras are designed, the flash is an inch or so away from the lense on the front of the camera. When you stick the lense in the intake, the flash is no help, so you have to go with the available light.

But at least Terry knows how to put the picture on the forum, whitch is better than I can do. :^)

Kevin

diamondj · Post by **diamondj** » Mon Sep 14, 2009 11:15 pm

Kevin,

Those might indeed be early style cylinders. Here's a picture of the intake port on what is supposed to be a '69 cylinder:

Notice the bridge is only a sliver of steel in the liner and the aluminum of the cylinder does not divide the port in any way.

Here's a '73 intake port lit from inside the cylinder:

and lit from outside:

You can see the aluminum of the cylinder is split along with the steel liner.

It was too late tonight to pull the intake off of one of my '68 Cobra cylinders but I suspect it looks like the '69 pictured above.

I was under the impression that the porting was changed between the early and later cylinders as well?

Jim

tz375 · Post by **tz375** » Mon Sep 14, 2009 11:28 pm

I have had nothing to do with T500s since one tried to kill me back in about 1970, but from what I have read penned by those much more knowledgeable, I though the big difference in jetting related to the length of the intake tracts and the resonance effects in the intake.

BTW, that sliver of a bridge is not a terribly sound design - the later short splitter is much better.

TLRam1 · Post by **TLRam1** » Mon Sep 14, 2009 11:54 pm

tz375 wrote:I have had nothing to do with T500s since one tried to kill me back in about 1970, but from what I have read penned by those much more knowledgeable, I though the big difference in jetting related to the length of the intake tracts and the resonance effects in the intake.

BTW, that sliver of a bridge is not a terribly sound design - the later short splitter is much better.

Now we are getting somewhere, thanks for the posts, starting to wonder if anyone had info regarding this subject.

Meaning you needed the larger jets to get about the same amount of A/F mixture as the later models have with smaller jets and longer intake boots?

muzza · Post by **muzza** » Tue Sep 15, 2009 5:11 am

that's right, the early cylinders have only a bridge on the steel liner.
The later cylinders have a cast bridge in the cylinder as well as the steel liner bridge.e
There is next to nothing in the jet sizes, they are completely different jets but deliver much the same flow in practical terms. one is a cheese head and the other a hexagon head...don't mix them up.

jkevinlilly · Post by **jkevinlilly** » Tue Sep 15, 2009 9:54 am

Jim/Muzza,
The cyclinders on the bike match your first picture above, the cast aluminum bridge in the intake port in the other pictures does not exist on these cylinders.
The heads will go with the cylinders, so that is not an issue.
Kevin

Suzukidave · Post by **Suzukidave** » Tue Sep 15, 2009 11:45 am

jkevinlilly wrote:Jim/Muzza,

The heads will go with the cylinders, so that is not an issue.
Kevin

I think he was referring to the heads of the main jets

TLRam1 · Post by **TLRam1** » Tue Sep 15, 2009 12:48 pm

tz375 wrote:I though the big difference in jetting related to the length of the intake tracts and the resonance effects in the intake.

muzza wrote: There is next to nothing in the jet sizes, they are completely different jets but deliver much the same flow in practical terms. one is a cheese head and the other a hexagon head...don't mix them up.

TLRam1 wrote:
Meaning you needed the larger jets to get about the same amount of A/F mixture as the later models have with smaller jets and longer intake boots?

Still searching for this answer from some of the tuners, if this is the case you would still have a larger volume of A/F mixture for the motor to burn, correct? Would I need the shorter intake tubes for this to work or will the later model tubes work as these are new ones and pliable?

Eric, do you have a take on this or experimented with this scenario?

Suzukidave · Post by **Suzukidave** » Tue Sep 15, 2009 1:23 pm

Here's a chart showing the size /number difference between the round head and hex head main jets http://suzukidave.myphotos.cc/suzukidave/jets.pdf

jkevinlilly · Post by **jkevinlilly** » Tue Sep 15, 2009 1:39 pm

Jim/Muzza,

The heads will go with the cylinders, so that is not an issue.
Kevin
I think he was referring to the heads of the main jets

Duhh...

Kevin