Intakes and Air Boxes - Questions

[ConnerVT]

First, tell me if what I have figured out so far is correct for the T500:

Intake Pipe -
Early -- Single piece -- Metal flange, with integrated rubber carb mount. Uses a single clamp.
Late -- Two pieces -- Metal flange, with separate rubber boot. Uses 2 clamps (1 for flange, 1 for carb)

Air box -
Early -- Paper filter element.
Late -- Two foam elements on metal frame.

The 71 T500R I'm working on (matching serial numbers, so 71 engine) came with the early single piece intakes, but a later foam element air box.

The later versions of the engine (such as the 1973 motor that is going on the bike) have the later, two piece intakes. Sizing things up, with the longer intakes, the carburetors will never fit in the remaining space.

Now, the PO was able to make the early intake/late air box work. My guess is the difference is the dimensions of the air box hose (boot)? Does that make sense, or am I overlooking something?

I would really like to use the late intake setup, as the early intake rubber pipes I have are pretty cracked. Also, the good set of carbs I have are jetted for the later models. How do I get this to fit?

[oldjapanesebikes]

First, tell me if what I have figured out so far is correct for the T500:

Intake Pipe -
Early -- Single piece -- Metal flange, with integrated rubber carb mount. Uses a single clamp.
Late -- Two pieces -- Metal flange, with separate rubber boot. Uses 2 clamps (1 for flange, 1 for carb)

Air box -
Early -- Paper filter element.
Late -- Two foam elements on metal frame.

The boots were offset - the alignment differs between the old style and the new style on the bottom of the airbox - obviously the PO made it work, but it is something to be aware of as I suppose airleaks are possible. Also at some point the oil pump cover was modified with a section being cut out. This allowed the bottom of the carb to clear the pump with the longer inlets fitted.

[ConnerVT]

Thanks for the reply, Ian. You are the second person to confirm that there is indeed a difference between the early and late model air box boot. I also learned about the oil pump cover today -- I was trying to figure out why the difference, as I have one of each. Now I understand.

I'm now strongly leaning towards grabbing a new air box boot, and going with the late model setup (I either needed new early intakes, or a new late boot, to have a complete setup). The carbs are already jetted at 97.5, and I don't mind losing a horse or two.

It was frustrating yesterday, when things just aren't going together right, and not having a plan of action. Feeling a whole much better now.

[ConnerVT]

The saga continues...

I still have not figured out how the late model setup fits in the available space. The additional extension add nearly 48mm of length (17mm vs 64.7mm, measured from base of flange to inner mating surface for carb). I'm currently set up with the old style intake and late model air box and boot, and things just barely fit. How to have things fit with an additional 1.8"+ of length? You'd need to move the battery box rearward (and move the frame mounting tab for the air box rearward as well). Suzuki shows but one part number for the battery box, and I would be surprised if there are significant differences in the frame year to year. So I'm taking another path.

The good news is today was the first day my project has fired up and run on both cylinders!

YouTube -- T500R comes back to life!

Most of my headaches have been self inflicted --

• Replaced the float valves with those from a Keyster kit. Turned out they were too long.

• Then installed the original valves. They leak badly (as well as the bad o-ring in the petcock, now replaced.)

• Left some crud in one of the needle valves, which the left cylinder really didn't like very much.

Found that Dennis Kirk has genuine 2.5 Float Valves for $16 each (needle and seat), as well as Pilot Jets and large round Main Jets for $6 (set of 2). Grabbed a set of Pilot Jets, as well as a grouping of Main Jets, which will be my next project.

Now that I've disassembled/reassembled the fuel system on the bike more than a half dozen times, I'm really fast at it now.

I'm running a bit strange of a setup --

• 1973 engine (should be long intake/new air box)
  Short intakes
  New Air box/boot

I have enough carb parts to build most any config (P-4 and P-5 needle jets, 5PF8 and 5PF17 needles, 150 and leaner jets, 97.5 jets). Currently, I have the carb in a stock 1971 config:

P-5
5FP8 in 3rd slot
30 Pilot Jet

Though I have a feeling it is running a bit rich at the moment (only have driveway time with it so far, can't get it on the road for the next few days). Does that sound right? What changes/actions would you do next? All input is welcome.

[Vintageman]

ConnerVT.

I went through this exercise. I was trying to make a late model like the early. Then later decided original is best

I find if you use part diagrams from like Dillon Power Sports for example you we see what is a different ... part# at least. Maybe you knew that?

http://www.powersportspro.com/pages/Oem ... uki/T500L_(1975" onclick="window.open(this.href);return false;)/CYLINDER_HEAD_-_AIR_CLEANER/091330024/56091330001

Yes the air boot is different if I recall. Early less restrictive as well I think the air box makes the most in length change. Same frames it looks like part# wise

In my experience the late airbox is restrictive. They did a similar change with 76/77 GT250 verus 73-75. Yes people will tell you other changes as well and they are correct, but the air box /filter is a significant diff. That affects jetting a lot of course

I would not run early Jetting with later airbox. If I had the early style I would keep it all early parts.

Are you in Vermont?

[ConnerVT]

Are you in Vermont?

I was for 25+ years, up in Burlington. Last year, I took a new job, and now I'm just south of Saratoga, NY.

As far as setting up the bike as a late model, that is what I have trying to do. I just don't see how everything will fit. The frame I have is a 1971, but the PO had a late model air box on it, with the early intakes. The motor was trashed, but picked up a 1973 motor up in Littleton, NH. That had the late model "Pipe, Intake 2" (the metal flanges for the cylinders).

I picked up a set of "Pipe, Intake 1" (rubber intake boots), but that puts the carbs so far rearward, to where the carb tops are nearly against the leading edge of the air box. I just don't see how to make the late model setup fit.

here's a picture of the early vs. late model intakes. Nearly 48mm difference in length. With the early intakes, the front/back length is nearly perfect.

Intakes.jpg

[Vintageman]

I am in SW NH. Was curious.

I think most of the difference in length is compensated by the air box late mode versus early. Have you checked that?

If you have the late style carb aluminum and rubber flanges, Y boot, and airbox, I believe all should fit inside early frame and with existing bat. box.

You can get a 159 series needle jet if the original (188?) is bad

Jet needle??? Not sure if the one that Keyster Kit offers is more like the late model or one of the early needle jet if either!

[ConnerVT]

I think most of the difference in length is compensated by the air box late mode versus early. Have you checked that?

This is exactly my issue. I have the late air box and the early intake, and all fits nearly perfect (a very slight vertical alignment issue). Front to back length is nearly perfect.

Installing the late intake with the late airbox, there is only enough space between the intake rubber boot and the airbox boot to fit maybe half a carb. It has me really puzzled.

As far as needles and jets, from the two sets of carbs (and extra Main Jets) I have, I have enough parts to build things in most any stock config (as well as non-stock). The 8 needles are a tad worn, but I'm still trying to get to 90% tuned first.

[AFRetired]

Don't know what yours looks like together, here my stock '74 T500 setup.

[ConnerVT]

AFRetired, Thank you! It answers a question for me, and opens up room for a bunch more.

This is what my setup currently looks like:

Modified air box.jpg

First obvious difference is the top mounting bracket for the air box. Look how much more extended the one on your bike is. Mine has the mounting bolt close to the air box, yours extends what looks like 2"+ from a much longer arm.

But my air box can't move back that far. There are two air intake vents along the back of the air box. They don't look like they are stock, not something added on afterwards. Also, the door on your airbox seems flatter than on mine, which curves on the sides (could be the picture).

So I would guess that the air box on mine, while probably Suzuki, is neither from an early or late model T500. Anybody recognize it?

[AFRetired]

I agree, it doesnt look quite like the same airbox. I have the snorkles on the back of mine too, butts right up against the battery box. Here's a bigger pic of mine, almost the same angle as yours.

Comparing the pics, it looks like the centerline of your filter box is well fwd of where mine is. In fact, it looks like the battery box is fwd as well, compared to the chain guard/trans case join.

[ConnerVT]

Thank you for the second picture.

I agree that my battery box seems a bit forward from yours. On my bike, the trailing edge of the box is just forward of the rear side cover hook/bracket. My battery box is stock. I picked up one on eBay to replace the original acid eaten one, and both are identical.

Interesting, it seems that your battery box does not align with the screw bracket on the inside of your oil talk. On mine, the battery box bracket aligns with the screw right to the oil tank.

My frame shows no sign of welding modification. Wonder if Suzuki did actually modify the frame in later years, to locate things in order to make room for the longer intake.

[AFRetired]

I'll try to get some more pics tomorrow of the batt box mounting

[AFRetired]

OK, here's a underside pic of the battery box to oil tank mount, as well as the batt box to air filter box. Looks like my oil tank has two mounting points, one fwd and one rear. Also a pic of the side view of my bike (just to see overall placement of parts from a side view).

[ConnerVT]

Thank you so *VERY* much for taking the time to take these pictures! It is very much appreciated by me, and will likely be a useful resource for others down the road. I have a few more pictures I took today (still in the camera), as I needed to pull the carbs of my bike one more time, so I documented a few more things. I'll post them next time.

I now am fairly certain that Suzuki made some changes to the frame (as well as the later oil tanks, based on your latest pictures). I believe on later bikes, they located the cross member which the battery box (and the voltage regulator) further rearward to allow room for the longer intake. They extended the mounting arm on the air box, and left that weldment on the frame the same.

On the oil tank, I only have 1 mounting tab hold for the battery box to bolt to (1971), while on yours (1974) there are two. I bet if you measure (but you don't need to!), they are 47mm apart. The difference I measured between the early and late intakes. manufacturing tanks with two mounts would make sense, as then Suzuki could only stock one replacement for all years, and not need two different parts.

In all, this has been an interesting exercise. The best news is I just took my first ride on the bike, which I have been working on since February. I've resolved all of the major issues, now just need to dial in the carbs. My wife is chuckling at me, as I got off the bike with a huge ear to ear grin on my face!