Suzuki 2 Strokes

Ok, I ordered the carb boots that go between the carb and the jug, I have a 1974 gt750 , I'm pretty sure it's an early model, you can tell by the head bolts and washers, also the engine and frame number are low, anyway I got the carbs off to put the new boots and they don't look the same! crap! The original ones are contoured to the intake and the new ones are just flat with a little raised area, is tis how they are supposed to be? I'm pretty sure the boots I have on the bike are original, but I'm not sure what the original owner might have done. I compared the new ones and old ones while they were on and the original ones seem better so I was thinking maybe it needs the early style ? The 1972 to 1973 ?

Hi,can you tell us the engine/frame numbers? You may very well have the wrong engine/frame who knows,so much gets changed around on these old girls !!!
Cheers,
GT750Battleship.

It shouldn't matter, the later or early style boots should work on either late or early motors. As long as the diameters and lengths are the same. I know the late models have a recessed ring around the intake flange on the cylinder. While the boots have an exposed area on the interior to fit into that recessed ring. All that ring does is keep the boots from slipping off and maybe help a little with creating a better seal. Regardless of your old boots having that shouldn't matter as long as they are the same length and diameter. Aesthetics means nothing. All they need to do is fit properly without leaking. Im pretty sure the jugs are identical, its only the style of the boots that changed. No big deal. I can't verify that the intake ports are the same diameter though.

I can't speak for the early ones, but if yours is a 74, all three carbs are mounted to a single 'rack'. The intake boots should have raised area on the cylinder side. Looks like a molded in half an o-ring. Did you buy NOS or aftermarket boots?
The early boots are different. I think the intake bosses cast to the cylinder are smaller in diameter for the VM carbs. The early ones used a cable to operate the oil pump while the later ones used an arm off the throttle shaft with a rod linkage to operate the pump. If yous is a 74, that rod should be obvious.
I might get hammered here, but without having special boots molded up, there is no way to mount early carbs to a later cylinder and visa versa.
Again, your boots should have a raised half an o-ring where it pops onto the cylinder IF it is a 74 - 77.

ok, i bought the bike as a 74, as the title says , but the frame number is 41113 and the engine number is 44604, im not sure if it is a 74? i have not looked it up in a book I just figured it was a 74, it has the rod for the oil pump and all 3 carbs are mounted on a rack. The boots that were on it, if you take them off and look at them from the sdie that the carb mounts to, it has a funnel shape that contours to the intake port on the jug. The new boots do not have this, they are just flat which kinda leaves some of the port exposed( if you put the boots on the jug you can see the metal from the jug, the old ones cover this) I wish I would have taken a pic, but i put the old boots back on because I thought the seller shipped the wrong ones, but they didnt. The boots are part number 13111-31201 oe suzuki and the part number is for a 74, so I was thinking maybe mine take a 72-73 style boot? i have never seen the early style boot so i have nothing to compare it to, but the boots that came do have a raised ring on both ends that fit into the intake side of the jug and of the carb, maybe they just stopped making the boots like mine , and started using these as replacement parts? it just seems that my old boots would have a better flow that the others.

Hi Eddie,thanks for the info on your bike,yes it's a '74 L model as such the boots should have a "raised moulded section" on the "INSIDE" of the boot,looks like a little ramp. Position this section at the bottom of the inlet port when fitting!! THIS RAISED SECTION is there for a REASON!! to help atomise the fuel as it enters the cylinders,so I'm afraid if anyone thinks a "boot is a boot" forget it!!! All things are designed for "a reason" ?
Cheers,
GT750Battleship.

pearljam724 wrote:It shouldn't matter, the later or early style boots should work on either late or early motors. As long as the diameters and lengths are the same. I know the late models have a recessed ring around the intake flange on the cylinder. While the boots have an exposed area on the interior to fit into that recessed ring. All that ring does is keep the boots from slipping off and maybe help a little with creating a better seal. Regardless of your old boots having that shouldn't matter as long as they are the same length and diameter. Aesthetics means nothing. All they need to do is fit properly without leaking. Im pretty sure the jugs are identical, its only the style of the boots that changed. No big deal. I can't verify that the intake ports are the same diameter though.

Hi,sorry to say "a boot is a boot" is not true in this case,the bikes intake rubbers are different,not only to look at & the way they mount,but internally,the later bikes, L,M,A,B models with the vacuum carbs have an internal raised section inside them,looks like a little ramp,THAT must be fitted with the raised section fitted at the bottom of the cylinder inlet port. This raised section is there for a reason...to help atomise the fuel as it enters the inlet port....

Regards,
GT750Battleship.

here are some pics of the old ones and the new one, I have some pics of the old ones mounted to the intake port and it is a smooth transition, the new boots when mounted leave a large portion of the port face exposed. I took pics of the intake ports without the boots and they are oval shaped? is this normal? anyway the old boots have a funnel shape on the inside which covers the exposed intake port side , I dont really know how to explain it so here are the pics, the new boots are just open on the inside while the old boots are funnel shapped...

1st pic is with the old boot mounted, 2nd pic is with the new boot mounted, then 3rd pic is with the old boot on the left and the new one on the right, this is the side that faces the jug, the last pis is looking down the boots from the carb side , if you notice the old boot has a funnel shape all the way around the inside diameter and the new boot is just open all the way around on the inside, both boots fit and will mount the only difference is the inside of the boot, and yes the new boots have the little ramp, that mounts to the bottom, the old boots basically have a ramp all the way around...

Sorry the last pic is of the new carb on the left and the old one on the right....I'm bad at computers!

Hi Eddie,yes use the one on the right in picture 3 ! THIS is the correct BOOT for your bike & all the later VM equipped bikes. Just make sure that the little raised internal "bump" is against the inlet port & situated at the bottom of the port,I have seen these rubbers the wrong way round on other bikes,with the internal "bump" end fitted to the carby,they still run,BUT not as good as they should!! I highly recommend you get a copy of the GT750 DVD Carby repair by "bluesmokebaz" available on Ebay...he also has a couple more DVD's on the model history & one on a nut & bolt full restoration of a bike... Great old motor bike when you get them sorted out....! PS the inlet ports look "stock" no one has tried to enlarge or modify them which is good... is the Air Filter "stock standard" or have you got pods fitted?

Cheers,
GT750Battleship.

thanks for the reply, the last picture on the bottom has the old boot on the right, and the one on the left is the new boot, the new boot has one little ramp, in one spot on the inside of the boot, the old boot has a raised funnel shape on the inside of the boot that goes all the way around instead of in one spot. I used the new boot with the one little ramp because they are soft and new, and I did place the little ramp at the bottom. I dont know if it is because I know in my head the new boots didnt look as good on the inside as the old ones as far as having the funnel shape (its hard to tell in my pics but they are very differnt boots) but it seems like the throttle response is not as crisp with the new boots? ohh well at least I know there should be no air leaks now...

Hi Eddy,

the first pic shows everything as it should be. The small sharp edge of the right side of the inlet port seen in the pic, is a result of a bad located core at the cylinders casting process. Inner and outer diameter of the port should be concentric.

The boot in the second pic is rubbish. Much too big inner diameter. May be a poor copy, but sure no OEM part. The ramp on the bottom is completely useless.
Poor throttle response with the new boots may be a result of the much too big inner diameter of the boot and the resulting sharp edges at the connection to the inlet port. There don't have to be any sharp edges on the way from carb to boot to inlet port. Very smooth fit on each connection is the best you can have. On the back side of the boot, carb and boot have to be concentric and same diameter. On the front side boot and inlet port have to be equal in size and concentric.

By the way: Atomisation of gas takes place in the carbs jets. Nowhere else.

Bought these http://www.ebay.de/itm/74-77-Suzuki-GT7 ... 3ccfed0535 and these http://www.ebay.de/itm/72-Suzuki-GT750- ... 3cce8122b1 boot sets for my J- and K- Buffaloes. Very good fit and quality for a great price.

Get a set of the first ones, try them and be happy.

Cheers
Dirk