Comparing 74 to 76 float bowls and complete carbs ?

[pearljam724]

The bowls do not appear to vary from one another ? Can anyone confirm if they are exactly the same or not ? And what exactly is different on 74 carbs compared to 76 ? From what I remember maybe reading, is the 74 carbs have a different air pilot circuit. Does that sound right ? If that is correct, what else ?

[GT750Battleship]

Hi,if you google "Suzuki Two Stroke Bulletins" there is a list there of the specifications of the models,including the L & M models,from memory some of jetting is different,due to the increased power from the M model onwards... 67hp to 70hp
Cheers,
GT750Battleship.

[RING_DING]

L Model carbs have the butterflies set at 120 degrees. M/A/B all have their's at 110 degrees. Jetting is different between L and MAB.

[pearljam724]

L Model carbs have the butterflies set at 120 degrees. M/A/B all have their's at 110 degrees. Jetting is different between L and MAB.

Can someone explain that, if different models have the butterflies set at different degrees at stock ? If someone let's say put 74 carbs on a 76. I know you could change the jetting and adjust the butterflies ( degree angle ) to suit a 76 ? Under that circumstance, I would assume 74 carbs would work fine on a 76 ? Same goes for putting 74 bowls on a 76 carb.

[tz375]

Butterfly angle is not adjustable, it's the way they are machined. Bowls bodies etc are all the same across years that used BS40 carbs.

If you fit late model carbs to say a 74, I would expect that no changes would be needed. Just run the later carbs and adjust jetting IF needed.

It is possible that changes to porting and pipe design may have been part of the reason for the jetting changes but I suspect it was more of a fine tuning from the first year to later years. Only one way to find out. Are your carbs damaged and you can only get a different year set or some other reason for the change?

[pearljam724]

Butterfly angle is not adjustable, it's the way they are machined. Bowls bodies etc are all the same across years that used BS40 carbs.

If you fit late model carbs to say a 74, I would expect that no changes would be needed. Just run the later carbs and adjust jetting IF needed.

It is possible that changes to porting and pipe design may have been part of the reason for the jetting changes but I suspect it was more of a fine tuning from the first year to later years. Only one way to find out. Are your carbs damaged and you can only get a different year set or some other reason for the change?

No, my carbs are fine. I appreciate your concern. However, one bowl had a chopped up pilot jet thread. I had to drill it out, retap and rethread the hole because a retractor bit would not remove it either. After retapping and rethreading the hole, the new pilot will not seat as far down as it should. No matter how long I work on it. I can not drill out the old tip. I have no drill press. Therefore, I was afraid if I drilled much longer by hand I would bore out the diameter too large. The new jet seats. But, it sticks up a millimeter or two higher than it should. As you probably know there is a small channel that runs into the pilot jet head. I'm hoping the pilot jet head being slightly higher than that channel doesn't affect my idle. But, if it does. I have one 74 bowl at my disposal. The problem with it, when I received it. It had gas setting in it for so long it turned harder than concrete. No exaggeration. I have most of that finally removed by drilling it out and all but one passage cleared. It remains soaking in carb cleaner for going on 2 weeks now and one cavity that goes from the top lip down to the belly of the bowl is still blocked with that concrete like substance. I am going to try boiling it in very hot water. If that doesn't work, I'm going to try an Ultra Sonic Cleaner. Hoping one of the two bowls will be fine. Any suggestions would be appreciated.