The “Moog Mod” air-duct replacement tip
This article is an edited version of a KTOF post by member “AtLarge”, about his 1983 KZ750-K1 LTD (reprinted/edited with his permission). The original can be found here: “I call this the Moog mod.”
…And this important caveat from the author, “…the earlier bikes have 38mm carbs where as mine is 34mm so keep that in mind. If your using it on other models there are probably other bellows at the auto parts store that would work if this one won’t fit for you. Just go during a slow time and have the counter guys help you rummage through the shelves. Most of them are pretty good sports.”
I needed replacement intake air ducts, because I had one good intake duct and one off of something else. As I’m sure the rest of you 750 people know, the ducts are very hard to come by. Frankly, I wasn’t all that pleased with the design anyway, so I stopped hunting for one and came up with my own.
Moog mod, side view, on bike
Here’s what I used: Rack and pinion bellows for a Prizm. You can buy them right online from O’Reilly….
MOOG – R/P BELLOWS (93-83 LEXUS/TOYOTA)
Item No: K9321
$26.99 per Box (at this writing)
Moog R/P Bellows
Bought two new ones and cut them to fit. Works great. Has some give, so it will handle the vibration. Much easier to connect to the carbs, and seals better than the originals I think, too. I haven’t put the carb clamps on yet because I don’t have any. I’m working on that next but it’s such a nice snug fit I almost don’t think it’s necessary. It’s automotive grade rubber so it should be okay with the heat.
Did all the work on it while the air box was still in the frame too which was no small feat I might add. Still retained all the original components (except the ducts).
Here’s a shot of the business end.
Moog mod, inside airbox view
Here’s a shot showing the bellows are actually sandwiched in between the clamps. The seal is impervious to water. All the air must pass through the air box opening and the filter.
Moog mod, bellows-clamp view
Note from Biquetoast: Please note that I have not done this/these mod(s) myself, so I cannot validate any of the claims here, nor do I know the models for which this will work. Although if you’re a 750 twin rider like me and AtLarge, you will likely face the need to find replacements like this someday too. So if you ever try this, please let me know and I will update this page if I ever do this as well. Good luck!!
