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the discussion on running an open primary triumph got me to thinking about an open primary ironhead. what modifications are invovled in doing that? is it worth all the work required? is there any reason to do it besides looks? anyone got any pics of 'em done this way?? thanks-
 

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Yes you can run an open primary on a Sportster, you have to plug the access door and devise a fill method. The drain plug is under the tranny as well as the primary so that is not an issue. The other thing is convert back to a dry clutch like the early till 71 sportsters had. I don't think it's worth it the only time anyone gets to see it is at a standstill and big deal it's a chain going round. I think on a big twin when all tin primary covers are off it looks ok, but I remember several people running jockey shifts and open primarys that lost a finger or two, I never saw the attraction but everyone is different.
 

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I was going to do it on the single downtube ironhead project I sold to patinaturner. Karata makes a belt drive kit for the Ironhead that would have worked out perfect. Beyond that, everything the guys said above, plus the fact that you need to fab. footrest/peg mounting business.
 

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its no ironhead but here was a sportster I saw at the smokeout last year that had a 3 inch open belt with a 5speed big twin trans...if someone has a picture of the other side of this bike please post it.

 

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Having been there, I would NEVER try to do it again. Sorry for the hideous photo. I put all my money into this bike, and not into a decent camera.

You can only do this with an early wet clutch model (pre-72). The clutch cable anchors on the later model primary covers.

You need to first plug the oil transfer valve/port that vents oil into the primary. Then you need to drill and tap the two holes in the trap door for pipe thread plugs. You'll need to replace the trapdoor bearing with a sealed one (the original on mine was just shielded, not sealed). You also will need to make an alternate way to fill the tranny. I made a filler through one of the bolts that anchor the rear engine mount. As you can see in the photo, I squeezed a bunch of Hylomar between the trap door and the case. That's where the problem is. The trap door was not intended to seal in oil. I didn't use a gasket there because that would mess up the tranny endshaft measurements. I couldn't get the tranny to stop leaking. I think the next move would be to machine an o-ring groove on both the trap door and case. It's Hackasaw's problem (er... challenge) now.

By the way, that's an old Primo setup (no longer available) that I got NOS from a Boston area shop with no instructions. I called Primo and a guy there (old enough to remember this product) told me it had to be run wet - the belt will survive in straight 30 weight.

Dan said:
the discussion on running an open primary triumph got me to thinking about an open primary ironhead. what modifications are invovled in doing that? is it worth all the work required? is there any reason to do it besides looks? anyone got any pics of 'em done this way?? thanks-
 

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tom said:
its no ironhead but here was a sportster I saw at the smokeout last year that had a 3 inch open belt with a 5speed big twin trans...if someone has a picture of the other side of this bike please post it.

So somebody took a motor, whacked off the transmission (which makes one useless tranny, who needs a unit tranny minus the unit?) and replaced it with essentially the same thing? For what, an open belt? seems a bit counter productive....
 

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So somebody took a motor, whacked off the transmission (which makes one useless tranny, who needs a unit tranny minus the unit?) and replaced it with essentially the same thing? For what, an open belt? seems a bit counter productive....
belt drive, kicker & 6 speed!
 

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So somebody took a motor, whacked off the transmission (which makes one useless tranny, who needs a unit tranny minus the unit?) and replaced it with essentially the same thing? For what, an open belt? seems a bit counter productive....
Sportster transmissions sometimes spontaneously whack themselves off and take a chunk of the cases with them.
 

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I happen to be doing that right now to a customers 75 sporty, same thing as one of the guys said above, I will be using 515 flange sealent on the trap door and was thinking of cutting a groov in it............pics when I'm done......Roach.
 

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Yeh, sorta, My Customer went side ways on me, listened to the wrong people, It still weeped a little, but not bad, the clutch cover was not the way I would have liked it to come out, It needed suports welded on and the customer did it him self, didnt listen again and it came out crappy, He still ows me a grand in labor not to menchen all the harware I threw at it!! It still looked Awsome...........Roach.
 

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It was a 75, so converted to right side shift, the pics are in my "custom sporty" thred. If you have a 77 and later, you will have to make a left side support for the shifter shaft and some kind of seal, it's harder on the 77 and later, I havnt done one of thoes.......Roach.
 

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So, lets see, after plugging the holes in the trapp door and locktite 515, useing a seald main shaft bearing, plugging the cross shaft end cap, and useing some locktite 515 on the shifter fork shaft, I allso had to make a plugg for the main shaft/clutch hub shaft inside the clutch hub, still weeped
 
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