Harley sportster crankcase hacked for tranny?

[southysuper]

I'm sure there are a few Harley guys that can answer this, but otherwise all suggestions are appreciated. I'm seeing quite a few 91-early 2000's Harley sportster frames about. The sportster unlike the evo and later "ultima" styles employees a crankcase design with the engine and trans cast a single unit like dirtbikes and most modern setups The sportster case splits in half. I'm wondering if I can hack up a crankcase and use with a yanclone shaft in place of the original crankshaft. I've seen a guy on here do something similar with a jawa but my aluminum fab skills are far from comparison. Ideas are welcome.

[bf109v7]

A 4stroke is not suitable, because engine and gear are in the same oil. Get an old 250 ccm 2 stroke, and put in a staight shaft with a puley instead of the crankshaft. This shaft has to be made by a mashineshop, but all other modificatons you can do with a saw.
Alex

[gearhead1951]

Ahh ... Excuse me but I think (KNOW) your wrong on one point at least . Sportsters DO NOT share engine oil with the trans !!

Neither does Most old britbikes ! A lot of pacific rim machinery does but you have to look to be sure !

I would not use the sportster for the conversion as there are better bottom ends made by HD that would be more likely to stand up to a diesel top end

[bf109v7]

my mistake, the gearbox shares only the primery drive oil. But this is olso makes it unsuitable.
Alex

[coachgeo]

my mistake, the gearbox shares only the primery drive oil. But this is olso makes it unsuitable.
Alex

It's been done. Folk just welded up a plate to close it up creating a box so it held oil. There are a few threads in here on builders who have done this. Don't think any used Harley bottom ends though.

[southysuper]

I would not use the sportster for the conversion as there are better bottom ends made by HD that would be more likely to stand up to a diesel top end

Thanks for the replies, but why would the sportster not be a good candidate? I would have thought the more narrow profile of the sportster primary would be better than the divorced harley tranny and very wide primary. Would the gearbox and primary sharing the same oil be a bad thing? I'm assuming there is some oil slinger in the trans that circulates oil?

Thanks,

[southysuper]

Here are some pics to help explain

[coachgeo]

I would not use the sportster for the conversion as there are better bottom ends made by HD that would be more likely to stand up to a diesel top end

Thanks for the replies, but why would the sportster not be a good candidate? I would have thought the more narrow profile of the sportster primary would be better than the divorced harley tranny and very wide primary. Would the gearbox and primary sharing the same oil be a bad thing? I'm assuming there is some oil slinger in the trans that circulates oil?

Thanks,

don't think he is referring to any limitations with size or design of the case itself, but other things such as bearings, etc. are not up the task of the torque of a diesel. Maybe he's got knowledge that they were prone to be weak in that model HD?

[pietenpol2002]

I might just take the bottom end out of the equation. Cut the crankcases off the gearbox and drop your Yanclone in front of the box. Dispense with all the extra weight, clutter and complexity of a crank replacement shaft driven from the Yanclone. Belt drives are readily available for the Sportster to couple the Yanclone to the box (although not cheap). Or, given the output of a Yanclone, you could fab your own belt drive much like Tim's Honda/Kubotas. Maintaining the original placement of the gearbox would retain mounts and final drive alignment. However, anything wider than a Yanclone would require a rather severe offset of the engine to the right in the interest of maintaining the primary drive alignment with the gearbox.

That said, the gearbox was perhaps the weakest link on the Sporty. Might be easier and ultimately less expensive to buy a Sportster roller sans engine and park an Enfield box behind the Yanclone. Primary drive components for that coupling are readily available on our friendly auction site. Not quite plug and play. But close.