Install steering stem on different Triple Tree? Need advice!

Hi,

I have a KTM triple tree that I want to mount on my HD Sportster.. unfortunately it is tiny tad longer than I'd like to. Maybe 1/8" or something like that. Not sure it will fly for me.. so I was pondering whether I can get OEM Sportster steering stem and replace the one that is on KTM triple tree? I have little experience working on bike so that's why I am asking on here.. And if it can be done then I assume that I must first find out whether the bottom part of stem will match the hole in lower Triple Tree?

Unless there is a way to work around this 1/8" space without dealing with changing steering stem??

Thank in advance for answering..

1/8"? Make a spacer.

Using washer as a space? And put it before bearing sealer?

And it would not harm to use OEM HD bearing with KTM triple tree?

Just wanted to confirm before I place order and all..

Thanks!

Yeah, I've used a longer stem and used a die grinder on a thick washer until it fit the stem. Installed between the spanner nut and seal.

The bearings should be the same, check for fit and use them.

Larryboy, many thanks!! Appreciate it! Save me headache!

Pressing out stems is a hassle. A coworker is using Suzuki stuff on his Sportster conversion, RM250 twin tube conventional forks.

I've done this a bunch of times. My recommendation is to utilize the stock HD bearings. Yes they do make conversion bearings but guessing that will be tough from HD to the weird ass KTM half size.

Have a machine shop turn you a steering stem to your dimensions. I forget exactly the size as it presses into the KTM lower but I think it's around 30mm. Or if the KTM stem is too long, have the shop just machine that one. The threads that the KTM nut use to hold the top clamp are 14mm or something I have the tap for it.

Anyways there is a lot more to it than that. I don't know what the sportster stem looks like so I can't tell you if it will work. KTM triples are different than Japanese triples. My advice is to use the stock HD bearings and have the stem made to fit the KTM triple and those bearings. I'm hardly a machinist but with the parts in front of me to measure I did one fairly quickly on my lathe. But the machinist would likely need the bike and the triples as there are bearing and press fits that need to be cut precisely.

If you read my ninja rebuild thread I have a lot more info and pictures explaining how I did mine. The first couple builds I tried a lot of different ideas but the latest gives the best results in my opinion.

The washer idea should be fine.
I'd assemble the bearings as per, then drop the washer on top of the shit shield, so there is less space for crap to get in.
The forks wont mind and you won't notice the triples being spaced 1/8" further apart.

This assumes you can get suitable bearings of course.

Otherwise take the two sets to a decent machine shop, explain what you want and let them sort it out.
It really is no biggy, I have machined up new stems loads of times.

The first thing you need to do is compare the Sportster stem to the KTM stem to see where the actual difference is with the '1/8".

Most stems follow a format.
A lower OD for a interference fit of the lower bearing.
Above that a reduction in OD until the upper bearing OD which will have a sliding fit.
Above that will be the thread for the locking/adjusting rings then either external or internal thread at the top for whatever method is used on top of the upper triple clamp.

If it is simply 1/8" of extra at very top its an easy mod, a spacer or stem reduction, it comes back to where the 1/8" is.
Are the stem OD's for the bearings even similar.

I don't know much about HD or KTM,so,my question is.

Is there any particular reason why you want to swap out the front fork?

I am always looking to learn something new!

Thanks...Alan

This perhaps.

http://advrider.com/forums/showthread.php?t=842005

Thanks looks like a fun project!!

I suspect the 1/8" gap is because of the dust shield (missing), which I will try to get one from local Kawasaki/Honda dealer this week or next.. I'm going to bring bearing & triple tree with me to the dealer. I'll update!

Edit: That's one of bad thing when you abandon the project for lengthy amount of time.. you can forget little important thing like this..

These sort of mods often come down to numbers (measurements)
If the numbers stack up its doable, followed by they can be made stack able but is it at the cost of logic.
What did RTW Douglas do on his Sportster, it had some form of off road front end.

Edit.
Looking through your thread (great house and woodwork skills) the Sportster looks to have a decent size steering head so it should be a straight forward mod adapting the KTM triples.

I agree.. I think I was being over-concerned before having all the parts together..

RTWDoug used KTM 300 forks but I am not sure if he used KTM triple tree, though.. I just know he turned fork upside down but I wouldn't want fork tube down.. I doubt his KTM forks are 50mm, though..

I have a 1999 883, used 2001 KTM forks, the KTM bearings go right in to the Harley head, then go together as normal. I think I used the Harley bottom shield and drilled it out to fit KTM stem, KTM is bigger

Did you use KTM's bearing? I find that Harley's OEM bearing was too small for KTM steering stem so my buddy who design truck for a company is coming over today to help me measure it and see if he might have one he can take out of the part dept there. If not then he can order one for me.

Use the KTM races and bearings, races fit perfect. The harley bottom shield needs to be drilled out to fit KTM stem, from there a bolt in. I also changed springs and revalved forks for harley weight, never tried with stock springs, might work. Frank 580 761 2858

What year KTM parts

97-99 KTM 300 with 50mm WP forks.

Stem measure like this:

1.104" on top part of stem
1.125" on the part where it get thicker
1.143" at bottom where the bearing sits. (or 29.10mm)

Race is 1.981" outside to outside.