Katan gs500 stem swap help

[swaggyp]

I successfully removed the gs500 stem from the triple tree .. it doesnt sit flush inside the katana lower triple. The bottom is off by several mm. For those who filed the katana stem, what do you mean by "filing" . Using a lathe?

[The Buddha]

If you pulled the GS stem out and cant get it seated in the kat lower triple (I'm thinking that's your question) that's due to the fact the GS lower triple is thicker than the kat's lower triple.
Several mm - Not sure about that, maybe. I did very few stem pull and swaps that I really dont recall. We usually weld it like a ring, and sometimes even cut notches in it and flare it out and then weld it (use your imagination) and yes may be several mm of "spare" GS stem.
You also have a 2nd problem. The thread boss on top is a smaller diameter on a GS. You would need that part from the katana stem. However you have solved many other problems and will end up with a functioning FE, albeit IMHO a bit more clunky.

If you wanted to go back to kat step - read below, else ignore this.
However the easy swap is the "lathe method" BTW There's all sorts of weld and grind and lathe nonsense in this, every swap almost is "make it fit".
IMHO easiest and least lathe dependent swap is this.
Anyway Kat stem and lower triple stay intact.
Lathe the upper bearing seating area (or hand file it ~3/4") down ward.
Thread the locknut threads downward ~3/4".
Cut the top threads with the top nut threadboss un damaged.
Grind or something that threadboss out undamaged.
Weld that thread boss into your cut stem.
Bolt it all together.

Couple of these jobs are easier with a lathe. In fact you can shave the bearing area, cut the threads down deeper, take out the thread boss and then the extra threads on top in 1 fell swoop in a matter of mins after you've done this a couple times with a lathe.

TBH I cant believe I did ~8-10 stems and only charged $50 for it. But I had a crusty old machinist/welder/biker from the 60's (probably the 1860's) that was older than dirt and was happy to do small creative jobs for young bikers. Then of course he died. So there went that bright idea.

Just went out and checked my bike. Yes running the kat stem intact. TBH, Dgyver posted a spacer method for the kat stem method back ~10-12 yrs ago. You only need to shave the bearing seating area. Then there's 2 spacers (made by lathe of course) that sandwich the locknut and avoid the threading and the thread boss removal and re-welding. However that wasn't an option to me. I needed a functional lock mechanism and I also have the stock GS gauges fitted in the stock location which I fabbed brackets for.

Cool.
Buddha.

[swaggyp]

Im trying  to wrap up my build and this is the only thing holding  me up.. local machine 
Shops want 100 bucks per hours.. ive contemplated building  my own 3d printed  lathe. Gonna go with the simpler method.

i"ve pmed Dgyver a few times but for some  odd reason im seeing there is a capcha error preventing  me from replying or sending pms to anyone. Would you be willing to lathe 1 more stem?

[Armandorf]

CAPTCHA goes out after having more than 5 or 10 mesagge count in your profile.

I have done a GSXR swap.
Not the nicest though.

I ended up using:

The GS stem(removed from the lower gs500 yoke)

Pressed it on the GSXR lower yoke.
 Beware of clearances and material /alloy for press fitting.
 GSXR is aluminum.i believe Katana is steel. Gs stem is steel.
Also note the locking ring and the flanged end.

Then I had to make a spacer to fill the gap between the larger stem hole form the gsxr top yoke.
This spacer was made of a sacrificial top gs yoke I cut with rotary tool and then was rounded on the external dimensions in a lathe.

If you look closely in the gs top yoke you have a flanged hole from the bottom that fits in the narrowed end of the stem.

Can you upload photos of what you got?

[The Buddha]

Actually the GS stem is much much longer than the kat stem. Several mm does sound right. If you seat the stem fully in the kat lower triple nearly nothing will fit.
The GS lower triple is thicker than the kats and the upper triple is a double on the GS but single on the kat.
Now if you get it right the bearing zone will end up in the right location with GS triple. The kat bearing zone is higher than the GS. That's why you have to file/lathe that area.
The GS stem has a lot of extra room on top. And a thread boss that's too small dia. That needs to be at a minimum pushed deeper into the thread and spacered or maybe get it from the kat's stem. These all need to be a tight tight tight fit. That's one reason I prefer to use all the original parts from the donor bike.
Cool.
Buddha.

[swaggyp]

Actually the GS stem is much much longer than the kat stem. Several mm does sound right. If you seat the stem fully in the kat lower triple nearly nothing will fit.
The GS lower triple is thicker than the kats and the upper triple is a double on the GS but single on the kat.
Now if you get it right the bearing zone will end up in the right location with GS triple. The kat bearing zone is higher than the GS. That's why you have to file/lathe that area.
The GS stem has a lot of extra room on top. And a thread boss that's too small dia. That needs to be at a minimum pushed deeper into the thread and spacered or maybe get it from the kat's stem. These all need to be a tight tight tight fit. That's one reason I prefer to use all the original parts from the donor bike.
Cool.
Buddha.

When i say several mm... i mean the stem is not seated flush inside the bottom triple-tree.. pictures will be attached shortly.

[The Buddha]

Try fitting it in the neck and checking where the upper bearing part will end up. A "not flush" fit may actually be to your advantage. I have literally fit it ~8-10mm and notch cut and flared the stem and welded it to the kat lower triple.
Cool.
Buddha.

[swaggyp]

Photo of the frame with the suzuki bandit swingarm





Photo of Stem and triple tree.




Photo of Katana 750 Stem (left) and GS500 Right

[The Buddha]

Oh frrrrrrruuuuuccccckkkkk - Kat 750. And I think its post 1996 as well. 0 experience with that.
Only kat swaps I have done are 89-95 Kat 600's.
Cool.
Buddha.

[swaggyp]

Oh frrrrrrruuuuuccccckkkkk - Kat 750. And I think its post 1996 as well. 0 experience with that.
Only kat swaps I have done are 89-95 Kat 600's.
Cool.
Buddha.

I stand corrected. The guy i purchased it from from listed it from a 2003 Katana 600..

[The Buddha]

Could be. Only know 89-95 kat 600's. The 88 600 was identical except for the rebound adjustment not being there in the fork legs.
Cool.
Buddha.

[The Buddha]

BTW I'd stay with the kat stem if I were you. That thread boss nose style to the external nut type swap is not going to be easier than the bearing zone shaving.
Cool.
Buddha.

[swaggyp]

I ended up doing the following

cutting the top of the kantana stem (where the top triple sits flush)
drilling the inside diameter several millimeters to where the gs500 top stem would sit flush inside it
welding the katana top stem to the gs500
cleaned up the threads..

Now i can apply the gs500 center bolt and the katana bolts to the top triple tree.. pics soon