SX/SXi/SXi Pro 1999 SXI PRO (It's 2025, I have 9 Skis, SEND HELP)

mrfist9 · Jan 13, 2025

Went on a trip again to visit my good buddy in Alabama!... This time just a double, no car trailer thankfully.
We needed a replacement motor for a friends 550, and a friend (who got cold feet) wanted the sxi pro

So stared at the weather all weekend like a hawk, we got 3 inches of snow here in ATL, and immediately it turned to a slushy mess.
Managed to have some fun though with friends before it all rinsed away.

Seller was in stock at his lake residence where he stores his fun stuff, so wanted to get the job done. Saw a good slot on Saturday where we could get back before temps got too low and everything froze back over.

Made the Journey!
I wasn't going to back out of the SXI PRO after agreeing to purchase it, decided I'll make something of it we know I love a good project. Got all sorts of various parts & engines.... But alas I had a double.. with one empty slot.. So we know what happened.

Obligatory Buc-ee's Picture

Finally All home, ZERO road drama, nobody was out, roads were gross but zero holdups.

NEXT DAY:

Let's start with a quick detour...
1988 650SX.. It's going to a buddy but we can talk about my short ownership.
I knew it was a good unit, didn't bother trying to run it or anything there, probably hasn't ran in years.
Some liquid encouragement she fired right up!

Back to the pro... Got it all cleaned up and out in the sun.

Plan is typical whole refresh.
Some pain points I'm not overly stoked about.

Fiberglass repairs:

something is DEFINITELY hiding under this sticker

Missing parts:
I have the i-body carbs... yes I know "jUsT rUn tHe foRTY sIx"
I am in need of the manifold and airbox arrangement. missing those pieces... DM me if you have!

Either way should be a fun little project when I have the time!

brapperdoodle · Jan 13, 2025

mrfist9 said:
something is DEFINITELY hiding under this sticker
View attachment 452990

Don't touch it, ignorance is bliss

mrfist9 · Jan 13, 2025

brapperdoodle said:
Don't touch it, ignorance is bliss

At minimum a more attractive stickers necessary

mrfist9 · Feb 4, 2025

For the first time actually wrenched on this thing. Finally got a twin mikuni 40 manifold apparently on the way. So figured I'd investigate.

Ripped off the intake manifold & the old junk fuel lines.

I realized the Kawasaki Green wasn't exactly right, cause the single carb manifold on it matched perfectly which was odd. So I proceeded to spend the next 30 minutes looking up part numbers to convince myself I actually had an sxipro engine here.

All checked out, guess someone repainted it to clean it up one day, original pistons in there etc. You can see the color difference in the intake ports. D head, cylinder part # ending in 29 which matches the parts diagrams.

I always complain about it but there's something therapeutic about cleaning the studs, chasing the holes and reinstalling all nice and clean.

Kinda at a weird stage, I'm not sure I have any belief that the Reed stuffers are helping. Same with the stock MLS outer Reed gaskets. I'm thinking I'm going to run no stuffers and just use 2 inner gaskets, I mean the stuffer & gasket themselves are both smaller than the intake manifold ports. Seems kinda counter intuitive, but what do I know.

So the next fun curveball. So I have this R&D pipe. Think we will start without it but we got options. Wish I could find some instructions, I know it's a top end pipe, sure I could optimize it to be a bit more fun if I drill it out a bit.

It's mostly fueling very little data about. I was gonna go off the factory pipe instructions for jetting but that just recommends basically stock carbs settings which sounds a bit surreal

More research to be done!

mrfist9 · Feb 6, 2025

Okay Got the sxr intake manifold... turns out the gaskets and stuffers mate up perfectly. oddly the pins on the manifold to align the carbs are way too long... maybe the sxr carbs are chewed out a bit deeper in the carb body... guess ill just cut them down.
Carbs are also HIDEOUS inside, one jet was NOT fun. oh well.. would love to find a stock airbox but probably a tall order.

SERIOUSLY WHO DOES THIS??? both were like this I couldn't believe it

Jiffyjet · Feb 6, 2025

mrfist9 said:
For the first time actually wrenched on this thing. Finally got a twin mikuni 40 manifold apparently on the way. So figured I'd investigate.

Ripped off the intake manifold & the old junk fuel lines.

View attachment 454125

I realized the Kawasaki Green wasn't exactly right, cause the single carb manifold on it matched perfectly which was odd. So I proceeded to spend the next 30 minutes looking up part numbers to convince myself I actually had an sxipro engine here.

All checked out, guess someone repainted it to clean it up one day, original pistons in there etc. You can see the color difference in the intake ports. D head, cylinder part # ending in 29 which matches the parts diagrams.

I always complain about it but there's something therapeutic about cleaning the studs, chasing the holes and reinstalling all nice and clean.

View attachment 454126

Kinda at a weird stage, I'm not sure I have any belief that the Reed stuffers are helping. Same with the stock MLS outer Reed gaskets. I'm thinking I'm going to run no stuffers and just use 2 inner gaskets, I mean the stuffer & gasket themselves are both smaller than the intake manifold ports. Seems kinda counter intuitive, but what do I know.

View attachment 454127

View attachment 454128

So the next fun curveball. So I have this R&D pipe. Think we will start without it but we got options. Wish I could find some instructions, I know it's a top end pipe, sure I could optimize it to be a bit more fun if I drill it out a bit.

It's mostly fueling very little data about. I was gonna go off the factory pipe instructions for jetting but that just recommends basically stock carbs settings which sounds a bit surreal

View attachment 454129

More research to be done!

kevbo · Feb 6, 2025

Make sure the carbs are perfectly clean and do initial runs with the stock pipe. It will be easier to burn a piston with the aftermarket pipe. Also get the bracket that connects the exhaust to the cylinder, It will also have the throttle cable mount built in.

spinyard · Feb 6, 2025

It’s cool to watch someone else do this thanks for sharing

mrfist9 · Mar 2, 2025

So I've purposely avoided staring at this thing too closely... Then I spotted the main feed line.

So pipe off.... Kinda frustrating I've convinced myself I'm sticking stock pipe for now so annoying buying more gaskets.

Cleaned the tank, ran fuel lines, got the kevbo bracket, rebuilt carbs, mocked up the battery cables and ordered some up.

Prince is running so this is now priority #1

mrfist9 · Friday at 12:18 AM

Carbs rebuilt
Went for a sort of tweaked stock specs off of frankly just a little experience at this point.

147.5 H stock
67.5 L stock
1.5 N/S stock
95g springs pop off ~35PSI stock was ~50
HS 1.25 (stock 1 +-0.25)
LS 0.75 (stock 0.5 +-0.25)

I figured without stock air box, I should atleast be at the richer end of the stock spectrum as a starting point. As well slightly lower pop off. Some research on the ole search feature I found 3 things.

1. Dropping Pop off helps a lot in this setup vs stock
2. Increasing to 72.5 or 75 Low jets helps. Factory pipe asks for a 75 low stock 147.5 high interestingly.
3. Epoxy the crossover...DOH

See what she do.

Got new battery cables in and installed.
Cut back the plug wires, both took 1/2-3/4in to get some copper back.

Close just need exhaust gaskets... Supposed to show up tomorrow.

mrfist9 · Saturday at 12:48 AM

Exhaust back on. Easy job.

Took some tinkering to get it happy idling. Old setup definitely flooded it out like a mad man, just spit out tons of disgusting fuel out the back.

.75 LS didn't work well, 0.5 was worse, landed at 1 turn on both carbs

Went up to 1.5 on the HS just out of security. Some more research sounds like the stock box on these is actually super restrictive... See how a test day goes but the answer may be those 75 low jets.

She's a runner though! Ready for testing.