1993 Seadoo SPX (587) Jet sizes

[mclearg]

Hi All, I've recently bought a project 1992/3 SPX (Title states Year built 1992, model year 1993) that I'm hooping to get some summer fun out of before I strip her down for a restoration over winter.
She ran like a dog when I bought her so I stripped and rebuilt the carbs (Mikuni OEM kits) using the springs that were in there.
Pop-off pressure is 25psi on both
Starts & runs a lot better now but has an issue where she won't rev out.
High speed adj. screw is fully in and I've adjusted the low speed from 1/4 turn out all the way to 1 1/2 turns out with the same issue.
At highest revs there is a slight back fire through the airbox - not really a back fire more like a cough.
I took the carbs back off to check I hadn't done anything stupid and this time I checked the Jet sizes.
Magneto side carb has 107.5 main and 62.5 Pilot, the other side has 125 Main and 60.0 Pilot.
I've had many two stroke motorcycles back in the day and I'm scratching my head as to why the two carbs would be jetted differently.
I'm going to order new jets which from the reference on this site should be 107.5 Main and 62.5 Pilot
The only thing I can say is not standard is it has no flame arrestor fitted and a K&N filter
Any thoughts?
Thanks

 

[mikidymac]

You will run really lean without the stock airbox so you should get one. Also the K&N are junk on these because there is nothing to filter and if it ever gets wet it will flow zero air.

Jets should be the same on both carbs...
62.5 Pilot
107.5 Mains
2.0 needle and seat
95 gram springs
LS Screw 1-1/4
High 0

 

[mclearg]

You will run really lean without the stock airbox so you should get one. Also the K&N are junk on these because there is nothing to filter and if it ever gets wet it will flow zero air.

Jets should be the same on both carbs...
62.5 Pilot
107.5 Mains
2.0 needle and seat
95 gram springs
LS Screw 1-1/4
High 0

 

[mclearg]

Thanks, I'll look for a stock airbox with flame arrestor and order the jets. Hoping that reverting to stock will have her running sweet

 

[2strokefun]

Thanks, I'll look for a stock airbox with flame arrestor and order the jets. Hoping that reverting to stock will have her running sweet

Did that solve your issue?