The X4 Thread
- Thread starter purple_people_eater
- Start date
- Status
Needles929
Member
I did read about that recently. Out of curiosity, what would you suggest?
I will likely tear the whole thing down over winter (don't kill me for being in AZ. I know it's not really winter). Thinking of replacing the carbs and a few other things also.
Needles929
Member
Nah, I don't think I'll detune it. I have two other X4's, a 2004 XPDi, and a stand up. I'll keep this one HOT! lol.
It does seem to run great, but the only thing I have to go off of is my 2 stroke dirt bike tuning experience. I've never owned a ski with more than a set of FAs, as far as the motor goes.
The carbs are what is bothering me the most. They're jetted quite a bit leaner than recommended from Buckshot's guide, and way leaner than I've seen others post about. I've said it before, either the guy found the secret sauce with these carbs, or everyone else's are correct and this should be a time bomb. I got my tach hooked up, went a little richer main, so we'll see how she performs tomorrow!
Needles929
Member
Lake was packed today! We were able to find some calm every now and then. She spun up to 7720 and topped out at 62.2mph. I'll play with her some more during the week. I gotta get it to 7800!
Needles929
Member
Yeah, that seems to be the consensus of others also. Some say it's the pump and prop combo, the tach might be reading off, or the GPS is not accurate. This level of boat is all new to me. I'm sure there's plenty of fine tuning to be done. I'd really like to find an old Racepak to install with EGT.
Otherwise, is everyone simply using the TinyTach brand with solid results?
Needles929
Member
That's a very valid point! No, the top speed and top RPM weren't recorded at the same time. I was testing RPM before I stuck the Garmin in the storage box. The 7700 number was indeed hooked up. I fought the rough water with that while testing as it would jump into the 7900+ range when popped up out of water. I really need to go out in the morning on a weekday and find a nice calm spot.
Yep, running 110 all the way! Makes for a really expensive day! Lol
1of500
Well-Known Member
Needles929
Member
I absolutely will look at this!
My '97 SPX 'resto' is almost back together, getting pretty excited for summer. I pushed it outside for some pic's. I modeled the sponson's after the newer style RIVA RXPX sponson's, 3d printed a template, then cut them out from UHMW. I may add a fourth hole. Do you guy's think the fourth hole is necessary? I've since trimmed the excess silicone from mounting. Only motor mod right now is an R&D power plenum (motor is obviously still out of the hull). Working on a water injection setup similar to the old EWCI but with new parts which is almost complete. I'll be ordering the steering setup from westside sometime soon as well. Then I plan on just enjoying it while gathering parts for a 'limited' type motor build. 
Last edited:
Well, it's not working yet, lol
I am looking into arduino and microsquirt. Still learning, I've watched the 2 stroke stuffing videos on his Arduino pickup a few times. Also, I have about ten years of experience with megasquirt/microsquirt setups.
At first I am trying to use a WOT switch in combination with an already available RPM window switch. I've talked to a couple technicians at big companies that do automotive electronics trying to adapt a readily available window switch to work with the 2 stroke, even if I have to 'trick' it in the cylinder and rpm settings. My background is in automotive drag racing stuff so that's where my brain usually goes to when trying to figure something new out. If it works like I think it will I'll post it all here.
Last edited:
I've got a line on a motor-less 95 800 I'm going to try to pick up cheap. I have a 787X that needs rebuilt. Would be great to put it in a pink bottom ski.
Stunnerable
Active Member
Interesting sponsons. Why the stepped design??
Purely because I thought it looked good, no good reason. I drew up some traditional beach house looking ones as well in case these don't work good. I 3d printed a bunch of different templates based on multiple designs out there already but sized them to work on x4's.
I should buy or build a cnc router just to cut out sponsons
Whus02
Member
Just pick a shape you like and go with it. A 3d printer will only help you create a template, you need a heavy plastic or aluminum for the actual sponsons
Exactly. I use fusion 360 typically. Not sure what the rules are here (and I'm not trying to advertise and break any rules so if this is out of line Mod's I understand and I'll delete) but I sell the STL files on Cults3D. Use the template to cut them out with however you see fit. Best case scenario, if you have a buddy with a CNC router they could cut them from the .svg
- Status
