Custom/Hybrid Changeover from an SXR hull to a bob hull
- Thread starter IceMahn
- Start date
- Location
- Edmonton Alberta
That's what I figured ha ha. Thx for all your advice /info rubbertoe! I'm quite excited to start this project!!!
- Location
- Sault Ste Marie
Are there any build threads on sxr power going into a BOB? I couldn't find one.
Icemahn,
Sorry, loooooooong post…
I think you will be pleased with the switchover to the BOB. The Ski Clinic built my Kawi BOB for me, so I can’t say anything about build experience (I was too busy at the time, I don’t have a good workspace to build a ski at my home, and I felt like having someone else doing all the heavy lifting for me while I waited for spring to break). But I can say a few things about riding one.
First off, I’m 220lbs fully suited up. Riding the ski is nose up for me. I think if I was lighter it would ride more level. However, once the ski gets moving it will level out fairly well, and once at speed it planes out just fine. If I could go 100% flat out on the SXR hull, I feel comfortable doing maybe 80% on the BOB. It actually carves and digs into the water pretty well, but at speed it can feel a little skittish. Nothing too bad, and it lets you know when it is starting to slide at speed. But it will go fast enough to let you come up on a boat wake as fast as needed to launch.
For slower speed turns, in spins and to set up wakes, it behaves much more like a superjet. Meaning it turns more on the jet than the hull. With the SXR I felt I could turn, cut and spin pretty good because I felt the SXR’s weight was more forward, and the rails and chines dug into the water along the whole hull length. On the BOB it will dig into the water just was well, but the feeling is further back. It is like the point at which the boat pivots is more back toward the jet than the center of the hull. It took some adjustment, but I have come to prefer that sensation. I can cut sharp turns much better than the SXR hull (well duh) and skid the ski much easier (double duh) but I state the obvious just to assure you it is a different sensation.
The tray is nice and wide. Lots of room to move your feet around, even with the foot holds. If I’m not in the mood for air, I remove the holds and just putt putt around with what seems like an acre of room to move my feet. The holds are a must once you try some air, and the ability to move them forward/back/up/down is really nice compared to locked in foot holds. When I am jumping waves and trying backflips (more on that in a moment) I move back in the tray. But if I want to go faster or just ride and get moving I step forward and it helps push the front down with my weight.
I have had the ski two seasons and have gone about ¾ rotation on a backflip. The first season I could not get the ski to run right. I’m at 4800 ft above sea level, and the jetting was off. In Wyoming, jet ski’s are not very common, and shops that want to work on them are even rarer. I was willing to try and rejet it, but everyone (including certified Kawi technicians) gave me so much BS on how to jet it was clear I’d have better luck trying brain surgery than trusting their opinions. So I rode my other skis that first season. The second season I grew a pair and worked the jetting over, while adjusting the settings on the wet pipe. The ski became another experience entirely (well triple duh!). Before getting it set up, It was hard for me to get onto the ski because there was a huge bog between 0% throttle and ½% throttle, so as I tried to get on it the BOB would and fall over, and then the motor would come on the pipe and launch like a rocket. After getting it running right, no issues. But this leads to my experience with backflips. I just have a stock motor with wet pipe, and I need more power. A stock motor will not rotate you unless you are very good, or have an awesome set up wave. The Kawi motor is not as peppy or spins up seemingly as fast as a SJ, so I have to run with just a little more throttle up to a wave face to launch, and then pulling the throttle to WFO it has just a little lag before the motor spools up. By contrast, on my SJ (stock also), I can pull the throttle and the power will pop me out of the water right away. I think this is the reason, as a general rule, why SJ motors are for freestyle/freeride and SXR motors are for racing. When you build your BOB, I would recommend your motor mods as follows:
- lightened flywheel (you need faster revs to time out your launches)
- domes and higher compression (more power to pull you through and out the water)
- wet pipe (well quadruple duh)
- different pump (whatever works for you, but one that emphasizes bottom grunt over top speed, the stock pump is a good middle of the road pitch)
- carbs/ignition
- tilt kit for pump (not a motor mod per se, but it will help)
All of these things are typical for many other modded skis, but I think they are not an option for the SXR motor and BOB hull.
Some things to be aware of (from my experience):
- there is no splash guard on the nose, so on choppy water you can get splash on your face if the wind is blowing
- Kawi’s are reverse to SJ’s for steering cables which means you will have to research tilt systems carefully to ensure they will fit
- after really just one season of riding the ski faithfully, the turf is starting to peel (mine was done by the Ski Clinic, but I would expect as much with all the foot movements you’ll be doing
- You’ll want your bilge pump at the absolute rear of the engine compartment, up against the firewall. But this makes it almost impossible to get to the pump to replace it as the motor is shoved up pretty darn close to the firewall. I never have good luck with bilge pumps lasting (I don’t run them all the time, but still…) so I don’t look forward to the day it conks out.
Good luck, and enjoy the BOB!
Sorry, loooooooong post…
I think you will be pleased with the switchover to the BOB. The Ski Clinic built my Kawi BOB for me, so I can’t say anything about build experience (I was too busy at the time, I don’t have a good workspace to build a ski at my home, and I felt like having someone else doing all the heavy lifting for me while I waited for spring to break). But I can say a few things about riding one.
First off, I’m 220lbs fully suited up. Riding the ski is nose up for me. I think if I was lighter it would ride more level. However, once the ski gets moving it will level out fairly well, and once at speed it planes out just fine. If I could go 100% flat out on the SXR hull, I feel comfortable doing maybe 80% on the BOB. It actually carves and digs into the water pretty well, but at speed it can feel a little skittish. Nothing too bad, and it lets you know when it is starting to slide at speed. But it will go fast enough to let you come up on a boat wake as fast as needed to launch.
For slower speed turns, in spins and to set up wakes, it behaves much more like a superjet. Meaning it turns more on the jet than the hull. With the SXR I felt I could turn, cut and spin pretty good because I felt the SXR’s weight was more forward, and the rails and chines dug into the water along the whole hull length. On the BOB it will dig into the water just was well, but the feeling is further back. It is like the point at which the boat pivots is more back toward the jet than the center of the hull. It took some adjustment, but I have come to prefer that sensation. I can cut sharp turns much better than the SXR hull (well duh) and skid the ski much easier (double duh) but I state the obvious just to assure you it is a different sensation.
The tray is nice and wide. Lots of room to move your feet around, even with the foot holds. If I’m not in the mood for air, I remove the holds and just putt putt around with what seems like an acre of room to move my feet. The holds are a must once you try some air, and the ability to move them forward/back/up/down is really nice compared to locked in foot holds. When I am jumping waves and trying backflips (more on that in a moment) I move back in the tray. But if I want to go faster or just ride and get moving I step forward and it helps push the front down with my weight.
I have had the ski two seasons and have gone about ¾ rotation on a backflip. The first season I could not get the ski to run right. I’m at 4800 ft above sea level, and the jetting was off. In Wyoming, jet ski’s are not very common, and shops that want to work on them are even rarer. I was willing to try and rejet it, but everyone (including certified Kawi technicians) gave me so much BS on how to jet it was clear I’d have better luck trying brain surgery than trusting their opinions. So I rode my other skis that first season. The second season I grew a pair and worked the jetting over, while adjusting the settings on the wet pipe. The ski became another experience entirely (well triple duh!). Before getting it set up, It was hard for me to get onto the ski because there was a huge bog between 0% throttle and ½% throttle, so as I tried to get on it the BOB would and fall over, and then the motor would come on the pipe and launch like a rocket. After getting it running right, no issues. But this leads to my experience with backflips. I just have a stock motor with wet pipe, and I need more power. A stock motor will not rotate you unless you are very good, or have an awesome set up wave. The Kawi motor is not as peppy or spins up seemingly as fast as a SJ, so I have to run with just a little more throttle up to a wave face to launch, and then pulling the throttle to WFO it has just a little lag before the motor spools up. By contrast, on my SJ (stock also), I can pull the throttle and the power will pop me out of the water right away. I think this is the reason, as a general rule, why SJ motors are for freestyle/freeride and SXR motors are for racing. When you build your BOB, I would recommend your motor mods as follows:
- lightened flywheel (you need faster revs to time out your launches)
- domes and higher compression (more power to pull you through and out the water)
- wet pipe (well quadruple duh)
- different pump (whatever works for you, but one that emphasizes bottom grunt over top speed, the stock pump is a good middle of the road pitch)
- carbs/ignition
- tilt kit for pump (not a motor mod per se, but it will help)
All of these things are typical for many other modded skis, but I think they are not an option for the SXR motor and BOB hull.
Some things to be aware of (from my experience):
- there is no splash guard on the nose, so on choppy water you can get splash on your face if the wind is blowing
- Kawi’s are reverse to SJ’s for steering cables which means you will have to research tilt systems carefully to ensure they will fit
- after really just one season of riding the ski faithfully, the turf is starting to peel (mine was done by the Ski Clinic, but I would expect as much with all the foot movements you’ll be doing
- You’ll want your bilge pump at the absolute rear of the engine compartment, up against the firewall. But this makes it almost impossible to get to the pump to replace it as the motor is shoved up pretty darn close to the firewall. I never have good luck with bilge pumps lasting (I don’t run them all the time, but still…) so I don’t look forward to the day it conks out.
Good luck, and enjoy the BOB!
Last edited:
subhard
TITS OR GTFO
- Location
- anchorage ak
Good info. I hope to do this someday
One more follow up post:
When the Ski Clinic was building the ski, they tried different drive shafts until they settled on the one they say is needed. Part of that process was confirming where to set the motor in the hull. As it turned out, (for centralized mass for better rotation) it is pretty close to the firewall. They told me mounting the electrical box was fun. I can imagine…
This vid is of my ski with stock motor, meaning the only things different than an OEM set up are: wet pipe and air box removed. The Bobfather (DK Sr.) was riding. So a stock set up can work (barrel rolls are apparently more difficult that back flips), but for me I need a really steep set up wake from a boat to almost get my complete rotation. I can say from experience that a ski falling on top of you in the water isn't too bad. I've taken my helmet's visor/bill off, though
:splatt:
http://www.youtube.com/watch?v=2_ZyeX95Nh4
When the Ski Clinic was building the ski, they tried different drive shafts until they settled on the one they say is needed. Part of that process was confirming where to set the motor in the hull. As it turned out, (for centralized mass for better rotation) it is pretty close to the firewall. They told me mounting the electrical box was fun. I can imagine…
This vid is of my ski with stock motor, meaning the only things different than an OEM set up are: wet pipe and air box removed. The Bobfather (DK Sr.) was riding. So a stock set up can work (barrel rolls are apparently more difficult that back flips), but for me I need a really steep set up wake from a boat to almost get my complete rotation. I can say from experience that a ski falling on top of you in the water isn't too bad. I've taken my helmet's visor/bill off, though
:splatt:
http://www.youtube.com/watch?v=2_ZyeX95Nh4
- Location
- Edmonton, AB
It will take some time to get used to, but youll be able to cruise your bob at higher speeds. My vote would be sell your SXR and build a superjet based bob hull
- Location
- Sault Ste Marie
edmoto: How much did it cost you to get the RTR ski from The Ski Clinic?
ProSouth
Seriously, Don't be a dick.
- Location
- kawasakis suck
^^ id have to agree. parts are way easier to find over all. whether it be the pump or the engine. and it seems like the stuff is getting a bit cheaper this year. good luck either way.
ssmsxr: Without being specific, cuz I honestly do not remember (it was built and completed between 1/11 and 4/11, shipping the motor and bits from WY to CA, and then me driving out to get it back), around $11,500? But I don't know or think it is that price anymore because I was supposedly the first one they did (Kawi-BOB) and they didn't charge all the labor it cost them as mine was a test mule. But I did pay for the hull at list price, and it is the fiberglass (not carbon or kevlar) hull.
XJ: If your comment was directed to me, it is funny you should mention that. I am content with the BOB and intend to hot-rod it at a later date. Because I started on an SXR I am partial to that hull and its handling. But I like the Yami motor better for playing in the waves and launching off waves. But I like the BOB because it is a playful hull and offers me no excuse not to practice my skills and flipping. So I am deciding whether or not to customize my SJ now (not for flipping but for launching off waves as big as I can go), or getting a carbon SXR hull for my other SXR. Can't decide. All I know is I've got $ much money to do $$$$$$$$ many projects! I like how things are becoming more reasonable in costs lately (agreed, ProSouth).
IceMahn: sorry to hijack your thread!
XJ: If your comment was directed to me, it is funny you should mention that. I am content with the BOB and intend to hot-rod it at a later date. Because I started on an SXR I am partial to that hull and its handling. But I like the Yami motor better for playing in the waves and launching off waves. But I like the BOB because it is a playful hull and offers me no excuse not to practice my skills and flipping. So I am deciding whether or not to customize my SJ now (not for flipping but for launching off waves as big as I can go), or getting a carbon SXR hull for my other SXR. Can't decide. All I know is I've got $ much money to do $$$$$$$$ many projects! I like how things are becoming more reasonable in costs lately (agreed, ProSouth).
IceMahn: sorry to hijack your thread!
- Location
- Edmonton, AB
The comment was for iceman, I was to lazy to read your long post haha
- Location
- Edmonton Alberta
Hey guys, thanks for all the info!! And edmoto, don't worry about hogging the thread ha ha you gave some great insight so it's all good. I'll be placing the order here in the next day for the hull! Thanks again for everything!