Legdragger
Bringing it back
- Location
- New Hampshire
I got a TBM Super Cone from Legdrag.com. He offered to take it back if it wouldn't work which is better than TBM would do for me. Luckily with my buddy at the machine shop we were able to set back the SXR big hub impeller and modify the tail section of the pump cone to work. If you want to put a TBM cone in you 650 X2 pump I will explain the way to get it to work.
First you need to understand that the 750/800 and 650/X2 pumps aren't very different. The most obvious difference is the 650/X2 pump has the shoe intergrated into it. That doesn't affect the cone. However the only other difference that does affect the pump cone is the center hub set back. The 650/X2 pump hub is foreward 6mm (1/4") That does a couple things. It first makes it so wa 750/800 impeller sits foreward that 6mm ahead of the stator which is undesirable. It also makes it impossible to get the pump bolts to drop in because it sets the whole pump back the 6mm making the holes off. It is an easy fix though. Simply call Skat Track and tell them to modify a 750/800 impeller of your choice to set it back 6mm and it will drop right in. They know the exact measurement. Just tell them you are running the 750/800 impeller in a 650 pump and they will take it from there. This is the spot they cut it back.
So now that the impeller is set you need to make one change to the rear bearing cover on the TBM cone and you are in busines. The picture here shows how the hub of the 650/X2 pump is foreward of the TBM housing.That also translates into needing a longer section on the bearing cover to get the O-ring to seal up the pump bearings. See the gap in this picture.
The silver section on the hub cover is what I had made. I took and removed the original piece and had it bored to accept a new longer one that was press fit in. That new section is 6mm longer that the original TBM unit. I didn't do anything about the gap between the TBM housing and the rear of the hub but that isn't an issue.
So now it fits perfect and I will be water testing Sunday. I am running a stock pitch SXR prop with an 84mm nozzle and the medium tail cone. I have another 750 nozzle that is way smaller than the PJS nozzle which is like 76 so I can change stuff around if it isn't right.
First you need to understand that the 750/800 and 650/X2 pumps aren't very different. The most obvious difference is the 650/X2 pump has the shoe intergrated into it. That doesn't affect the cone. However the only other difference that does affect the pump cone is the center hub set back. The 650/X2 pump hub is foreward 6mm (1/4") That does a couple things. It first makes it so wa 750/800 impeller sits foreward that 6mm ahead of the stator which is undesirable. It also makes it impossible to get the pump bolts to drop in because it sets the whole pump back the 6mm making the holes off. It is an easy fix though. Simply call Skat Track and tell them to modify a 750/800 impeller of your choice to set it back 6mm and it will drop right in. They know the exact measurement. Just tell them you are running the 750/800 impeller in a 650 pump and they will take it from there. This is the spot they cut it back.
So now that the impeller is set you need to make one change to the rear bearing cover on the TBM cone and you are in busines. The picture here shows how the hub of the 650/X2 pump is foreward of the TBM housing.That also translates into needing a longer section on the bearing cover to get the O-ring to seal up the pump bearings. See the gap in this picture.
The silver section on the hub cover is what I had made. I took and removed the original piece and had it bored to accept a new longer one that was press fit in. That new section is 6mm longer that the original TBM unit. I didn't do anything about the gap between the TBM housing and the rear of the hub but that isn't an issue.
So now it fits perfect and I will be water testing Sunday. I am running a stock pitch SXR prop with an 84mm nozzle and the medium tail cone. I have another 750 nozzle that is way smaller than the PJS nozzle which is like 76 so I can change stuff around if it isn't right.
