How to: repitch your own impeller for a change..

[jetdave56]

I've read here numerous times how frustrating at times for riders as the top shops are very busy or back logged and if you add on the shipping time and cost for a slight bend of metal its something that you finally can learn to do yourself,I just did my first pitch and Here's how it went...

First there are some great old GH threads on prop repitching by Jerry ,Duke and a few others they became great info to make the process and step by step go easier,but I did add a few extras of my own ...


to be continued later ..

[jetdave56]

Here's the simple tools you will need to complete the job ,I'm adding a heat gun to the tools mix ..

1) sturdy vise on a strong table
2) a quality large adjustable crescent wrench(10" or more)
3) pitch gage thats the proper size of your pump
4) ruler,sharpie marker
5) spline holder for your prop
6) heat gun or a propane touch
7) heavy duty thick gloves
2-3 towels

[jetdave56]

Depending what you want to do with your prop you will bend accordingly..

1) leaner leading edge more RPMs on holeshot but possibly more cavitation but RPM spin up quicker
2) steeper leading edge less RPMs on holeshot but less if no cavitation but RPMs spin up slower
3) leaner trailing edge more RPMs on top
4) steeper trailing edge less RPMs on top but possibly more top speed

[OzarkYamMonster]

Gosh Dave, you make it sound so easy

[jetdave56]

In my situation the Leading edge of my stock prop was lean spinning up too quick due to having a reflash with faster timing and my prop measured a true 13*,I was looking for a 13.5* as I like the quick spin up of RPMs and great acceleration but had a little cavitation on holeshot though prop blades were perfect and pump lining was normal and clearance was in spec...

I took the prop and with a sharpie put it on the table with the backside of the prop down and marked each leading edge blade 1 " from the edge and labeled each 1-2-3 but Important to draw an arrow for each blade in the Direction you will be bending as this important reminder can have you pitching the wrong way you intended..



I'm bending steeper pitch slightly up BUT when I need to put prop with the spline in the vise it will sit upside down SO you will bend down!..

Will be continued with pics later..

[jetdave56]

For what I had researched for a small pitch adjustment (1mm ) a half a degree you would grab the blade 1 inch from the edge putting your wrench on the inside of your 1" Mark(pic3) ,with your heavy duty gloves and a towel (pic1)on the prop to lean your free hand on to try to prevent the vise from flexing with your attempt to bend press down with the wrench with all your strength.After the attempt to bend take your prop out of the vise and check how much the angle changed from your initial reading .
I found that nothing really changed in the pitch gauge as the OEM impeller is a strong piece steel by the few dings I've seen in the many hrs Ive put on it, to get somewhere I assumed heat on the area of the blade would soften it a little so I used a heat gun on both sides of the prop area(pic2) .Steel heats up real fast compared to aluminum which reflex heat so 30-45 seconds on both sides of the area on the blade make it real hot so now back to the spline in the vise and the prop sitting on top I attempt to bend with the wrench and this time felt that very small amount of bend so took out and sure enough bent it a slightly as I checked with the pitch gauge and had started with 13* but now approx. 13.5*at least on this one blade.


to be continued later..

[jetdave56]

Here's the two bends compared side to side and close up the bend is barely 1 mm, the top pic is original 13* and the bottom is 14* on all 3 blades as the difference was noticable in my holeshot as I felt a little bit more bite though rpms were about the same give or take 50 rpms on top end and speed was faster 74 mph but that might have been due to a faster TBM/Riva ride plate I was also testing..

[jetdave56]

Overall it's worth doing your own prop and with a little heat and practice after a few bends you get the hang of it .This was a stock Kawa prop and was differcult to bend and a popular Solas might be easier to bend if that's your choice of impeller ,might not need the heat gun..

[munther abdulla]

great thread