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running a leopard 4082 timing 11 degrees on 6-s rigger octura x-450 octura 3/16 " cable collet . with cable removed I get a stutter or a knock at certain rpm's. however it spins freely to wide open ( do not hold there of course ) looking at the size of this collet compared to the motor shaft i see a possibility of imbalance. am I correct?
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The Octura couplings can be a bit hit or miss re balance & running true. Take a look at the MBP collet coupling from rocketcityracing. These are said to be the best couplings around re balance & trueness, i believe Gill is now using these coupings to very good effect & i know Tyler was waiting for one to arrive to try. Speak to them im sure they can give hands on advice on these couplings. -
MOre details like batteries and esc would help. it is possible your timing or number of cell's programming is messed up or batts insufficient... Just guessing at this point.
Stuttering isn't usually a collet problem, vibration is a collet problem.
Nortavlag Bulc Comment
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2000 kvComment
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proboat makes one ,but alittle pricy. prb3308 is the number.Comment
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make sure your prop is balanced.i took my new genesis out today with octura 440 prop did good new setup ran well with new electronics.Comment
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The problem does sound like it's in the motor not the collet or remaining driveline. It is possible that the rotor is not well balanced and is transitioning through a reasonance. Or it could be an electrical commutation issue. Easiest way to identify the problem is try a different motor with the same controller and try a different controller with the Leopard motor.
I would highy recommend the MBP collets. I have used almost everyother brand from Octura's to Lehner's and the MBP has the best design and very low runout. The Octura's have been the most inconsistent of the group. Some are reasonably true, but others are out by as much as .015". A lot depends on the fit beteen the collet ID and the shaft. If the fit is loose and with the set-screw clamping method it forces the coupler to offset relative to the motor centerline.
If this was the case an offset coupler would lead to more imbalance in the shaft(unless by chance it was clocked to help the imbalance) and make the knocking sound more audible.
TGTyler Garrard
NAMBA 639/IMPBA 20525
T-Hydro @ 142.94mph former WRComment
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Definitevely I second Martin/Tyler on the MBP collet and your timing is too much advanced for this motor(play with 3,75-5 max).I have seen some bad collets produce this problem with Leopard shafts.Also I think the X450 is too much prop for this set up..you can go in the mid 80's with a 1450 reduced to 44-46mm and 3,5 cup.GillGO FAST AND TURN RIGHT !
www.grsboats.com.brComment
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I've experienced a situation which may (or may not) be related to yours. I would hear what could be best described as a knock throttling up from rest. Turns out it was excessive rotor endplay. The rotor would slam into the internal thrust bushing and emit the sound. My initial fix was to use an external thrust bearing, but ultimately I sent the motor back to Neu for endplay blueprinting which cured the problem.2008 NAMBA P-Mono & P-Offshore Nat'l 2-Lap Record Holder; '15 P-Cat, P-Ltd Cat 2-Lap
2009/2010 NAMBA P-Sport Hydro Nat'l 2-Lap Record Holder, '13 SCSTA P-Ltd Cat High Points
'11 NAMBA [P-Ltd] : Mono, Offshore, OPC, Sport Hydro; '06 LSO, '12,'13,'14 P Ltd Cat /MonoComment
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I find that most Leopard motors coming with quite a bit of end play on the rotor, probably down to being Quite cheap motors where they seem to use a few standard length spacers. If theirs to much play on my Leopards i open the motor up & make the desired shims to reduce excessive end play.Comment
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closer look shows that its an out of balance situation at that certain rpm runs smooth wide open (quick bursts ) gonna try mbp colletComment
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