Bush Devil (king Blackfoot?) Bevel Gears, Known To Be Weak?

[HomerJHandley]

Had the bush devil out earlier and after a while it was making a loud grinding noise when turning, anyhow took the gearbox apart (fully ballraced) and noticed the sealed diff had metal flakes in and looking at the gears they have sheared enough so it works in a straight line, but any turning makes this noise, so they need replacing.

the car is running a std 540 silvercan (old and probably fit for the bin tbh) and nothing else out of the ordinary.

So is there a known issue with these and any way to prevent it occuring when they get replaced?

Also with a 3600 battery and ESC i got 25 mins runtime, woudl this be due to the battery only having about 5 or 6 cycles through as it maybe not up to top performance and run time or is it the motor which doesnt sound to run smooth so likely taking more power to run?

ta

glyn

[NJhopper]

Had the bush devil out earlier and after a while it was making a loud grinding noise when turning, anyhow took the gearbox apart (fully ballraced) and noticed the sealed diff had metal flakes in and looking at the gears they have sheared enough so it works in a straight line, but any turning makes this noise, so they need replacing.

the car is running a std 540 silvercan (old and probably fit for the bin tbh) and nothing else out of the ordinary.

So is there a known issue with these and any way to prevent it occuring when they get replaced?

Also with a 3600 battery and ESC i got 25 mins runtime, woudl this be due to the battery only having about 5 or 6 cycles through as it maybe not up to top performance and run time or is it the motor which doesnt sound to run smooth so likely taking more power to run?

ta

glyn

Not that I know of. These gearboxes are usually goo. I know it seems like a dumb question but.. was there grease up in those gears? Also if they are utterly toast I believe that other tamiya models bevel gears fit the same? I can't remember...

A 3600 bat with a 25 min run time.. sounds like a good run time to me, but its "shortness" may be becuase it is relativly new.

[HomerJHandley]

TBH cant recall any major grease in it, probably my fault as i bought the car from ebay in 2006 and it has had little use for 2 of them so whatever in there may have dried up?

anyhow not much of an issue as i got some new gears from Ebay US for £3.17 delivered, just have to grease these ones up

[SteelRat]

Usually the KBF and BD gearboxes are really strong. I replaced the standard ORV gearbox in my Monster Beetle for a Bush Devil one, and it now runs on an 8.5 EZrun BL motor and LiPo 2S battery. There's no way on this earth I'd even consider putting that sort of power through a standard MB gearbox.

I reckon replacing the gears as you have is a move well made and it'll serve you well for the future

[HomerJHandley]

Think it is probably abuse & no grease, and once upgraded intend to run a lower turn motor in it just to up the speed.

[stampede killer]

i haven't broke the gears in my super blackfoot, but i did do this with a 17t motor the gears looked good, but the y thing broke

[HomerJHandley]

Ended up replacing the entire box, the main gear sheared a few teeth on a jump (can assume it was on full tilt then when it hit the floor something had to give!) and that also had a replacement plastic diff section.

Rebuilt the diff as earlier and put a thin layer of silicone grease on the other parts, also fitted my vintage motor (stock but 20degree timing), seems quieter, not sure of speed as was using 1/2 used 3600, so just waiting for the rain then will try with the fully charged 4600 to see just how much difference it makes. Also replaced the plastic bearings with spare metal ball ones when i did the diff previously, which made the car wheelie a little bit from standstill

with the new diff parts, bearings, plastic gears and slightly more tuned stock motor should make it noticably quicker than before (hopefully!)

also fitted a new steering servo saver, this has made a big difference as well to the performance of the turning, ie it does now

[HomerJHandley]

--dupe post--

[stampede killer]

mine did wheelies with a 17t motor no problems

[HomerJHandley]

took it out earlier, basically it has been ballraced all the way through, new gears & diff, freshly greased/etc, new motor pinion and got a vintage modded stock motor in rather than the silver can.

WHAT A DIFFERENCE!!

its like a new car, very quiet and smooth, and a lot quicker than before.

on grass it easily wheelies (considering a DIY wheelie bar to save the lexan body any more damage) from standstill, on dust/stoney ground it easily loses traction and on roads it just whirs along smoothly as it should

its now my favourite basher car, has a reasonable turn of speed on all surfaces, handles the pitted & damaged area of road fine (just bounces off the potholes) and more fun than a buggy which struggles with the smaller wheels, the nitro that is limited, and the clod that will now be getting a full ball race and regrease of the gears, seeing the difference it made to the bush devil, may speed the clod up a bit!