3 speed gearbox

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Nitroholic

Active Member
Messages
75
Location
Sweden
ive mounted the 3 speed tranny and åt the same time i did change the tranny gear go 52 in Steel, clutch Bell hd 13 teeth, 3 arms alu clutch inc flywheel. But i have 2 issues now that its put together. The big gear from the tranny and the clutch Bell cant align, there is not enough room between them. The second problem is that the clutch Bell loves very poorly, it does not spinn freely. This causes the engine to cutout. No idle. Have to start on full throttle. Am i missing something? Please help if you can.
 
When you shimmed out the c/b did you check it spun freely before fitting into savage?
If your flywheel is 34mm or bigger that might be the reason you have run out of room?
 
When you shimmed out the c/b did you check it spun freely before fitting into savage?
If your flywheel is 34mm or bigger that might be the reason you have run out of room?
I cant shimmed it out because its The other way around. The opposite of shimming. No, it did not spinn freely. Yes, its 34 mm flywheel. I thougt that was the original diameter of it?
 
For a start your c/b must spin freely, that will be why you have to give it some stick on start up & wont idle!
 
Either over tightened screw securing clutch bell onto motor shaft, or clutch shoes/spring rubbing against clutch bell.

Not sure why using 52/13, not really typical gear ratio in Savage.

1585596696732.png
 
For a start your c/b must spin freely, that will be why you have to give it some stick on start up & wont idle!
Yes, of Course, the question is how. I got shims at home but it don't need it because Theres no gap to shim. So when i mount the hex-screw and tighten, i just put more load on the bearings. All shim are removed but still no gap, nothing to shim. Bad parts? Everything is new, everything is hpi made, except 3 arms clutch. Is some china made noname i guess. But the mesurements seems accurate by eye, at least.
 
Have you made sure the fly wheel is tightened down as possibly tight as you can do it against the brass collet, have always had to shim my c/b’s out very strange!
 
Was the engine new? If everything is installed right, kind of sounds like your crank is shorter than it should be.

Here's a video I found quickly about installing a bell and shimming:

Pretty much the same for any engine.
 
the engine is used before by me. Ive mounted as the clip shows.
 

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If you enhance the last image, isnt that the brass collet shown in the image? Seems like the flywheel should be more to the left, that would explain the Most of it, right?
 
Flywheel isnt far enough on due to brass collet, however flywheel isnt stock hpi flywheel. So either find smaller brass collet or carefully increase diameter of hole in flywheel centre or grind back of brass collet to shorten it. As they say a picture paints a thousand words.
 
Flywheel isnt far enough on due to brass collet, however flywheel isnt stock hpi flywheel. So either find smaller brass collet or carefully increase diameter of hole in flywheel centre or grind back of brass collet to shorten it. As they say a picture paints a thousand words.
I Will fix it tonight and post pictures. Thanks!
 
Yes as lokky points out collet appears to be to big a diameter to fit into f/wheel centre hole when tightened up fully!
You could drill out bigger but caution & precision is needed on this to not mess up!
 
Will be easier to sand a bit off the back side of the collet (the fat end). You don't want to go too far, unless you have some spare shims or the flywheel will hit the crank case/bearing/carb.

The flywheel looks a bit thick in the center. There's quite a bit of space between the back edge of the bell and the face of the flywheel. That alone is eating up 3-4mm of space.
 
HPI flywheels are shorter than most others, not having a big step and different brands have different centre hole diameters and associated collets. Life aint always simple. Also clutch bells from other brands can be different sizes to add to the variation. Best to stick to stock HPI parts If you don't want alot of messing around, but usually there is a solution. Depends if you enjoy the challenge.
 
Hi! I tried uploading a videoclip of me spinning the clutchbell, but the filé wasnt allowed. Your tips was excellent. I grinded of in the hole of the flywheel and everything works just fine.
 
Pics
 

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Happy Days,glad you got it sorted! ??
That’s the thing with RC nitro & owning a savage sometimes you have to keep at it with trail & error until you get the results you wanted!
 

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