clayc2727

iTrader: (11)

Someone please help here. I CANNOT get my gear mesh right. Now I'm not a newb so I like to think we can avoid the simple issues here. Mugen MBX6 is what I'm running. O.S. .21 XZ-B engine, 13T/46T. Now, about 2 weeks ago I stripped my crank screw and had to tear engine down and drill it out. Since that time my gear mesh will not get back to its old perfect ways.
In order to get the buggy to roll like butter I have to get almost zero contact between gears. I move the clutch bell in slightly and get absolutely zero rotation out of it. I've tried to turn the tires and get absolutely nothing. Now this is still with way to little mesh. It's such little mesh in fact, that I can pull a piece of paper out with almost no indentations of gear teeth. I literally have to back the clutch bell off to the point where I can't turn the engine over because I know I'll chew my bell up. It's as though when my clutch bell seizes up the mesh is way to tight, but it's the opposite. There is almost no mesh whatsoever. The engine is aligned perfectly straight as well. And yes, I went through 3 pairs of clutch bearings trying to figure this out. 1 of them being ceramics. So you can imagine how this is pissing me off. Help please?

My ST-RR EVO

iTrader: (5)

Definately sounds frustrating. Let me see if I can remember a quote from one the old time racers su my track. Oh yeah. ... "stupid nitro". Pretty much sums up a lot LoL

anyway some things to check you may have overlooked-

make sure you have clutch bell end play i.e. you can move the bell forward and back. .2mm is good. .1mm is probably the minimum.

Make sure that with the engine out you can tweek the bell on its axis and it will not scrub the flywheel at all.

Make sure your clutch shoes are the right ones and not mushroomed.

make sure your flywheel nut is actually tightened down and not backing off binding stuff up.

Make sure you center diff bearings didn't take a dump.

Make sure center bulkhead where bearings sit isn't worn out.

Make sure clutch bell and spur are the matching set and in good shape. Sometimes worn ones have an ugly mesh.

Make sure the mesh issue isn't from binding elsewhere in the drivetrain like brakes or bent axles.

Make sure spur gear is seated flush in the diff case and didn't get tightened and seated at an angle.

Try new spur and new clutch bell

one8updragracer

iTrader: (5)

Did you bend the crankshaft while drilling out the screw?

clayc2727

iTrader: (11)

Hey guys, thanks for the input. Apparantly when I rebuilt my diffs I moved around the bottom bearing blocks on the diffs. I never realized they were universal so I guess the 50/50 chance of putting the one that had a piece sticking out was just bad luck. I had a new clutch bell on and realized upon yanking the engine out that the outer casing of the bell had run marks around the outside. Here's a few pics in case you guys ever have a similar issue. Thanks again!

clayc2727

iTrader: (11)

Clutch bell

30Tooth

iTrader: (1)

I think I found what's wrong, just a sec I'm heading downstairs to see my MBX6.

*edit* Yap, with the stock flywheel and CB there's a ~3mm gap between that brake disk holder and the CB. MBX6 needs a smaller diameter CB - yeah I found out this way too.

masher81

iTrader: (16)

You can't run the clutch shoes showing that much.

Frank L

iTrader: (148)

What clutch are you running?
Instead of shimming the cb out shim the flywheel out.

clayc2727

iTrader: (11)

Does it perform the the same purpose? Problem is I'm running a 4 shoe werks clutch and I can't find a clutch bell with a big enough housing to seat the entire clutch. Should I go back to a 3 shoes clutch/flywheel?

clayc2727

iTrader: (11)

Would I shim behind the collet (between bearing and collet) or in front of collet (between collet and flywheel). I saw a YouTube video of someone shimming between the collet and flywheel. My question is, wouldn't that crush the shim when you tighten the flywheel but and be counterintuitive?

JsK

iTrader: (10)

Werks clutch? looks more like a Losi 4 shoe, never seen a blue werks maybe the older model. Anyway a serpent bell will fit deeper and not require odd size bearings.

clayc2727

iTrader: (11)

I stand corrected. It is a losi 4 shoe rig. Sorry bout that. But, the OFNA clutch bell if not shinned a little will rub the hex BH screws that hold in the shoes. Currently I have 4 shims between clutch and CB. Can I use 3 of those behind the flywheel (between flywheel and collet) to bring back the CB where I get full coverage of the shoes while still clearing the screws for the shoes? If not I'll go back to the 3 shoe setup