first time rebuilding tranny, need pointers

seanmx57 · Post by **seanmx57** » March 25th, 2010, 8:32 pm

So I tore her down. I was getting oil that looked like it should be paint, plenty of metal. I was also occasionally missing shifts from 3'rd to 4'th.

So I get the tranny out and notice the bearing that has the idler gear on the other side isn't in the case. It came out with the tranny but was not stuck to the shaft. I have to get a magnifying glass to closely inspect it but I was able to instal and remove the bearing by had. Not exactly the fit I was hoping for. Looks like the bearing was spinning in the hole and giving me pretty oil. What would make this happen?

The motor is a 2000 with MX gears in 4'th and 5'th that are lower ratio. The motor has been apart 3 or 4 times for gear changes, crank work etc. Not a whole lot of hours on it.

Is the case junk or can I use locktight and a new bearing to hold her together? is there another product similar to locktight to fill the void? The bearing fits pretty tight.

I noticed that 4'th gear dogs are a slight bit rounded off. I use 4'th a lot for MX so I'm guessing I should not mess around and just change them.

I've read stuff Adam has posted about the 98+ trannys having wider gears. Will having the older 4'th and 5'th mess up the spacing thus cuasing the 4'th to round off?

100hp honda · Post by **100hp honda** » March 26th, 2010, 1:17 pm

i had same problem with one of the tranny bearings spinning. mine had just barely started to spin, so it was easily repairable. depends how bad your hole is wallered out will determine which path you take.

seanmx57 · Post by **seanmx57** » March 26th, 2010, 1:21 pm

M4/M3
C2/C4 gears all have a rounded edge, guessing .025" for depth of rounding, definately not square.

The forks looked good but some showed sign of mild wear at the base, opposite the tip. not enough to wear the whole flat surface just the bottom edge.

The bearing has a slight amount of slop in the hole.

noticed the bearing behind the clutch acts like it had dirt in it, doesn't turn very well but is still tight. Blew it out once with brake clean, didn't seem to help.

Do the old gears being narrow contribute to the rounding problem?

100hp honda · Post by **100hp honda** » March 26th, 2010, 1:40 pm

if the bearing wobbles in the hole, you may have a larger scale problem. if its kind of tight but still slides in and out by hand then the problem isnt that great. theres supposed to be a small amount of interference fit. except on one of the bearings that has a plate holding it in, that one wont have any interference fit, or very very little at most. its hard to judge how bad the problem is through a keyboard

Post by **AlisoBob** » March 26th, 2010, 1:48 pm

Keyboard or no keyboard.... if the oil looks like silver paint.... its bad.

100hp honda · Post by **100hp honda** » March 26th, 2010, 1:52 pm

AlisoBob wrote:Keyboard or no keyboard.... if the oil looks like silver paint.... its bad.

i understand what your saying. he might have a small amount of spinnage, or he might need a new case half, some of the grey oil may have been from the clutch plates also, so the problem may not be exteremley severe. however "wobbling" dont sound good

... could be why the tranny didnt work very good, the shafts werent staying parallel

seanmx57 · Post by **seanmx57** » March 26th, 2010, 2:03 pm

definately no wobble.

Hard to feel the slop between the bearing and hole

oil is far from silver but you can see metal in it that was not normal.

I can't believe it happened. I change oil every 3 or 4 rides which means about every 6 to 10 hours. Maybe it has something to do with the motor being torn down so many times messing around.

i don't see any product on the locktite site othe than maybe epoxie made for metal that might help.

100hp honda · Post by **100hp honda** » March 26th, 2010, 2:06 pm

oh i thought you mentioned a wobble but i guess not, my bad. well in that case your probly just fine. it might be permatex that makes the bearing goop, cant remember. definatly use new bearings though but im sure you already knew that

seanmx57 · Post by **seanmx57** » March 26th, 2010, 2:09 pm

I've never run an AL plate in the clutch. This motor used to vibe REAL bad before the STR crank. Bad enough to crack all kinds of stuff, Cracked the left case around the crank seal. I swapped the cracked Left case for a 92 case not long ago, 15 hours ago maybe.

100hp honda · Post by **100hp honda** » March 26th, 2010, 2:12 pm

found something bob could use

http://www.permatex.com/products/motorc ... ir_Kit.htm

thestuz · Post by **thestuz** » March 26th, 2010, 3:29 pm

i had the same problem with my 01 engine.
the gbox oil would come out looking like graphite paste. kinda metalic silver.
i pulled the thing down twice to try find the problem.,replaced bearings, couldn find any signs of bearing spin either. i replaced the clutch and filed down the basket fingers smooth again(to fix my clutch drag problem) and that seemed to help a bit.i still get the problem, although its not as bad as it used to be.
i installed a strong earth magnet in the drain bolt and realised that the metallic stuff was alloy, not steel.
judging by the wear on my clutch basket, and how fine the particles are and the absence of any mechanical failure, im assuming its wear from the clutch basket in my case.because after tearing it apart twice there are no other signs of it being anything else!

remedy=change gbox oil after every ride, use 900 ml of cheap grade motor oil everytime

thestuz · Post by **thestuz** » March 26th, 2010, 3:37 pm

and yes ive had steel plates the whole time.
and i use locktite for loose bearings. they do have a product for the problem you have.
ps, what gearing are you using for mx?

Post by **AlisoBob** » March 26th, 2010, 3:46 pm

100hp honda wrote: he might have a small amount of spinnage...

Thats like saying someone has a "small amount" of being pregnant.

thestuz · Post by **thestuz** » March 26th, 2010, 3:48 pm

AlisoBob wrote:
100hp honda wrote: he might have a small amount of spinnage...
Thats like saying someone has a "small amount" of being pregnant.

if its not spun too badly, the case is still salvagable with loctite.

Post by **AlisoBob** » March 26th, 2010, 3:50 pm

I properly rebuilt CR500 Shortblock lasts YEARS!!! I know a few guys who did the Loctite thing.... none lasted more than a few months.

seanmx57 · Post by **seanmx57** » March 26th, 2010, 4:36 pm

AlisoBob wrote:I properly rebuilt CR500 Shortblock lasts YEARS!!! I know a few guys who did the Loctite thing.... none lasted more than a few months.

Thanks Bob. That's some real info I needed to know.

I looked at the locktite site, didn't see any product that looked like it was for this type of problem. Checked the permatex site too. All gone for friday beers at customer service. I definately do not want to tear down again for many years.

I noticed that the locktite epoxy is "resistant" to chemicals. Not sure if if would do the job if the case and the bearing had small grooves cut in them to give the epoxy a mechanical way to grab.

My basket is billet, stormin normin, no notches in 9 years.

I run 14/51 gearing. you won't understand. regardless, I start in 3'rd and never EVER go below 3'rd on a MX track of any type. I use 4'th A lot and 14/51 pulls very well with new 140/80 tires with the motor breathed on a bit. Anything taller than 14/49 would be like taking a nap for me. I like her to shit and get. No waiting. When I'm not in shape, after watching it snow for 4+ months I run 14/49 for a couple rides or for very, very fast tracks.

100hp honda · Post by **100hp honda** » March 26th, 2010, 4:45 pm

i did the dimple thing on mine. i havent seen any large chunks in the oil so im assuming its still working. might give that a try also.

eventually you might need to replace bearings again, make sure you dont get it in there too good if you know what i meen

britincali · Post by **britincali** » March 26th, 2010, 4:53 pm

Green loctite is the stuff to use for loose bearings, I think its marketed as stuff to hold wet sleeves in place.

britincali · Post by **britincali** » March 26th, 2010, 4:55 pm

http://eastcoastgearsupply.com/i-129994 ... ainer.html

seanmx57 · Post by **seanmx57** » March 26th, 2010, 5:11 pm

I still don't get why they spin in the first place. They are a press fit. I've had CR250 motors last for well over 3X the hours this motor has.

2strokekyle · Post by **2strokekyle** » March 26th, 2010, 5:15 pm

I've used the green stuff on a snowmobile crank bearing that had spun in the case. It held up for years untill a rod bearing let go and destroyed the crank and case.

Post by **AlisoBob** » March 26th, 2010, 6:13 pm

britincali wrote:http://eastcoastgearsupply.com/i-129994 ... ainer.html

THats not it......

http://kraftindustrialsupply.com/bearing_retaining.htm

#640 and #680 is what they used.....

Honda didnt design the cases to be apart 4x times...

britincali · Post by **britincali** » March 26th, 2010, 6:29 pm

AlisoBob wrote:
#640 and #680 is what they used.....

Honda didnt design the cases to be apart 4x times...

Whose they? Ive used the sleeve stuff before with no issues....

fastkart · Post by **fastkart** » March 26th, 2010, 8:45 pm

AlisoBob wrote:
britincali wrote:http://eastcoastgearsupply.com/i-129994 ... ainer.html
THats not it......

http://kraftindustrialsupply.com/bearing_retaining.htm

#640 and #680 is what they used.....

Honda didnt design the cases to be apart 4x times...

If you click the pic on the East Coast Gear Supply to enlarge it, you will see a tube of Loctite 640.

thestuz · Post by **thestuz** » March 26th, 2010, 9:05 pm

it only works for slight clearances. if its real loose, your lookin for a new case or get an insert put in.

BannedCR500Riders.com

first time rebuilding tranny, need pointers

first time rebuilding tranny, need pointers