gearbox mods

[darkrider]

ok so we all know there are almost endless modifacations for power for the head
but im wondering what can i do to upgrade my gearbox. i have heard goodthings about ceramic bearings but i have no idea were to get the right sizes

 

[sean01]

shimming the excess play out of the gearbox can help
as for bearings look in my sig for the link to bearing, tho the 175 may have 1 or 2 different ones..
IMO ceramic bearings are a waste, just good quality bearings will do..

 

[darkrider]

thanks im planing on doing a full rebuild of my 175 new head so i will defently chuck some of these in would it be worth taking the engine apart then bringing the bearings into the dealer to get the right size

 

[sean01]

the bearings can be a pain to find in aus..

your 175 hasnt got many hours on it has it? why rebuild it

 

[darkrider]

im going to get the v2 head and 184cc bore up from tb and i was hearing that the ceramics were a good mod so im just going to do them both at the same time

 

[sean01]

to do the bearings you need to strip the engine totally to bits.. check all clearance and adjust if needed..

 

[darkrider]

?.........???

 

[sean01]

going by that response your in over your head thinking about doing this lol

 

[DHZ_XR8cing]

Where do you get the shims from Sean? Bearing traders? When shimming the engine is it just a matter of taking all the free play out of the shafts?

 

[The_GDFP]

$400 in bearings for a $40 stack of gears is a waste, IMO. Having the stock gears tumbled and swapping the three Chinese bearings for Jap/Euro bearings will help more. Idler/output bearing is Jap in the stocker. Crank bearings would make WAY more sense to run ceramic, as it's spinning 3.72 times faster than the input shaft of the trans and 8-10 times faster in lower gears. Fine tuning cam and ignition timing, quench, jetting will reap much larger rewards than a bearing swap. For pennies.

 

[sean01]

Where do you get the shims from Sean? Bearing traders? When shimming the engine is it just a matter of taking all the free play out of the shafts?

other gearboxs, but depends what shims you need i guess.. some engine rebuilding shops have them as spring seat washers/shims.

you dont take all the play out tho.. maybe terry will elaborate a bit more if he's keen to give away some trade secrets lol

 

[The_GDFP]

If some one's willing to dig in that deep, I'm keen to loan a shovel
Z's have been bad for shift drum end play, more than trans, in the handful I've done. I see over a mm of float, causing shifting issues. Only decent ways to fix it is to trim the end of the drum, or source shims that slip over the end of the drum pin. A steady hand at the grinder will work, but mine's not so I cut the excess off the end in my lathe. For trans end play, shimming for .5 to 1mm has worked for me. I've also left the right bearings a couple mm shy of seated, with Loctite 640 and let them find home on their own. Gotta tap lightly on the sprocket end and input case area to get rid of binding. Works well to keep the main bearings from fretting around in the case bores, too. Some say.

 

[Minibiker05]

What would good crank bearings be worth

 

[The_GDFP]

What would good crank bearings be worth

Ceramics should add .5hp, or so, I'm guessing, on a high-rev build. Smoother and quieter, for sure. Even decent steel ones are quieter.