Crank bearing housing resleeving?

[1983_Enduro_YAMI]

G'day all,

On my '84 Xt600 the crank bearing housings are worn out...bearings could free spin and be taken out while the case is cold. I'm thinking about resleeving the case by enlarging the housing, make a 2-3mm sleeve then press it in with dowel pins so it won't spin in the housing. Has anyone done the similar thing before because of the worn out crank bearing housing?

[Mick D]

Easily done though only necessary(badly flogged).
Of course the setup for machining needs to be on the correct intended center(which can easily be established).

The thing is a lot modern engines seem to be using loctite on their bearings ANYHOW now.
So if they are only just starting to move and in actual case the journals are not REALLY sloppy?
Just use loctite. 601  ,,,, or 609...
Make sure you clean the surfaces well with acetone if you don't have the loctite brand surface primer.

good luck with your build 

[1983_Enduro_YAMI]

Thanks mate...yeah it's not sloppy nor out of round however the bearing can be installed into the housing easily in normal temp and i can spin the bearing with my fingers in the seat so might as well while i have to apart i will do it properly that way i won't have to worry about it permanently. These early XT600s are bulletproof motor..will do 120,000kms from the showroom floor but this is the only problem. I am a bit doubtful about the using loctite for this time because the bearing is hardened steel and the case is aluminium..once it expands the loctite may not be strong enough to hold on and break up.

[80-85 husky]

any chance of finding another set of cases?

[Momus]

I'd go with Mick's suggestion. I've had good experience with Loctite retaining compound in all sorts of similar situations. Plenty of engines with cast in iron or steel housings and assemblies have none or almost no nip.

When the bike is running the mains will warm up and the changing difference in fit- assuming an aluminium case- will not be much at all.

If the Loctite is not satisfactory you can sleeve it; if it is good you have saved a lot of time and mucking about.

[sleepy]

I've sleeved plenty of different make and models using steel sleeves. Pins are not necessary if you get the correct interference and use loctite retaining compound. Once fitted with sleeves it is important not to heat the cases when fitting bearing as the heat will damage the loctite bond.

[OverTheHill]

Speedy sleeve any use. Confused me reading numbers but think i came up with 3.146 [79.9084 mm] ID on the nearest size i could find on page 26. Your 6307 should be 80mm OD, so 'what's that'--too tight on the bearing to fit. Think i read they're 11 thou thick so no doubt ya bearing's not that loose in the case. good old DT1 & all related early motors have a steel piece cast in with the case, never a problem--till later motors like , oh, my yz125e or f--e i think where they started casting the case around a separate 'alloy' ring which then came loose in the case!!. Wasn't obviously visible unless you looked closely or had got caught out as some did. case was cast right up over the front edge of the ring so had to look in a couple of mm or more to see where the ring started, & with the bearing in place you could--click click click the complete thing. Not sure what the theory was but was a pain when it went wrong. Even had an RM250X "81 where 'that alloy ring' same set up--had broken into bits, so bugger it, sold it in bits to someone clever with machine shop gear.

 http://www.waikatobearings.co.nz/file/anytime4e796e5b88a5a/open

[1983_Enduro_YAMI]

I've sleeved plenty of different make and models using steel sleeves. Pins are not necessary if you get the correct interference and use loctite retaining compound. Once fitted with sleeves it is important not to heat the cases when fitting bearing as the heat will damage the loctite bond.

so basically just heat up the cases, drop all the bearings in and leave the crank bearings at last and install it with loctite once it cools down right? I was told by a couple of people that loctite might break up when the engine is at normal temperature due to the case is aluminum and bearing is hardened steel?

[1983_Enduro_YAMI]

Speedy sleeve any use. Confused me reading numbers but think i came up with 3.146 [79.9084 mm] ID on the nearest size i could find on page 26. Your 6307 should be 80mm OD, so 'what's that'--too tight on the bearing to fit. Think i read they're 11 thou thick so no doubt ya bearing's not that loose in the case. good old DT1 & all related early motors have a steel piece cast in with the case, never a problem--till later motors like , oh, my yz125e or f--e i think where they started casting the case around a separate 'alloy' ring which then came loose in the case!!. Wasn't obviously visible unless you looked closely or had got caught out as some did. case was cast right up over the front edge of the ring so had to look in a couple of mm or more to see where the ring started, & with the bearing in place you could--click click click the complete thing. Not sure what the theory was but was a pain when it went wrong. Even had an RM250X "81 where 'that alloy ring' same set up--had broken into bits, so bugger it, sold it in bits to someone clever with machine shop gear.

 http://www.waikatobearings.co.nz/file/anytime4e796e5b88a5a/open

I had a look at it...it's mainly design for the shaft that's worn out?

[sleepy]

I've sleeved plenty of different make and models using steel sleeves. Pins are not necessary if you get the correct interference and use loctite retaining compound. Once fitted with sleeves it is important not to heat the cases when fitting bearing as the heat will damage the loctite bond.

so basically just heat up the cases, drop all the bearings in and leave the crank bearings at last and install it with loctite once it cools down right? I was told by a couple of people that loctite might break up when the engine is at normal temperature due to the case is aluminum and bearing is hardened steel?

The loctite is to hold the sleeve in place. The machine shop needs to make the sleeve about 3mm in diameter bigger and make it a good interference fit then pressed in with  620 retaining compound. Once in it is machined again to give a lesser interference fit on the bearing. The bearings then need to be pressed into the case to avoid overheating the loctite. Loctite 620 is good for 200*C which is well above the operating temp of the motor. The other bearings in the case can be pressed in with use of good lubricant without damaging their fit if kept square.
I have used the 620 loctite on loose bearings but only when time didn't permit sleeving. It will work for a while but as there is quite a difference in thermal expansion rates between bearings and alloy cases, it will give up after a while of heavy use.

[TT5 Matt]

my 84 tt600l had the dreaded but very much std noise at only 4k clicks on it along with a missing tooth on 3rd gear,apon tear down signs of rotating crank bearings and even with new bearings and the best retaining compound Loctite had they spun again by the end of practice on piree 1/2 mile long track soooo good luck finding good cases or even sleeving it.those things wernt even half a tt/xt500 as far as reliability goes

[1983_Enduro_YAMI]

Even though i'm able to find a new set of cases it's just gonna happen repeatedly  Maybe i should of waited a bit longer for a 500 Thought these 600 would go just as good but it's way below from my expectation...now i just have to speak to the machinist about it for a best solution of this... 

[TT5 Matt]

xt600 were quiet for longer due to a much heavier rotor compered to the tt but in time they all spun crank bearings around here to the point everyone didn't take much notice of the noise and just rode them.me I got tangled up with a car coming home from finke in 86 which damaged the frame and I had had a gut full of the 600 so I sold mine off for parts and got a xr600 which are far better then the yams and had good old tt500 reliability.id go a xr600 again but never one of those shite box tt600,couldnt even give me 1

[1983_Enduro_YAMI]

Yeah looks like i have been brainwashed by the yammies a bit too much hahaah...me and my old man have been riding Yamahas for our whole life...the old man had a XT500 in which a very little maintenance was conducted back then but never had a problem with it at all..now i've got a collection of IT250K, YZ250J, YZ490L, KX125 (it popped up one day and swapped it with a set of car ramps lol) and the most recent one is this XT...i really enjoy riding it until i discover this issue but i'm just gonna look into it a bit more since it's registered   

[80-85 husky]

hijack!! havent got a good shock for an it 490 L???