"correct" oil change for 3AJ
 

i have noticed in several places reference being made to the "correct" way to change the oil on an xt600. it seems that the correct way is more laborious than the "normal" way. as i only know one way to change the oil, i am not sure if mine is the correct way or not.

i have noticed that there is a warning on the bike that the oil must not be removed directly from the crankcase (or engine damage may result, apparently), so i would like to get to the bottom of this and clarify exactly how an oil change should be done according to the book.

any ideas?

thanks
cabron

(ps also does anyone know the DOT spec on the brake fluid to be used on the rear disc brake of a 3AJ?)

[This message has been edited by cabron (edited 03 February 2003).]

missunderstanding!
the warning says that you should not disconnect the pipe leading from oil tank to the oil pump (this is the one connected to the crankcase on the bottom left side).
the reason for this warning is that if you disconnect the pipe from the crankcase there is the potentional danger that the oil pump sucks air.
of course you can disconnect the pipe but you have to take care to fill it again with oil before you connect it again. just fill the oil tank and wait until oil drops out of the end of the pipe - then connect. also the pipe inside the crankcase which leads directly to the oil pump should be filled with oil. lean the bike to the right side and fill the pipe with oil.
but usually this is only necessary after an engine overhaul, it doesn't belong to the standard oil change procedere which is as following:
- warm up engine to appr. 60°C
- place bike in upright position
- unlock drain screw / oil filter housing (the lower one, don't take it out completly now)
- drain oil tank (screw out pipe until groove appears)
- drain crankcase (left side next to gear lever shaft)
- disconnect oil pipe from oil tank. check/clean metal filter. check/replace o-rings, copper washers.
- open oil filter housing (it should be empty by now) and replace filter. check/change o-rings. clean thread of the three bolts. tighten the bolts with 8 Nm max.
- tighten all drain screws
- unlock air bleeder screw on top of oil filter housing
- fill oil tank up to the top
- start engine
- watch air bleeder screw. as soon as oil appears lock it. if no oil appears after 1 min. something is wrong. stop engine immediatly and check
- refill oil tank (engine should be filled with a total amount of appr. 2,5 l)
- ride about 20 kms. stopp engine and check oil level. if level is still below max., refill.

repeat every 6000 kms, at least.

regards
klaus

hi klaus

thanks very much for that. why do you heat the oil up before doing the oil change? does it not make it very difficult to work with when this hot?

thanks again
carl

60°C is not really hot.
the reason is that 'warm' oil is not so stiff as cold oil is. it makes it easier and faster to drain the oil, that's all.

regards
klaus

hi klaus

thanks very much for the reply. which oil would you recommend for use in the UK during winter? i have just done an africa trip and i was using 20W/50 there, but that was because it was very hot. it is the opposite here - very cold - and i am thinking of using 10W/40, but i am not sure if perhaps 5W/40 is better. what would you recommend? (my bike is an '89 3AJ, with 22K on the clock, and i use it for short distance commuting around london, so it is mostly start-stop and i never go above 4th gear or very fast.)

thanks again
carl

the cheaper one.
let her run idle for a minute or so after starting, that is more important than the viscosity of the oil.

regards
klaus

hi klaus

got round to that oil change yesterday, and it went smoothly, but i have one or two questions for you!

1. after i have drained the oil tank by means of the drain screw, you mention that i should disconnect the pipe from the oil tank and check the copper washers and filter. i found it very difficult to move this pipe from its location on the oil tank (it is wedged in quite securely behind the frame plate in the V), and i could not turn it around to check the passage of the hole in the pipe. as such, i could not check on the filter (which i presume is in there, out of my view!) is this important? i could see the metal ring and that looked ok. in the end i just cleaned away the excess oil and reattached it the pipe to the tank.

2. what happens to the oil in the pipe from the oil tank down to the oil pump in the crankcase when i have removed the crankcase drainage bolt and drained the oil? you mentioned that i should not remove this pipe unless i replaced the oil in it before reattaching it - but would the oil in it not run out anyway when i drain the crankcase by means of the main bolt?

lastly, after going through the technical spec you sent me (just to show that your effort was not wasted ;-) )...

3. what is the difference between "feed" and "scavenge" oil" is it as simple as "feed" coming straight from the oil tank and "scavenge" coming from the run-off at points through the engine?

thanks again for your help in advance!

cabron

[This message has been edited by cabron (edited 10 February 2003).]

[This message has been edited by cabron (edited 10 February 2003).]

1)
the filter is a metal mesh type. if this filter is blocked, engine gets less oil or -in the worst case- almost nothing. but it's very unlikley that this filter gets blocked unless you throw something inside the tank. it is there to catch small parts which might have entered the tank when refilling oil.
to check the filter it is helpful to unlock the two bolts which fix the tank to the frame. when reinstalling the bolts, degrease first and use a drop of blue loctite to secure against loosing.
2)
this small amount of 'old' oil will stay inside the engine because it cannot pass through the oil pump and oil filter resp.
you can assume that about 0.4 l of the old oil will stay inside the engine because it is captured behind corners, in pockets / bearings
3)
the scavenge circuit brings back the 'used' oil from the bottom of the crankcase to the oil tank (via oil cooler on teneres).
the feeding circuit delivers 'fresh / cold' oil from the tank to the greasing points. remember that the task of the oil is not only greasing, but also inner cooling of the engine.
here you will find everything about the oil circuit:
http://www.xt600.de/xt_werkstatt/+sp...lauf/index.htm

hope this helps,
regards
klaus