|
|
Post by wotavidone on Apr 3, 2007 18:07:35 GMT -5
Gents,
I've got the dreaded puff of blue at cold start-up in my XT. The daily riding bike naturally. No drop in oil level before starting, so I think wet-sumping is not the culprit.
Has anyone done just valve stem seals on a SR/XT motor?
In cars we used to get the piston at bottom dead center, pressurise the cylinder with air to hold the valves shut and replace the valve stem seal without taking the head off.
Anyone done this on the SR/XT and can you get enough bits off the head to do it with the engine in the frame?
Mick
|
|
|
|
Post by StewRoss on Apr 3, 2007 21:38:42 GMT -5
Hi, No the engine has to come out...it's a relatively simple task and I think it could be done with air pressure...although I've not done it myself. Should stop the oil usage pretty well straight away unless the rest of the engine is worn. One tip, use genuine seals, not aftermarket. I have had bad results with aftermarket stuff and it's not worth having to remove the engine again to do it over. SR  |
|
|
|
Post by aero on Apr 4, 2007 3:58:14 GMT -5
In removing the rocker cover to gain access to the valves you have to remove the nuts that hold the head in place. So you certainly wont be able to pressurise the engine. But that method is an extremely good way of telling you what condition the motors in, by how well it holds the pressure. The thing hissing is where the problem lies, breather/carb/exhaust etc. I just had the rocker box off my SR, I did it in 4 1/2 hours start to finish, back on the road and riding. To lift the head and ponce about with that another couple of hours or so. Definately use genuine seals, been down that road and it aint worth messing about with ones a few pence cheaper. Same goes for head gasket, good Japanese as a minimum.  |
|
|
|
Post by flyereddie on Apr 4, 2007 6:04:18 GMT -5
Hi
Ive never tried the compressed air (dont own a compresser) but when i used to change the oil seals on my van i was know to stuff the cylinder with nylon rope then turn the piston up to near the top, the rope holds the valves up , change the seals turn the moter back to bottom pull the rope out and done . I changed the seals about 4 times that way with no problems.
|
|
|
|
Post by davedunsboro on Apr 4, 2007 6:21:28 GMT -5
That's a beauty ! I wouldn't have known about that method if I hadn't been a member on the forum . Thats got to be worth a try if you needed a quick cheap fix , cheers from Dave .
|
|
|
|
Post by StewRoss on Apr 4, 2007 6:22:00 GMT -5
Hi, It's probably too much mucking around and you'd need some unusual tools. A mate of mine had a small spring compressor that compressed the springs by holding onto the spring coils about 2/3 way down against the retainer...worked well, but I haven't seen another one of these tools since...you could hold the head down by making up alloy spacers to go under the head nuts as well... Reckon it's simpler to remove the engine in the long run. It'd be an interesting exercise to try one day...have to make up the spring compressor tool though I feel... SR  |
|
|
|
Post by aero on Apr 4, 2007 8:05:05 GMT -5
I really dout it would work on the SR. As you have got the head unbolted you will just lift it off trying to get the collets out anyhow. You may as well take it off and work on it on the bench with normal tools. Just whip the cam chain adjuster out, cam out and off you go. Its a 5 min job to time it all up again on a single. |
|
|
|
Post by fenz on Apr 4, 2007 17:35:11 GMT -5
Have to agree that the extra messing around trying to get the valve springs compressed while the heads on the motor it just is not worth the skun knuckles.
|
|
|
|
Post by wotavidone on Apr 4, 2007 18:17:40 GMT -5
I certainly got a conversation started.
So, aero, is the picture telling me that you got the rocker box off the engine while still in the frame? I reckon by the time I combine all the comments here, I can see myself doing the following;
Remove rocker cover in frame.
Hold the head on with some spacers and the nuts put back on.
Stuff engine full of nylon rope to stop valves falling out.
Use little "slip over springs" valve spring tool to get collets off.
Replace valve stem seals.
Back on road next day.
On the other hand, it only blows blue smoke on the occasional start up.
Might leave it till it gets really bad. i.e. have done nearly 1000k and don't yet have to top up the oil, so its currently only an intermittent cosmetic problem.
Mick
|
|
|
|
Post by aero on Apr 5, 2007 5:12:22 GMT -5
Hi Mick
The photo is deceptive. The motor is completely undone in the frame, you won't get the rocker box off with it in situ. I had to twist it round so the head was clear of the top rail.
As the engine has recently had new oil I didn't want to undo the oil lines, which is why I did it like that.
I was hoping to simply lift the rocker box as the previous owner had assembled it with no gasket sealant and it was hoofing out oil. I was able to lift it without undoing any of the engine mounts. When I got it lifted I saw that a dowel was missing too. So I had to take it off completely to put a new one in.
|
|
