Author Topic: Anyone adjusted their valves?  (Read 2016 times)

GaryL

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Anyone adjusted their valves?
« on: October 01, 2010, 04:22:25 PM »
I'm thinking it may be about time to adjust the valves on my RV-250.  Is it hard to do?  Must lots of tupperware come off or does just removing the seat box give enough access?

Also, what does it typically cost to have the valves adjusted by a shop?

Thanks!
Gary
Sym RV-250 - Silver w/Orange Trim - 9,000 miles.
Bali 250 Chinascoot - Bright Yellow - 16,000 miles

Brucifer

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Re: Anyone adjusted their valves?
« Reply #1 on: October 01, 2010, 06:01:00 PM »
I do all my own maintenance, which is a good thing since my dealer went out of business. This summer I turned 10,000 miles on my RV250. I decided to adjust my valves, among other things. I've adjusted valves lots of times in the past, on both cars and scooters. I removed the pet carrier and some side panels and eventually the valve cover, exposing the cam shaft, rocker arms and valve stems. There is a frame member right in front of them and given the way it is all consructed there was no way to see into the area under the valve cover, where you have to do the adjustment. I eventually decided there was no way I could do it properly without unbolting engine mounts and tilting the front of the engine down so I could see what I was doing. I didn't feel like doing that at the time. With my hand I could move the rocker arm ends up and down and the clearance did feel about right. Again, I have adjusted lots of valves so I have a feel for this. But on this 4-valve design each cam lobe operates two valves. So when rocking the rocker arms by hand I was only feeling the tightest valve. The other could be looser. That's not real bad since loose valves don't burn. However, if they get real loose they can hammer the end of the tappet screw (the thing you turn to adjust the valves) and increase the clearance still further.

In the service manual they show how to adjust the valves. Piece of cake. They've got the engine out and on a bench.

For now my plan of action is to open things up and feel them once in awhile. If I ever think one is tightening up I'll see if I can tilt the engine down and adjust them. If I can't tilt this engine down I'll drop it and do the job. I'll also get real serious like that if I ever hear the clacking of a loose tappet.

Having seen how it's all put together and if I had a dealer and wanted them to adjust my valves, they'd have to give me a pretty detailed explanation of how they could actually do an accurate job of setting the tappet screws. I'm sure there are dealerships somewhere out there with a really good mechanic and I'd make absolutely sure by talking shop with them. It would be really easy to get it wrong with the engine in place.

Does anybody know any tricks for doing this that I didn't think of? I'm all ears.
Scooter riders don't give a shift.

jim63

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Re: Anyone adjusted their valves?
« Reply #2 on: October 02, 2010, 02:53:51 PM »
My bike is pushing 26k miles now and still have not adjusted the valves. The thing starts everytime 1st push of the starter and runs just as well as when I bought it. Have thought about it a few times, but IMO the valves are one of those deals if it is running good dont mess with it. I'd be realy bummed to tear the bike apart to find the valves are just fine or still within limits, and risk damaging something in the process of tearing it apart. Wifes bike at 10k same story not touched the valves on that one either. I know the service manual says to adjust them periodically, but I have a hard time with the thought of it for no reason other than the manual says to, it is not like lubrication or other items that you really should check. Maybe I am just lazy...

Brucifer

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Re: Anyone adjusted their valves?
« Reply #3 on: October 02, 2010, 05:38:07 PM »
I'm glad to hear you're at 26k with no problems. I think our RV250s are really good scooters and I'm looking forward to years of dependable service. I'm at 10k now and want to just keep going on and on. About valves, they really are a regular maintnance item. But on this scooter they appear to be pretty much impossible to adjust with the engine in place. Normally though, valves just veeeeeeery gradually loosen up as the heads of the tappet screws wear. That's not especially bad. In the extreme case you could lose performance if they got so loose the valves were not opening far enough. In a well built engine with proper lubrication, I don't think that'll happen within the lifetime of the engine. The bad thing is if the valve gap tightens up. That will burn the valves and then the engine has to come apart. I don't know of too many things that cause that. One is valves hammering down the valve seat if the seat is just not hard enough. Another is if the material in the valve stem can't quite take the extreme temperatures it encounters. Then the valve stem slowly elongates and the valve clearnce tightens up. I've seen both those things happen a number of times ... but not for a lot of years. Materials have gotten so good now that if it's built right the valve seats and valve stems will be just fine.

Again, thanks for telling me you're up to 26k with no problems. It eases my mind a little, since I'm only checking my valves by feel and not actually checking the clearance properly. Maybe one of these years scooters will get the hydraulic, self-adjusting, systems used in cars. Anyway, I hope we both make it to 100k with our RV250s!

Happy riding!
Scooter riders don't give a shift.

SYMmike

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Re: Anyone adjusted their valves?
« Reply #4 on: October 03, 2010, 02:10:44 PM »
I have over 19,000 miles now and have thought about a valve adjustment when I had trouble starting it for a while. Come to find out all I needed was a new spark plug.
I'm the person if it's not broken, don't fix it .... or mess with it!
2008 dark grey RV250, 27,000 miles

GaryL

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Re: Anyone adjusted their valves?
« Reply #5 on: October 04, 2010, 03:22:15 PM »
Thanks for the great responses everyone  Sure sounds like I shouldn't need to worry about the valves for quite a while.

Regards,
Gary
Sym RV-250 - Silver w/Orange Trim - 9,000 miles.
Bali 250 Chinascoot - Bright Yellow - 16,000 miles

steveduhl

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Re: Anyone adjusted their valves?
« Reply #6 on: March 27, 2017, 01:02:50 PM »
Thanks Brucifer.  Since it was relatively easy to get to the valves, I thought that there wouldn't be a problem adjusting them (I have the advantage of small hands).  But, once I was there, I couldn't see much.  My usual strategy is to ignore timing marks and adjust when the camshaft lobe is pointed away from the rocker.  In this position, the clearances are as big as they are going to get.   But, on the RV, I couldn't see the camshaft.  What I was able to do was get a feeler gauge in between all four valves when there was play in the rockers.  All were within specs.  So, at least I know they aren't too tight.  It is possible that they are too loose (because, maybe, I measured before they came off the cam lobe) but I turned the engine over a few times and re-checked to minimize this possibility.   I am hopeful that someone better than me will pull the fuel tank AND pull a couple of engine mounting bolts to swing the engine down...then, let us know which method is easier and write up the procedure.  I will sent the man/woman who does this beer money.

steveduhl

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Re: Anyone adjusted their valves?
« Reply #7 on: March 27, 2017, 01:20:00 PM »
While it is fresh in my mind.......I should do this....
-Remove pet carrier...10mm socket w/extension...unscrew light fixture and remove through rear...as you lift carrier out, unplug light/seat-open switch from right side.
-Remove "garnish" from each side.  These are 14" X 4" panels on either side of tunnel/floorboards.  They just snap out.
-Remove four 10mm bolts from valve cover (need an angled 10mm box end for the bottom right).
-From pipe at the bottom of valve cover, remove 2 8mm bolts (socket with long extension) and remove or loosen the two 8mm bolts on the other end of the pipe.   Swing pipe out of the way.
-Remove spark plug (so that cylinder compression doesn't effect where piston stops when you are trying to get the cam in a good position to adjust).
-Remove hose from front of valve cover by squeezing clamp open and wiggling hose or (as I did) using 8mm socket to remove 2 housing bolts.
-Remove valve cover (after making sure, if you are following these instructions, that I didn't mention something you were supposed to take remove).   Note:  For my valve over: Rubber mallet?  Didn't work.  Jiggle? Didn't work.  Taking flat screwdriver and gently pushing (reusable rubber) valve cover gasket a millimeter out of the way near bolt holes and then gently twisting screwdriver a tiny bit and then repeating at all four corners (at the bolt holes)?  Yup.
-Figure out how to align timing marks (I didn't...see my previous post)....shrink hands to the size of a 6 month old baby....attach mirror to back of gas tank....gloat in your success.

sunfish

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Re: Anyone adjusted their valves?
« Reply #8 on: April 08, 2017, 04:53:22 AM »
Faced with hard cold starting I too attempted to adjust the valves on my 2009 RV 250. Once into the heart of the matter it was quite evident that all my efforts were for not and the only way to complete this job was to drop the engine from the frame. My scoot is only at 7500 Km and I attempted the valve job at the beginning of last season 3000 Km. This season I will make an effort to only use premium fuel to help with cold starts and I have put in a new spark plug also. Have just taken the scoot out of winter storage and rode it back home and I am looking forward to another enjoyable season of riding.

Sunfish
« Last Edit: April 08, 2017, 12:06:10 PM by sunfish »