Valve Adjustment on BS Motor

[OldDiyer]

Craftsman Tractor:

Model Number 917.272452

Serial Number 042902A005400

Briggs & Stratton

21.5 HP I/C Platinum Intek

Family: YBSXS.7242VF 274844

Model: 445777

Type: 0154 E1

Code 010418Y G

So being that I have had this tractor since 2002 and it is a LTX1000 and I believe I take very good care of it I would like to adjust the valves. Many repair people on this site seem to really push how important it is to adjust the valves on these engines I want to at least check mine as I have noticed a small bit of possible rocker noise. My question is how do I check to make sure that the piston is 1/4in past TDC ? I have an auto repair backround but car engines have marks on crank pulleys and I found nothing about this in the repair manuals. So how do you small engine guys find this spot? I also do know that you need the compression stroke not exhaust to set the valves. I haven't jumped into this till I get all the facts first so I don't run into any problems. Thanks in advance most of you repair fellows are always helpful. And yes I did check You Tube but none of those people do the 1/4in past TDC.

 

[ILENGINE]

The easiest way to find the 1/4" PTDC is with either a pencil or screwdriver down the spark plug hole. While turning the engine over by hand with the spark plugs removed watch the screwdriver come up and then start back down and that both valves are closed on that cylinder. If one valve is open then need to go a full revolution and try again. Now with that being said, the 1/4" measurement is not that critical. The principal behind it is to get the camshaft lobes past the compression release mechanism so it isn't effect the valve adjustment process.

With some experience you can feel TDC and BDC when the crankshaft makes that final arc. and by watching the valves you can guestimate close enough that you don't really have to measure piston position.

 

[StarTech]

And for some of us it is just easier to use the old method. That when one is fully open adjust the opposite valve. Yes it takes longer but don't have to hunt a measuring rod or risk accidentally breaking it off requiring head removal.

Also engine needs to cycle a few times after the adjustment to make it is set correctly. Just a single cylinder yesterday that the intake had to be reset several times to get it stay set. The camshaft apparently had a slight build up on the lobe. The customer had ran it so with the valves out of adjustment that may have caused this.

Just a note these V-twins one is 90(270) degrees off so setting at TDC on one side will not allow setting the valves on the other cylinder at the same.

 

[OldDiyer]

Thank you, guys, for the help and answers I will be doing this as soon as I get the gaskets and the weather warms up a bit.

 

[OldDiyer]

OK So I received the gaskets for this and now will be doing the adjustments. I have one manual that is like a block rebuild that has valve adjustments but then another spec sheet has a different valve setting. Is there any way to get a really good manual for this engine? Please let me know or just give me the proper setting. The reason I'm asking is I don't want to make any errors when I do this. Another thing I noticed is the 20page manual I have is from 1999 and my engine is 2002 so not sure if those specs are the same. Thanks !!

 

[OldDiyer]

Just to let everyone who replied to this for me everything went well. I did use the suggestion of turning engine over till one valve was fully closed and then did the other worked out great. I was really surprised has to how much adjustments were off the specs. Mine were like .010 at the most but others were between .008. the .010 am glad I did this. Well doing this I also found the vacuum line to the fuel pump from new was not seated in the valve cover correctly so had to replace it. After the adjustment it did smoke just a bit but seemed to clear up and seem to run well. I really wish to THANK YOU ALL for the help.