Just thought I'd mention results of valve adjustment on my '05 350 Rancher that has about 60 hours on the meter. I pretty much assumed that prior owner never had the valves adjusted.

After having read importance of adjusting the valves, over the last few weeks here, I decided to take a look at the Rancher. Removing the plastics and fuel tank and hoses is a bit of a PIA, but it wasn't particularly difficult.

Oddly, I found that it was not easy to see the 'T' mark indicating TDC through the timing hole cap. The crankshaft is bathed in oil and is thus shiny, which made it difficult for me to see clearly even with a shop/trouble light. Next time I'll use a small flashlight to peer into the opening.

In fact, I never did see the 'T' index mark, but instead two dash marks on the crankshaft. I assumed that TDC was when the index marker was lined up in the middle of the dashes (??). Anyway, at this rotation point, there was some play in the rocker arms and the valves appeared to be closed, and piston was at the top of the cylinder, so this appeared to be TDC on the compression stroke.

At this point we measured the gap between the valve stem and rocker arm pad on both valves with a feeler gauge, and they were both .006" - ie within spec. So as it turned out, we didn't have to adjust the valves. So we replaced the spark plug, tubing, fuel tank, and plastics, and it started right up, and ran like it did previously.

A word of caution, my friend over torqued one of the two bolts that holds the fuel tank to the frame, and snapped off the head of the bolt! The replacement bolts are about $6 at the Honda dealer. He says Asian hardware is not as good as USA made bolts/nuts.

The Rancher engine never did have a bunch of valve clatter noise, but it's one of those things where you don't know for sure unless you check.

 

Sometimes they need adjusting, and sometimes they don't. As you said, you don't know for sure unless you check.

In addition to the T for valve adjustment, there is likely an F and some marks for ignition timing.

Generally you have to turn the engine very slowly, or remove the spark plug, otherwise the resistance of compression makes it easy to fly by the T. In any case, you can probably accurately check the valves when the piston is anywhere close to TDC at the end of the compression stroke or the beginning of power stroke. Both valves will be fully closed for quite a few degrees either way from TDC, and the base circles on modern cams are very uniform.

 

i just adjusted the valves on my 350 rancher myself, saved 150 dollars. im only 16 and it wasnt hard at all. you should try it haha

 

One more note. On each cam profile, there is the toe, the heal and the lash point.
I still see where mechanics will turn the cam so the lobes are facing away from the rocker then set the clearance for lash and it is wrong as they are measureing it at the heal of the cam. This will happen more and more on lazy mechanics who don't think the crank must be set at TDC, just have the lobe toe facing away from the rocker. The cam must be in the lash position to correctly set lash. I see this more often in multiple cylinder engins than on single cylinder engines, but it does happen.

----- Gimpster -----

 

Yeah, I wasn't trying to suggest that you just park the crank anywhere, just that it seems that if you are off a little bit it doesn't seem to change the valve gap.

Some multi cylinder engines are designed to have the other pistons adjusted in other than TDC. For example on a CR ISB Cummins you set the crank mark at 12:00 and if the rockers on #1 are loose you adjust intake on 1, 2 and 4 and exhaust on 1, 3 and 5. Then turn the crank one turn and you adjust intake on 3, 5, 6 and exhaust on 2, 4 and 6...

I always check the factory manual if I'm working on an engine I haven't done before.

 

I did the valves on my 07 Rubicon, and at first it was hard to find TDC and the T. But after looking at the manual I guess there are three dashes then and F then a T.

Once at the T check the rocker for play, if there is play you are at TDC. if not rotate the engine one more rotation and look for the T again.

My Valves were actually REALLY TIGHT! (Explains the hard starting) Once I adjusted them to what they should be the rubitank ripped! It also started way easier. PLUS lean back with your feet on the pegs and hit the gas and it would wheelie on command.

I didn't think there would be a big difference but there was.

Did the same thing on my friends 05 Rubicon and he had the same results. He had never done his though and had like 750miles on it.