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Author Topic: Determine compression stroke????  (Read 929 times)

Offline postmaster

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Determine compression stroke????
« on: March 28, 2011, 01:48:00 AM »
This is related to my other question about the decompression lever.

When I adjusted the valves on my DR 350, I might not have adjusted them on the compression stroke, which is required.  I properly got TDC, but maybe on the wrong stroke.  When I got to TDC, and adjusted the valves, the rocker arms were solid and did not move even a little bit.  There was no play at all and even the smallest feeler gauge I had would not fit.  So, I adjusted the valves from there.  I know have a very loud ticking that wasn't there before and the decompression lever does not work.  I tried it again and this time at TDC, the rocker arms were loose, or had play, but I did not adjust from there.  I think maybe I adjusted on the wrong stroke and have them open way too far.

My questions is, on a single piston, 4 stroke engine, my DR, will the rocker arms, both intake and exhaust, have play in them while at TDC on the compression stroke?  If so, then I adjusted from the wrong stroke.

In simple terms, how do I know I am on the compression stroke?  If I am on the compression stroke, will the rocker arms be a little loose or have play?  I think maybe I have made them way too loose.

Offline dredman

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Re: Determine compression stroke????
« Reply #1 on: March 28, 2011, 04:18:29 AM »
pull the plug, but that should be in the manual  ^-^

Offline springer

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Re: Determine compression stroke????
« Reply #2 on: March 28, 2011, 06:00:34 AM »
 On the compression stroke @ TDC ALL the valves are closed and spring pressure is holding them closed against the inside of the head. The rocker arms for both the intake and exhaust valves should be loose. The rocker arms act against the spring pressure to open the valves.
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Offline yamahamer

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Re: Determine compression stroke????
« Reply #3 on: March 28, 2011, 06:07:47 AM »
Most cams have a "E" and a "I" stamped on them. With the "E at the exhaust side and the crank mark, This is TDC.

Offline catang5oh

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Re: Determine compression stroke????
« Reply #4 on: March 28, 2011, 10:07:43 AM »
On the compression stroke @ TDC ALL the valves are closed and spring pressure is holding them closed against the inside of the head. The rocker arms for both the intake and exhaust valves should be loose. The rocker arms act against the spring pressure to open the valves.

What springer said, thats how i always have found it. Crank at TDC rocker arms should have some play.
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Offline papa snow

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Re: Determine compression stroke????
« Reply #5 on: March 28, 2011, 10:27:12 AM »
I would be very careful and go with any/all timing marks you can find,,don't trust that your rockers/valves will have slack, since you think you adjusted them in the wrong position the first time,, ;D
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Offline postmaster

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Re: Determine compression stroke????
« Reply #6 on: March 28, 2011, 10:44:24 AM »
What springer said, thats how i always have found it. Crank at TDC rocker arms should have some play.

I adjusted mine when there was NO PLAY, which was not the compression stroke.  Now they are waaaaaay loose.   

Online SlowRoad

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Re: Determine compression stroke????
« Reply #7 on: March 28, 2011, 04:26:40 PM »
When you pull the plug, you can put your finger over the hole in the head and feel the compression pushing against your finger when the cylinder is coming up on compression.  This will let you know it's the compression stroke.  Then look for timing marks for TDC.
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Offline postmaster

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Re: Determine compression stroke????
« Reply #8 on: March 28, 2011, 07:57:38 PM »
Worked on the bike again when I got home and boy do I feel like an idiot!! 

I had adjusted the valves properly but  not on the compression stroke. >:D

I adjusted them again, this time on the compression stroke and all the previous problems went away.   933

The decompression lever now works like it is suppose to.  I guess I had the valves so far open, that there was very little compression.

The ticking valves also went away, again because they were opened up too much.

Also, I had a previous problem of the hard cold start.  After the bike was warm it would start pretty easily, most of the time.  Now that the valves are adjusted correctly, the bike started from a dead cold start in, get this, 3 kicks.  It has never started that easily!  That is a blessing within itself.

Thanks for all the advice.  I've done it so many times now, it only takes about 30 miutes.  It takes me more time to get the plastics, seat and tank off than it does to adjust the valves.

weirdbeard

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Re: Determine compression stroke????
« Reply #9 on: March 28, 2011, 08:02:15 PM »
  Ahh man.. I didn't get to say anything..  :(

Offline EL GRINGO

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Re: Determine compression stroke????
« Reply #10 on: March 28, 2011, 08:06:09 PM »
great that u got it figured out!

 hard to start when warm is sometimes a sign of tight valves, so sounds like everything is groovy!

Offline Racerjoe

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Re: Determine compression stroke????
« Reply #11 on: March 28, 2011, 08:42:33 PM »
Sounds like you learned something that will stick with you. Sometimes that is the best way..... you never forget it when you learn by hard knocks. But the easier start sounds like it was worth it all.
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Online SlowRoad

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Re: Determine compression stroke????
« Reply #12 on: March 29, 2011, 06:02:03 AM »
Good news.  Glad you got it going and all is well. 
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joeyputt

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Re: Determine compression stroke????
« Reply #13 on: March 29, 2011, 09:53:44 PM »
I was late seeing this but I am happy that you got it adjusted Brother.