TDC AND FIRING QUESTIONS

aquaholic
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TDC AND FIRING QUESTIONS

12 Feb 2022 15:08

Hello fellow riders, I have a question about TDC that you have probably answered a million times. I had to remove the cams to do some valve work and I'm trying to get it to fire and run.
I have lined up the timing marks on the coil pick up (the "T" for #1 and #4} and the exhaust and intake arrows lined up with their respective front and rear surfaces. I counted out the 44 pins and lined up the cams.
My questions are as follow:
1) How do I know whether the cams are not 180 degrees out ? Both valves are closed. When I manually turn the engine over the exhaust valve one #1 cylinder is moving in the direction toward opening. It would seem to me that the intake valve should be opening.???
2) How can I tell which coil and/or cylinder should be firing or ready to fire ?
The engine did fire up with the above set up but I had a knocking noise from the valve area so I shut it down immediately and pulled the valve cover. I rolled the engine over without the plugs in and did not hear any noise. Everything was in place as I thought it may have been a shim out of place.
Any help would be appreciated and I will thank you in advance. It may take me a day or so to reply, be well and stay safe. Jon

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Warren3200gt
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Re: TDC AND FIRING QUESTIONS

12 Feb 2022 15:24

#862188

There's only one timing mark on the cam sprockets so if the exhaust mark is facing forward and the inlet is facing back and both are level with the surface and there is 44 pins between the marks the cams can't be 180 deg out or the marks would be pointing inwards not outwards.

Z1000J2 somewhat modified!

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hardrockminer
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Re: TDC AND FIRING QUESTIONS

12 Feb 2022 16:54

#862195

Set your timing mark on TDC for 1&4. Install the exhaust cam first, with the arrow on the cam sprocket facing forward and parallel to the head surface. Count back the correct number of chain links and install your intake cam on the mark. I generally install it, then count the links and then adjust backward or forward if necessary. If the J engine is the same as its predecessor your cam lobes for #4 cylinder should face each other. The exhaust cam should face backwards and the intake cam should face forwards. See the photo below.

I have several restored bikes along with a 2006 Goldwing with a sidecar. My wife has a 2019 Suzuki DR 650 for on and off road.

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Mikaw
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Re: TDC AND FIRING QUESTIONS

12 Feb 2022 17:28

#862198

I have see timing procedures posted before. All start at installing the exhaust cam. My question is what is the correct procedure for the cam chain. After the engine is set to “T” what is done with the chain before exhaust cam placement?

1976 KZ 900 A4 kzrider.com/forum/11-projects/613548-1976-kz-900-a4
1976 KZ 900 B1 LTD
1978 KZ 1000 B2 LTD
1980 KZ 750 E1
Kowledge Speaks, But Wisdom Listens.
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aquaholic
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Re: TDC AND FIRING QUESTIONS

12 Feb 2022 18:12

#862204

My point that I do not understand is this. If I was installing the camshafts and the "T" for #1 and #4 is aligned with the mark on the engine, I know that #1 and #4 are at TDC but is it on the compression stroke or exhaust stroke ?? Hence then the cams could be installed 180 degrees out.
The way they are installed now with everything aligned as you stated, when I manually rotate the engine shouldn't the #1 intake valve begin to open NOT the exhaust valve ? As it is now when I rotate the engine, the exhaust valve begins to open which makes me think that I'm 180 out.
Also is there anyway that I can tell when the #1 plug will fire ?
Stick with me friend, I'm trying lol.

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aquaholic
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Re: TDC AND FIRING QUESTIONS

12 Feb 2022 18:15

#862205

Thank you for your reply. Your engine looks beautiful, so clean and shiny. Want to trade lol. Ill check them out tomorrow.

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aquaholic
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Re: TDC AND FIRING QUESTIONS

12 Feb 2022 18:20

#862206

As soon as I figure out which "T" mark is actually TDC I will let you know. The big thing is to make sure that the cam chain stays engaged on the gear in the base and make sure your chain tensioner is removed.

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Mikaw
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Re: TDC AND FIRING QUESTIONS

12 Feb 2022 18:40 - 12 Feb 2022 18:44

#862208

Your on the power stroke. Compression and spark has just happened. The exhaust should be opening first. When the piston hits BDC as it rises it will exhaust. When it piston gets back to TDC again the intake will open drawing fuel/air in. Down to BDC again and start compression stroke, spark at the “F” mark as the piston get close to TDC back to were you started.

Edit. Above is true for a single cylinder. Add 3 more cylinders and a wasted spark system someone will have to make corrections as needed.

1976 KZ 900 A4 kzrider.com/forum/11-projects/613548-1976-kz-900-a4
1976 KZ 900 B1 LTD
1978 KZ 1000 B2 LTD
1980 KZ 750 E1
Kowledge Speaks, But Wisdom Listens.
Jimi Hendrix.

Last edit: 12 Feb 2022 18:44 by Mikaw.

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hardrockminer
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Re: TDC AND FIRING QUESTIONS

13 Feb 2022 04:49

#862220

wrote:

I have see timing procedures posted before. All start at installing the exhaust cam. My question is what is the correct procedure for the cam chain. After the engine is set to “T” what is done with the chain before exhaust cam placement?

I check to ensure the chain is on the crank sprocket. I do this by putting the chain over my spread fingers to hold it taut and then rotate the engine once or twice before setting it on the T mark. The chain will slide over my fingers and the engine will turn over if it's on right. It will lock up of the chain isn't on the sprocket.

I have several restored bikes along with a 2006 Goldwing with a sidecar. My wife has a 2019 Suzuki DR 650 for on and off road.

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krazee1
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Re: TDC AND FIRING QUESTIONS

13 Feb 2022 08:58

#862240

wrote:

My point that I do not understand is this. If I was installing the camshafts and the "T" for #1 and #4 is aligned with the mark on the engine, I know that #1 and #4 are at TDC but is it on the compression stroke or exhaust stroke ?? Hence then the cams could be installed 180 degrees out.
The way they are installed now with everything aligned as you stated, when I manually rotate the engine shouldn't the #1 intake valve begin to open NOT the exhaust valve ? As it is now when I rotate the engine, the exhaust valve begins to open which makes me think that I'm 180 out.
Also is there anyway that I can tell when the #1 plug will fire ?
Stick with me friend, I'm trying lol.

The installation of the camshafts is what determines whether or not the engine is at TDC of the compression or exhaust stroke. As Matt said it is proper for the exhaust valve to open first after the end of the compression stroke/spark/combustion, and then the power stroke, which is the pistons trip down. As HRM said there is a spark at TDC, (actually slightly before) on both the compression and exhaust strokes, referred to as a "wasted spark".

Mike

Former M.E. at Kawasaki Motors Manufacturing, Lincoln, NE
1966 W1 (the Z1 of 1966-50H.P. and 100mph!)
1974 Z1
1978 KZ1000 LTD
1976 KZ900B pile O parts
1980 KZ750E
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DOHC
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Re: TDC AND FIRING QUESTIONS

13 Feb 2022 09:12

#862241

Mikaw post=862198My question is what is the correct procedure for the cam chain. After the engine is set to “T” what is done with the chain before exhaust cam placement?

The important detail is that the cam chain needs to be taught between the crank and the exhaust cam, once the the exhaust cam is set in place. Then, when you later begin to turn the crank clockwise as indicated by the manual, there is no change in the relationship between the 1-4 TDC mark and the alignment arrow on the exhaust cam.

The idea is to take up the slack starting at the crank, moving to the exhaust cam, then putting a very specific amount of slack between the exhaust cam and intake cam (by counting links), and then leaving all of the extra slack to be taken up by the chain adjuster.

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hardrockminer
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Re: TDC AND FIRING QUESTIONS

13 Feb 2022 11:15

#862252

There is a pin on the crankshaft that only allows the timing mechanism to go in one way....the correct way.

I have several restored bikes along with a 2006 Goldwing with a sidecar. My wife has a 2019 Suzuki DR 650 for on and off road.

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