General Engine Questions - Star Motorcycle Forums: Star Raider, V-Max, V-Star, Road-Star Forum
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post #1 of 8 (permalink) Old 07-24-2018, 12:53 PM Thread Starter
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General Engine Questions

When should you test your oil pressure?

When/why check engine compression?

Can you tell if your valves are off & need adjusting listening to an engine run?

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post #2 of 8 (permalink) Old 07-24-2018, 02:01 PM
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Not sure about the ear test but my manual says to check and adjust valve clearance every 16,000 miles as routine maintenance.
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post #3 of 8 (permalink) Old 07-24-2018, 02:22 PM
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Just IMO:

Oil pressure should be checked if your low oil pressure light comes on. If your bike does not have a low pressure light then I'd check the oil pressure at every oil change - it is very simple, there are screws on the heads that you can slightly lose and see if oil comes out when engine is running. Oil pressure is critical to your engine as you can imagine. Insufficiently lubricated parts wear out very fast.

Engine compression is checked when you feel a power loss. Low compression may mean worn compression rings, cylinders, lose valve, bad valve seats, etc. It is a bad sign anyways. Compression is normally measured thru the spark plug port using compression gauge.

Valve clearance is important to make sure valves operating properly (open up enough and close tight to seal the cylinder). As engine heats up valve stems are expanding (just like everything else) and if clearance is not enough they gonna start hitting rockers and not close completely. If gap is too big valve is going to "tick" meaning it's hitting hard onto the seat which breaks valve and seat seal surfaces.
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post #4 of 8 (permalink) Old 07-24-2018, 03:20 PM Thread Starter
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The reason why I asked the value clearance question is when it is 85+ degrees the engine sounds different when it idles at stop signs, etc. then when it is 80 and below.
Have you done a valve check job? Is it a pain in the arse?

My bike is suppose to be automatically adjusted because it has a hydraulic valve lifter. But, it does suggest checking every 15k.
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post #5 of 8 (permalink) Old 07-24-2018, 03:33 PM
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Quote:
Originally Posted by Scrumdown View Post
The reason why I asked the value clearance question is when it is 85+ degrees the engine sounds different when it idles at stop signs, etc. then when it is 80 and below.
Have you done a valve check job? Is it a pain in the arse?

My bike is suppose to be automatically adjusted because it has a hydraulic valve lifter. But, it does suggest checking every 15k.
I remember my Stryker had changed its engine "tone" after the very first oil change when I switched to 20w50 full synthetic. I believe oil viscosity affects it just like the temperature. Since hydraulic lifter's function depends on oil (oil properties and oil pressure) - that might be the reason. Just my guess.

I've done valve check and adjustments on the Stryker (1300 motor). Wasn't too bad if you do NOT follow the service manual which tells you to remove entire intake and drain a coolant. I was able to get to the valves without all that just used longer feeler gauges. Took me about 4 hours. Valves were ok except one that was on the lower spec (still within the spec though). Not sure why you need to check them if you have hydraulic lifters which are self-adjustable.

If valve clearance is out of spec you should be able to hear a ticking sound inside the heads - it is more or less pronounced. Check some YouTube videos - they give you an idea what it sounds like.

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Last edited by nurtaeff; 07-24-2018 at 03:40 PM.
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post #6 of 8 (permalink) Old 07-24-2018, 04:26 PM Thread Starter
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Ticking sound -- I heard it loud on the left side rear of the engine the worst. It does give me an idea as to what to listen for. Thanks, nurtaeff.

The oil change was 3k ago. I assumed the mechanic used conventional. Maybe it's time to upgrade Big Bertha's oil to synthetic!
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post #7 of 8 (permalink) Old 07-24-2018, 05:17 PM
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you are suppose to check and adjust the valves after the bike has been sitting overnight -stone cold for at least 12 hours.

but the other side is, dont worry about how it sounds when the engine is cold, ride it about 5 miles, and then listen to it.

The thing is, the tappets always tap, even when they are adjusted perfectly. Thats why they are called tappets. When the clearance is too wide the tappa tappa gets louder, which is not great but its ok.

The thing you have to watch out for, is if the tapping goes away. Then the clearance has gone to zero or less, and the valves could be staying slightly open. This is only for engines that do NOT have hydraulic lifters.

Hydraulic lifters are suppose to adjust in perfectly - no tapping and no gap while the engine is running (after a few minutes).

If your bike has lifters and they are tapping, one of them has failed. I have never seen an engine with hydraulic lifters that had an adjustment - that is new one on me.

On the oil pressure, if you are going to test it, you would have to put a gauge on it. I dont know if there is a fitting for an oil pressure gauge or sensor anywhere. Gear mesh oil pumps should last for the life of the engine. If you have low oil pressure its because your bearings on the crank, throw rods, or cam shaft are worn out, and the gap is too big, letting the oil flow thru without building up enough pressure. They usually only show low pressure at idle, but that can be enough for the cam bearings at the top of the engine to get oil starved, because the oil is blowing thru on the main crankshaft bearings.

Last edited by KCW; 07-24-2018 at 05:20 PM.
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post #8 of 8 (permalink) Old 07-24-2018, 06:38 PM
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Quote:
Originally Posted by KCW View Post
you are suppose to check and adjust the valves after the bike has been sitting overnight -stone cold for at least 12 hours.

but the other side is, dont worry about how it sounds when the engine is cold, ride it about 5 miles, and then listen to it.

The thing is, the tappets always tap, even when they are adjusted perfectly. Thats why they are called tappets. When the clearance is too wide the tappa tappa gets louder, which is not great but its ok.

The thing you have to watch out for, is if the tapping goes away. Then the clearance has gone to zero or less, and the valves could be staying slightly open. This is only for engines that do NOT have hydraulic lifters.

Hydraulic lifters are suppose to adjust in perfectly - no tapping and no gap while the engine is running (after a few minutes).

If your bike has lifters and they are tapping, one of them has failed. I have never seen an engine with hydraulic lifters that had an adjustment - that is new one on me.

On the oil pressure, if you are going to test it, you would have to put a gauge on it. I dont know if there is a fitting for an oil pressure gauge or sensor anywhere. Gear mesh oil pumps should last for the life of the engine. If you have low oil pressure its because your bearings on the crank, throw rods, or cam shaft are worn out, and the gap is too big, letting the oil flow thru without building up enough pressure. They usually only show low pressure at idle, but that can be enough for the cam bearings at the top of the engine to get oil starved, because the oil is blowing thru on the main crankshaft bearings.

Good point on no ticking sound, KCW. “normal” ticking should be very light when engine is cold and should go less as engine warms up.

As to oil pressure both service manuals I have (for Stryker and 650) say that you just slightly lose those bolts on the heads and if oil is sipping thru - pressure is good. So pressure gauge is not really required unless you want to get a number. At least for those 2 models.



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