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Old 10-27-2009, 03:39 AM   #11
pplassm
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What are the compression readings, wet and dry?

That's the only way to determine if you need new rings.
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Old 10-27-2009, 07:15 AM   #12
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Originally Posted by mscuddy View Post
Hmmm, sounds like you've got to "re-break" that bike in again. Same thing happened to me with a '70 CL350 that had been sitting for 20 years, I rebuilt the carbs, changed the valve guide seals, a few top-end gaskets and it smoked a little for about 200 miles, then started running perfect.

Ride that sucker! Being it's an old Honda it will most likely run perfect in a few hundred miles.
Man, I hope your right. Would save me the expense and time and trouble of breaking it down again.

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Originally Posted by pplassm View Post
What are the compression readings, wet and dry?

That's the only way to determine if you need new rings.
I don't have a compression tester right now. I'm trying to find one to borrow. Since it's not something I normally have a use for, I hate to buy one.

In the event that it may be just that the rings are stuck, I put some Marvel Mystery Oil in each cylinder and let it sit overnight. It's raining today and since I really need to take it outside of the garage to start, I don't know if I will get to try it today or not.
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Old 10-31-2009, 02:08 PM   #13
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Finally gotta hold of a compression tester. With the engine cold I get these readings in order: 110, 95, 120, 100.

Bike is still not wanting to run when the engine is cold. Hits and wants to run but just not enough to take off and run on it's own. If I keep trying eventually I can get it to run. When that hapopens and I can keep it running long enough to get the engine hot, it runs pretty nice. Actually drove it down the road the other day when I got it to this point. Little low on power on the low end, kind boggy feeling. Higher rpms, it felt really good.
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Old 10-31-2009, 08:49 PM   #14
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I recently purchased a 1985 Honda 700s Nighthawk. This bike has been sitting and not run in a couple of years. I pulled the head and took it to a machine shop to have the valves ground and new seals installed. I now have the bike together but am having issues. It is extremely hard to start when cold. Once I get it running and the engine warms, it runs pretty good and will restart fine. It also is smoking fairly heavily out both exhaust pipes. I've been reading some about stuck pistons rings. Could this be my issue? If so, what's the best remedy for that. And if not, anyone have any ideas what else it could be.

Thanks for your help,
Kenny
What happended prior to it sitting and you deciding to pay the expense on the head? Wouldn't you want to confirm fuel, spark, compression, and timing first, before spending the money?
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Old 11-04-2009, 08:09 PM   #15
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I've tried Honda and it's quite good and comfortable even if it's old. It can still go the extra mile.
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Old 11-05-2009, 05:20 AM   #16
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Originally Posted by Munkey990 View Post
Finally gotta hold of a compression tester. With the engine cold I get these readings in order: 110, 95, 120, 100.
Sounds like a good candidate for re-ring job. They're a ittle low.
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Old 11-05-2009, 05:48 AM   #17
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Originally Posted by pplassm View Post
Sounds like a good candidate for re-ring job. They're a ittle low.
Not just low. Look at the spread.

Some Marvel Mystery Oil or Bardahl might help break any stuck rings loose. But a hone/ring job looks to be a necessity.
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Old 11-05-2009, 02:57 PM   #18
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Not just low. Look at the spread.

Some Marvel Mystery Oil or Bardahl might help break any stuck rings loose. But a hone/ring job looks to be a necessity.
I've let it soak overnight with Marvel Oil twice without making much difference.

Rings are ordered, just waiting on them to arrive.
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Old 11-16-2009, 06:09 AM   #19
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Got the new rings installed over the weekend. It has a issue with being pretty hard to start cold. But once it warms up, it runs really nice. Rode it about 50 miles yesterday. Get this cold starting issue figured out and I'll be very happy with it. I'll recheck compression values again once I ride it some more to get the rings seated in good.
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Old 11-16-2009, 08:02 AM   #20
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Originally Posted by Munkey990 View Post
I recently purchased a 1985 Honda 700s Nighthawk. This bike has been sitting and not run in a couple of years. I pulled the head and took it to a machine shop to have the valves ground and new seals installed. I now have the bike together but am having issues. It is extremely hard to start when cold. Once I get it running and the engine warms, it runs pretty good and will restart fine. It also is smoking fairly heavily out both exhaust pipes. I've been reading some about stuck pistons rings. Could this be my issue? If so, what's the best remedy for that. And if not, anyone have any ideas what else it could be.

Thanks for your help,
Kenny

Kenny, one thing to always remember. If you reowrk the heads, you always want to re ring also. By re working the heads, you are creating more compression . That magnifies any weak points in the rings. You might try pulling the plugs and shoot some brake fluid on top of the pistons,and letting it soak overnight. Of course, you will want to change the oil after doing that. I would re ring the motor while you have it down.
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