Author Topic: '86 C10 Engine Rebuild. Questions about valves.  (Read 482 times)

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Offline Martini

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'86 C10 Engine Rebuild. Questions about valves.
« on: October 20, 2017, 05:03:26 pm »
Hi everyone,

In the middle of fully restoring a '86 ZG1000A left by my late uncle to me. Has been sitting in the garage with a blown head gasket for at least 17 years so the engine was flooded with oil and coolant, but the engine only has 6,100 miles on it so I think it's worth saving. Lots of fun gunk to clean from the coolant lines and engine so far during the rebuild and I've fully stripped and cleaned the carbs which were in nearly factory condition except for the gunk left from the fuel that sat in them for a while.

Thus far me and a friend initially tested compression around 15psi which was not surprising giving the blown gasket. The cylinder wells were dry, but had rust on the top of the pistons and in the spark plug wells. The spark boots had moisture trapped inside them too. Since then we have swapped all the spark plugs, installed new aftermarket spark boots, stripped, cleaned and replaced the valve seals and removed all the rust off the valve cover. We re-lubricated the cylinders after soaking them in a gentle rust remover made for motorcycle engines. Very much did the trick in removing all the rust. After replacing the head gasket and tightening everything to spec in the Clymer manual, we're up to 60psi now in the cylinders.

We did a leak-down test and noticed a fair bit of air coming out of the intake and exhaust ports which tells us it's an issue with the valves meaning we'll want to remove and clean them all because they're probably gunked up from sitting around for years. The Clymer guide suggests using a film canister to help with the springs, but we're not sure which tool we'll need for this job to do the spring compression. Any tips?

Online Steve in Sunny Fla

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Re: '86 C10 Engine Rebuild. Questions about valves.
« Reply #1 on: October 20, 2017, 06:25:06 pm »
 OK, I made my living rebuilding engines, you might want to rethink this, at least until you've done a FULL tear down. When coolant is in the crankcase it will cause rust issues, and that can mean severe pitting on the machined surfaces. I've seen crank journals that were destroyed from sitting on oil/ coolant for a couple years. Same thing with cylinders / rings and in this case transmission and bevel drive ball bearings. Until you've confirmed that all are good - and if your facts are correct they probably are not - I would not proceed. JMO, Steve
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Re: '86 C10 Engine Rebuild. Questions about valves.
« Reply #2 on: October 20, 2017, 06:33:29 pm »
Hi everyone,

In the middle of fully restoring a '86 ZG1000A left by my late uncle to me. Has been sitting in the garage with a blown head gasket for at least 17 years so the engine was flooded with oil and coolant, but the engine only has 6,100 miles on it so I think it's worth saving. Lots of fun gunk to clean from the coolant lines and engine so far during the rebuild and I've fully stripped and cleaned the carbs which were in nearly factory condition except for the gunk left from the fuel that sat in them for a while.

Thus far me and a friend initially tested compression around 15psi which was not surprising giving the blown gasket. The cylinder wells were dry, but had rust on the top of the pistons and in the spark plug wells. The spark boots had moisture trapped inside them too. Since then we have swapped all the spark plugs, installed new aftermarket spark boots, stripped, cleaned and replaced the valve seals and removed all the rust off the valve cover. We re-lubricated the cylinders after soaking them in a gentle rust remover made for motorcycle engines. Very much did the trick in removing all the rust. After replacing the head gasket and tightening everything to spec in the Clymer manual, we're up to 60psi now in the cylinders.

We did a leak-down test and noticed a fair bit of air coming out of the intake and exhaust ports which tells us it's an issue with the valves meaning we'll want to remove and clean them all because they're probably gunked up from sitting around for years. The Clymer guide suggests using a film canister to help with the springs, but we're not sure which tool we'll need for this job to do the spring compression. Any tips?

You truely have me lost with your question /description....
You say you replaced valve seals...... how? What seals?
I'm confused....

You need a spring compressor for valve removal...
https://www.walmart.com/ip/10-Pcs-Valve-Spring-Compressor-Kit-Removal-Installer-Tool-For-Car-Van-Motorcycle-Engines/209827683?wmlspartner=wlpa&selectedSellerId=11922&adid=22222222227092252328&wmlspartner=wmtlabs&wl0=&wl1=g&wl2=t&wl3=207536269583&wl4=pla-336279691329&wl5=9015276&wl6=&wl7=&wl8=&wl9=pla&wl10=117084300&wl11=online&wl12=209827683&wl13=&veh=sem


Do you have a factory service manual?

 :??: :truce:

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Offline Cal

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Re: '86 C10 Engine Rebuild. Questions about valves.
« Reply #3 on: October 20, 2017, 07:53:03 pm »
one additional item that may assist in determining a move forward on expenses - the 86 version of the engine was known to have valves that would recede into (tulip) the head over time.  I doubt that 6000 some miles has allowed time for this to happen.  I probably had over 100,000km on mine before I did any work (yes - it was really needed by that time).

Steve S may be able to tell you if just new valves will cut it - properly lapped in, etc.

Cal

Offline Martini

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Re: '86 C10 Engine Rebuild. Questions about valves.
« Reply #4 on: October 20, 2017, 09:14:07 pm »
You truely have me lost with your question /description....
You say you replaced valve seals...... how? What seals?
I'm confused....

You need a spring compressor for valve removal...
https://www.walmart.com/ip/10-Pcs-Valve-Spring-Compressor-Kit-Removal-Installer-Tool-For-Car-Van-Motorcycle-Engines/209827683?wmlspartner=wlpa&selectedSellerId=11922&adid=22222222227092252328&wmlspartner=wmtlabs&wl0=&wl1=g&wl2=t&wl3=207536269583&wl4=pla-336279691329&wl5=9015276&wl6=&wl7=&wl8=&wl9=pla&wl10=117084300&wl11=online&wl12=209827683&wl13=&veh=sem


Do you have a factory service manual?

 :??: :truce:

What I meant to say up there was seals for the valve cover along with the head gasket. I have the Clymer Shop Manual which has served me fairly well so far in terms of rebuilding. My question more specifically is around cleaning and rebuilding the valves since that is where the leaks during the leak down test seem to be coming from.

Offline Martini

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Re: '86 C10 Engine Rebuild. Questions about valves.
« Reply #5 on: October 20, 2017, 09:16:34 pm »
OK, I made my living rebuilding engines, you might want to rethink this, at least until you've done a FULL tear down. When coolant is in the crankcase it will cause rust issues, and that can mean severe pitting on the machined surfaces. I've seen crank journals that were destroyed from sitting on oil/ coolant for a couple years. Same thing with cylinders / rings and in this case transmission and bevel drive ball bearings. Until you've confirmed that all are good - and if your facts are correct they probably are not - I would not proceed. JMO, Steve

Thats a good point. So far we've been through every part of the engine short of the crank case below and while some parts were definitely gone, the rest are near factory condition. The carbs had a light coat of soot on them. I think we'll plan to look at the lower half of the engine anyway to make sure we're not hiding a bigger problem. Our goal so far has been to get the compression back to spec since we knew the head gasket was blown.

Offline Bucky

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Re: '86 C10 Engine Rebuild. Questions about valves.
« Reply #6 on: October 24, 2017, 04:09:46 pm »
Steve in Sunny Florida makes an excellent point. As you know the transmission is all part of the same potentially contaminated and now corrosive oil supply. You might want to pull this transmission apart prior to putting too much time or money into the project.
As you know, aside from seals and hoses and intact cooling system, there's really nothing in that transmission or engine that is supposed to be in contact with anything but oil.

Water will almost always lay on the bottom, with oil on top.


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Offline Martini

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Re: '86 C10 Engine Rebuild. Questions about valves.
« Reply #7 on: November 16, 2017, 03:47:49 pm »
Well we're at the point of tearing into the lower half of the engine, if what you folks are saying is true, should I spend any more time with this engine or scrap it and locate a decent used motor? If the transmission does have issues from the coolant leak, is it a repairable/replaceable thing or is that just game over and salvage what's left on the engine? It's such a low mileage engine that I want to save it, even if it costs me $1k because a used motor with 60k miles at least on ebay seems to be around the $600 to $800 mark before shipping.

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Re: '86 C10 Engine Rebuild. Questions about valves.
« Reply #8 on: November 16, 2017, 05:01:17 pm »
Well we're at the point of tearing into the lower half of the engine, if what you folks are saying is true, should I spend any more time with this engine or scrap it and locate a decent used motor? If the transmission does have issues from the coolant leak, is it a repairable/replaceable thing or is that just game over and salvage what's left on the engine? It's such a low mileage engine that I want to save it, even if it costs me $1k because a used motor with 60k miles at least on ebay seems to be around the $600 to $800 mark before shipping.

Removing the covers and oil pan and insection of everything down there is free... so that's kind of a "open it up and look" thing... first off....
With the engine upside down on the bench, and "nekid", you can tell what's what, and clean it all up accordingly with solvent. Make sure to inspect the clutch also.
Asking us if you should spend money on a hit or miss bigger headache engine off ebay is, or should be, not relevent untill you do the inspections..
Just beware what you buy as a "good replacement" engine, it may well be a junker right off...... as someone is trying to sell it....
Best of luck

30 YEARS OF KAW.....Rich R. (the other one..)  COG 5977  JUSTAMEMBAHNOW

Online Steve in Sunny Fla

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Re: '86 C10 Engine Rebuild. Questions about valves.
« Reply #9 on: November 17, 2017, 02:50:55 am »
I have disassembled ebay bevel drives that had water in them and the bearings were shot. I also had a bevel drive from a bike that got water in it from hurricane Sandy up in the northeast that had water in it, those bearings were shot, too. In fact that bike belonged to a fellow who owns the Kaw Barn, and it was a bike he was reso'ing... IIRC ha had onter transmission bearings that were pitted also. Be very careful as you go, this engine's history is a landmine.  steve
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Offline drumstyx

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Re: '86 C10 Engine Rebuild. Questions about valves.
« Reply #10 on: November 18, 2017, 06:52:50 pm »
Complete engines run something like $600 on a bad day, and are plentiful. IMO, if you have to put more than a few hundred into the engine, including preemptively replacing those '86 valves, you're better off buying a complete engine. Depending on how you value your time, you could eat up the entire cost in the complete teardown, not to mention the fact that gasket kits are around $150 at a minimum

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Re: '86 C10 Engine Rebuild. Questions about valves.
« Reply #11 on: November 18, 2017, 09:59:18 pm »
Complete engines run something like $600 on a bad day, and are plentiful. IMO, if you have to put more than a few hundred into the engine, including preemptively replacing those '86 valves, you're better off buying a complete engine. Depending on how you value your time, you could eat up the entire cost in the complete teardown, not to mention the fact that gasket kits are around $150 at a minimum

I guess your not grasping my comment about buying an engine, that is not in a bike, and running... simply put, if you are a gambling man, and want to chance paying for an engine, and shipping, only to find out it has a bent rod, bad oil pump, bad valves, bad clutch, bad tranny gears or output drive, or some other invisible gremlin.. then go right ahead.

Best of luck.

30 YEARS OF KAW.....Rich R. (the other one..)  COG 5977  JUSTAMEMBAHNOW