Conrod bolts

[Old Fogey]

I believe the 78-79 cases were made thicker, so I've heard, to cut down mechanical noise. Also they had a primary chain tensioner fitted. Don't know if there was anything else.

[Whiskerfish]

Yes there are differences in the case thickness in that area and from what I have been told it is only to mask the noise.

I had made a post a over a year ago about early model engines not being rebuildable but I have searched for over an hour now and can not find it. My memory is very poor so do not take any of this as gospel but this is what I recall.

I had heard a rumour regarding early wing main bearing cap issues. I went down and talked to Dave at my local dealership. Dave is the Lead Mechanic there and has been there since before the wing came out. He recalled a problem with cranks seizing after rebuild using the color scheme method of selecting main bearings. He claimed there was a service bulletin that spoke to the issue. I spent the afternoon going through his books and could not find anything specific. He showed me the Bulletin he interpreted to mean that the early engines were not rebuildable. When I read it (and I can not remember the subject but it was internal to the engine) I did not read it that way at all. According to him it was written with ambiguity on purpose and he had been briefed (in 76) by a regional rep not to attempt any further rebuilds and to just replace any engines with lower end issues.

Sorry but I have racked my head and can not remember anything else. I really wish I could find the post about this as this is partial information and I am not certain on it's validity.

[Cookie]

That's about what I recall you said. Given a choice then I'd use a later case.
This may just have been a gesture of care on the part of Honda. When BMW and Subaru have warranty engine problems they usually just replace the engine. I recall GM doing that one some too.
At dealer rates I'm not sure it pays to rebuild over here. They may have erred on the side of caution.

[puffy75]

A bulletin from that time was a bulletin reguarding the core plugs on the heads. The bulletin started with a sealant change to the zinc cores. Engine #100001-1001378 were assembled at the factory with a zinc core plug and a sealant that was not up to the task. It stated that the tech was to pull the core and reseal it with a new sealer. Engine # 1001379-1017465 had this proceedure done at the factory. When some of the tech attempted this first proceedure the zinc core plug broke. The last fix was a steel plug and new sealer at the factory from engine #1017465.
Any engine before this last fix could have been interpreted in the manner WK described. If a tech tried to repair the motor and followed all of the rules and it came back with damage from the resulting coolant breach and internal damage, as a rep I would have replaced the motor also and possibly told the techs not to attempt a rebuild until further notice.
I do not recall any bulletin about a GL1000 not being rebuildable. I will however inquire in some archeives and see what I can find.

[hoganJr]

Oil pressure (oil pump care) is another.

never heard you guys talk about oil pump care before...how do you care for your oil pump, seriously
hoganJr

[puffy75]

The first step is to check the pressure. If it is below spec:

At cranking speed
19psi cold
5psi hot

At 900 rpm or idle
60psi cold
12psi hot

At 5000 rpm
64psi cold (I would only use this one as a last resort)
60psi hot

:then you would need to check the pump itself and measure the clearances and all things involved in keeping the pressure up. Section 7 of the manual.