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Looking to buy an Airhead R90S - first time buyer

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schrader7032
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Re: Looking to buy an Airhead R90S - first time buyer

Post by schrader7032 »

Some comments:

j. -- likely the grease on the input shaft of the transmission is dry. The clutch plate is sticking and not moving freely. Even if the clutch worked OK, this is one thing you were eventually going to have to check.

k. -- the noise could either be coming from the top-of-engine crankcase breather. There is a replacement that works better. It could also be high internal pressure of the engine plenum due to excess blowby past the rings. This pressure has to escape somewhere and one place it can go is past the rear main seal. If you were to crack open the oil dipstick with engine running, the excess air would come out the hole and the quacking should go away.

l. -- wonky voltmeter could just be a bad ground for the meter.

m. -- front brake lines from the master cylinder to the calipers might be holding internal pressure because fluid can't reverse course back into master cylinder. This should be cleared by doing a fresh bleed of the brakes. The issue could also be that the pistons in the caliper are sticking and the o-ring in the piston bore is not working to pull the pistons back when pressure is released.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

SDCR
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Re: Looking to buy an Airhead R90S - first time buyer

Post by SDCR »

Bayou,

Thanks for posting pics. I would imagine that, being 40+ years old, it will needs some attention. The rust is unfortunate, but with a lot of elbow grease, it could be rectified. Still think it’s priced very fair, considering what it is.

The R1100RS and RT models are considered highly. Very reliable, with much more power than an airhead, about 95 hp. I like the 1997-2001 models in particular. My 2000 R1100 RS has just rolled over 94,000 relatively trouble free miles.
1983 R100
2000 R1100

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r67boxer
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Re: Looking to buy an Airhead R90S - first time buyer

Post by r67boxer »

Sounds like you gave it a good look over. I take back what I said earlier WRT 'sounds to good to be true'. The bike looks good from a distance but up close there are issues/patina.

"The bike is original all round. Nice patina. Paint looks original to me, if not, it's an awesome job!".

I personally like patina unless it came from a rattle can.

"Gear shifting is smooth and effortless because of the Mod. Wow!

Triple matching #s verified. Same key opens all the three locks."

All good.

"Sadly, IMHO, the motorcycle has taken a toll due to being in the beach/oceanside area for the last ~2 years. The bike has rust allover (see sample photos). Getting rid of rust is a project in and of itself. Plenty of oxidation on rims, spokes, front forks, rear shocks, engine casing, etc."

Most oxidation can be cleaned up in a number of ways save for the cylinder jugs and hubs. Lots of elbow grease.

"Strong gasoline smell around the bike. I bet that if it is parked in a house garage, the whole area smells of gasoline in no time. Didn't see any obvious leaks."

Could be coming from a number of areas but I would put my money on the fuel lines. If they're the cloth braided type they often seep through when old.

"Thin oil coating at multiple places (not visible in the photos): oil pan under carriage, shaft-drive end points, black rubber elbow/hose that connects the carburetor to air filter, rear brake light switch, etc."

First off you'll need to give it all a good cleaning to determine where the oil is coming from. Most are quite easy fixes, others are not.

"Clutch jumpy: as I gently released the clutch when I took it for a spin, the clutch engages in one snap with a "clang" sound that's clearly heard and bike jumps somewhat, and it happened every time I released the clutch. Owner is aware of this, he asked me to give it some gas when that happens.
This is interesting. During idling, duck quacking like sound is quite noticeable. Gary says that's how they sound by design and apparently there's a fix for it. :shock: Is that right?"

Covered by previous post. I would agree.

"Front wheel is hard to turn by hand. Shouldn't it turn freely? Other "R90S" also exhibited the same behavior but that was lot harder to turn."

Likely old grease in an old bearing. Some drag may be coming from the disk brake in which case the caliper pucks may be seized or not moving freely. Overhaul regardless.

"Lastly, if I decided to buy, he'll bring it to me on his trailer. :o He is eager to get rid of it. He has an older Police Harley that he wants to keep."

That's code for "I don't want you to ride it home". Good advice regardless as you really have no idea about the bike until you've taken it on a number of shorter trips. I have never taken a new-to-me vintage bike home without the use of a trailer.

Finally, IMHO I would buy the R90S as a project and in the meantime purchase and ride a newer R100RS, R1100 or even newer. More is better. My regular response to questions such as: Why do you have 8 motorcycles? ..... because I sold one.

Kevin

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Re: Looking to buy an Airhead R90S - first time buyer

Post by srankin »

Give yourself a big pat on the back for taking a really good, careful look at this bike and pausing to think about buying it!

None of the issues you have listed can't be fixed but it will take labor. Labor is the killer on bike restorations, LOL, parts are too but to a slightly smaller degree.

If you want a bike to restore, this is the bike for you, if you want a bike to hope on and ride or ride after some minor work, this is not the bike for you.

You know what to look at and that is great, I don't know however how much or skilled you are at fixing things you have spotted. LOL, I am an advanced amateur having done a few restorations on my bikes over the years as well as two others.
The two I restored were R90S bikes and I took a hammering on the sales, I had way too much time and parts into them for what the market would allow. Obviously I was not intending to keep them and if I had, maybe I would have recouped some of the time and effort in the restoration on at least one by riding it till it dropped, like I am with my current RT, LOL

I have to admit, I know nothing at all about the oil head boxers that came in after the airheads. I do know my friend changed a clutch in one and it was far more work involved than on an airhead. Frankly, I would think they would not be that much different to work on than the airheads, the only thing different being fuel injection rather than carbs.

The early oil heads I see for sale are priced very low, I don't know if that is because they are junk, LOL, or just because they are not loved like airheads.

Anyway a long note, maybe I got carried away? Good luck what ever you do, and let us know the outcome. St.
Owner of a 84, R80RT and 78, R100RS

SDCR
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Re: Looking to buy an Airhead R90S - first time buyer

Post by SDCR »

St,

Post 1997 Oilheads have a updated transmission, which is preferable.

The clutch is a royal PIA, parts alone are about $400. + incidentals. Basically, the rear half of the machine needs disassembly. IIRC, Labor hours by the book are about 9.
1983 R100
2000 R1100

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Re: Looking to buy an Airhead R90S - first time buyer

Post by srankin »

LOL, my friend chooses not to work on anything but airheads. The 96 oil head he changed the clutch in convinced him his is in his mind a wise choice.

Yea, there was a lot to do with the frame as well as BMW forgot? to put a plug in place for the rear lights meaning they all had to be messed with in order to split the frame to change the tranny.

None of this is a major problem when the owner is doing the work on his or her dime, but things can get expensive in a hurry on a shop's time. I don't know other than this one experience if this could be why the prices are so low? Then again, owning one, you find the same thing happens with any vehicle out of manufacture's warranty, is the cost of repairs going to be more than what the bike is worth. With most shops running $100 to $150 an hour labor and the clock starts ticking and is shut off when the job is done. Whew, I am so happy I can work on most of the stuff on my bike and have a shop to do the rest of the stuff.

I guess that is why all I own and am interested in are airheads. St.
Owner of a 84, R80RT and 78, R100RS

Bayou
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Re: Looking to buy an Airhead R90S - first time buyer

Post by Bayou »

schrader7032 wrote:
Tue Feb 21, 2023 6:17 am
Some comments:

k. -- the noise could either be coming from the top-of-engine crankcase breather. There is a replacement that works better. It could also be high internal pressure of the engine plenum due to excess blowby past the rings. This pressure has to escape somewhere and one place it can go is past the rear main seal. If you were to crack open the oil dipstick with engine running, the excess air would come out the hole and the quacking should go away.
Since I don't know about the engine internals, this is a bit hard for me to understand now. I'm sure I'll come back to this and re-read as I learn. Thank you!

Bayou
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Re: Looking to buy an Airhead R90S - first time buyer

Post by Bayou »

SDCR wrote:
Tue Feb 21, 2023 7:24 am
Bayou,

Thanks for posting pics. I would imagine that, being 40+ years old, it will needs some attention. The rust is unfortunate, but with a lot of elbow grease, it could be rectified. Still think it’s priced very fair, considering what it is.

The R1100RS and RT models are considered highly. Very reliable, with much more power than an airhead, about 95 hp. I like the 1997-2001 models in particular. My 2000 R1100 RS has just rolled over 94,000 relatively trouble free miles.
Yeah, rust all over is unfortunate. I'll end up spending a lot of time and money replacing and/or removing rust from the parts that I wouldn't have to touch otherwise.

Good to know RS and RT are reliable. Two things I keep seeing are the Clutch and ABS issues, ABS being the notorious one. Wonder if it is due to lack of maintenance or bad design? Thank you for your time and inputs.
Last edited by Bayou on Wed Feb 22, 2023 8:21 pm, edited 1 time in total.

Bayou
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Re: Looking to buy an Airhead R90S - first time buyer

Post by Bayou »

r67boxer@gmail.com wrote:
Tue Feb 21, 2023 7:48 am
That's code for "I don't want you to ride it home". Good advice regardless as you really have no idea about the bike until you've taken it on a number of shorter trips. I have never taken a new-to-me vintage bike home without the use of a trailer.

Finally, IMHO I would buy the R90S as a project and in the meantime purchase and ride a newer R100RS, R1100 or even newer. More is better. My regular response to questions such as: Why do you have 8 motorcycles? ..... because I sold one.

Kevin
Thanks, Kevin. Wow! Eye-openers for me. Now I'm connecting the dots, no wonder he didn't want me to ride it back. Whatever I end up buying I'll take it on short trips first, it makes so much sense.

Bayou
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Re: Looking to buy an Airhead R90S - first time buyer

Post by Bayou »

srankin wrote:
Tue Feb 21, 2023 12:19 pm
Give yourself a big pat on the back for taking a really good, careful look at this bike and pausing to think about buying it!
Thank you for saying that, assures I'm doing the right thing. :D
srankin wrote:
Tue Feb 21, 2023 12:19 pm
None of the issues you have listed can't be fixed but it will take labor. Labor is the killer on bike restorations, LOL, parts are too but to a slightly smaller degree.

If you want a bike to restore, this is the bike for you, if you want a bike to hope on and ride or ride after some minor work, this is not the bike for you.

The early oil heads I see for sale are priced very low, I don't know if that is because they are junk, LOL, or just because they are not loved like airheads.
That's my thinking too, this is a project bike that needs lot of time and money. It'll be couple of months plus another ~$3k at least as I've to rely on a mechanic for things like clutch, brakes, oil leaks, lubing splines, etc. All of this will set me back by $10k easily. If I want to go the Airhead route, I'm better off buying this completely restored R100, and there's some room for negotiations too.

https://sfbay.craigslist.org/sfc/mcd/d/ ... 65405.html

As you said, I'm looking for a bike that I can ride from day 1 or day 7 at the very least. :)

Coming to my DIY skills, I can do oil changes, replaced ignition distributor assembly with built-in timing cam on my Altima and adjusted the timing using a timing gun (this is a bit involved). In short, whatever is straightforward to disassemble and assemble, I can do that. I'll be able to adjust valve clearance if I see someone do, for instance.

I want to believe "... early oil heads are priced low because they're not loved like Airheads" :lol:

Thanks a lot for your feedback and responses!

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