What can you owners of 85 to 95 airheads tell me a pre 84 airhead owner?

[stevenrankin]

So, I wrecked my RS and am missing having a second bike. Lots of good bikes are showing up and going fast, a good thing.

One thing I have to admit is that I am pretty ignorant of the Post 84 airheads, features, plus and minus traits. What can those of you tell me about them? If I were to look to buy one what are some of the things I should look for that are Not or are on the Pre 85 bikes?

How does the power compare to older bikes? Handling? Are they easier to maintain or worse? Thanks, St.

 

[robsryder]

I have a 77 R100RS and a 93 R100 GS/PD. The 93 bike has a single sided swingarm and the drive shaft is not in an oil bath. I have replaced the original driveshaft with a rebuildable unit purchased from Ted Porter. The 77 still has the original driveshaft.

The 93 has cylinders lined with nikasil and still has original pistons, rings, and cylinders. The 77 was burning oil and the pistons, rings, and cylinders were replaced with units from Ted Porter; the cylinders are nikasil lined. No more oil burning.

The 93 gets periodic valve checks and adjustment as necessary (I don't actually recall the last time I "needed" to adjust the valves, but I usually loosen the locknut and valve clearance and re-set to spec.). On the 77 I sent the heads in to Ted Porter (back when he still did machine work) and had hardened exhaust valve seats installed, along with new valves, valve guides, and valve springs (and keepers). The re-worked heads look like new units. Same valve "checks" - no observable valve recession.

Both the 77 and 93 bikes seem to need push rod seals around 15 years or so.

Transmissions in both have been rebuilt by me. I had the output shaft on the 93 modified (by Boxer2Valve) to accommodate the "missing" circlip. Rear shocks have been replaced on both bikes. Front forks have been rebuilt on both bikes.

Electronic ignition (Boyer) on the 77. A nipon-denso-based starter from Rick Jones (MotorRad Elektrik) replaced the 93 starter (Valeo starter failed and and was replaced with Bosch starter). Bosch starter on 77 has been rebuilt and will be replaced soon with MotorRad Elektrik starter.

Carbs have been re-built a couple of times on both bikes, usually just replace rubber bits.

Front brake rotor replaced and caliper re-built (new o-rings) and brake pads on 93. Calipers and master cylinder re-built on 77 (have replacement rotors and pads, but not yet installed).

Final drive splines on 77 welded / re-machined (by Bombar's Beemers), new driving dog for hub [rivets replaced with 1/4-28 stainless bolts]

Obtained new charging systems for both (one from EME and one from MotorRad Elektrik) but not yet installed.

Otherwise just regular maintenance - oil, filters, etc.

 

[stevenrankin]

cir clip

I have heard about the c clip or cir clip? I really haven't paid much attention to the issues as I thought it only applied to post 84 year bikes. Intriguing issue, what are the ramifications of a failure or what are the negative issues?

My 84 RT had nikasil lined jugs, I blew them out at about 90K miles, bored out and pressed in cast sleeves. So far knock on wood, running strong. However, if I ever have to rebuild again, I will replace with the excellent units from Ted or another source. LOL, to replace back in the day was too much bite my wallet. I hear good things about the replacement kits and the cost is reasonable.

St.

 

[20774]

Original ~'85-'94 transmissions don't have the circlip. Anton writes about it here:

http://largiader.com/articles/circlip/

It's not a go-boom situation, but there are tests along the way to see if the circlip is moving and binding up.

 

[stevenrankin]

Thanks

Leave it to Kurt to come up with an article of use. Thank you. I suppose I could have looked it up on Snowbum's site but Anton's is easier to find stuff on. Both great guys. St.

 

[88bmwjeff]

I'm not that knowledgeable of the differences, but here's my take.

The standard monoshock bikes have their driveshafts in bathed in oil. The GS and Mystic's that have the paralever swing arms are dry.

The later bikes with the 32mm carbs have a less power (60hp) than their earlier counterparts with 40mm carbs (69hp). HP based on a quick Google search, which I assume to be accurate.

The forks are the same design that is on the early/first gen K bikes, which I've heard are better than their predecessor's.

Parts are little less available for the monoshock suspensions than the dual shock, but not that they are unavailable.

Given the age of these bikes, a large number have had their transmission's rebuilt, and a grove cut into the appropriate shaft for that circlip. But, that would still be a good question to ask a seller.

With regards to the final drive, they don't have splines, but you do need to take not of excessive play. Grab the rear wheel at 3 and 9, and there should be minimal play at worst. I had to get my final rebuilt at around 90k due to excessive play.

My guess is that they would be just as easy to maintain as your 84. I can't see where the maintenance would be significantly different.

 

[stevenrankin]

32

LOL, I am well aware of the 32mm carbs. I love my R80RT until it comes to passing a car or truck. Sippy cup versus fire hose. That is when I miss the power of the 78 R100RS. LOL, I have been on the fence for years thinking about building the 800 into a 1000, with components from a 78 bike I have on hand.

Right now, things are running fine with the bike, maybe the next engine rebuild? Or, I could buy another bike. St.

 

[melville]

LOL, I am well aware of the 32mm carbs. I love my R80RT until it comes to passing a car or truck. Sippy cup versus fire hose. That is when I miss the power of the 78 R100RS. LOL, I have been on the fence for years thinking about building the 800 into a 1000, with components from a 78 bike I have on hand.

Right now, things are running fine with the bike, maybe the next engine rebuild? Or, I could buy another bike. St.

I have an R100/7 with 32mm carbs and an R100RS with 40s. I actually prefer the power delivery of the 32s and passing power isn't a problem on the 1000cc motor.

The R75 with 32s does give the sippy cup experience. No replacement for displacement!

 

[pauls1150]

I had an '89 R100RT... wonderful machine, lots of power, better handling than my earlier airheads (except for my '81 R100S) but the windshield was too big and not very aerodynamic; it was also a bit wide for white-lining...
I don't recall which carbs it had, but drilling thru the "front" muffler (fat crossover) and setting the needles one notch richer gave it a bit more oomph.