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New bike - some help please

NMBeemer
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Re: New bike - some help please

Post by NMBeemer »

srankin wrote:
Tue Nov 12, 2024 7:26 pm
I am kind of loosing track of just what you have done and are having problems with, sorry, it its this method of communicating.

When you put the twist grip back together are you sure you lined up the chain gear and grip properly. There are timing marks on them. If you did, any take up will be at the carb barrels. The trick is to take up as much slack as possible yet still let the throttle sit on the idle stop when turning the handlebars. This is dead set first thing to do because if you have any upward movement you won't be able to adjust idle. Visually, when you have then set, you can see as you slowly twist the grip the two throttle levers move. Set them visually so they both move at the same time by taking up or reliving the barrel adjustment. Even better yet is to have a carb sync tool but it can be done by eye and ear.

I would not worry so much about the butterfly shaft, if it is worn or the seals are bad, spraying it with something will seal the vacuum leak and idle will change. No change means there is no problem. Like I said earlier in a post to you, it takes a lot of mileage to wear out the shaft and o-rings. They are pretty bullet proof.

As for the exhaust, your bike should have a cross over in the front of the engine and behind the engine, a one crossover set of pipes is either from an older model bike or aftermarket. In the past there were issues with some of the aftermarket header pipes not fitting together well, Mac being the worst. Before each muffler there should be a clamp to clamp the muffler to the header pipe. No clamp no seal.

Admittedly, from my experience the stock two crossover pipe system can sometimes be a pain to reinstall after being removed. However, BMW went to the two crossover system to improve low end torque and balance of exhaust. Who know why it was switched out to a single, but it was the wrong thing to do as far as I am aware.

As for discoloration, yep, airhead headers don't stay chrome, They get hot and depending on the chrome used in manufacturing will most likely turn dark blue or yellow, Road crud will also add a bit of character to then as well. I use simicrhorme polish on mine and they so far have stayed blue, shows I ride the bike LOL.

Keep up the good work, St,
Yeah, sorry, there's a lot going on...

On the exhaust, it's a stainless--and therefore I believe an aftermarket--set. Whenever I remove it to sand and polish the headers, I may just add slots and clamps on the crossover (only one) to perfect the seal at that point. No big rush unless after the carb refurbishment it contributes to rough running. I'll try cleaning up the sealing rings at that point to save the $40.

For now, there's just a subtle 'clack-clack' from the small leak where the header joins the exhaust port (and which people often mistake for tappet noise). So long as it's small, it shouldn't affect sealing sufficiently to endanger the exhaust valve--but I won't let it go for long.

On the throttle grip: I had noticed the indexing marks (thank you) but evidently didn't get the little notch that separates the cable's casing from the chain just right or something... at any rate, R&R'd it again, took the remaining freeplay out at the adjuster where the single cable merges into two... now it's perfect. Very light action, immediate and crisp return, very small freeplay rotation at the grip. Feels as a new bike's throttle would. Love, love, love those GT grips in my hands.

On the carbs: the more I thought about 40-year-old O-rings and gaskets in there--and needles with 64K on them--the sillier (or lazier and cheaper) I felt, so removed the L/H carb this morning to soak it in Berryman's overnight.

Attached are photos of badly deteriorated O-rings and gaskets. The throttle shaft O-ring was indeed the only one that looked as if it might have been sealing properly--or closer to it than the others. It at least had some elasticity left, whereas the others had close to zero. But if you zoom in on the close-up of the removed O-ring, you can see it, too, has aged sufficiently to have a wear groove around its circumference...

The others were unquestionably toast: flattened, hard as a rock, distorted, torn... including the idle mixture and main jet O-rings, so those alone could explain the imperfect running. The enricher gasket was brittle and very likely passing air into what I gather is a carefully metered air/fuel mixture for startup. That would explain the slow-to-start behavior.

On the penultimate photo, there's an embossed number on the butterfly, so no need to make marks on it to get orientation right, as I've read. Also, no need to Dremel the butterfly screws, as some do: the peening is very subtle, and they back right out.

If you want to peen the new screws rather than use loctite, the method is to place a brass or aluminum rod on the anvil portion of your vise, align the plate and tighten the screws, then set each screw's head on the rod for peening to avoid bending the throttle shaft or ovaling the carb body's hole.

You can get one carb's components in the basket, then slip the carb into the can on its side under the handle as you lower it in, to soak one complete unit at a time.

Mañana I'll do the R/H carb, and this weekend we'll see what's what.

main jet carrier.jpeg
idle jet.jpeg
idle jet(1).jpeg
throttle shaft.jpeg
throttle shaft(1).jpeg
idle mixtute.jpeg
butterfly position.jpeg
soak.jpeg
1984 R100RS (converted from RT), 1971 Triumph Bonneville custom cafe, 1951 Harley Pan-Shovel

NMBeemer
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Re: New bike - some help please

Post by NMBeemer »

**NOTE: Berryman's indicates that aluminum alloys and pot metal--read that, carburetors--should not be soaked for more than 4 hours, and half that is usually more than sufficient.

So, cool: I'll get both carbs cleaned up today.

IMG_4429.jpeg
1984 R100RS (converted from RT), 1971 Triumph Bonneville custom cafe, 1951 Harley Pan-Shovel

NMBeemer
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Re: New bike - some help please

Post by NMBeemer »

The carbs cleaned up nicely. Got the L/H one reassembled and installed; will assemble the R/H carb tomorrow and see if startup and idle are improved.

The only fiddly part was getting the push-and-turn needle adjustments right. The specs do not seem to correspond with the detents on the needles, as you end up a few thousandths shorter or longer--and I noticed Brook had the same issue.

Presumably, it doesn't make that much of a difference--and perhaps the measurements they give you are approximations, just to guide you in confirming you're in the right detent. Second one, per the info I found--but of course I could ultimately end up having to drop the needle a touch in view of my elevation anyway...
1984 R100RS (converted from RT), 1971 Triumph Bonneville custom cafe, 1951 Harley Pan-Shovel

NMBeemer
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Re: New bike - some help please

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Ohhh, yeah... very nice with new O-rings, needles and needle jets. Idles nicely, excellent throttle response... below is a video clip. Just the tiniest intermittent miss, but I'm guessing that's the R/H side exhaust leak--which I'll fix whenever I R&R the exhaust for a sand and polish session.

Whenever I ride into the city to get the VIN inspection and New Mexico tags, we'll see if the mileage is improved. I'm sure it will be.

Next items: figure out why the brake light is suddenly on all the time, R&R the rear wheel to install a new rotor & brake pads, repack the bearings, clean up the spokes, and install new stainless braided rear brake hose and OEM reservoir hose.

https://youtu.be/jI0WWBcpnSI
1984 R100RS (converted from RT), 1971 Triumph Bonneville custom cafe, 1951 Harley Pan-Shovel

NMBeemer
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Re: New bike - some help please

Post by NMBeemer »

Here's a shout out to Katdash's voltmeter and clock LEDs, which I ordered after being so impressed with his replacement flex dash with LED warning and indicator lights. The photo on his website does not do them justice. This is more representative of their brightness, I think...

LED dash lights.jpeg
1984 R100RS (converted from RT), 1971 Triumph Bonneville custom cafe, 1951 Harley Pan-Shovel

NMBeemer
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Re: New bike - some help please

Post by NMBeemer »

Rear wheel bearings are pitted and the races worn, so I've ordered a new pair with races. Just $12 on Scamazon with free shipping: FKG 30203 tapered roller bearing set, identical to SKG dimensions and engineering specs, same carbon steel, etc., just 1/3 the price of the usual suspects.

Question: Euro Motoelectrics says regarding BMW # 36 31 1 240 238, "Axle Seal 40mm x 22mm x 7mm for cast wheels - 2 on front wheels and 1 on the rear wheels" - and (naturally) the rear wheel in my case--which appears to have never been serviced since new--used two metal-housed seals BMW # 36 31 1 235 832, whereas Brook indicates using one such seal, which EM calls a "shaft seal on rear wheel hub" and which measures 40mm x 22mm x 5mm.

What gives?

Ordered the Cycle Works tool to R&R the races, which if I understand correctly will also fit the swing arm bearings--so well worth the $50.

Now, back out to the garage to R&R the rear hydraulic lines, new fluid, and new pads in the caliper. Then I'll figure out why the brake light is suddenly permanently on...
1984 R100RS (converted from RT), 1971 Triumph Bonneville custom cafe, 1951 Harley Pan-Shovel

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schrader7032
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Re: New bike - some help please

Post by schrader7032 »

Are your rims snowflakes? Be careful changing out the bearings. The rims are aluminum...might have a steel insert IDK...and you can't just pull them out. Heat is needed. Also be sure and get the right preload.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

NMBeemer
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Re: New bike - some help please

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schrader7032 wrote:
Sun Nov 17, 2024 3:28 pm
Are your rims snowflakes? Be careful changing out the bearings. The rims are aluminum...might have a steel insert IDK...and you can't just pull them out. Heat is needed. Also be sure and get the right preload.
They are... I'm a snowflake! 8-)

Yes, the rim's hub has got a steel sleeve pressed into it.

The removal procedure looks very straightforward with the Cycle Works puller I ordered. The aluminum Sporty hub I used on the DIY front disc conversion for the '71 Bonny is subject to a similar procedure, but using a more traditional, expanding collet puller--and the same tool draws the sealed bearing into place (without the collet, of course).

Snowbum writes in this regard, "Hubs that have cast-in steel inserts can have the races pulled (Kukko blind puller) or pressed out ...without heating." And re: installation, "Stock 1979 to 1984 wheels are all cold pressed wheel types." Sounds right to me. I think Brook must have misread or misunderstood Snowbum's article, which emphasizes it's the early type lacking the pressed-in steel insert that needs heating. Brook beat the race in with a hammer and aluminum block, whereas 'pressed in' means just that...

Yeah, I watched with interest Brook's elaborate formula and method of checking preload--which, again, he appears to have gleaned from Snowbum's article. (And by the way, I now see SB's discussion of the differing grease seals, so I'm good to go there.)

Clearly, Snowbum is really careful, but ordinarily, the specs for tapered wheel bearings are: (i) zero discernible wobble; (ii) [x] end play along the spindle's long axis--usually, you just listen and watch for teensy movement of the thrust washer as you yank in and out--hard to see with this style of hub though; and (iii) a freely turning wheel. SB calls this the 'feel/shake' method--what I learned to do working in a garage ~ 50 years ago.

Here, things are simplified--or made more foolproof, I guess you could say?--by the spacers ('wedding bands') BMW uses in the hub. Seems like you could just reassemble, torque the nut to 25 ft. lbs or whatever the spec is, and then you'd either like it or add a few thousandths in shims and try again. What's wrong with that...?
1984 R100RS (converted from RT), 1971 Triumph Bonneville custom cafe, 1951 Harley Pan-Shovel

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Re: New bike - some help please

Post by schrader7032 »

I'm glad that you're reading various trusted websites about some of the intricacies of working on BMWs. We don't know all of your capabilities and experience, but by taking in information from others and meshing that with what you know, that's a good thing. It's so easy to charge into these things and turn something easy into an expensive mess! :D
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

NMBeemer
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Re: New bike - some help please

Post by NMBeemer »

schrader7032 wrote:
Mon Nov 18, 2024 6:16 am
I'm glad that you're reading various trusted websites about some of the intricacies of working on BMWs. We don't know all of your capabilities and experience, but by taking in information from others and meshing that with what you know, that's a good thing. It's so easy to charge into these things and turn something easy into an expensive mess! :D
Absolutely, and I appreciate the help--and patience with my relative lack of experience with this Beemer. But tinkering, learning new stuff, and 'hanging out' is what this is about for me. Only wish I could afford to buy some old gas station and turn it into a combo garage and vintage bike clubhouse... 8-)
1984 R100RS (converted from RT), 1971 Triumph Bonneville custom cafe, 1951 Harley Pan-Shovel

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