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New bike - some help please
- srankin
- Posts: 1281
- Joined: Fri Jul 14, 2017 8:45 pm
- Location: Spencerport, NY USA
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Re: New bike - some help please
These have served me well for 40 years on the same bike, no transmission problems other than worn out clutch and such. As for the engine, I am on my second set of jugs and pistons, running on third head rebuild, three timing chains. No work done to engine driveshaft or cam system all original lifter and rockers. Just new rear main seal three times and cam shaft seal.
Oil and gear oil is cheap, it can't hurt anything but the wallet to change more frequently than recommended and of course more frequently if the bike is ridden hard. I did that the first 100,000 miles, things have tapered off as I have gotten older.
As for carb rebuilds save a buck, replace the manifold's and see what you got. Carbs are always the last thing to mess with and from what you are writing rough running and lean mix could be due to tight valves and bad manifolds.
I never rebuilt my carbs until I started having issues with drop off in mileage. Turns out the main needles and seats had eroded over time. That was near the 180,000 mile mark. I did a rebuild that lasted to 200,000 and started having problems. Turned out one cab had excessive wear on the butterfly shaft and could not be fixed. I bought two newer carbs rebuild them and have now made it to almost 245,000. St.
Re: New bike - some help please
Very helpful - thank you for taking the time. I may change my gear oil more frequently than 30K, though...srankin wrote: ↑Fri Nov 08, 2024 4:02 pmI have changed engine oil every 2000 miles, Gear oil 30,000, valve adjust 15,000 or sooner if idle drops off.
These have served me well for 40 years on the same bike, no transmission problems other than worn out clutch and such. As for the engine, I am on my second set of jugs and pistons, running on third head rebuild, three timing chains. No work done to engine driveshaft or cam system all original lifter and rockers. Just new rear main seal three times and cam shaft seal.
Oil and gear oil is cheap, it can't hurt anything but the wallet to change more frequently than recommended and of course more frequently if the bike is ridden hard. I did that the first 100,000 miles, things have tapered off as I have gotten older.
As for carb rebuilds save a buck, replace the manifold's and see what you got. Carbs are always the last thing to mess with and from what you are writing rough running and lean mix could be due to tight valves and bad manifolds.
I never rebuilt my carbs until I started having issues with drop off in mileage. Turns out the main needles and seats had eroded over time. That was near the 180,000 mile mark. I did a rebuild that lasted to 200,000 and started having problems. Turned out one cab had excessive wear on the butterfly shaft and could not be fixed. I bought two newer carbs rebuild them and have now made it to almost 245,000. St.
In other news, I installed the Katdash you recommended... wow, what an improvement. The only light not working is neutral, which from a quick test with the multimeter I've confirmed is a bad switch. I'll change it next time I do the gear oil.
Clearly, I'm going to need to replace the anemic clock and voltmeter bulbs with LEDs...
- srankin
- Posts: 1281
- Joined: Fri Jul 14, 2017 8:45 pm
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Re: New bike - some help please
Be prepared for a bit of fun with the neutral switch. You shouldn't have to take the transmission out but may have to pull the swing arm bearings and rear engine mount to get the thing up in the air where you can get at it. Frankly I have been lucky not to have to try that but I hear it is possible. Maybe someone else will give more detail or perhaps you could open another thread asking about it? St.
Re: New bike - some help please
I think you may just (just!) have to remove the big stud that goes through that aluminum spacer tube immediately beneath the switch, then knock it out to access it. If I heard him right, Brook in a video seems to suggest that you merely have to shift it back 1/2" rather than removing it, but perhaps I'm misunderstanding that...?srankin wrote: ↑Sun Nov 10, 2024 5:06 pmI bought the two little LED replacement bulbs for the clock and voltmeter a year ago. I just haven't gotten around to installing them. LOL, I don't ride at night so really don't need them.
Be prepared for a bit of fun with the neutral switch. You shouldn't have to take the transmission out but may have to pull the swing arm bearings and rear engine mount to get the thing up in the air where you can get at it. Frankly I have been lucky not to have to try that but I hear it is possible. Maybe someone else will give more detail or perhaps you could open another thread asking about it? St.
I got real excited just now because noticed that the lead was off the switch... nope. Pushed it back on and still got the same failure to ground. Ah, well...
- schrader7032
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Re: New bike - some help please
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
Re: New bike - some help please
Excellent, thanks. I've ordered the switch, as I tested the loom down under there and it's fine--clearly the switch. It'll get replaced whenever I do the tranny oil again. Maybe sooner... it'll be cool to have those super-bright warning lights all working. That Katdash is way cool.schrader7032 wrote: ↑Sun Nov 10, 2024 5:40 pmSnowbum discusses a process to knock that engine spacer out to access the switch. On installation, you should chamfer the edges a small amount to help with getting the spacer started...plus leave it in the freezer for an hour or so as well.
The RS handlebar is sitting in the post office, so in anticipation of getting it mañana, I de-gunked the throttle grip--yuck. I had thought I'd be R&Ring the cables with the new set in the PO has in the box-o'-parts, but they're retracting well. It was definitely the nasty old, heavy grease inside the gear-and-chain mechanism and all over the revolving sleeve that was causing the failure to retract all the way.
On the carbs, two things:
First, the throttle cables were adjusted just a hair out of synch. It was subtle but the L/H carb's cable becomes taught just a bit before the R/H cable, and IMHO that can lead to wonky performance.
Second, I have decided that what are almost certainly 40-year-old butterfly shaft o-rings really should be replaced. So, after installing the stock RS handlebar, I'm going to disassemble and dunk the carbs in Chemtool. Ordered up some new throttle plate screws--though these do not appear to be like the ones used on SU carbs, where they have a slot in the threaded end so you can spread it slightly to prevent backing out. Maybe the ends get peened instead...? Nothing like a butterfly screw getting sucked into your cylinder to ruin your day...
Anyway, I installed the new 'manifolds' this morning and the 40-year-old originals were hard as a rock. I'm hoping that freshly rebuilt carbs, new pliable manifolds, and properly adjusted valves will net a nice, even idle and better low-rpm manners.
Re: New bike - some help please
Need to figure out how to eliminate the now-evident freeplay in the throttle cable: I assume I do not take it out down at the carbs, but instead use those barrels to synch the butterflies...?
Beston GT grips finish up a comfy change to an OEM RS handlebar. Coming along...
Re: New bike - some help please
As it warmed up, the pronounced stumble off idle mostly went away. If it persists, I will do as I had anticipated doing in an earlier post and dunk the carbs and R&R the butterfly shaft O-rings, replace enrichener gaskets, etc. Well, I'll R&R the needle jets and needles tomorrow, as that doesn't require removing or dismantling the carbs.
On the exhaust: I mentioned earlier that the PO put a stainless exhaust on this bike. The mufflers look like they'll clean up nicely with just polish, perhaps a pass with 2,000 and 2,500 grit first. But the headers--whenever I get around to it--will require more significant sanding first, as they're badly yellowed and have some blemishes. However, it'll be worth it as they should look like new whenever I get around to it...
A couple of questions:
First, per these photos, the crossover pipe (just one; this stainless setup lacks a rear crossover) has no slots cut in the ends for clamps, so none are installed. It isn't leaking terribly, but there is a slight pulse escaping where the crossover fits over the stubs on the headers. Are these stubs likely to be tapered, to make up for the lack of clamping provisions? If not, and if they persist in leaking, I may cut slots and add clamps to the crossover pipe.
Second, there is a leak from the R/H mating joint at the header and exhaust port. I tried loosening and re-tightening the finned nut but with little effect. Such a leak can, of course, contribute to imperfect running, so I'd like to correct it.
Has anyone had luck with cleaning and reusing the pair of sealing rings that fit inside this joint? It'd be nice to save $40 by not having to replace them.
- schrader7032
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Re: New bike - some help please
And the exhaust pipe has to come into the port perfectly otherwise the rings can't possibly seal.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
- srankin
- Posts: 1281
- Joined: Fri Jul 14, 2017 8:45 pm
- Location: Spencerport, NY USA
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Re: New bike - some help please
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,