About 1,000 miles since carbs were rebuilt by Bing, synced by my local/reputable airhead mechanic, idle set at about 800 rpm. When the engine gets real warm and I quickly let off the throttle, the rpm drop way down, below 500 rpm and I have to blip the throttle to keep it from stalling, the idle will then come back to 750-800 rpm and remains stable. Engine runs flawlessly otherwise. Any ideas why I get the drop and then return to normal idle with the warm engine?
-
Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password. If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?
-
Beginning April 1st, and running through April 30th, there is a new 2024 BMW MOA Election discussion area within The Club section of the forum. Within this forum area is also a sticky post that provides the ground rules for participating in the Election forum area. Also, the candidates statements are provided. Please read before joining the conversation, because the rules are very specific to maintain civility.
The Election forum is here: Election Forum
'77 r100rs low idle at times
- Thread starter Gpr100rs
- Start date
First, I'd suggest you reset the idle to at least 1000 maybe even 1100...ensures good oil flow at idle...800 seems too low IMO. The next thing I would check is the height of the floats, or rather the height of the fuel in the float bowls when the floats shut off flow. You could have a lean situation which shows up when you chop the throttle.
headhog
Pistol Shooter
I concur with the above. I set my idle just to the + side of 1000. This provides adequate oil pressure/flow at idle. The next logical step is checking the float levels.
toooldtocare
Active member
I never trusted the tach anymore that I did the speedometer and had the same problems as you at 800 RPM, thus moved my bikes up to 1,000 to 1,000 range too.
Wayne
Wayne
brewmeister
New member
Hi guys, what condition is the mechanical advance unit in?? How are the springs? Is the mechanism free moving gunk free?
A 77 r100/7 would not come down to idle smoothly because the advance unit was sticky and wouldn't always retract completely , the bike would idle with the advance ingauged causing rough,inconsistancely smooth idle.
never the less,good luck.
A 77 r100/7 would not come down to idle smoothly because the advance unit was sticky and wouldn't always retract completely , the bike would idle with the advance ingauged causing rough,inconsistancely smooth idle.
never the less,good luck.
22600
rsbeemer
Plus on the idle
None of the 100rs I've had would idle good at 800 but at 900-1000 would idle fine if everything else was set up right. I've had mine idle at 800 before and it sure sounded pretty but when I came to stop after it warmed up good it would drop down under 800 and sound like it was gonna die. The 750's I owned would idle somewhere under 800rpm's, again if timing and all was good. So, try cranking it up some and see if that will help. Let us know what you find.
DW
None of the 100rs I've had would idle good at 800 but at 900-1000 would idle fine if everything else was set up right. I've had mine idle at 800 before and it sure sounded pretty but when I came to stop after it warmed up good it would drop down under 800 and sound like it was gonna die. The 750's I owned would idle somewhere under 800rpm's, again if timing and all was good. So, try cranking it up some and see if that will help. Let us know what you find.
DW
lmo1131
New member
I remember the first BMW motorcycle that I'd ever saw. It was an an old, somewhat derelict, R69s that a friend bought for his dad. Despite it's ragged appearance it ran like a top, and would sit there and idle happily at something under 800 rpm. With that gear-driven cam it seemed like all you could hear was the intake tract breathing against the exhaust.
My R75 ... 1000-1100 rpm, with a slight tendency, depending on ambient temperature, to idle faster when coming off a long run on the freeway; it always returns to "normal" within a few minutes. Not quite as pleasing (or as impressive to motorheads) as that slow ticking over of the older machines but you need to keep the oil moving and the amps up.
My R75 ... 1000-1100 rpm, with a slight tendency, depending on ambient temperature, to idle faster when coming off a long run on the freeway; it always returns to "normal" within a few minutes. Not quite as pleasing (or as impressive to motorheads) as that slow ticking over of the older machines but you need to keep the oil moving and the amps up.
