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F650, F700, F800 twin exhausts

rjmorel

New member
Are the twin exhausts the same dimensions where they bolt into the cylinders? I'm asking cause what if a person wrecks the exhaust on one of these bikes , would the other models bolt on at least into the cylinders, then a muffler shop can go from there to get it working? thanks
 
Saw that one on Ebay. I was thinking about using the tubing to make new header pipes that would be 1" farther away from the stator side cover to keep the exhaust heat away. Or do you guys feel the stator frying problem is not that big of a deal. And just replace the stator when needed? Mine looks crispy but is still putting out 12.4-14.3V on my LED voltage gage. thanks rob
 
Replacing a stator is usually not that difficult, and the cost of aftermarket is reasonable.
If my bike had 40k on it and the stator was looking burned i think i would just replace it as a normal maintenance item before it quit.
 
Voni's F800S had a stator failure at 61,000 miles. My G310GS had a stator failure at 19,000 miles. What is with BMW that they don't seem to be able to provide a simple electrical part without it being fragile and prone to failure?
 
Voni's F800S had a stator failure at 61,000 miles. My G310GS had a stator failure at 19,000 miles. What is with BMW that they don't seem to be able to provide a simple electrical part without it being fragile and prone to failure?

Maybe someone from the RV industry has infiltrated BMW? The RV’s are, for the most part, assembled with Cheese-Wizz and hope. :hungover
OM
 
Voni's F800S had a stator failure at 61,000 miles. My G310GS had a stator failure at 19,000 miles. What is with BMW that they don't seem to be able to provide a simple electrical part without it being fragile and prone to failure?

I'm guessing BMW is not even aware who the component suppliers are for these engines.
650-700-800 F-Twin engines were provided by Rotax, and the 310 is a TVS product.
Many brands have had stator issues over the years. Most are not very sophisticated charging systems.
Suzuki recently replaced stators out of warranty at no charge for certain model years of the Wee-Strom.
Good thing Ebay has replacement stators for the F-Twins for $60, so it's pretty cheap to replace them.
 
Saw that one on Ebay. I was thinking about using the tubing to make new header pipes that would be 1" farther away from the stator side cover to keep the exhaust heat away. Or do you guys feel the stator frying problem is not that big of a deal. And just replace the stator when needed? Mine looks crispy but is still putting out 12.4-14.3V on my LED voltage gage. thanks rob

All F650GS (twin), F700GS, and F800GS use the same exhaust system (headers and muffler)

Helpful to know the year of your bike - the redesigned stator housing in 2013 has drastically (AFAIK) reduced the problem of the burnt stators. As I understand it, the stator flywheel rotates around the stator, the flywheel is bathed in oil, but not a lot reaches the actual stator, so the stator has a tendency to cook (hence the new flywheel housing design).

I would assume that adding longer headers wouldn't change much internally, as the outside portion of the casting may be cooler (because it's picking up less heat from the header), but internally the temp of the stator is going to be pretty consistent because of the oil/liquid cooling inherent to the design of the engine (since the flywheel is going to be rotating around in oil, thereby cooling any heat that it momentarily picks up from the hotter side of the engine casing).

Plus you have all of the wacky stuff with changing header length: correct back pressure, insert other technical terms here that deal with exhaust manufacturing, etc.

Buuuuut... I'm just some guy on the internet...
 
drneo66,
mine is a 2009 F650GS with about 55,000 miles on it, 3rd owner. I do have a new aftermarket stator off Ebay and also another flywheel that I drilled 4 holes in kinda like the newer BMW flywheels.
I'm a tool and die maker, plastic injection mold maker so I made sure when drilling the holes to put them all in precisely to keep flywheel balanced.
The difficult part now is getting the old flywheel off. I made a puller and tried some heat but was afraid to get it too hot or smack the puller to hard to pop flywheel off. Its stuck on harder then any other bike I've pulled the flywheels off of.
Any suggestions to get flywheel off? should I get a BMW puller tool? Where?
How hot can I heat up the flywheel hub?
I take it there is no oil seal on the crankshaft behind the flywheel since it's 4 stroke?
thanks, rj
 
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