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Popping

1998f150

New member
I recently purchased a 2004 r1150rt-p with 48,000 miles. The man I bought from got it from the WSP online auction about a year ago. He knew nothing about BMWs and thought the bike was in perfect condition. It was not, but I did not think there was anything seriously wrong and the price was right so I purchased it. My friend and I (he's an A&P and has 3 BMWS) did fluids , brakes, and valves also did throttle body sync put on new steel quick connects and changed plugs. The difference is amazing. I have 2 issues. One is popping on deceleration and the other is a top speed of 109 mph. I have checked the speed on two occasions and in both 5th and 6th gear. Top speed is always 109. Any help would be appreciated.
 
Re: popping, is the exhaust stock? Check for air leaks if it is.

Re: top speed, possibly your in-tank fuel hoses are leaking keeping fuel flow low. You can measure the volume of fuel returning from the fuel distributor at idle. If it is 2 liters per minute you're good.
 
I don't think any of my bikes goes above 109 mph, including the k1100RS I just sold. The rev limiter on my R1100RT seems to cut in sooner than I would like as well. It could be the way it is. Keep in mind, that I live in Canada and the max legal speed limit anywhere is barely 70 mph and in almost any jurisdiction in Canada, getting caught 20 mph over the speed limit will result in very significant fines and if a Yellow Stripe is having a bad day, it could be a criminal charge.

I don't test my max speed very often.
 
Top End

5th and 6th are limited in miles per hour. 4th gear isn't. Unhook the battery for an hour, hook it back up, try red lining the bike at full throttle in second gear
to clear the crud out of the engine. By full throttle I mean crank it back as far as it will go as soon as you shift into second and hold it there until it red lines.
 
Keep in mind, that I live in Canada and the max legal speed limit anywhere is barely 70 mph and in almost any jurisdiction in Canada...

For the record, the speed limits in many areas of BC have recently been raised, some to 120 km/h (75 mph).
 

Hope to Merritt. Merritt to Kamloops. Merritt to Kelowna. All are 120 km/h.

Speed limit from Abbottsford to Hope was raised to 110 km/h. As well, there are a number of other roads which have had their limit raised.
 
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Top speed

I have a 2004 R1150RTP a with 175k and I had her to 120 MPH in the Nevada desert this summer and still had 500 rpm to redline in 6th gear. 109 is low. Speedo could be off, what is your RPM?
 
I don't know how severe this popping is, but I would expect it- briefly as you come off full throttle. The initial excess of unburned gasoline has to go somewhere- watch a NASCAR short-track race. When they let off, there is a fire out the exhaust....Again the build up of unburned gas from a system that was full on flow.
If it is continuos, I would think the gas flow is staying on- used to see this in carb days when the butterflies in the carb were staying open.
Some engines you can actually make this happen on demand but going from full throttle to, let's say 1/8th throttle, leaving the engine and drive train engaged. The unburned gas has to go somewhere.
OM
 
A few of the bikes I've had my grimy mitts on popped less after a careful "Zero=Zero" realignment of the TPS, so search this forum and the Internet BMW Riders for the procedure.
Roger04, please chime in here, what's the "better" Zero value again?

Air leaks may also be found in the short manifolds that connect the throttle bodies to the heads; and in the vacuum abortion that is the charcoal canister assembly (with switch + hoses) - recommend that be totally deleted with extreme prejudice, and the ports on the bottom of the throttle bodies be capped.
Another possible source (usually on the higher-mileage bikes) is the throttle shaft bushing on the side; sometimes you can hear that rattle.

Prior to readjusting your sync/etc. - Did you pull the two "Big Brass Screws" (the idle air adjustment) from the throttle bodies and clean off the tips? And then use a liberal amount of carb cleaner (or gas) and Q-Tips to clean out that passageway? And also clean out the bores of the throttle bodies, especially where the throttle plate meets the inner bore. Any buildup of old stuff in these places will affect idle and airflow, resulting in overall mis-adjustments as you attempt to sync.

Have you verified that the bike has the correct Catalyst Coding Plug in there? I think yours should be pink; sometimes people pull these, or plug in other versions in an attempt to dink with the tuning.
 
Exhaust popping and top speed

Exhaust popping on closed throttle decel can be caused by leaks in the exhaust, intake or over-lean AFR. Or any combination of the aforementioned.
Top speed should be approximately 120mph at normal elevations and on flat ground. Use a GPS to eliminate speedo error.
I have an '04 RT and it will now run 120ish given enough room. Prior to changing the internal tank fuel lines and filter, it would be hard pressed to touch 100. Amazing improvement. I could hardly blow through the old filter and could have breathed through the new one. 47K on the. Bike and I don't know if the filter had been changed before but it looked like everything inside was undisturbed from new.
PS. I had a K1100RS prior and that one was good for way over 130 without even breathing hard.
 
Exhaust popping on closed throttle decel can be caused by leaks in the exhaust, intake or over-lean AFR. Or any combination of the aforementioned.
Top speed should be approximately 120mph at normal elevations and on flat ground. Use a GPS to eliminate speedo error.
I have an '04 RT and it will now run 120ish given enough room. Prior to changing the internal tank fuel lines and filter, it would be hard pressed to touch 100. Amazing improvement. I could hardly blow through the old filter and could have breathed through the new one. 47K on the. Bike and I don't know if the filter had been changed before but it looked like everything inside was undisturbed from new.
PS. I had a K1100RS prior and that one was good for way over 130 without even breathing hard.

My son has a k1200rs that will do over 140. And my r1150r would indicate 135. Also if I wanted new injectors, what flow do I want? There are several available.
 
My son has a k1200rs that will do over 140. And my r1150r would indicate 135. Also if I wanted new injectors, what flow do I want? There are several available.

You want the stock injectors:
Same flow rate
Same spray pattern
Same reach into the TB bore
Same dimension from TB bore to fuel distributor
 
You want the stock injectors:
Same flow rate
Same spray pattern
Same reach into the TB bore
Same dimension from TB bore to fuel distributor

Ok, but that doesn't help me order new or rebuilt injectors. Is there markings on the injectors? How do I know what I have?
 
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