I purchased a 71 r75/5 about 6 months ago and have been working and riding it on and off during that time. Recently bought a mikunis carb conversion and I am having an issue with the throttle returning to closed. Enough time has lapsed that I can't remember if I always had to force the throttle closed. I order a new throttle cam gear and throttle tube and it still does not want to return on it's own power. I should mention that for some reason the new throttle tube does not fit so I am still using the old one. Think they may have sent an incorrect part. The cables are new and don't seem to bind. When I pull the cable end it seems to move back with sufficient power. I have a 2 cable system. Any pointers on setting this up send what to check would be great.
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71 r75/5 New owner stumped on throttle not returning
- Thread starter gwrodzhi
- Start date
Welcome to the forum! First check the easy stuff. Are you aware of the screw that's on the underside of the throttle housing? Number 16 in this figure:
https://www.realoem.com/bmw/enUS/showparts?id=0260-EUR-01-1971-2476-BMW-R75_5&diagId=32_0752
That's primarily used to lock the throttle during routine maintenance...it can hold the throttle at a constant setting. Secondarily, it has been used while riding to create a bit of friction on the throttle to slow it's tendency to close...kind of a crude cruise control.
Let us know what you find.
https://www.realoem.com/bmw/enUS/showparts?id=0260-EUR-01-1971-2476-BMW-R75_5&diagId=32_0752
That's primarily used to lock the throttle during routine maintenance...it can hold the throttle at a constant setting. Secondarily, it has been used while riding to create a bit of friction on the throttle to slow it's tendency to close...kind of a crude cruise control.
Let us know what you find.
OK, great! So you say that the cables, when pulled by themselves, seem to have some return tension to them. With the cables unhooked from the throttle tube, when you turn the throttle tube does it have resistance? I suspect that there might be a minor amount of resistance to turning, but if it takes quite a bit of effort, then there is some binding or it needs lubrication, or it's not the right part.
The original tube had some webbing missing and the teeth were looking fairly sharp and worn. The new tube does not want to slide in all the way. Cleaned out everything and cannot see where the new part is not fitting correctly. 32721233307 is the replacement throttle tube I got. Is this not the correct part. Also thanks for your help.
That part number seems to be correct per RealOEM:
https://www.realoem.com/bmw/enUS/sh...969_2476_BMW_R75_5&diagId=32_0752#32721233307
Sounds like you need a second pair of eyes to look things over...sure seems like there's some interference.
Where are you located...would be helpful if that was in your profile? Potentially someone near you could come by. There is the Anonymous Book...have you looked to see if there's an Airhead owner near you? The Airheads Beemer Club has tech days scheduled in various states throughout the year...maybe there's something coming up.
https://www.realoem.com/bmw/enUS/sh...969_2476_BMW_R75_5&diagId=32_0752#32721233307
Sounds like you need a second pair of eyes to look things over...sure seems like there's some interference.
Where are you located...would be helpful if that was in your profile? Potentially someone near you could come by. There is the Anonymous Book...have you looked to see if there's an Airhead owner near you? The Airheads Beemer Club has tech days scheduled in various states throughout the year...maybe there's something coming up.
Another easy check for sticking throttle cables. Is the rubber hand grip rubbing against the front brake perch impeding free rotation? The friction between the hand grip and the perch can make throttle return slower.
Friedle
Airheads Beemer Club www.airheads.org
Friedle
Airheads Beemer Club www.airheads.org
Push/Pull throttle
ebeeby
Member
Nah. Now you can help the next guy. Now my pal filling his Porsche Boxster with diesel, that was stupid.
