Search found 7 matches

by AndyFitzGibbon
Wed Jul 19, 2017 8:23 am
Forum: Post 1970 Airheads
Topic: Bing 64/32/13 vs. 64/32/9
Replies: 0
Views: 1655

Bing 64/32/13 vs. 64/32/9

Hi all, The '71 R75/5 that I'm slowly rehabilitating for a friend (sat for ten years) has a mix of carbs on it- the right side is the appropriate 64/32/10, but the left side has a 64/32/13 off a later bike. Both carbs are jetted the same. Does anyone know if there are any differences in the carburet...
by AndyFitzGibbon
Thu Oct 13, 2016 10:41 pm
Forum: Post 1970 Airheads
Topic: 1972 R75/5 charging problem
Replies: 11
Views: 4014

Re: 1972 R75/5 charging problem

I took the relay apart today, and discovered some corrosion. I also discovered that, due to the way the relay internals are assembled, there's no easy way to access/repair the connection between the two No. 30 terminals. I ended up jumping them externally, by drilling small holes in the base of each...
by AndyFitzGibbon
Thu Oct 13, 2016 9:29 am
Forum: Post 1970 Airheads
Topic: 1972 R75/5 charging problem
Replies: 11
Views: 4014

Re: 1972 R75/5 charging problem

Yeah, the start prevention relay is exclusive to the /5, I think. Kind of a weird circuit, made weirder by BMW's decision to run all of the battery charge power through a bunch of unnecessary wire length and couple little spade terminals on the relay. A direct wire from the rectifier to the positive...
by AndyFitzGibbon
Thu Oct 13, 2016 7:43 am
Forum: Post 1970 Airheads
Topic: 1972 R75/5 charging problem
Replies: 11
Views: 4014

Re: 1972 R75/5 charging problem

Hi Kurt, This schematic shows how my bike is wired: http://w6rec.com/duane/bmw/electrics/Slash5_bmw_motorcycle_Schematic.jpg I tried to post it here, but it wouldn't post the whole image, for some reason. The red wire from terminal 30 on the diode board carries alternator output to a terminal on the...
by AndyFitzGibbon
Thu Oct 13, 2016 6:27 am
Forum: Post 1970 Airheads
Topic: 1972 R75/5 charging problem
Replies: 11
Views: 4014

Re: 1972 R75/5 charging problem

Well, using the link above, I determined that the bike's alternator is fine. Repairing a few corroded crimp connections on the alternator output wiring did create some charging action, but I was still only getting 12.9 volts to the battery. Yesterday, I traced the problem to the starter relay. All o...
by AndyFitzGibbon
Sat Oct 01, 2016 7:46 am
Forum: Post 1970 Airheads
Topic: 1972 R75/5 charging problem
Replies: 11
Views: 4014

Re: 1972 R75/5 charging problem

Thanks, guys, that gives me a lot to go on. Haven't had a chance to do anything with it these last few days. Hoping to get into it on Sunday. The regulator is a plastic-bodied Wehrle electronic type, which I think is probably a replacement. I think this bike would have come with a mechanical one ori...
by AndyFitzGibbon
Thu Sep 29, 2016 7:25 am
Forum: Post 1970 Airheads
Topic: 1972 R75/5 charging problem
Replies: 11
Views: 4014

1972 R75/5 charging problem

Hello, first post. Good to be here. I recently started resurrecting a friend's 1972 R75/5. It's been parked for nearly ten years, due to a charging problem (along with various other factors not related to the bike). I attached a photo of when it first came out from under the porch... I have it runni...