Page 1 of 1
Time to rebuild 75 R90/6
Posted: Sat Sep 04, 2021 8:43 am
by Joe Crable
Okay I have a 1975 R90/6 that has been waiting for me to put back on the road for the last 20 years. There is a lot that needs to be done. I was in Austin TX and came across someone who had a airhead that inspired me to do something with mine. His had been converted to electronic ignition and didn't even have to use a key. He used his phone like a key-fob to unlock the bike and activate the ignition. He didn't know what system it is as he bought it already set up like that. I would like to remove the points system and convert mine to electronic ignition. I would also like to convert to fuel injection as well. I've herd about a stand alone system called microsquirt could this be what was used on his bike? If not does anyone have any idea on what system was used?
I plan on pulling the block and going through it of course as well as the transmission to start off with. I'm wanting to do something like a scrambler for those Sunday morning rides with friends.
Re: Time to rebuild 75 R90/6
Posted: Sat Sep 04, 2021 9:01 am
by Kurt in S.A.
Welcome! If you have the passion and money and like to tinker, go for it. There are a number of aftermarket electronic ignitions that work. As for the fuel injection, that is not something that comes up very often. But in the end you won't have a simple bike anymore and you probably won't really improve the bike. Sounds like to me you should be looking at an Oilhead!
Kurt in S.A.
Re: Time to rebuild 75 R90/6
Posted: Sat Sep 04, 2021 10:09 am
by Joe Crable
I have one of those, a 2002 r1150r as well as a 2014 t1200rt. Both are great bikes but I want to do something different with the 90/6 as it was my dad's when I was growing up.
Re: Time to rebuild 75 R90/6
Posted: Sat Sep 04, 2021 10:31 am
by SteveD
Welcommen Joe.
Try Tom Cutter for a Wedgetail EI for the bike. Latest version of EI available.
Re: Time to rebuild 75 R90/6
Posted: Sat Sep 04, 2021 10:36 am
by Kurt in S.A.
When you order the EI from Cutter, talk to him about fuel injection. I'd be curious to hear what he has to say.
Kurt in S.A.
Re: Time to rebuild 75 R90/6
Posted: Sat Sep 04, 2021 11:32 am
by melville
I've seen pix of injected Airheads. Looks like the starting point is throttle bodies from an R850R for most.
Good luck, and post pix as you do it!
And post pix of your 90/6!
Re: Time to rebuild 75 R90/6
Posted: Sat Sep 04, 2021 5:55 pm
by gspd
I have ridden well over 500,000 miles on 'carb' bikes and must state that I have never, not even for a minute*, longed for any of them to have fuel injection.
I am very familiar with modern fuel injection systems and all their pros and cons.
High pressure pumps, computers, wiring & sensors all over, etc.
No way would I put all that crap on my cherished '
simple by choice' airhead.
If you don't intrinsically understand why, no explanation or justification is possible.
*er... well...maybe just once for a minute when I got '
gasstinkboot' from a sticking float.
Gravity feed rules!
Re: Time to rebuild 75 R90/6
Posted: Sat Sep 04, 2021 6:55 pm
by Zombie Master
I rode an R90/6 for 11 years. I never had a problem with the points and condenser system. Is greasing the point cam felt really that challenging?
Re: Time to rebuild 75 R90/6
Posted: Sun Sep 05, 2021 2:53 pm
by Seth
An older thread on the fuel injection topic
https://forum.boxerworks.com/viewtopic.php?f=1&t=3335
One significant point is the electrical power requirements for fuel injection. A big problem with Airhead charging systems, even the aftermarket ones, is they spin at crankshaft speed. Oilhead BMWs have alternators that are belt driven and spin faster than the crankshaft, so they can provide more power even at idle.
Regarding conversation to electronic ignition, I’ve had 2 condensers fail in the past 50 years of riding. I’ve not had a problem with any electronic ignitions, including a converted R90S. The R90S does start much faster with the new ignition.
Re: Time to rebuild 75 R90/6
Posted: Mon Sep 27, 2021 10:24 am
by RPGR90s
Joe Crable
The stock Bing's are an extremely reliable and well engineered carburetor. Converting to fuel injection is doable but you're not going to see much benefit as the rest of the system is a 50 year old design.