860 Kit

[dogshome]

Go faster stripes 

[mrclubike]

The kit should come with those decals 
I was wanting to do that to mine but I removed barrels 

[dogshome]

Spurred on by shiney blue paint and stickers and against my better nature, I'm going to touch up the tank. The Faberge eggs have arrived (hopefully not egg shell). Wish me luck 

[dogshome]

The (Bosch) starter has been complaining about another 200cc and much increased compression. Seemingly increasing with every mile still. Cold weather not helping. A balmy 11C today and she was not playing. Several goes later and she finally kicked-off on one quickly followed by the other. Subsequent starts after only a minute or so, no issue.

So a bush and bearing kit is around £40 and a whole new epicyclic Arrowhead starter just over £100. I was going to strip the starter, but 40 years old and I'm thinking that the armature will probably want a proper fettle. Then I read about the very series wound current guzzling Bosch type and the geared ones. Seeing the voltmeter dip to 8V after a 2 second burst on the starter made up my mind. I'll clean up the old one and sell it if it just wants bushes.

The car just blew PS fluid out (my fault, didn't check all the joints on the new pipes) so the bike had better start tomorrow so I can fetch my 87 year old mums shopping!

[Bob_Roller]

Most likely the starter has never been cleaned and lubricated since it was assembled 40 years ago .
I would disassemble it clean and re-lubricate it .
There are sintered bearings at each end of the armature shaft, they could be worn as well .
There used to be  a link in the FAQ section about overhauling a Bosch starter, the link shows a Guzzi starter it's the same as the airhead starter, just a different output gear, one more tooth than an airhead.
I've done four so far, not a difficult job at all .
If the battery voltage drops below 10 volts or so during starting, the electronic ignition doesn't work very well, if at all .

[dogshome]

I was (not really) surprised that a new epicyclic starter was only £100 when a bearing and brush kit was over £40. You are probably right, I have no reason to think it is anything other than dirty with worn brushes and bearings. The price of things due to modern manufacturing and consumer preference is a bit off though. 3 carbon brushes and 2 oilite bearings shouldn't cost £40 (more than a week's shop for my mum). A whole starter costing about 2 weeks of my mums local shop (bananas, veg, sausages, bread, butter, chicken, yogurt etc) is also a bit off the the other way (too cheap).

Identifying the bushings and brushes and buying as misc parts would get the price down to maybe £20 plus postage, in which case it might be worth rebuilding. Epicyclic makes more sense with a high compression 860 in a 650 frame that can't fit a 1,000 size battery though (shorter swingarm).

I've noticed more rocking upon opening the throttle at idle with a few more miles and the ability to time-warp away from lights. Definitely nothing like the (perfectly good condition) 650 parts. The ability to outstrip lorries coming down the slip road has easily been surpassed! Equivalent modern 250 to probably 600 performance now.

Gratuitous power and (more importantly) torque chart below. I have no reason to doubt it.

[Bob_Roller]

I was surprised to see the cost of replacement parts .

I got my last kit from Euro Motoelectric in the central US .

https://www.euromotoelectrics.com/Starter-Tune-up-Kit-BMW-MG-BO157-TK-p/bo157-tkplus.htm

[dogshome]

I got around to fitting the geared starter to replace the direct drive Bosch one. It has not been out at all in 40 years looking at it. I've not stripped it yet, but I think I will find a grubby armature and worn brushes exactly as you said.

The new one whips the 860 around like it should do, even when stone cold. I have to re-learn pressing the starter button now, jab and release - not press and hold!

Since I had the diode board out recently and didn't want to take all that out again, I left the Bosch support bracket in. Both 8mm nuts can be reached from the top with patience and the bracket itself just needs a tweak (gentle bend) forwards to let the old starter out and the new one in.

Luckily a combination of 13mm ring spanners, 1/4 and 3/8 drives meant the two big bolts could be removed and replaced without taking the airbox off or taking a chainsaw to the cases. They are poxy things and should have been capheads like the rest on the bike. I used the bolts that fitted the Bosch to fit the geared unit and they fitted fine. 

[Tony Smith]

Bit of an omnibus reply to a number of posts.


I have just bought a brand new set of R-65 decals to put on my new sidecovers (more on this below). I see no reason to advertise the increase in capacity, I prefer that to be a big surprise. :-)




The reason I needed new sidecovers is that I have gone long wheelbase. At the cafe I go to on Sunday there is a resident expert on BMWs, the long wheelbase, different sidecovers and K100 front end has him flummoxed.




Starter motors


I hate Valeo starter motors, they are poorly made,l and do not last anywhere near as well as the Bosch starter.


I have two of them, albeit Chinese copies. The first was bought for my R1150, I was surprised that it is actually better put together than the OEM Valeo. But then that is no ringing endorsement as a 5 year old armed with a bucket of parts and flinging them in the same direction would result in "assembly" at least as good as Valeo's efforts.


I pulled the Arrowhead apart, greased it properly and resoldered a few things. It works, but I wish the GSA had a kickstart as I do to to some remote places from time to time.


For reasons I can't recall I also bought a Chinese starter for Airheads. At the time the Bosch starter I rebuilt in 2013 seemed to be struggling with the 860 kit, but that proved to be a poor choice of battery and a Motobatt cured that.


A Bosch starter works perfectly and frankly I would fettle it instead of buying a Valeo clone.


There is a problem with coil voltage robbing on startup - that is down to BMW's less than ideal wiring harness and is not the Fault of the Bosch starter.


For less the $20 you can fix that.


Take the hot lead off the coil and use it to trigger a simple 4 pin relay connected directly to the battery - use a fuse if that excites your.


The days of voltage drop while cranking are over. The wife's bike which hAs always been a hard starter now leaps into life on the first revolution.




Lastly, I took the plunge and bought an Australian made Wedgetail ignition system. This hAs a total rethink on coil driving and fully electronic ignition. I love it!

[BPT]

How much is the Wedgetail system going for?

[dogshome]

RE Starter: The Bosch one was in good condition, brushes still got life and bearings with very little wear. The commutator was still level and unscored, but was no longer copper coloured, even on the wearing surfaces. It took a little cleaning, but more than a quick swipe or two i've found on cars. The unit is cleaned, greased and marked 'good' for future use. The Arrowhead one was short of grease, but otherwise looked well-put together and hopefully won't (by design, it should not) consume the massive current the Bosch did when it gets down to 0C and below here again. I have Motobatt and all new power wiring.

I may look at the coil feed wire as it does meander around the bike. I'll fit a proper distribution box when I do that as I already have auxiliary supply for fairing lights.

RE:Wedgetail. I expressed an interest via the website some time ago with no human reply. The facebook page also seems to be cold. Hopefully it's just a Covid glitch and there is still a plan to make these to buy. I hope they have not got snagged by some Directive or regulation that needs 100 items to be proof tested / EMC / colour of box compliance. Or worse, lack of interest. In the RC field, auto-advance ignitions are cheap and plentiful. 28 degrees is a common advance value for 10cc - 50cc engines..... The RPMs are very similar to our much bigger engines. 7,500RPM being a typical 'redline'. We run them at that on the ground with the prop chosen for that sort of RPM. They may speed up or load a bit when moving in the air, but not greatly. tickover is usually a bit higher at 1,500 to 2,000 RPM depending on skill at tuning/prop weight/tuned pipe.

[dogshome]

My friend has come across a 37/11 final drive. Mine is 31/9. So not a huge increase, but probably worth a go for what it takes to swap it. I've not seen it yet so don't know if its a finned or plain type. From Snowbum it might be an early R80 at that ratio.

Any pointers (apart from inspecting the splines and obvious leaks) or do we go by his suggestion and "rebuild it if it howls"?


Driveshaft end gasket I suppose. Dose of oil in it. bit of grease on splines. Owt else?

[dogshome]

8mm studs. Conrod style 12 point flange nuts. Original fitment, never been out and very floppy in a 12mm ring spanner. So awaiting a 12mm 12 point socket before I make a mess of it. 13mm 6 flat 12.9 BZP Nyloc nuts also on way. My friend fitted A4 M8 nuts (which have had no issues in several thousand KM) but the "engineers disease" in me says they are not up to spec. He gave me 4off the same A4 M8 dome nuts. They are very shiney and look great.

So shiney vs technically correct?