BMW K bikes (Bricks)

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1Back to top Go down    Engine swap on Thu Sep 19, 2013 1:24 pm

Tenox

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I have many plans for future bike. One of them is buying a standard K100RS (RT/LT is a bit too tight for me) as cheap as I can (can be with motor damaged etc.) and put my current heavily modified K100RT engine, clutch, transmission and final drive in to it.

I have one question so far. It is about the wirings. My current bike has quite alot modified electric wirings. I would like to keep the wirings of the "new" bike, but all the parts like ecu, starter motor etc. from my current bike. How hard is this to do?

What else do I have to take in consideration?

Why?

Because there is some grey in my hair and I would like to have a bike with good wind shield for long distance travels...Wink



Last edited by Tenox on Tue Jun 10, 2014 8:37 am; edited 1 time in total


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2Back to top Go down    Re: Engine swap on Thu Sep 19, 2013 5:19 pm

robmack

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@Tenox wrote:I have one question so far. It is about the wirings. My current bike has quite alot modified electric wirings. I would like to keep the wirings of the "new" bike, but all the parts like ecu, starter motor etc. from my current bike. How hard is this to do?

What else do I have to take in consideration?
So, when you say "modified electric wiring", is that a good thing (i.e. aftermarket accessories) or a bad thing (i.e. clipped off connectors)? Let's assume it's the former. That means, the new harness has to have the modified wiring or be able to accept the aftermarket wiring from the donor bike. This could get really involved depending on how much modified wiring and accessories you wish to transfer to the new bike. It could mean cutting into the new harness. I'd recommend not doing this type of work until AFTER you've swapped over the engine and subsequently had the bike up and running. Modified wiring during a new build is one more thing that can go wrong and you won't know what caused the problem -- bad parts on the new bike or bad modifications.

On the other hand, if it is the latter, then the effort is low. It becomes figuring out how to swap OEM standard electrical components from the donor bike. This is a relatively easy task since it involves just unbolting components and swapping over after removing the donor's equivalent components.

There are some deeply buried parts like the ignition unit that need a great amount of disassembly of the mechanics to get out. Since you're into this build up to your ears, that shouldn't be a problem. You'll have to strip down the donor bike as well as the new one to do the engine swap. It's a matter of planning your project, to make sure you tear down and build up in an organized fashion.


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Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer
http://k75retro.blogspot.ca/
    

3Back to top Go down    Re: Engine swap on Fri Sep 20, 2013 5:05 am

Tenox

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"...or a bad thing (i.e. clipped off connectors)?"


It would be this.


Thank you for the answer. I really have to think do I have the time and skills to start this project during winter.


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4Back to top Go down    Re: Engine swap on Fri Sep 20, 2013 6:06 am

92KK 84WW Olaf

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Your bigger issue is getting the electrics right but its not a problem.

When you have all the fairing and plastic off the RT then its not so hard. I had to change the ECU on my LT and when I had the tank off it actually wriggled out quite well. Its buried for protection but if you are methodical its a lot easier than one would think. A bendyflexible drive and some 8 9 10 12 13mm sockets will be very useful. Before you do much havea look in the electrical relay box under the tank and see how the relays are. I have a 92LTABS and 84RT non ABS and the electrical relay boxes are quite different inside but the relays themselves seem quite similar. Before you go deep into the new bike see what the electrics etc are like. A lot of other components are different too, radiators, exhaust, footplate hangers, forks, seat, clocks [LT has a 5L warning, RT has the 7 and 4L warnings, fuel tanks differ, even the fuel pump wiring connections differ but easily dealt with if you work slowly. The guys here will keep you well posted and will offer advice on suitable years/versions to go for.

A little thought into what you want is important too. Things like making sure fuel pipes are new and in good order, breather, coolant overflow pipes, all cheap and easy to get at if swapping over.

If you can get the two bikes side by side so you have something to refer to is good.

You will need manpower for moving engines but there are only 4 bolts although they require careful shimming and careful tightening up, method is important.

When you have petrol tanks off the electrics are there to see. Don't be afraid to label them either, test each one by either removing fuse or breaking connection [with ignition off] and label it. Do same on new bike too and it will keep you out of a lot of trouble.

I would not be afraid to take on that job with the amount of help that's available on this forum.


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1992 K100LT 0193214 101,000 miles
1984 K100RT 0022575 Baja Red bought 36,000 now 89,150 miles
1997 K1100LT 58,645 now 60,500miles
    

5Back to top Go down    Re: Engine swap on Fri Sep 20, 2013 11:50 am

AJ.Valente

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Ya-no, I don't think so. I have an engine and drive train from a K100 same year as mine but with only 28k on it, and when the time comes I'll swap out to keep the bike on the road.

If I read you correctly, what you are talking about is converting an RT to an RS. That is much simpler than the approach you are taking. If you find a burned-out RS, then simply transfer the faring, handlebars, cables, etc. from that onto you existing bike. That would be much more straightforward than swapping engines IMO.

    

6Back to top Go down    Re: Engine swap on Fri Sep 20, 2013 3:57 pm

Tenox

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My bike looks like this:

https://www.dropbox.com/s/vjhh91wr24t96lu/BMW_VFinal_02.JPG

One does not simply convert that to a fully functional RS.Shocked

Bike has completetly redone engine with only about 15000km on the odo, new oil resistant clutch with about 8000km on odo and good transmission/final gear + lots of other good clean components for spareparts. So it would be swap or nothing.



Last edited by Tenox on Tue Jun 10, 2014 8:49 am; edited 3 times in total


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7Back to top Go down    Re: Engine swap on Tue Jun 10, 2014 8:43 am

Tenox

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Let me make this question a bit more simple.

I now have a perfect engine (86 RT) and I may someday want to transfer it to my other bike (88 RS with ABS). So if I take out the engine, clutch, transmission and rear from that old bike, inclueded with alternator, start etc. Am I able to plug it in that RS easily so that ABS would be OK?

What I basicly mean is: How many connectors there is to unplug when I take that section off of the bike. Is there like 3-4 plugs or like 20-30?

I don't know am I capable of telling what I mean in english...


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8Back to top Go down    Re: Engine swap on Tue Jun 10, 2014 1:54 pm

robmack

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3-4 plugs to disconnect to separate the engine from the frame (lower harness with injectors/coolant temp sensor, HES, oil pressure, MAF, choke). 3-4 connectors to separate the transmission/driveline from the frame (speedo sensor, TGPI). Full procedure is on page 11-25.0 of the official K100 maintenance manual.


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Robert
1987 K75 @k75retro.blogspot.ca
2011 Moto Guzzi V7 Racer
http://k75retro.blogspot.ca/
    

9Back to top Go down    Re: Engine swap on Tue Jun 10, 2014 3:49 pm

Tenox

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Thanks! That does not seem so bad.


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