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My R1100S twin spark nipped up and now has damage to the right piston and cylinder only. It appears to have overheated on this side only. Where can I get reasonable priced parts. Is a big bore the way to go?

The best bet would be to source the parts from a reputable BMW specialist in Oz. Contact Lennie on here as he is from down under.

Depending on how much money you want to spend going big bore, you could end up with a HP2 slayer kind of machine. Most common would be the 1150 kit as sold by San Jose BMW, then high compression pistons etc, etc. You have been warned.

I'd want to find out why it did that before proceeding ?

What does "nipped up" mean?

Do you mean "seized"?

As prev suggested - find out why.

The lubrication fluid film remains for a long time in bearings after pump failure, not so long in liner lubrication.

If seized (even if micro-seizure of bore/rings and not seized now) - a bit more investigation is warranted.

Al

As Al and Nigel above said find out why it nipped up otherwise you will be throwing good money after bad

Big bore personaly i wouldn't bother unless you are going to recon the whole motor as a 1100 it's a tough old lump but quite highly tuned even in stock trim

Good luck with it Dai

Blackal wrote:What does "nipped up" mean?

Do you mean "seized"?

As prev suggested - find out why.

The lubrication fluid film remains for a long time in bearings after pump failure, not so long in liner lubrication.

If seized (even if micro-seizure of bore/rings and not seized now) - a bit more investigation is warranted.

Al

Didn't quite seize, just lost power and then kept going.

I am not 100% why it has happened, every 'expert' I have talked to gives me a different reason. Cannot really test some stuff if it is not running. Definitely overheated on one cylinder only. Could be mixture or lubrication issue. Maybe there was a flaw with this particular engine. I do check balance regularly, and oil before each ride.

Sitting idling for an extensive time? Like a lot of engines off-load.... Not every cylinder fires- not so handy when you only have two to begin with, and no coolant flow.

Al

Not saying this is relevant here but...

Some time ago my local petrol station was selling a sort of unleaded-diesel mixture for a day (idiot tanker driver filled wrong tank).
All the cars affected just stopped.
My bike seized the RH piston - tore through the nikasil along the lowest part of the bore. Symptoms; loss of power, horrible noise and smoke.
Rebuilt my 'seized' bike with a new piston and barrel, still ran rough (it was running on part diesel after all) so I did what all highly-trained mechanics do, I took it back out on the slab and revved its tits off. It seized up again, exactly the same.
After fitting the second replacement barrel and piston, and this time swapping all the fuel delivery system trying to find the fault, it was still running rough (on diesel), I only eventually found out by chance about the real cause.
Running on diesel, or part diesel (probably about a 1:3 diesel:petrol) produces a consistent result: the RH pot seizes.
Thought I'd point this out.

Has the motor been rebuilt on the side that nipped? if so it could have been a bad rebuild, piston ring grooves not cleaned out, gudgeon pin circlip not renewed or fitted incorectly, barrel and piston not matching, head gasket fitted upside down, silicon gasket cement used incorectly, rebuild done perfectly but in dirty conditions [pet fur contaminating oil, saw dust in oil, metal filings in oil, etc]
Was the motor ready to sieze anyway one side will always nip up before the other!
It could be any one of many things i would get both sides off the good side may give you a clue as to what happened or you may see wear[spelin] on piston, gummed rings etc that will need looking at

Have you stripped the right side? it could be a exhaust valve that has given up the ghost
If you have stripped it some pics may help us diagnose what went wrong,
Hope all this helps Dai

Just realised your in Australia

Your police use GS's and have some dam fine fitters working for them [there bikes do upwards of 80.000 k anually] a word or two in one of their ears may help

I had a very similar experience to R550s a year or so after I'd bought my bike with 38k on the clock.
Rode a couple of miles from home, filled up at my usual garage and then another mile up onto the M55.
First handfull and a big loss of power and lots of smoke.
The independant mechanic I took it to (RGM, Croston)replaced the extensivly damaged R/H piston and the slightly smeared barrel with new oe parts. (The pistons are graded from the factory so get the correct weight) He found no real cause except that the fuel in the tank "smelt and looked funny ". Tank and lines drained, motor run in a bit and I've thrashed it ever since with no long term problems.
It runs Lennies, SJ, loud Laser and PCIII. 96BHP at Frank Wrathalls.
The garage wouldn't do anything without proof of purchase, although their misfueling was reported in the local paper.

Thanks for that Bruno.
Lots of people I spoke to sad 'nah that wouldn't happen with diesel'. I've never figured out why it should, but exactly as you describe, first big handful and it just loses all power, and the nikasil bore is 'smeared'.
Strangely enough, 'my' garage (or rather their insurers) were c***s as well. I was lucky to have paid by switch so, after an awful lot of communications, they finally accepted that I could prove I'd filled up there. Oddly enough, during my very last phone call with them, the guy I was speaking to asked "is your bike yellow?" (it is).
In other words they'd had the CCTV all along, with registration numbers too.
C***s.

r550s wrote:Thanks for that Bruno.
Lots of people I spoke to sad 'nah that wouldn't happen with diesel'. I've never figured out why it should, but exactly as you describe, first big handful and it just loses all power, and the nikasil bore is 'smeared'.
Strangely enough, 'my' garage (or rather their insurers) were c***s as well. I was lucky to have paid by switch so, after an awful lot of communications, they finally accepted that I could prove I'd filled up there. Oddly enough, during my very last phone call with them, the guy I was speaking to asked "is your bike yellow?" (it is).
In other words they'd had the CCTV all along, with registration numbers too.
C***s.

When i was working for local authority we would often employ temps very often they would fill the machines with diesel instead of two stroke mix they would come over saying there's something wrong with this strimmer, hedgcutter,blower, etc every time it would only run on full choke every time it would go to the fitting shop every time it would have glazed the bore and piston nothing would remove this glaze the only repair was a new barrel and piston kit

Talking of garages selling contaminated fuel we were on our way to brighton for a weekend four trikes and a car, we all filled up at one garage we all broke down at the next junction half a mile down the road, i drained about a pint of water out of mine then replaced the fuel filter with a airline coupler that i had with me the other trikes wern't so lucky we managed to get the water out of Carl's V.W.and get that running again luckily[spellin] he had no fuel filter, the other two trikes had to get recovery out both were running paper fuel filters the water caused the paper to swell and not let any fuel through. When we all finally got to brighton we found a motor factor and bought nylon gauze filters all round drained carbs got them all runing properly again
Both trikes were recovered by the RAC who were next to useless when we tried to claim from the garage even the recovery driver said he had had a few call outs in the vacinity of that perticular garage all with water in the fuel!

Sorry none of that helps the O.P. ok it looks like the right side will nip up first with no damage anywhere else, it's looking very possible it could be contaminated fuel that has caused this to happen so get that fuel out and check it you may well have a claim from the fuel supplier

Thanks for the advice, the engine is a genuine low km and I am the second owner. Fuel is a possibility, but there is not much way of checking it here. I will keep digging, I really only have time. Certainly don't have much money to fix it. I did get it hot one winters morning, idled it for about 15 minutes to warm it, when i looked down the headers were glowing red. That was months ago and i have done a few thousand kms since that happened.