I have a 1991 r80gs and am wondering if anyone has done the siebenrock upgrade. I carried this out and have now covered about 4500 kms since doing the conversion. The bike has a definite increase in torque and power and feels much better except for one area fully loaded under load/acceleration there is the metalic pinging a bit like pinking - similar sound even at 60/70 mph top gear roll on acceleration.
As per the siebenrock instructions no changes have been made to valves/carbs or timing this did not happen at all with the stock barrels also a marked increase in oil consumption - upto about 1 ltr /1500km before this the bikes use of oil was very low at best. I accept that the running in period for the pistons etc may have given to this rise in oil consumption. The plugs are a tiny bit oily around the outer edges(I mean just minute traces) but nothing to worrying.So far the bike has 73000kms and otherwise runs perfect any suggestions advice or experience would be great before I contact siebenrock for there point of view. I know I can always go back to standard barrels if need be. Ta Jake.

...you are not supposed to run in an engine like that... You may have caused the problem or a part of it by not running in the new parts correctly.
Yes - there is a bit of pinging in my unit to. I did however get 1000cc and dual-plugged 1000cc 70hp heads from them as a whole kit.
Did you smoothen the sharp edges on the pistons and in the heads to "soft as a babys bottom" before installation ?

Friend of mine have an up-grade kit, and his R80GS does ping quite a bit to my ears; he on the otherhand does not even notice the sound.
The rubber dampers inbetween the cooling finns are in place on your barrels ?

The first 1000-2000 something my unit used a bit of oil to - but not even close to yours.
What did you do to your heads ? New guides ? New valves ?
You did install the oil-scrape ring in the correct direction and with the opening upwards or... ?!...

Nevertheless, there is a point in contacting 7-rocks and ask them about what is happening.

__________________
Drive Safely,
Albert

Albert sorry first of all I have done 4500 kms since conversion not 1500 i accidently put in the wrong mileage)thanks for the reply the new barrels were run in very carefully( considering these are modern pistons with nickasil barrels however i ran in the bike as follows) 500 miles on bendy back roads giving changing revs and loads below 3000 then 3500 revs then an oil/filter change, then the next 400 hundred mile kept below 4000 revsmax, the last few hundred miles kept the revs about 4-4500 only after covering well in excess of 2000kms (1500) mile did I open up over 4500 always below 5000 revs. Since then I have stretched the use of the revs very occasionally but never really pushed the bike hard. (other than as stated for overtaking and 2 up acceleration even then nothing dramatic no where near the upper rev limit - i usually ride within 50 /70 mph with some 80 mph when solo. The piston rings were all put in the right way up and very carefully. The rest of the engine was not rebuilt at any time, the heads and valves are all original and in good order -however I will probably put new valves, springs and guides in after christmas. I never took any edges off the pistons as they were fine and had no rough edges. all the rubber grommets are in place. thanks for your comments/observations.

1500km would indeed have been much too short distance; 5000 is adequate.
You've gone by the book - therefore there is obviously a problem that 7-rocks needs to look into for you.

The planing of the pistons to accomodate the valves have sharp edges, and there are sharp edges around the plug and sometimes around the valves in the heads. All these edges should have been grinded away to produce an absolutely smooth surface - this is to avoid hot-spots which cause pinging.

Then, the lightweight pistons that 7-rocks sell does creat sounds that stock does not, nor does Venolia forged pistons either make these sounds. The sounds could be a "personality" of these pistons - but that is for 7-rocks to lay out / describe.

As for the oil... that is bad.
Usually it means leaking guides... but with that amount oil oil being burnt you are running almost a 2-stroke... and that does indicate a ring problem. However, it can be a nicasil problem - if you by any chance have damages to the nicasil that can cause an excessive oil consumption.
There is a third very perculiar option to - valve-cover ventilation problem. Friend of mine had oil consumption like yours and in his engines case it simply had something to do with poor ventilation of the valve-covers (I know this sounds weird, but I have pic on a sidecar racer with valve-cover ventilation, so the problem is real).

__________________
Drive Safely,
Albert

I have a R80 converted to Siebenrock (but I also have ported tops and a different camshaft). This setup has been used for almost 35kkm.

Before I converted the bike I could drive a service-interval (7500 km) without topping up, now I have to top up after 4000-5000 km.
One funny thing I have noticed the engine runs hotter when (approx 10°c) when I top it up, I never noticed this when it was a 800.

After 73kkm it might be a good idea to check valves and guides.
Have you done a compression test on the bike?


The pinging is not a problem for me, what grade of fuel are you using? Are you sure it’s not running to lean? What kind of plugs are you using?


I totally agree in Lindbergs suggestion, it might be smart to remove all the edges. This is how it looked on mine (original):

Good point Alibaba!

I totally missed pointing-out the petrol issue and plug issue.
Friend of mine bought a 1983 R100RT this summer. The bike was reluctant to start and had some funny sounds. The previous owner had done some service, like NGK BP6ES... We installed WD5 and the engine fired-up at the first try -
Pluggs matters!

I always try to fill at stations offering "clean/pure" 98-octane (EU: Super or Super Plus ?) - using 95 results in "extra sounds" and "less mileage". I do make it a point to use the "best" petrol companies; Statoil, Shell, BP and avoid Jet, OK/Q8, and other minor stations - in an effort to get as clean petrol as possible at the best octane possible.


Here are some plug options:
R100RT 1981.
Bosch WR8 LTC+ ; ran like a dream and was easy to start!
NGK BUR6 ET; Hard to start, but ran as smoothly as with the Bosch plugs.


R80/7 1984. (Siebenrock kit with dual-plugging)
BUR6 ET (long thread) och BP7 HS (short thread); exactly like the R100RT, a bit reluctant to start, but runs like a dream!


3 electrodes:
*
R100;
NGK: n/a. Bosch: n/a, but W5 DP 0 have 1 side-electrode instead of the .
*
R75-80;
NGK: BUR6ET, Bosch: W 7 LTCR, W 7 DTC


I have not yet tested Bosch Super, 4-electrode special VW plugs - for those who want to test them:
*
R100 = WR56 only long threads available.
R75-80 = WR78 long thread, WR78G short thread.
Spark gap 0.8mm.

__________________
Drive Safely,
Albert

thanks again for the advice, I am running standard bosch w7dc but was trying to find the equivelent in the super 4 bosch but have not sourced them yet. I also use mainly shell 95 grade fuel but have tried shell 98 grade for about 4 tanks and found it made no real difference of note. I have thought a lot about twin plugging when I am re doing the heads anyway so maybe this will all help. When I was doing the conversion I noticed the valves had quite a bit of burnt on carbon built up this might also not help like you say creating hot spots - but I did not want to start doing the valves at that time but will be doing them soon so will have a good look at the barrels and pistons while I am in there. As for the oil consumption I am off to Germany on the bike this week (about 1000km round trip) I am doing an oil and filter change tommorow before I set off so will take have the opportunity to get an accurate mileage/oil consumption check done by the end of my trip next weekend.