ISO = crankshaft measured power. Predominantly used in Asia.
Horsepower - Wikipedia, the free encyclopedia

DIN = rearwheel measured power. Predominantly used in Europe.
Deutsches Institut für Normung - Wikipedia, the free encyclopedia

E.g.
BMW K100 90hp (DIN) = ca 120hp (ISO).

Hello

I found this numbers:

Does any one want to comment?

1070CC (+dual plugging)
61.69 BHP @ 7002 RPM
53.89 FT/LB @ 4932 RPM

(why is the max torque at 4932 RPM? Should be much lower…)

Original engine:
51.06 BHP @ 6943 RPM
47.26 FT/LB @ 3619 RPM

Omega Long Skirt:
58.14 BHP @ 7003 RPM
52.96 FT/LB @ 3484 RPM

I’m still looking for more information about the Sport kit 1000cc, 7.5mm shorter from Moto Israel.

(I still have some doubts about pinging with the 11.2:1 compression ratio…)


thanks

It's not easy to compare numbers from different dynos, but it's a rough guideline.

First off all there are two different 1070-kits from Siebenrock. The first was Italian-made and the one they are selling today is Mahle. I would guess they have different performance.

I tried to gain as much information as possible about the 1070-kit last year but couldn't find much so I went for another option. Later I talked to a guy who installed the kit on a friends bike and he was pleased with the quality of the parts and how well it ran. Hopefully we will se a dyno-graph next year, but this bike will probably not be used outside Europe.

When it comes to the numbers it (62BHP/73Nm) I think they are low. I had 55BHP/80Nm with a 1000cc upgrade-kit and a few other modifications. The engine is much stronger now, I expect 65-70 hp (rear wheel) but it will not be tested before next year.



The camshaft is probably replaced, but it looks a bit odd.


Looks okay to mee.

my r80gs has the following engine mods along with many other mods
siebenrock 1000cc upgrade, polished balanced conrods,high torque cam, twin plugging, lightly ported and improved inlet and exhaust tracks, twin plug electronic ignition (motoeuroelectrics), two twin tower dyna coils. (several other mods that would not improve power output).the bike is also fitted with Siebenrock sbs exhaust (excellent) and K&N air filter. The gearbox has lower first and higher top gears, I have not had the bike dyno tested but comparing it to other bikes I have ridden and owned over the past 35 years, I would suggest the power would be closer to 65 + bhp maybe even 70 and the torque is flat in its delivery curve and strong from little over 1800 revs, in comparison to modern bikes claiming 75 /80 nm it feels as though it has better spread of torque its really hard to put a figure on it the torque is at its strongest between 2500 and 4250 but then there is a good kick of power above 5000revs. Power tails off from about 6250 revs The engine however is very smooth and returns an average now of around 54(uk)mpg , that includes all kinds of riding (motorways, A and B roads fast country riding and slow touring) the consumption has improved with the bedding in and getting the carbs running as right as they do now, it is more economic at a steady 55/60 on a long run. The siebenrock exhaust really made a notable difference as did the twin plug electronic ignition, which really smoothed out the power delivery and delivered a huge hit of torque in the low to mid range. Cant say what the power figures really are - but does not really matter to me so much because it is a really really nice machine for an old BMW and certainly comparable if not better than most modern machines in the 195 kg /800 to 1000 capacity class.

Question for the boffins here if any can help please. As my bike is modified as above what heat range plugs should be used - As usually higher compression bmw engines (r100rs etc) use a cooler plug than the standard bikes, would twin plugging negate a need for heat range change (if its needed) or not. I find using a cooler plug the bike runs well but gets a little bit carbon on the plugs at lower speeds (suggesting they are too cool around town at low revs) I am currently trying standard heat grade plugs for the Gs but with platinum tips to see what these do but if anyone has any suggestions what would be right please advise me.
Also I am trial running a K&N filter since October - K&N say it allows 40% more air to flow - not that I am so bothered just thought I would give it a go, the bike seems to run very well with it with the exception of starting in the colder conditions - it cranks longer sometimes starts to struggle in minus 10 conditions, (Battery is Oddessy and in very good nick so good power) before firing and is impossible to kick start from cold. I will be reverting to standard filter if I cant sort it - but just for knowledge would I be right in thinking the cold start system is getting too much air and as such running too lean to get the initial fire up (obviously this is more so with the kickstart as its not cranking as quickly and as long on each stroke of the kicker compared to whizzing up on the starter.)Or am i way off the mark and its going to be something else and I am just associating the filter to the starting)I Have just ordered a new paper filter to try - and see if it fixes the problem.

Hi Adventure950,

Twinn-plugging and sideeffects.

Plugs:
- You present what I have experienced. The solution I stumbled up-on is multi-electrode sparkplugs, Busch Super 4 and NGK BUR. I am running Bosch Super 4, 78 (upper, long) and 56 (short lower) plugs. Perfect combination on my present/current engine - all my engines have had their own preferences... "personalities"!
78 = 7 and 8
56 = 5 and 6
=> wider heatrange.
NGK seems to have their temperature steps midway between that of Bosch. BP6ES does not act as Bosch WD7, but they are listed as the same heatrange...
I.e. - you will have to test a few different marks and heatranges.

K&N:
- You will have to re-jet the carbs... Motorworks - BMW Motorcycle Spares - home can assist with jettings; they've helped me with some odd sizes. Look at Bing USA, Throttle Body Rebuild Kit - they have all parts and a tuningmanual that you will need.
After you get the engine running well using dual-plugging and K&N it will not start using a standard air-filter made of paper... well, at least I found myself in that postition with a R100RT... That bike refused to start untill I pulled the paper filter. With no filter it started easilly. When I put the filter back... choked bike.

Thanks Albert I am trying out NGK bp6evx platinum plugs at the moment and the bike feels quite good riding it yesterday, so maybe the heat range difference you mention might sit broader between the bosch heat range w7dc. I have not pulled it out yet but will see later today if there is any fouling.
Re jet the carbs - just what I did not want to hear but suspected the bike runs really well its smooth, power is good but the cold start not so good, I will speak to Motorworks see what they have to say - Thanks for the advice. Jake.

hello

Has you know I’ve been looking for a solution that will give me more torque at low speed.

I look for several solutions including displacement increase, compression increase but with a tight budget

If I didn’t need barrels Richard Moore would be the best price/power solution (eventually some ping problems)

Since I need the barrels Moto Israel 10.5:1 and Richard Moore were very similar price solutions.

I decided that I would go to Richard M but he was out of barrels so after more then one month I when to Motor Israel Kit

First comments: This is a MAHLE motorsport engineering design but nowadays is being sold with MAHLE barrels and Wossner pistons and pistons rings. The barrels are very good but the pistons are not up to Mahle standards. I’m only referring to end product finish look. Most probably the performance will be similar (I would like very much to compare the pistons with the ones from Richard M.)

Installation remarks:
The kit should came with installing instructions since I lost to much time with small details like wrong push rod pipes installation (I will give details if any one is interested)
To avoid more costs I decided to modify myself the barrel bolts and push rods. Easy job but will had a couple of hours to the total installation time.

Since I work in the piston ring area I also lost some time with unnecessary measurements.

After two working evenings I started the engine. The lightness of the engine is instantly noticeable as the engine reacts mush faster. Will see about power/torque and fuel consumption…

I only did one km so no more results for now.

For now I will not touch the carbs to avoid miss results

:)

Think you will find the kit to be quite pleasing.

As you seem to have your engine apart at the moment why not play safe, fit secondhand standard barrels and pistons then after you trip modify your engine in whatever way you want and sell the standard parts. I would also keep the engine standard in other ways, carbs, air filter etc, they might not give the most exciting performance but reliability is more important where you are headed.
I have never had much problem with standard parts on my R80GS despite having run it on 80 octane in Egypt and something equally awfull in Iran, although the latter was only 1.5 pence per litre.

Did the tube between the air-filter and carb fit? Problems with the exhaust?

Nice job, congratulation!
Yes, please keep us informed.

hello

I had some fears with those items but those were the easiest assemble. To be honest the tubes between the inlet and the air filter fit better now and were easier to assemble the with the standard cylinders…

Concerning the exhaust you only have to unbolt the connection pipe between the two main pipes and you will have no problem.

The problem with the push rod tubes is that you should only push them into the cylinders till they reach the top surface of the cylinder. They are machined to go more then that but after you can not install the head and you can not pull them back…
(if you put them in the freezer they are easy to install)

Just one more detail concerning the piston rings.

The second groove ring gap should always be similar or superior then the gap of the first groove to avoid “fluctuation” problems. If the gap is too small in the second groove some pressure will be created between the two grooves and the fist (top) one will not seal properly.

With Wosner piston rings this was the case. To solve this the gap in the second groove should be increased or you should assemble a top ring with smaller gap… (ideally something like top=0.15(+0.10)mm and second=0.30(+0.20)mm)

Back in the day I used compression plates on my R75/6 and R80 so that the bikes would not ping too much on the fairly poor quality fuel available in india and afganistan. This seemed to work, except in India whenever petrol was adulturated with kerosene.

Modern engines (such as KTMs) can run highcompression ratios because they have better cylinder head shapes and better electronics, not a good idea to compare their compression ratios with our old airheads.

When travelling (rather than racing) power is not an issue, reliability, fuel efficiency and tractability are much more important, so i would go with a standard low compression ratio engine, I might go to twin plugging as well, but not much else.

On the power discussion my 1070 kitted bike develops 72 BHP at the rear wheel with just over 60ft lbs of torque, with a flattish torque curve from around 3000 rpm. It is gas flowed, twin plugged with 38mm dells and 40mm pipes and a jim Cray conti type silencer. It runs well! This compares to around 52BHP at the rear wheel for a standard 82 RS/RT engine. The standard later bikes are less powerfull, mainly due to lowering of compression ratios.

Charles

well thought i would let you know the results of the changes I have made on my bike in measured terms ie on a dyno, The bike is a r80gs 1991 model,to save you checking backover to previous stuff i wrote - it has the following engine mods, siebenrock 1000 upgrade,K&N air filter, twin plugged heads, lightly gas flowed, standard 32 mm carbs and valves, 1 piece rocker guides (really quieten down rocker gear noise and save adjusting for rocker shaft play - nice kit), balanced conrods, (balanced over entire length to match each other),matched pistons, balanced crankshaft, heavy duty clutch, siebenrock sgs2 high torque exhaust, 296 enduro camshaft, bronze bush cam bearing, endurolast alternator and twin plug ignition system, gearbox 1st gear 5%lower, top gear 5% higher, Now she is running near perfect with electrics for the spark from the endurolast ignition ,NGK bp6 iex plugs, ngk plug caps copper core race HT leads, twin tower Dyna coils. After all that work Phew! the figures on paper are not spectacular but riding the bike is very much a different story to a standard 800gs or 100gs.

Dyno measured power at the back wheel, 52.76 hp at 6000 revs (65.95 at the crank - approx calculation some internet guides would have calculate it to be 72.01hp),
Back wheel measured Torque 72.08nm (53.16ft/lb)at 3400 revs However Torque reaches 66.44nm (49 ft/lb) at 2400revs reaches oits peak at 3400 where it continues pulling at 72.8nm through to 5800revs when it tails off slightly to 44nm by 7000 revs - but then the max hp kick is taking over pulling the bike forward with a descent surge.
In rideable terms the engine is very quiet (i mean as quite as I have ever heard an airhead), very smooth all through the rev range and so tractable and usable at all road speeds and will happily cruise at 90mph and pull top gear cleanly from 1800 revs without protest on a level tarmac road and about 2400 when under more load or on an uphill gradient.

Fuel mix ratio stays fairly steady throughout the entire rev range at about 14.6 with only slight variation at the bottom end where it dips to around 13 for the transition at 2,500/3000 revs maybe the next size idle jet would smooth that out but I dont think its worth changing for the tiny difference it would make.

Fuel consumption appears to be steady around the 50 /52 mpg (5.6 litre per 100km) in normal riding.

Bye the way kept the K&N air filter - bike kickstarts again from cold - turned out I had the idle circuit a touch to lean originally and more so after putting in the K&N so now its just fine.