SP2 rebuilt 0 , SP2 rebuilt 1 , or SP2 rebuilt 2


Thats what i've typed somewhat November:

Acrapovic-Exhaust:if YOU have got one,and IF you want to go for a dyno next days (only if you've got Ti-Cans,please),can you do me a favour- at a 2nd (or whatever) Run:close the left Can anyhow and have a look for the power-curve then,i'm not really convinced the Diagram will look much worse: + 1Nm at 7.5k is worth -1hp at 9.5k ! And the weight lose then:4lbs the Can + approx 1 lbs the header-remove. Ha-and the economics:next crash-a spare Can !
It's an idea-worth to check it,i think.



Ta-veryveryinteresting-got the diagrams from Steen Sörensen,he  made the Test on the dyno (thanks Steen!),this is what he wrote me

Hi Thorsten
We have made some runs on the dyno with an SP1 with closed left can and the link pipe closed.
Rød/Red      1. run bike with your airbox and Akrapovic
Blå/Blue       2. run with can closed
Grøn/Green  3. linkpipe sealed completely
It seems that it need the can as an extra chamber of some sort. We have a theory that the collector are to little and the link pipe to short if it's going to work with only one muffler.
I hope you can use this for something.
best regards
Steen/ Denmark
SS motorcykler

 .....................worth to think a while about it !!

sweep_sp1.jpg (59617 Byte)

Close the can.......,Close the Can,ta-simply close it.........................................

Just a thought:it should be possible to reach a without Fuel and road-rideable RC51 weight of 155kg (345lbs),precondition hardcore measurements.I think you're able to find  another (based on my own RC51) 4-5kg kg at the Engine  (incl. removing all quietening gears),somewhat 1.5 -2 kg by Alloy screws and Titan-Axles and bolts,1.5kg by going for 2 in 1,maybe 1kg by verylight rearbrake assy,3kg by a light cpl.front-end,0.8kg by a hardcore thin Carbon-fairing + Tailsection.If i calculate my Bike raw without Fuel at 169kg (373 lbs) and add the mentioned above weight savings up to 12.55 kg  i'd end at 156.5 kg (345.36 lbs). Also raw calculated costs for these 12.55 kg:   10000 USD,i think it's worth to do that,i.E if you compare lap times of 125 cc (GP) 49hp- 70kg with 600cc (Supersport) maybe 129hp - 160kg ,125cc are bit faster or at least similar.The max. Hp use (incl. all of your worthful power-increase mods) is maybe 5% at track,the use of weight (- loose) all the Time.

Ho-forgot: is anyone intersted in my PCII-III Map ?I got a call yesterday,and the customer told me,that he tested all the different Maps,and my one had best results of all,made for Airbox and Acra,simple for you,E-mail me at: info@durbahn.de 

I know,it gets confusing........

Sth. personal :some of the pages listed in directory i probably havn't reviewed for a year.At present it's impossible for me to check if the content is still topical,consider,at present incl. the thumbs there are 869 Pictures distributed among all pages! .I estimate i'll find the necessary Time to restructure this Web somewhat autumn,since then: if you cannot find an inf.-contact me !



Of no real concern maybe,but received the adjustable Fuelpressure valve and mounted it,an advantage yet-prolonged the adjuster with a rod so it's going through my fueltank dummy with a small adjuster outside to in-or decrease the Fuelpressure valve during succesive dynoruns,or riding-we'll see.

Not really News but maybe of some interest for all who wanted to see a before/after dynorun compared with only slip-ons and then equipped Airbox,well,it's of course an ad in own matters.Mike from USA made these runs:


............another no compromise-Item soon available (I'm still working on the draft),not as dramatically as the cable clutch,but a very necessary Item I guess.There are estimated a lot of similar Products on Market,and I don't know,if these Bits are already available same shape as I intend to turn and mill it. It's: I've got no Time to search the Internet therefore and want to get sure the availability and delivery soon.

14.Jan.:here a new added Pic of the below mentioned Manifold mod   Injection manifold mod.jpg (88193 Byte)
also:guess tomorrow i pick up the anodized steamgun-machine Parts,so maybe end of this Week i'm able to provide you with Pics of the assembled one !

Here the Comparison of RC51 vs. SP2 throttle -Bodys:       Throttle Body-comparison RC51vs.SP2.jpg (72071 Byte)

08.Jan.:well ,some of you may know the torque an Hp comparison diagrams of RC51 and SP2.when had a closer look at these diagrams i realized,that the torque weakness from 5000-7200 Rpm of SP2 is not to justify by 3 or 4 HP more-my opinion.Seems the middle of 3 mm more throttle diameter mod (as done at Lloyd cooper Motorcycles),will give best compromise.

If you don't want to search for these diagrams,i will post the next days here. 

HERETHEYARE:built your own opinion-the dip at the beginning is the typical 5000 rpm-dip   744.jpg (44253 Byte)

03.Jan.:what i've typed conc. my Note of 13.Dec-looks like i found someone , who's able to realize my Steamgun-project faster than i expected. I calculate to present this strange Item end of next week.Well,as i've said,not a Revolution,but of interest anyway.

21.Dec:Indeed-with ref's what i've mentioned below-you get best Powercurve with the Acra on the dyno if you re-weld the 2in1in2 Section for only one right Header.I've been told you should use 52mm diameter headers to duct  all further  into one can.I'm after it to provide you with comparison-diagrams.

.....a btw. Q: Hi-Beam you've got at the very front end-why is the Relais therefor at the very rear end  ?

18.Dec:my wire guy is a bit out of order and didn't found the Time to proceed with the wire-mod.So i took the next std.wireloom and made this Job with a new one on my own.Sth. i remarked:don't confuse the green/purple wires of grey and black connector from  ECU-they've different Job's. And put the green/white + the green/red wire of ECU on Ground (to get rid of side-stand switch and clutch-switch).Also get rid of of Bank angle sensor and use the Fuelcut-Relais as main-Ralais for Power supply-therefor put the red/orange wire also on ground.
More Hints:Wireloom-mod 2

13.Dec.,sat in front of my Laptop in my workshop,a few milled different bits from the early years idea's on the table,thought-this you should attempt today,sth.i wanted to do for a year now .A calculator ,some calculations,some raw drafts ,milled Parts combined with hammered and sawed components,a dremel gave up,some milling-pen's broke-but finished it this day ,and: it works  !A Strange Item,looks like a part of a steam engine,11/2"  x   21/2"  .Today the fine-work,i'll try to shrivel it up for less dimension,and perhaps i get some more possibilities out of it.The end-drafts will take a whole day -the milling then probably 5 months,well,you're curios ? It's not a really great or brilliant thing,but an eye-catcher.

Ta,also in Work:started with leftright same shape Carbon-brake and shiftlevers for rearsets-if i get the Material i need to do the pressure.moulds-you can see the result already this year !


Left Frame:cpl.RC51 Bodywork-Pics



 I, (better:Stephen) began to mod the 2nd RC51 wire-harness,i made a bunch of Pics with details , where you've to pay attention doing this Job-could be a guideline for you.Cpl.finished it's ~ end of Dec.Next days i'll provide you with the Pics i've made.Below:thats the Situation now.Enlarge Pic and go for Wire harness-mod2

A Note,07.Dec.:it seems i won't find the Time until April-May to finish my upper Durbahn  fairing-even 90 % of the work is done -the lower section already IS done.I'm convinced the optic of my cpl.Bodywork will be more than exciting,but additional (it's somehow my very personal Project) i've got a lot of technical idea's and Solutions  i want to solve and fab before.I.E i've got a twin Alternator Idea with seperate wiring, which is even lighter than my light Alternator Solution now-and all this combined with a dry-Clutch i want to use from AP-racing (that's a F3 140mm Racing Car Clutch 1.8 kg,guess i've to fab a new clutch gear then if it'll be impossible to mod the std.one -but i'll fix it,because i have to fix it-regardless time and money).Then HRC ,Omega,or pistal-Pistons,Ti-connecting rods combined with Alloy milled adjusters to fix the Engine,next - i've to develope pressure-moulds to built Carbon Brake and shift-levers (already prepared for Quickshifter) maybe also a rear-brake assy with a carbon Bracket...........  .

I'll give you an idea of how it could look :my RC30 centre-view:SitemapQ5.jpg (89888 Byte)

NEWS I :only a (whatwasit?) short step for me-but nice bolt on Solution-a (i hope) 0.05 lbs (it's actually: 0.048!)Carbon -Bracket will be finished today-then i'll provide you with Pics of the cpl.Snorkel assy !Please read my Notes reg. the Snorkel. That's it,a bunch of Pics i made of the Evolution-Snorkel-click pic to go for latest Intake-News : Evolution-Ram-Air-Snorkel_righttopQ6jpg.jpg (80869 Byte)

NEWS III: Famous Joe (hi Joe!) from Germany  promised me to mod the fuelpressure-regulator adjustable !,so as i guess you've all read it in the HRC -Manual:with an increased Fuelpressure (392 kPa,as far as i remember it,stock is 330kPa ),you've to keep your std.Fuelpump-seems it's already prepared or built for more  pressure-that's what i wanted all the Time-i prolong the adjust-screw with a rod-bore a small hole in my -no Fuel -Tank- dummy and can make the dynoruns each 1/2 turn wise to see what happens .And btw.you extend the adjustment -possibilities  of a PCII into + and -

P1010009 Kopie.jpg (50716 Byte)

NEWS IV-i simply forgot,but there was sth...........it wasn't this,but it's worth to post it anyway and maybe ask you,reg. Pistons:i guess meanwhile there are some more-compression Pistons on Market (apart HRC),so i'd like to go for Italian (Pistan-racing) Pistons-if someone  got some experience with them,please contact me.

So yet this Work is done i started yesterday with my full Projects wire loom mod,began again at 0,but i've made Pics of each bracket you've to create for the Electronics,it'll be a good guideline for you also not to waste time and not to rack one's brains over where to deposit all that stuff.But somehow it's still a drudgery.CLICK on Carbon-Battery Bracket Pic below

Ha-aaaannnnnd :i'll make a mould for a Carbon -below-Oilfilter-Battery-Bracket today,where you also have the Opportunities to locate your starter-relais ! That'll be a nice detail bolt-on Solution !    Hey........first is done:0.07843 lbs,incl Bracket for Starter-Relais-a word?Anyway,pics  2.11.Tested the bracket with my,std. and Acra-Headers:fits all.     Battery-bracket2.JPG (71929 Byte)