from another thread:
Mec, what are you up to now??!! It's been kinda boring around here without your amazing projects!
hi fellows,
2013 i had much fun working on my lightweight rotax.
from memory we had 5 weekends on the racetrack, 2times pannoniaring, 1 slovakiaring, 1 rijeka and 1 weekend euroring near budapest.
conclusio: its fun to battle against heavier bikes, especially when we do have some power advantage too
. but there is one or the other 500er yamaha SR with equal power, if not more
problems that had to be sorted out:
engine vibrations are bad, but it did not do any harm to the frame nor swingarm nor anything else. our next engine will get improved and stronger engine cases, higher CR and racing cam as well as a balanced crankshaft and counterbalancer shaft.
in the beginning of 2013 we had to do the normal setup procedure for the wheel suspension (stiffer front fork oil, more spring preload in the rear). after this changes the bike run well and everybody riding the bike was happy cause of its cornering ability.
luckily we always had the possibility to do conversion testruns between my rotax and the race rotax of my friend robert. his bike was much more conservative and oldfashioned in its chassis design and numbers. it had advantages on the straight but was not as willing to cornering than my radical racer.
we noticed one point more: on the one hand my rotax was easy to steer through turns, on the other hand there seems to be a limit and the bike seemed to be over this limit. the slightest amount of input on the handlebars and you are doing a 90° turn (exaggerated). not easy to find an exact and shortest way through turns. i believe that this setup is ideal for 1st gear turns but does have disadvantages for everything else faster. thats why i changed the chassis setup to 67° rake and corresponding more trail 4 weeks ago. see pics.
for my racer friend robert i ordered one set stronger rear springs, cause he does have 15kg more than me. hoping the stronger springs will arrive in time (2014?
).
summer 2013 we did some test runs with our new ignitech ignition. advantage full programmable, disadvantage we shot 3 black boxes without knowing why. first we thought that my dyno is killing the boxes, but end of the year it was clear that ignitech had a batch with boxes killing itself when setup according to some specific parameters. in our new engine we will give ignitech another try.
the first cold days in autumn and i fell into a deep depression cause i did not know what to do in winter. thats why i bought a bunch of krimskrams: it was a disassembled aprilia pegaso (with rotax SOHC 4V engine, the same as in my racer), a complete spare engine, a stronger CCM engine case and a watercooled DOHC cylinder head for this engine. i remember, with this setup the fast guys raced their UNO-rotax (
https://www.google.at/search?q=uno+rotax&source=lnms&tbm=isch&sa=X&ei=NyqfUu3wB8yX7QaB2oCoDw&ved=0CAcQ_AUoAQ&biw=1680&bih=818) with up to 90HP. not bad for their 115kg bikes.
my plan is to build such a DOHC engine, hoping for nearly 70 reliable HPs. but that means that i have to build a new bike, frame, swingarm, tank.....as i did before.
ah, forgotten: my rotax suffers from a broken in-valve spring. a failure pretty new to a modest modified rotax race engine. at the moment the engine has ~54rwHP, 59NM, bike 99,5kg.
first thing to do:
# repair and complete build up of the engine used in my racer.
# buildup of the dohc engine
# bike build
# learning welding and doing brace welds (see pic: my very first brace weld)
# playing with my grandsons
funny clip:
https://www.facebook.com/photo.php?v=567671399955283&l=7218998806970773867mec
