Author Topic: DIY Egli Sohc 4  (Read 135494 times)

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Offline turboguzzi

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Re: DIY Egli Sohc 4
« Reply #400 on: June 10, 2013, 09:03:30 am »
http://rotax.net/index.php?main_page=product_info&cPath=7_95&products_id=255

ron wood would have sold you one ready, but i guess that yours was cheaper

good source for other parts .... but coming to think about it, you are in Austria, maybe not far from the factory ::)

guess you can find rotax parts for free on the street :)

Offline mec

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Re: DIY Egli Sohc 4
« Reply #401 on: December 04, 2013, 06:46:18 am »
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=7218998806970773867

mec
Honda Monkey
Takeuchi TB 070
Massey Ferguson

Offline rickman cr750

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Re: DIY Egli Sohc 4
« Reply #402 on: December 04, 2013, 07:52:45 am »
Hi Mec,

nice to notice you are trying to prepare for next season.
It was very impressive how your HARO worked! Really enjoyed test riding at Slovakiaring, even if I was too lightweight for the setup.

I hope you dont want to race the watercooled head at GTF, ´cause it will not be allowed! I already asked for permission. No chance!

By the way, I suceeded in buying one of those 95HP twincam UNOs from Portugal (piston stuck, frame No. 4).
If you need some pics, just tell me!


Best Regards, Klaus

P.S. If you´re ever welding an new exhaust, please give me a call!
« Last Edit: December 04, 2013, 08:07:12 am by rickman cr750 »
Rickman CR750 1975
BMW R5 1936
XT500 1979
SR500 Racer
UNO-Rotax Airhead Frame No. 1
UNO-Rotax Twincam Frame No. 4
UNO-SR500 Frame No. 1

Offline 754

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Re: DIY Egli Sohc 4
« Reply #403 on: December 04, 2013, 08:12:23 am »
Mmmmm ASTRALlites..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline mec

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Re: DIY Egli Sohc 4
« Reply #404 on: December 04, 2013, 11:18:40 am »
Hi Mec,

nice to notice you are trying to prepare for next season.
It was very impressive how your HARO worked! Really enjoyed test riding at Slovakiaring, even if I was too lightweight for the setup.

I hope you dont want to race the watercooled head at GTF, ´cause it will not be allowed! I already asked for permission. No chance!

By the way, I suceeded in buying one of those 95HP twincam UNOs from Portugal (piston stuck, frame No. 4).
If you need some pics, just tell me!


Best Regards, Klaus

P.S. If you´re ever welding an new exhaust, please give me a call!

hi klaus,

nice to hear from you. PM sent.

mec
Honda Monkey
Takeuchi TB 070
Massey Ferguson

Offline turboguzzi

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Re: DIY Egli Sohc 4
« Reply #405 on: December 13, 2013, 03:27:39 am »
hello mec

nice to hear about all the new developments. would be nice to come to do some GTF rounds as there seem to be a few supermonos running  there, but of course, i first have to finish mine, a few personal issues came up that slowed process... assuming that my TZ/XTZ supermono can be accepted of course

one warning though, the rotax dohc head has been defined by one tuner as a "hand grenade". maybe you should talk to this guy who raced them extensively in the past. just to let you know... http://www.barebones.net/machines.htm  scroll to "water cooled BBM"

Klaus, if your offer is not limited to mec, I could definetely use some help in the exhaust of my TZ/XTZ supermono,

cheers

TG






Offline mec

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Re: DIY Egli Sohc 4
« Reply #406 on: December 13, 2013, 09:44:19 am »
hello mec

nice to hear about all the new developments. would be nice to come to do some GTF rounds as there seem to be a few supermonos running  there, but of course, i first have to finish mine, a few personal issues came up that slowed process... assuming that my TZ/XTZ supermono can be accepted of course

one warning though, the rotax dohc head has been defined by one tuner as a "hand grenade". maybe you should talk to this guy who raced them extensively in the past. just to let you know... http://www.barebones.net/machines.htm  scroll to "water cooled BBM"

Klaus, if your offer is not limited to mec, I could definetely use some help in the exhaust of my TZ/XTZ supermono,

cheers

TG







@ TG:
thx for this link, it was new to me.

from what i know, the weakest point is the rotax engine case developing cracks between the crankshaft and balancer bearings (with max HP and a lot of rpms). we will run moderate numbers therefore.

the GTF series is a pleasant unbureocratic race serie with sympatical and helpfull people. but there are a few rules, unfortunately not good for our watercooled head.
but hopefully there is a chance to do some pratice sessions and test runs nevertheless.

mec
Honda Monkey
Takeuchi TB 070
Massey Ferguson