SO wirds gemacht leute!

The machine shop wizard, mossbergs.se, has done his thing!

[Blockierte Grafik: https://lh3.googleusercontent.com/-9YNyIE0Bf80/UwEqxD6wmgI/AAAAAAAAAkc/zovfUyYfM_M/w878-h494-no/Ramsidor.jpg]

Original von Flo
hey mats!

now i found some time to watch all your new vids! thanks alot again - very interesting (and sometimes funny) stuff !

to part 5:
- you put in a longer conrod. does this help against the cracking crankcases? you mentioned there would be less acceleration in the top/low end of the crank - could you please explain this a bit more detailed?
it sounds like this would be a proper way to improve the reliability of the old bergs !

to part 6:
- its not enough to build an engine and a frame alone. you increase the level even further - a welded tube with thread-inlay instead of a milled aluminium cyclinder oO ! great

please keep us up to date .
cheers
flo

Thanks for the kind words, Flo!
With a taller conrod, the piston will remain "still" at TDC and BDC for a couple more degrees at the crank, compared to a shorter conrod. This means that with a given crank speed, the piston will decelerate/accelerate a bit smoother at TDC/BDC. Does this explanation make sense to you? If this will have a positive impact on the stress on mains and crankcase, remains to be seen. My main objective is to reduce the contact force between piston and sleeve.

We have made some analyses on the OEM crank shaft, to see if an even larger big end pin would reduce the bending of the crank (which seems to be the culprit in reducing the life span of the mains). Reasonably larger pin (say up to 40mm) will not give the expected advantage. What would have a positive impact is thicker crank cheeks (keeping better control of the pin) and/or less distance between the mains (appr. 12-15mm could be reduced if the counterbalance wasn't there...). A much tougher mtrl in the crank (higher E-modulus) would also do the trick, but that's another project!

Well... high material quality is used according to each application! Alu for some parts and steel for others!

..mit längerem pleuel bei gleichem hub sinkt die max. kolbenbeschleunigung und die seitenkräfte am kolbenhemd ..beides erhöht die lebensdauer in nicht unerheblichem mass..

Hm. Difficult to explain with only words... With a shorter conrod the linear acceleration to the piston, will be higher due to the "gear ratio". Imagine a REALLY short conrod (length close to the stroke). When the crank pin comes up at some 70-80 deg BTDC, the rod will be almost perpendicular to the linear axis of the cylinder bore. When the crank pin approaches TDC the gearing will cause the piston to accelerate very fast up to TDC, causing a corresponding high retardation. Now imagine a VERY tall conrod (say 1 meter). When the crank pin is at 70-80 BTDC the rod will be almost parallel to the linear axis of the cylinder bore. This will not add any acceleration to the piston besides the actual movement in the direction upwards. Does that make sense?

Here is my new swing arm under development:

youtube.com/watch?v=S1pYBqAfhWI

Bending 2" CrMo-tubes turned out to be a real challenge...

Original von MiKe2F4u
Amazing work and a great project!

Looking forward to a video of the test drive

Me too!
Until it is completed, another build video will have to do:

youtube.com/watch?v=zQ4PVVQtKfM

Now the CrMo-parts are back from powder coating.

[Blockierte Grafik: https://dl.dropboxusercontent.com/u/5862751/Ram%20efter%20pulverlack.jpg]

..very nice ..but the season is allready running..

Great job, mate

Great job, seriously admiring your work

Thank you for the kind words! It´s getting closer now:

[Blockierte Grafik: https://dl.dropboxusercontent.com/u/5862751/20140530_184306.jpg]

Next week testdrive videos?
I hope that you will gain some improvements compaired to the Honda frame. It looks like a ton of work.

Original von Flo
hey mats!

would you tell us the weight of your self-made frame? is it heavier or lighter than the one of aluminium?
it's amazing that you build your frame around your engine !

please keep us up to date

cheers
flo

Thanks Flo!
I haven't been able to measure the weight in exact comparison yet. The swing arm is a bit heavier and the front end a bit lighter, so I guess they will be similar in weight. I will check once the bike is complete again!

Sorry, still no test video: Husaberg 650 DOHC - part 10

Here is the headpacker that goes with the taller conrod. I have machined a new cylinder sleeve, so next weekend is engine assembly!

[Blockierte Grafik: https://dl.dropboxusercontent.com/u/5862751/2014-06-19%2017.46.07.jpg]

Erste proberfahrt morgens!

Husaberg DRC680 video