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Long story short after YFZ piston and conrod installation I was satisfied with the level of vibration for the first time. But after all I decided to reassemble the engine with the intention to balance the crank+piston the same way as YZF done. So I found YZF parts to measure original balance factor and then it was a lot of grinding and polishing. Now I am absolutely
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happy with the result!
 

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I am thinking about swingarm shortening. Actually I have not complaints about swingarm lenth but the friend of mine has TIG welding machine. So I have TIG welding for free of for beer (that is much better!). I feel it is time to buy a dozen of cutting discs for aluminium! Today. Photo tomorrow...
 

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I am thinking about swingarm shortening. Actually I have not complaints about swingarm lenth but the friend of mine has TIG welding machine. So I have TIG welding for free of for beer (that is much better!). I feel it is time to buy a dozen of cutting discs for aluminium! Today. Photo tomorrow...
Here u can find the way how i did it. Maybe it helps.
Chasing after tenths of second, DIY swing-arm shortening of CRF450R 2017+

 

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Thanks a lot for advice! So inspired by your success and with the help of my TIG welder who had a lot of free time today...and beer...
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just look at the result! Swingarm is 40 mm shorter now. Shock is the next.
 

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So today it was the day of measuring, grinding, cleaning and changing of worn bearings of shortened swingarm. After all I have established that 40 mm of shortening is overkill. 25-30 mm will be perfect. I can move the wheel only halfway forward and then the tire meet the front/right part of swingarm. Despite I have cut off the part of right leg and welded it inside. But nevertheless I am satisfied!

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Rear shock has 495 mm original length. I know reduction is approximately 1/3 so I need 20 mm shortening on shock rod to have 60 mm rear end lowering. I collected all spacers I have in workshop plus one DIY Al.
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Rear shock spring rate is 6.0 like RaceTech calculator says siutable for my weight, age and abilities. Front springs are 0.52. The most stiff I was able to find.
 

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So now it has such funny shape! The bike is very short and low. Rear fender was too long I had to shorten it too. It reminds me my first foreign motorcycle - Simson S51 but much more powerfull despite almost equal size.
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Perfect! It vibes less then original engine. Returning to the engine - some offtopic words about bigbore kits. I'd like to say that in my opinion it's not right way just to throw bigger piston in. My experience says such engine will have more punch but less overrev. To have the best possible result you need to balance it to OEM specs. So it is necessary to calculate OEM balance factor using stock parts and then to make some work to achieve the same numbers with bigbore kit. But actually if you posess the technik of balancing you can use almost any appropriate conrods and pistons to change engine displacement. And needless to say many aftermarket pistons and conrods have less or more weight then OEM and have to be balanced too.
What's about my project it's finished except new graphics but I have to make some extra money for this. I haven't trying it yet it's rainy all the time. Hope in the nearest time it would be possible to ride and make report about. Cheers!
 

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Hi! I was affraid of the bike will be unstable at speed, but thanks to Scotts stabilizer I feel nothing bad. I have short walkaround video but the language is Russian so sorry you switch off the sound. I need new backgrounds and after all bugs elimination I'll try to make new photos and English version video.

 
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