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DIY engine from scratch, billet cases


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  • 4 weeks later...
  • 4 weeks later...

So we have obvious success with the engine. It exceeded our expectations and shows approximately 90 kg of thrust but this can be brave statement. May be less and we need to fabricate new stand for accurate measuring. The engine needs new pipe and some flying hours to eliminate all bugs. Look for updates I'll make new photos soon.

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  • 2 weeks later...
  • 2 weeks later...

Next step is expansion chamber. Everybody knows to make good power it is necessary to have 1/2-valve design and do not use mild steel. We decided to use temperature resistent stainless steel and  hydroforming process. It was some period of tests and now we have obvious sucess. Wait some days and I'll show you photos.

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So you need matrix and 100000 kg oil pump to make hydroforming pipe. We take two sheets of 0.5 mm steel and weld them carefully together then pump them with oil inside the matrix. This is the photo of the first attempts.

 

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  • 3 weeks later...

Hi! Bad news! The first start of this engine was with the use of our old style exhaust and was absolutely great. But with  new chamber we have lost approximately 1000 RPM of high range. So it is needless to say how difficult now is to make changes to produce new matrix and so on. 

But the aim of this project is to develop the best race engine ever and to win every championship and cup stages we can participate this year in our country so we have to make everything quickly. 

I have video but sorry the language is Russian. You can see the weight of the engine. I'm going to make English version after exhaust repair to show you.

Cheers!

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Hi everybody! So good news! I was trying to check the dimensions of chamber and the decision was that it was too short. We are trying the engine to be the best at 7000 rpms but that pipe was suitable for 12000 rpms. OK! Yesterday some parts were welded additionally and the result is suitable but not perfect. It is very strong on 7800 rpms but not lower.

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OK! Yesterday I was trying to find the solution of the carb issues and have found that it has very simple design. Such carburetors like Walbro are intended for use with not modified engines that have RPMs not higher than 6000 preferable less. They have only two metering systems, one for low RPMs and another for high. But this statement is not correct. It means one for lower and another for higher RPMs. So in reality you can adjust this carb on the middle range  4000-4500 RPMs but it will be lean on 7000 RPMs. Or you can tune it on 7000 RPMs but it will be rich on 4000 RPMs. You know the common motorcycle float type carburetor has needle for mid range and main jet for top range and in many cases accelerator pump. Google says the only solution is to use additional low pressure pump but I don't think so. So solution is to add one more jet for high RPM range.

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