Few questions before finishing a rebuild



4 replies to this topic
  • Maks Tutan

Posted January 05, 2016 - 12:50 AM

#1

It is my first time rebuilding a dirtbike engine.

 

I bought a 2004 YZ450F for $250.

Top end was beaten and connecting rod was bent.

 

I bought all the parts I needed and almost finished rebuilding.

 

But before trying to kick it to start, I am considering a few inspections.

 

Seller of the bike mentioned that the oil supply was suspesious, because engine was hotter than before.

 

So my concerns to check are:

- oil delivery lines,

- coolant flowing lines,

- breathing, exhaust and draining vents.

 

Checking oil and coolant supply or flow directories or lines is prior.

 

Please let me know some ideas and share your thoughts when you first start your bikes after full rebuild.



  • T-Bone 426

Posted January 05, 2016 - 02:44 AM

#2

On my 02 426 i would crack the oil supply line to the head after every oil change, i was told once that they were prone to losing prime. Once it starts oil should weep out after a few seconds.

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  • grayracer513

Posted January 05, 2016 - 07:15 AM

#3

 i was told once that they were prone to losing prime. 

 

 

They aren't.

 

If the PO said he was suspicious of the oiling system, you should critically examine the oil pumps. There are two, an inner (return) and an outer (feed) that are driven by the same shaft. Look especially closely at the pin that drives the inner pump and replace it if it's even slightly damaged or worn.  

 

BTW, the oiling system will not make the engine run hotter.



  • Maks Tutan

Posted January 05, 2016 - 05:29 PM

#4

They aren't.

 

If the PO said he was suspicious of the oiling system, you should critically examine the oil pumps. There are two, an inner (return) and an outer (feed) that are driven by the same shaft. Look especially closely at the pin that drives the inner pump and replace it if it's even slightly damaged or worn.  

 

BTW, the oiling system will not make the engine run hotter.

Thanks,

 

I checked the pumps by rotating the shaft. it was rotating freely. Now it is quiet impossible to double check the inner pump since I assembled main cases. wish me luck, hehe.

 

and BTW, PO said that it was hotter.  :thumbsup: 

 

How about cooling system?



  • grayracer513

Posted January 05, 2016 - 07:26 PM

#5

Thanks,

 

I checked the pumps by rotating the shaft. it was rotating freely. Now it is quiet impossible to double check the inner pump since I assembled main cases. wish me luck, hehe.

 

and BTW, PO said that it was hotter.  :thumbsup:

 

How about cooling system?

 

You can run water through the radiators to see if they flow freely.  Otherwise, just make sure everything is hooked up and working when you build it.  There isn't very much to it.







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