Yamaha SRX600 Reborn. Part2.

So I put engine on workbench and began disassembling it in February 2013 . There was nothing worrying at first glance. Camshaft was in good shape, without signs of oil starvation.

SRX600Carbon depositions persisted in liberal amount on the combustion chamber and on the valve surfaces.

SRX600But there were less of them on the piston.

SRX600I got first bad news when removed piston. There were scratch marks on a bush of the connecting rod’s small end.

SRX600The second bad news was the picture I saw when disassembled cylinder had. Carbon depositions looked unordinary, such like backed caramel, glossy and resistant to mechanical and chemical affects.

v SRX600 SRX600I have an idea, that reason for this lies in fuel tank liner. In fact tank was covered from inside twice. First time it was done with poly-something liner long time ago in Japan. Secondly it was recoated with red iron oxide in Ukraine, after SRX was imported, due to  pre-selling maintenance. I think that iron oxide coating could be slowly dissolved by gasoline and then could be baked in intake channels, on valves and other surfaces under heat exposure.

But these difficulties had to be solved anyway. As for scratched bush of connecting rod, after much thoughts and consideration I decided to bought new rod kit and to repair crankshaft with it. The best one I could find on ebay was T.K.R.J connecting rod kit. I received the parcel with it in March 2013.

SRX600Nice kit included all needed parts to renovate crankshaft and it was of high quality.

SRX600 SRX600But before crankshaft could be repaired it needed to be ejected from crankcase. And I got yet another difficulty at this point. I found out that rotor nut was stuck, firstly. I managed to remove it only after heating and using electrical impact wrench. It turned out the rotor itself became another disappointment. It not only needed special puller, but stuck on shaft also.

SRX600So I made the puller with materials I had at hand. These were a huge and thick metal pancake and hardened bolts.

SRX600But it was hard to pull of rotor even with it and impact wrench.

SRX600I saw a reason of this when rotor was pulled. A bit of rotor and shaft stuck together. Nothing to worry about, but the point is, that rotor seating surface needed to be cleaned before assembling.

SRX600Next step was separating halves of crankcase.

SRX600And then crankshaft was pulled out. Engine had about 50K kilometers and laid on table disassembled that was a good reason for crankshaft bearings change. I ordered and got them in April.

Procedure of crankshaft repairing required to use press and some special stuff and skills I hadn’t, so I gave it to expert.

IMG_8084Then was interruption in work for some time. I had to maintain my Zephyr, to do some works with Yamaha XJ Cafe-racer, to undertake traditional May ride to sea and so on and so forth.

To be continued.

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  1. Jefferson

    Hi! You have a nice work on your SRX 600. Great job done!
    I have a question in mind, because I’m planning to rebuild my SRX 400. When you tighten the rotor nut. What is the proper torque? How many foot pound do you use and so with the balancer nut?.
    Have a great day!

    1. gazzz (Post author)

      Hi and thanks!

      The engine of monoshock SRX600/400 (equipped with electrical starter) is pretty same as one on XT-TT600/400. So in questions of torques you may fully rely on their manuals. You can find a plenty of them in the net.

      The torque for rotor nut is 120 Nm (12.0 m·kg, 85 ft·ld)
      Nut (balancer gear): 60 Nm (6.0 m·kg, 43 ft·lb)
      Nut (primary drive gear) : 120 Nm (12.0 m·kg, 85 ft·lb)

      And there is a Japanese language manual for 3SX and 3VN. Useful as source of pictures and specifications.

  2. Bruno

    Hi! What was the reference of the conrod you used? I “heard” that the one for the XT600 doesn’t fit as it’s approx. 2mm wider on the big end….

  3. gazzz (Post author)

    Hi Bruno. At the moment I couldn’t answer your question, since I am far from my workshop. I am from Ukraine. After the Russian invasion in 2022 I volunteered for the army (more than a year ago). War is still raging, and I am still doing my best defending my country. Hope one day I’ll return to my workshop and my projects.

    Kind regards,


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