SV650 motor rebuild

[Champ]

Well I bought my bike with a blown motor. Put in a motor I bought on ebay, and put the blown motor in the garage and forgot about it for 2 years. Decided it's finally time to build it back up and have a spare.

Thread of that here:
Race Bike


Last year I bought an "engine in a box" from someone with the intentions of using those parts to rebuild this motor. It was complete-ish minus a crank. Not sure what the story is on it. I was hoping it would have stock pistons for me to put in, but with some good luck it has stock bore (81mm) JE forged pistons. Yay!

Last weekend with some help from a couple friends I got the whole thing torn down.




This is the rod that was on the blown up piston. It looks like the picture is bad, but the rod is really that dark from getting so hot.



Old JE, these were 2mm overbore @ 83mm.


Transmission:


Blowed up piston:




Next on the docket is to figure out what size bearings I need, and probably send off the crank for inspection/polishing.

[ShowCar]

Not buildy enough.

[Champ]

Not buildy enough.

Yes unfortunately I am going to have to "bought" new gaskets and bearings, as I can't build them myself.

This build will be very little about cosmetic stance, and very much about engine mods.

[Champ]

Well Kyle from 2K motorsports came over last night to asses what I've gotten myself into.

This is definitely going to be a frankenstein motor, mix and match from 2!

He is going to start ordering parts - cam chains, bearings, new shift drum, shift fork, gaskets, etc.

I am calling today to a guy who will hone and measure my cylinder walls to make sure the pistons I have will work.

Should be underway before x-mas...

[JK9K]

Vroom vroom!

[travis325i]

How much power are you shooting for? Or are you just going to see where it lands and be happy with it?

[Champ]

How much power are you shooting for? Or are you just going to see where it lands and be happy with it?

Well my 2 stock 1st gen motors are right around 67hp. A stock 2nd get motor is probably 3-5 more than that, low 70's.

This motor is going to have stock bore pistons, but they have a little more compression (higher dome) so combine that with degreeable cams and I would imagine low 70's. Not going to be very high but it should be SUPER smooth (it has a balanced crank) and SUPER reliable.

[travis325i]

Will that put you in a different class for racing?

[Champ]

There are 3 "lightweight" classes which this bike runs - super sport (SS), super bike (SB) and Grand Prix (GP).

SS is pretty much stock everything - so the pistons and cams would take me out of it. That's not to say people don't still run SS with mods like this. This motor will probably be "on par" with a fresh SS motor in a newer bike, so it's not like there will be a glaring advantage.

SB and GP are pretty much anything goes. A proper SB motor build for a bike like this is 80-90hp. Over 80hp your motor longevity goes down quite considerably.

[Champ]

Long overdue for an update.

The cylinders I had were too corroded to use the stock bore pistons I wanted to use (JE forged). They would have needed .5mm overbore to get to clean cylinder walls.

So I bought new (used) cylinders from a guy who bundled them up, I got 4 (2 sets) pistons / cylinders / heads for cheap. 1 of the sets was overbore +3mm, so 84mm (stock bore = 81mm).

I took the stock sized cylinders and had them honed so the JE fits - as the forged pistons need a little extra clearance than the stock pistons.

Here is my mass of parts:



The transmission I am going to use had some mild corrosion on it from sitting, so I took it apart and soaked it overnight in a de-ruster and then dunked it all in oil, it is shiny clean now!




Here is my list of yet to do's:
1: Clean up the cases
2: Choose a set of heads, clean them up. Then dismantle them to replace valve springs and check they are good. If not good then choose another set of heads
3: Get the cases to Kyle's (2k motorsports) shop so he can press in the new end bearings + transmission roller bearings
4: Start assembling!

[mattdesmond]

Looks like good progress. Better rock out, Spring's here. :-)

[Champ]

Gotta get it done soon - first ride date is May 12th. Be nice to have it dyno'd at that point.

[Aladinsane07]

Out of curiosity, what kind of de-ruster did you soak it in?

[Champ]

Out of curiosity, what kind of de-ruster did you soak it in?

I'll look when I get home, but it worked really well (I was skeptical) and is somewhat reusable as you can pour it back in the jug.

[Champ]

Out of curiosity, what kind of de-ruster did you soak it in?

Evapo-rust

http://www.evaporust.com/evaporust.h...FQIBQAodeGcmzQ