Top-End Reassembly

A frequently discussed topic...
In my opinion, it always depends on the intended use of the engine/bike: higher valve spring pressures are more justified on a drag bike/race bike than on a pure street bike (especially since the engine of a race bike is disassembled and inspected after the second race anyway), but on a street bike, where a higher mileage without damage is the goal, I wouldn't choose excessively high spring pressures... just my personal opinion and experience. IMHO, most deposits come from worn valve guides, oil seals on shafts, and piston rings/cylinder wear anyway.

But everyone does it the way they want to, according to their own convictions. M-)

I'm after something in-between, and unaware of an other way to achieve it.

Stock just doesn't get it for me anymore, and racing is not in the program either...

😜

And another hotrod guy joins the club...   

sf4t7 wrote:

And another hotrod guy joins the club...   

Never knew what I was missing before Y2K when the Kaw moved in.

So many years...and I'm still trying to figure it out.

🤪


 

 Driven 40 is a dedicated break-in oil with even more ZDDP.  Not sure how much, but a LOT.  It's dedicated for breaking in engines, and avoiding cylinder wall and piston scuffing during early engine life.  

 

 

Ok Ed...

Uncle!
🤓

I always do this with my truck engine...but does anybody here manually pre-fill their filter (filter enclosure) with oil before cranking the engine over with the starter?

Normally I rely on the pump to push oil through, but am debating whether a different approach may be advantageous for a fresh build.

🤔

 

Pure theory: fill the filter with oil.  Reality: it's not critical.  

As long as you don’t build “dry” the oil/assembly lube will do the job 

Just lube on assembly, add engine oil and start it.
Additionally you can also crank the engine on the starter with the plugs removed until the oil light goes out before the first start but it isn't really necessary.. 

Wookie58 wrote:

That's an interesting and ingenious way to resolve it - I guess at this point in time they are ornaments unless you want to get into a legal battle with Wiseco so what have you got to lose ?. You might want to check the weight afterwards so you can get them as close to equal as you can
 

Hmmm...

Found a never installed-unused twentyish thirtyish year old Wiseco K1172 piston kit listed on ebay, and now have it in my possession!

Holy cow, man...my initial assertion with Wiseco was that the valve pockets were manufactured too close together...which would not allow the intake valves to clear properly.

Their response was that I must have been running oversize valves (not stock), and there was NOTHING THEY COULD/WOULD DO ABOUT IT, SORRY.

Well...take a look at this:





Huh!   🧐

Note the fourth piston fitted inside the jig in the background.
It's less than .5mm  different from the modified set that I just put back in the engine, and these are essentially brand new!

Clearly the set you installed where the later "enhanced" fitting 

Wookie58 wrote:

Clearly the set you installed were the later "enhanced" fitting 

 

Original installation Dec.19, 2024
with 62mm pocket dimension:


Original pocket distance from edge.  Exhaust shown...intake similar:


Both sides modified equal +/-:


Result:


😵‍💫
Newly acquired pistons:
Exh.


In.


This old piston set is very nice...