03-14-2011, 01:19 AM #1
in depth SHO motor building discussion
Just seems like none of this info is really out there yet and would make for a good discussion.
To any of you guys who have rebuilt or are running around with built motors what kind of specs are you running?
I think we've already hit on the stock sleeves being pretty bad. Anyone running R&D's or Riva's sleeves yet with any feedback? Also I think I heard somewhere the stock ring gap on our motors is set at round .014. That is crazy tight for a boosted motor IMO. So anyone who has rebuilt set the ring gap much higher at like .018 to .022?
03-14-2011, 02:20 AM #2
*Riva stock comp pistons 86.5mm stock sleeves , Riva carrillo rods.
*Riva head and main bearing bolts (A Must for high RPM/HP motor) Stock bearing bolts dont hold up at all, the crank moves at high RPM and HP twists the motor to the left at high HP and the crank eats out the stock bearing cradle . I know as I have a eatting crank and bearing cradle still waiting to come back from the engine shop.
*Still running stock cams and cam gears (Soon to be change for custom cams from R&D in the next couple of months)
*Full ported race head , over sized valves.
03-14-2011, 03:50 PM #3
Richie, what did you set the ring gap at? Also, how did your stock sleeves look when you had it apart? I'm assuming pretty good if you reassembled without resleeving. But was there any signs of waviness in the bores? If so how much honing did it take to clean it up?
03-14-2011, 05:11 PM #4
A couple of my bores where badly scored. Hence why we went 86.5mm pistons. Even at that there was no need for sleeves in the block. So NO my motor wasnt in a good way. But pushing for high speeds & high RPM will do this to ANY stock motor. The SHO motor has a limit, which some of us have seen earlier then others. But every motor is made differently.
HIGH RPM RATTLES THE MOTOR APART!
* Crank Eaten out
* Bearing cradle Eaten out
* Bores scored
Lucky I had a spare motor sitting at yamaha for my GPR SHO build, which parts where swapped into my new motor. Bad thing is it has put that build back.
03-15-2011, 12:14 PM #5
Good info. So nobody has any more input? Nobody? SHObiz? Jerry? Gunna? Woody? Jim? Any of you other guys doing builds?
03-15-2011, 03:26 PM #6
- Join Date
- Apr 2007
I think high rpm with the wrong oil rattles them apart. I rev my Fz to 9 and no problem yet. Had 65 hours on my FX at 8900 and no problem. I think the amount that the airfuels change when they are heat soaked after stopping and then going again has a major effect on engine life.
Sorry Hitman did not want to high jack the thread
03-15-2011, 05:40 PM #7
Ive been there done that, smashed that! ( And i'm talking about a ski )
Mike , you will be surprised whats happening in the motor. Trust me, Ask Jordan. we still dont have the crank back yet from engine 1. My last setup, the motor was making so much power it was bending to the left. We have now changed engine mounts , shortened the pump shaft and balance the shaft to make it so there is no movement in the bay due to the massvie amount of power we will/are be making.
03-15-2011, 08:57 PM #8
Engine is in the ski. Turbo kit arriving this week.... I hope? And I'll be water testing the following week.
03-15-2011, 10:04 PM #9
Mine is by Jim.
Same here as Jerry with the exception of the Cams (using the gears instead) and I am doing the sleeves while in there.
03-15-2011, 10:07 PM #10
- Join Date
- Oct 2007
- Brisbane, Australia
Yamaha (the Japanese) make these motors very tight compared to the old days of GM V8's etc.
The stock oil pump is suited to within a spec and runs out of pressure very quickly if you vary from the norm. That's why I asked about oil flow blockoff at the intermediate sc gearwheel, when you run a turbo setup (new turbo kit thread).
So using someone who "can do a rebuild for yar cheap mate", compared to someone who REALLY knows their shite about this part of the world (Like RIVA and Gary Watson, etc etc) will make a difference at the topend of the envelop of performance.
Going with the standard clearances for the recipricating parts seems to be a wise choice.
Now remember, I give the motor rebuilding side of things to Gary but there is a lot of information that can be picked up along the way.
Gary, and I'm sure others, have a few things they are trying to the motors. But the results will only show up when things go bang.
Anyway, that's a 2 cent donation from this end.
I also can tell you the 9.5 to one pistons work well but detonation can be within a very close tolerance. Be careful.
PS Flattered that you included me in with those guys but I'm way behind what they can share.
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