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120 st

Mojo

Mojo

Administrator
Dec 6, 2013
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So Spazz, Give us an overview of what exactly is done to make an engine a 120 ST or R.
Inquiring minds want to know. :)
 
• 4.060 big-bore cylinders
• 4 5/8-inch stroke SE Pro stroker flywheel and rod assembly
• 10.5:1 high-compression nickel-plated forged pistons with Teflon® coated skirt
• Titanium SST piston rings
• SE-259E high-lift cams
• Perfect Fit push rods
• SE high-performance lifters
• CNC-ported MVA heads with automatic compression release
• SE Pro High-Flow 58mm EFI Throttle Body, high flow injectors and manifold clamps
• Machined lower rocker boxes for valve spring collar clearance
• Factory-machined engine cases
• Unique piston oilers for stroker clearance
• SE inner crankcase full complement cam needle bearings
• SE Lefty high-performance crankcase output bearing and nitride bearing race
• SE Performance spark plugs
• 120ST cam cover and cylinder head medallions
 
Thanks Gunner....

HIGHLIGHTED are the differences between the 120ST and 120R:

120R Specs

4.060" big-bore cylinders.
4-5/8" stroke Se Pro Stroker Flywheel and rod Assembly.
10.5:1 high-compression nickel-plated forged pistons with teflon coated skirts.
Titanium SSt piston rings.
Se-266e high-lift cams.
Perfect Fit push rods +.030.
Se high-performance lifters.
CNC-ported MVA heads with ACR (19206-12 and 19220-12 only).
Machined lower rocker boxes for valve spring collar clearance.
Factory-machined engine cases.
Unique piston oilers for stroker clearances.
Screamin Eagle inner crankcase cam needle bearings
Lefty high-performance crankcase output bearing.
Se Performance Spark Plugs.
120r cam cover and head medallions. • High Volume Oil Pump.
Billet Cam Plate.

So to make my 120ST into an R.... cams, pushrods and cam plate.... this can pull up to 140HP and 135TQ with the right exhaust and perfect tune.


The 120R DOES NOT come with the 58mm throttlebody... it must be purchased separately


I am changing back over from SE plugs... too many issues with them.

Also changing back from synthetic to conventional.... just as I did with my SGS
 
I test rode a 120st last week in a SG. That thing was a monster out of the hole. I could see rear tires being an issue If it was mine.
 
How's the vibration when cruising 55-85 mph as compared to the 103? Mirrors still clear? Foot-boards vibrating? Handlebar grips buzzing?
 
hulkss said:
How's the vibration when cruising 55-85 mph as compared to the 103? Mirrors still clear? Foot-boards vibrating? Handlebar grips buzzing?
Click to expand...

vibrations are minimal and mirrors are fine... the only REAL difference is when idling and when you rip on the throttle....

GreetSlide808 said:
Spazz, why are you changing back to conventional oil from synthetic?
Click to expand...

Same reason I did on my SGS... I can't stand hearing every moving component in the engine.
 
So did you already change back to conventional on the RG? And if so did it quiet down considerably?
 
Baggerjay said:
So did you already change back to conventional on the RG? And if so did it quiet down considerably?
Click to expand...

1K service next Sunday... You heard it last week ... so you know what I am talking about. It may very well be the nature of the beast, but I gotta try something. I had my guy listen to it, and he said it may be normal, but to keep an eye on things and he will look into it at the 1K. He recommended adjustable pushrods instead of the 'perfect fit' style. IF I go that route, I may dive into a little more.... who knows.... lol!
 
Yeah I think you are gonna have to change the cams to quiet it down cuz it sounds just like mine does. And I have the adjustable push rods curious on the oil though I would change back to conventional as well if it makes it quieter.
 
Baggerjay said:
Yeah I think you are gonna have to change the cams to quiet it down cuz it sounds just like mine does. And I have the adjustable push rods curious on the oil though I would change back to conventional as well if it makes it quieter.
Click to expand...
I will let you know...

Btw... heading over the hill to Roseville.in a few... wanna do lunch? Shoot me a text Brother...

Gotta get my miles in for the 1k...lol!

Sent from Note4
 
Good ride today... met up with Baggerjay for lunch... good times as usual. Tore up Roseville a bit... he got me off the line... I hit my Rev limiter twice before I caught him... lol... can't wait for a tune. Jay's scoot is a built beast for those who don't know

Sent from Note4
 
Spazz said:
1K service next Sunday... You heard it last week ... so you know what I am talking about. It may very well be the nature of the beast, but I gotta try something. I had my guy listen to it, and he said it may be normal, but to keep an eye on things and he will look into it at the 1K. He recommended adjustable pushrods instead of the 'perfect fit' style. IF I go that route, I may dive into a little more.... who knows.... lol!
Click to expand...
This has me thinking.....Why in the world do they put synthetic in there during the break-in period?? Any time I've built an air cooled engine I always run mineral (non-detergent if possible) during the break-in period......I have always wondered how you can really seat the rings with synthetic.....sorry to get off-track but Hmmmm:confused:
 
Oh come on it's just a little 103 lol that was the true definition of there's no replacement for displacement. Until I get a little more work done I think you will always pull ahead at about 90-95 I just can't compete with the extra inches. But I will surely try brother
 
Baggerjay said:
Oh come on it's just a little 103 lol that was the true definition of there's no replacement for displacement. Until I get a little more work done I think you will always pull ahead at about 90-95 I just can't compete with the extra inches. But I will surely try brother
Click to expand...

LOL!!!

I NEED A TUNER!!!!

I am soooo used to revving out to 6300 that I kept falling on my face at 5800rpms.... not once, BUT TWICE~~~~ lol!!! It was fun... definitely gotta get more ride time in next time.....

Thanks for lunch Brother....
 
No doubt on the more riding next time and for the record that bike runs great for just off the shelf once you get it tuned I don't know if I will be able to get you anymore. I would bet I will spend all my time chasing you or hoping you miss a shift so I can blow by ya lol but I am glad ya came to town today and we got a little drag race time. And for now I get ya up to about 95 so I guess I have to pick the roads a little better lol
 
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