Group K 849cc big bore kit

kevbo

kevbo

Location
dfw
Some guys can do that on a stocker. Everyone else needs to spend big $$$ to make it happen.
 
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J

jrddillon

Location
dillon co
jrddillon said:
don't bother, I ride at 8000 feet so spent big $ with harry to try and get it to run like sealevel,was a tuninig problem at first but ok now,but only a afew feet quicker,but no faster than my 2 other stockers,probably because of impeller, so verry dissatisfied, he did lighten flywheel,true or taper bore carbs,stock pipe mods,porting,big bore to 849,I made it very clear that he needs to weld fill the doems and then recut for an extra 50psi but it is only 150psi,now I have a wet and dry pipe to try, I guess the tuning nightmare is about to start again.
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harry might have read this, he called me and is going to send me another head! nice!!!!
 
rollin5150

rollin5150

Location
Idaho
My buddy just had a stock superjet head milled down to increase compression by GroupK. He installed it last night and it is only reading 155psi?? WTF?? We are going to check with a snapon gauge after riding it a bit.
 
tshank123

tshank123

Yo hablo ingles
Location
Vegas
rollin5150 said:
My buddy just had a stock superjet head milled down to increase compression by GroupK. He installed it last night and it is only reading 155psi?? WTF?? We are going to check with a snapon gauge after riding it a bit.
Click to expand...

My friend just had a head milled by Harry, he told him specifically that he wanted 185psi. What did he get? 165psi.
 
hillbilly550

hillbilly550

Rich L
Location
Lewis Center oHIo
I have had nothing but compliments on mine. I like the linear power & outa hole punch. two years with no troubles & (in my ski) and one year with the prev owner no issues. i'll check compression on it tomorrow and let you know what comp its running (snap-on guage). I am used to it now so i ordered a TBM charging FW for it (on backorder GRRRRR). so we will see what that adds to it. I will prob put a wet pipe on it next year but time and funds will tell.

BTW, my big bore also has the 9-17 (i think) prop, TBM pump stuffer with short cone. 80mm pump nozzel. light coupler, exhaust mod, true bored carbs, stock fw lightened, alum bed plate and straight cut ride plate.
 
J

jrddillon

Location
dillon co
jrddillon said:
got new head from harry,200psi at 5200ft,175psi at 8000ft.rick at peakpower sports in denver set me up with 80 pilots and 152.5 mains,1.5 needle@seat,short silver spring to match wet pipe and repitched solas dynafly for high altitude,i will radar next week and post.
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got my goal of sea level speed 49 on radar,but off idle bog and surging throtle responce still sucks bad! who can help?
 
cmeripper26

cmeripper26

Ripper26
Location
Connecticut
If the off idle bog isnt to bad you can turn out your low speed adjusters on your carbs start with a quarter turn out and see if that starts to correct your off idle throttle response.
 
djkorn1

djkorn1

kidkornfilms
Site Supporter
Location
Cleveland Ohio
For freestyle, I recommend flywheel, compression and head. Next, you HAVE to drop weight on the SXR. That made my 800cc Kawi hit like a mofo.

I rode a GroupK big bore and it was all top end. (Harry is more of a race guy. I wouldn't bother with porting or big bore (your allready at 800!!! until you have a wet pipe and flywheel)
 
the WaTeRhAwK

the WaTeRhAwK

fryin' up a/m electrics..
Location
okc
djkorn1 said:
I know 5 people who have had them...4 have cracked and/or blown couplers every other week.

The wetpipe is the way to go for reliability and low end.
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they're breakin' those bastards too. a guy showed up at the shop the other day with a wetpipe that was welded and a makeshift shock absorber bracing it to the motor with a damned 440/550 motor mount...lol
 
Johnny2722

Johnny2722

Location
Bullhead City Az
Only problem I've ever had with the wet pipe was my coupler cracking, easy fix and that was after a year of hard riding. My buddy has the dry pipe on his ski, he hasn't had a ton of problems with it but he's deff. not happy with it
 
MEZZ

MEZZ

"Life is good Green"
Location
clermont, FL
Its not the guage its the shrader valve there are 4 diffrent psi setting shrader valves. white ring and red ring valves are the weakest ones and used for low compression motors like mules and atv's black ring are harder and used on motorcycles or higher comp. engines
 
SXRguyinMA

SXRguyinMA

Life's a beach
Location
Leicester MA
djkorn1 said:
For freestyle, I recommend flywheel, compression and head. Next, you HAVE to drop weight on the SXR. That made my 800cc Kawi hit like a mofo.

I rode a GroupK big bore and it was all top end. (Harry is more of a race guy. I wouldn't bother with porting or big bore (your allready at 800!!! until you have a wet pipe and flywheel)
Click to expand...

stock is only 781cc. if you go 1mm overbore on each it'll bring you to 800cc :Banane13:
 
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