HI, just 2 questions for the experts. 1. I would like to replace the conical single springs with that: Kibblewhite 96-96000 (Valve Spring Kit 460" Lift). Is this the right kit or i should look for something better? 2. A second thought is to change the standard valves (35-30) with oversized, could you give me a part number for a set of Kibblewhite oversized inlet and exhaust (37-32)valves? What valves should i use?
i know that the kibblewhite's are the best option, but i don't know if i'm looking for the right part number (96-96000)
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
Hi Johnnyberg
yes thats it
http://husaberg.org/mechanical/10680-all-about-valve-springs-nice-pics.html
valves as drop ins from kibblewhite are std and 1mm oversize
the intake seats are not big enough to go to 37mm, exhausts are OK for 32
there are bigger available for the polaris predator but they are about 5mm longer
Search Results On Kibblewhite Precision Machining
Spanner made some out of subaru WRX valves http://husaberg.org/mechanical/17935-32mm-exhaust-valve-ordering-info-2.html
if you want drop in oversize valves kibblewhite can make them for a price ... or go through Glen woodman Glenn Woodman GWR Race Engines - Alice Racing or thumperacing ThumperRacing
yes thats it
http://husaberg.org/mechanical/10680-all-about-valve-springs-nice-pics.html
valves as drop ins from kibblewhite are std and 1mm oversize
the intake seats are not big enough to go to 37mm, exhausts are OK for 32
there are bigger available for the polaris predator but they are about 5mm longer
Search Results On Kibblewhite Precision Machining
Spanner made some out of subaru WRX valves http://husaberg.org/mechanical/17935-32mm-exhaust-valve-ordering-info-2.html
if you want drop in oversize valves kibblewhite can make them for a price ... or go through Glen woodman Glenn Woodman GWR Race Engines - Alice Racing or thumperacing ThumperRacing
Thanks bushmechanic, i will get the springs and search for the bigger valves. I guess the polaris are the same except the length. Our valves are 100mm right?
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
no worries Johnyberg
ours are 97mm long
if you go to the 2mm oversize they need to be longer and anywhere between 99 to 100mm is about right .. im not 100% sure but I reckon you could make the 3mm oversize Polaris ones work (38/33) as they need to be longer again and are 102.5mm long, just watch for contact between the upper valve spring seats and the rocker arms .. can grind 2mm out of the rockers no problems at all
kibblewhite also do oversize seats and nice bronze guides
good deal on valve springs
Valve Spring KIT Kibblewhite Precision 96 96000 | eBay
ours are 97mm long
if you go to the 2mm oversize they need to be longer and anywhere between 99 to 100mm is about right .. im not 100% sure but I reckon you could make the 3mm oversize Polaris ones work (38/33) as they need to be longer again and are 102.5mm long, just watch for contact between the upper valve spring seats and the rocker arms .. can grind 2mm out of the rockers no problems at all
kibblewhite also do oversize seats and nice bronze guides
good deal on valve springs
Valve Spring KIT Kibblewhite Precision 96 96000 | eBay
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Today my mechanic suggested to go for a 37mm inlet and 35mm exhaust valves. It will help revving much easier, the piston will be a cp high compression and oversized valves help the motor. He has a point but 35mm exhaust valves??? What do you think?
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
I reckon the exhaust headers are too small for a 35mm valve to make all that much difference
the person who did the most playing with valve sizes is Dr_C
the person who did the most playing with valve sizes is Dr_C
Bluto the 650 engine has plenty of torque at the low-middle rpms but at the higher rpms it lack in revving. I think bigger valves in combination with a high compression piston help the engine revving much easier.
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
mine has 80mm stroke 12.5:1 CR 37/32 valves and a stupid hotcams 3015, it can rev to 10K .. loves to rev
thumperacing stage 4 or 5 RFS cam would be better
thumperacing stage 4 or 5 RFS cam would be better
Joined Nov 2001
17K Posts | 774+
Ely, England
My 37s are gas flow tested and I came up with a shape that flows a lot more air. the tester described their shapre as an 'aberation'!!!
35mm exhausts are so completely wrong that I question whether you should take any advice off your friend. certainly be very careful.
why not go for an ordinary set of DVSK?
just take it easy, go for a nice hop-up. spend good money on getting the head ported and a big carb.
regards
Taffy
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Joined Sep 2007
782 Posts | 291+
???
I ran some back cut valves in my last build, seemed to be getting a lot
of wet flow, by the look of the top of the piston, this time I am leaving the back cut off, may sacrifice a little flow at low lift with the extra turbulence but hope to improve the fueling
Will be running 38 inlets 33 exhausts Ferrea blanks modified by me.
Will post some pictures soon.
of wet flow, by the look of the top of the piston, this time I am leaving the back cut off, may sacrifice a little flow at low lift with the extra turbulence but hope to improve the fueling
Will be running 38 inlets 33 exhausts Ferrea blanks modified by me.
Will post some pictures soon.
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Spanner, i know the best combination is the 37-32, i have already try that and it worked fine. I would like to know if anyone ever tried bigger valves. Please let me know how 38-33 goes. Our bergs love bigger valves! Many thanks to Taffy for his advice!
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
...
I think this was the standard head with some modifications .. valves moved apart and different rockers, then a billet sohc and a dohc
if you look at the valve sizes of most 450 MX bikes or roadbike cylinders at around 100mm diam 37/32 is small, they have bigger throttle bodies than our carbs though.
I think this was the standard head with some modifications .. valves moved apart and different rockers, then a billet sohc and a dohc
if you look at the valve sizes of most 450 MX bikes or roadbike cylinders at around 100mm diam 37/32 is small, they have bigger throttle bodies than our carbs though.
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The head with the bigger valves and dual springs are ready! Now i'm looking for a high compression piston. My first choice is the cp from thumper racing but i was wondering if something else will do the job. The easy way is to use a 450 piston but i think the wossner piston after the ''diet'' in order to make the right cr, wouldn't be that strong. Any suggestions?
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
Joined Jun 2007
4K Posts | 1K+
south east WA Australia
from the specs
piston volume + 0.8cc
.. should be about 13.75 :1 in a 628
there is also the "hicomp" 570 CP piston
Johnny FWIW most of the pistons up to 12.5:1 are about 4mm thick in the centre
piston volume + 0.8cc
.. should be about 13.75 :1 in a 628
there is also the "hicomp" 570 CP piston
Johnny FWIW most of the pistons up to 12.5:1 are about 4mm thick in the centre
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