Bigger valves in 650 -04 Supemotard?
- Thread starter CUL8ER
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- 650 bigger supemotard valves
Strictly theoretical, I'd say that bigger valves will improve performance if they are 35/30 from the factory. On the 450 they will suffice.
Also, retaining the present valves and having the valve seats moved "out" on the valve will also increase flow. As it is from the factory ( I know, looked yesterday) this is far from optimal.
Also consider if valvesizes are the restricting factor. Maybe the restriction is further up the airflow. Port runner shape/size.
On my 450, I'm keeping the runner size, just improving the shape, especially around the valve throat.
Husaberg engineers have cut the steel insert at an angle which is not ideal with standard valves. If you go for 1mm bigger valves, the seats may be cut with a decent 60degree (or even better a radius) undercut which will undoubtedly increase low lift flow.
I'll get some pictures of the "new" head today.
Also, retaining the present valves and having the valve seats moved "out" on the valve will also increase flow. As it is from the factory ( I know, looked yesterday) this is far from optimal.
Also consider if valvesizes are the restricting factor. Maybe the restriction is further up the airflow. Port runner shape/size.
On my 450, I'm keeping the runner size, just improving the shape, especially around the valve throat.
Husaberg engineers have cut the steel insert at an angle which is not ideal with standard valves. If you go for 1mm bigger valves, the seats may be cut with a decent 60degree (or even better a radius) undercut which will undoubtedly increase low lift flow.
I'll get some pictures of the "new" head today.
Joined Sep 2004
186 Posts | 0+
for supermotard go 35-32or 35-31,5.You will see it will be the best result.
It is also the question what kind or power you want,bottom or toppower for expl. monobike.
Ask Dale Lineaweaver,who has several models for valve options,mine I bought with him and so far no complaints at all.
I flowed my cilinderhead also but little result in peak hp.
The only thing i had was that the power comes faster at the backwheel-regarding to time.
With 15-40 in 5th It takes only 3.5seconds to have full power and before with stock head about 4.6seconds
It is also the question what kind or power you want,bottom or toppower for expl. monobike.
Ask Dale Lineaweaver,who has several models for valve options,mine I bought with him and so far no complaints at all.
I flowed my cilinderhead also but little result in peak hp.
The only thing i had was that the power comes faster at the backwheel-regarding to time.
With 15-40 in 5th It takes only 3.5seconds to have full power and before with stock head about 4.6seconds
Joined Nov 2001
17K Posts | 774+
Ely, England
not sure what madero knows about tuning that i don't but if you want to share it i'd be glad to hear about it? PM me if you wish.
for me though? i'd say up 1mm on both would suffice to 36/31. keep the original seats, just blend them in nicely and get the valve seat widths down from 3mm and 4mm to 1.5 and 2.5mm.
that way it's the equivelant of going up 2mm in valve size even though both continue to be standard. larger valves increase the revs at which peak torque and power are potentially produced all else being good. but you don't want this with SM or MX especially. enduro you can use a broader spread.
the inlet ports need material adding whilst the exhaust ports want it removing IMHO. this is why maddel hasn't had much of a gain.... anyone listening?
regards
Taffy
for me though? i'd say up 1mm on both would suffice to 36/31. keep the original seats, just blend them in nicely and get the valve seat widths down from 3mm and 4mm to 1.5 and 2.5mm.
that way it's the equivelant of going up 2mm in valve size even though both continue to be standard. larger valves increase the revs at which peak torque and power are potentially produced all else being good. but you don't want this with SM or MX especially. enduro you can use a broader spread.
the inlet ports need material adding whilst the exhaust ports want it removing IMHO. this is why maddel hasn't had much of a gain.... anyone listening?
regards
Taffy
ale Lineaweaver, who has more experience on husaberg engines than probably anybody else.
Joined Nov 2001
17K Posts | 774+
Ely, England
well in a way i have maddel!
he is quoted as working on 37/32! engine CC? not sure! however i have it recorded what he used on what as well. it's on a long thread in fuel i believe. i often can't find things in the search but that one comes up now and again.
he hasn't put it up here that just 3.5mm between inlet and exhaust is 'waytogodude!'. but you live and learn right!
me? i desperately want a full DOMA system-used-sorry can't afford new! that would really make my day!
regards
Taffy
he is quoted as working on 37/32! engine CC? not sure! however i have it recorded what he used on what as well. it's on a long thread in fuel i believe. i often can't find things in the search but that one comes up now and again.
he hasn't put it up here that just 3.5mm between inlet and exhaust is 'waytogodude!'. but you live and learn right!
me? i desperately want a full DOMA system-used-sorry can't afford new! that would really make my day!
regards
Taffy
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