Joined Sep 2004
186 Posts | 0+
to JBS racing;
What do you want or hoping for power-output???
Here in Belgium,they have in motocross,about 75-80HP on the backwheel(SAE).ZABEL 2 stroke.
The guy I know on his supermono husaberg 730cc,they talked about 80HP on the wheel,I can not confirm this with dyno outprint,but I do know that his bike is very fast,last year at the track in Belgian monobike championship,a speed of 233km/u.monitored.
What do you want or hoping for power-output???
Here in Belgium,they have in motocross,about 75-80HP on the backwheel(SAE).ZABEL 2 stroke.
The guy I know on his supermono husaberg 730cc,they talked about 80HP on the wheel,I can not confirm this with dyno outprint,but I do know that his bike is very fast,last year at the track in Belgian monobike championship,a speed of 233km/u.monitored.
Joined Nov 2004
158 Posts | 0+
Hi Madero
Yes I know about Zabels I used to have one, they are very powerful but grossly un-reliable and very expensive to maintain. You got 8 hours out of the piston and they were nearly £200 a time. Thats not an exageration 8 hours was the life if you ran on at about 10 the piston fails. This is in my opinion, because the pin is only 18mm and the rod is 137mm whilst the stroke is 89mm (bore 100mm). This gives very high rod angularity FOR A 2-STROKE and very high bearing stress so ware is accelerated.
On the question of power from this 750 Husaberg I'm doing I think high 70's is reasonable and achievable. This may sound low but I am a realist I think 76-78 RWHP is achievable. This will be a figure of the day not some hyped up advertising claim. HP through rubber to dirt is what counts not HP though some questionable correction factors to the ads page. Well with me at least.
If it all goes well I will sell the end result as a big bore kit for 650 Husabergs. I am putting a billet 86mm (may be 88mm if possible) crank in and the 105mm piston in my gallery. Once tested I'll make the 105mm Piston, Long rod and new liner/head packer available for a stock stroke 105mm bore Berg and the whole package including the crank for a 105mm x 86mm Berg.
I think that a 105mm Piston on the stock crank would make a great road reg' Supermoto. Anyway this 750cc baby is destine for a sidecar, if anyone is interested in the kit mail me at [email protected] for more info'.
As for sidecars this year a few guys road KTM 525's bored and stroked to 630cc (why didn't they use a Husaberg?????????) they were competitive against the Zabels even though they were nearly 20 HP down due to trackablity and drive i.e. a lot of Zabel and MTH power goes in spinning the wheel. So hopefully this 750 4-Banger will have the legs of the 2-Tooters.
Anyone know anything more about this Belgium 730cc motard?
Yes I know about Zabels I used to have one, they are very powerful but grossly un-reliable and very expensive to maintain. You got 8 hours out of the piston and they were nearly £200 a time. Thats not an exageration 8 hours was the life if you ran on at about 10 the piston fails. This is in my opinion, because the pin is only 18mm and the rod is 137mm whilst the stroke is 89mm (bore 100mm). This gives very high rod angularity FOR A 2-STROKE and very high bearing stress so ware is accelerated.
On the question of power from this 750 Husaberg I'm doing I think high 70's is reasonable and achievable. This may sound low but I am a realist I think 76-78 RWHP is achievable. This will be a figure of the day not some hyped up advertising claim. HP through rubber to dirt is what counts not HP though some questionable correction factors to the ads page. Well with me at least.
If it all goes well I will sell the end result as a big bore kit for 650 Husabergs. I am putting a billet 86mm (may be 88mm if possible) crank in and the 105mm piston in my gallery. Once tested I'll make the 105mm Piston, Long rod and new liner/head packer available for a stock stroke 105mm bore Berg and the whole package including the crank for a 105mm x 86mm Berg.
I think that a 105mm Piston on the stock crank would make a great road reg' Supermoto. Anyway this 750cc baby is destine for a sidecar, if anyone is interested in the kit mail me at [email protected] for more info'.
As for sidecars this year a few guys road KTM 525's bored and stroked to 630cc (why didn't they use a Husaberg?????????) they were competitive against the Zabels even though they were nearly 20 HP down due to trackablity and drive i.e. a lot of Zabel and MTH power goes in spinning the wheel. So hopefully this 750 4-Banger will have the legs of the 2-Tooters.
Anyone know anything more about this Belgium 730cc motard?
Joined Jul 2001
3K Posts | 1+
El Sobrante, Ca. 94803
JBSracing said:
As pasted from page one of this thread:
"Acceleration rate is directly as a result of total power (power under the curve) An increase in average power output shall reduce acceleration time for a given set of variables. BHP is Brake Horsepower and is intended to represent that which is derived directly from the crankshaft. Correction factors are very misleading as well. My power output is derived via the rear wheel using a street tire. Conditions are uncorrected (actual power @ the time of testing) @ seal level and most often with 30% - 40% humidity and between 55 and 75 degrees Fahrenheit."
Great minds eh Ben?
Kind Regards,
Dale
Joined Nov 2004
158 Posts | 0+
Yeah I guess so. Still you know some nasty people say that fools seldom differ...........
I've looked at your 600/650 RWHP graph and based on that and others I've seen I think a high 70's figure is a real target. The peak HP increment from the 600 to the 650 looks like 5-6 HP roughly if you give the 650 the same increment twice for the extra 110ish cc's I'm putting on then high 70's is were you get.
No point trying to tune a Fizzy 50 to 50 HP, or worse still being silly enough to tell every body else that you can. For any doughters out there work out the BMEP of some of the real high claimed figures, then compare them to F1 figures. Higher than a Farrari? From a single? - porky pie!! :^o
I've looked at your 600/650 RWHP graph and based on that and others I've seen I think a high 70's figure is a real target. The peak HP increment from the 600 to the 650 looks like 5-6 HP roughly if you give the 650 the same increment twice for the extra 110ish cc's I'm putting on then high 70's is were you get.
No point trying to tune a Fizzy 50 to 50 HP, or worse still being silly enough to tell every body else that you can. For any doughters out there work out the BMEP of some of the real high claimed figures, then compare them to F1 figures. Higher than a Farrari? From a single? - porky pie!! :^o
Joined Oct 2003
955 Posts | 1K+
Sweden
Last year I raced with my modified cylinder head with 40/34mm valves, larger diameter rocker pivots, billet rockers, extra cover bolts and a single 50mm carb. I have just finished off a 3D-model of an improved head, with a billet coming up. Anybody who would like a seriously tuned head? As I am not a very frequent visitor on this list, please drop me a private mail at [email protected]
/Dr_C
/Dr_C
Joined Nov 2001
17K Posts | 774+
Ely, England
i have studied both heads and have come up with the following;
the 35/27 head
this has a huge compression advantage over the bigger valve head. it has some 1.75-2mm less aluminium on the head. the 35mm valve is right on the upper edge and i suspect a bigger valve would be difficult to fit. the in to in is 4mm nearer and so is the ex to ex by the same amount. therefore larger valve seats are very difficult to fit on the exhaust side especially. i'm taking the 27mm out to 29mm on the original seats. the ports will just about take the reprofiling.
the larger exhaust valve is the tuning tip here IMHO. also the smaller the valves, not only the larger the compression but the lower the power will be produced.
the 37/30 head
has 1.75-2mm more head surface all of which rob compression. the exhaust valves now have plenty of room for larger seats whilst the inlets struggle. as said above they are 4mm further apart.
tuning tip again would be to put 32mm exhaust valves in IMHO.
overall
the inlet ports are too big for all bar the 550/650 and need reducing on the 400/470/450. although unproven, i expect that the 41mm (DL) will add power and that will apply to nearly all the models.
the camshaft has proven the major restriction so far.
regards
Taffy
the 35/27 head
this has a huge compression advantage over the bigger valve head. it has some 1.75-2mm less aluminium on the head. the 35mm valve is right on the upper edge and i suspect a bigger valve would be difficult to fit. the in to in is 4mm nearer and so is the ex to ex by the same amount. therefore larger valve seats are very difficult to fit on the exhaust side especially. i'm taking the 27mm out to 29mm on the original seats. the ports will just about take the reprofiling.
the larger exhaust valve is the tuning tip here IMHO. also the smaller the valves, not only the larger the compression but the lower the power will be produced.
the 37/30 head
has 1.75-2mm more head surface all of which rob compression. the exhaust valves now have plenty of room for larger seats whilst the inlets struggle. as said above they are 4mm further apart.
tuning tip again would be to put 32mm exhaust valves in IMHO.
overall
the inlet ports are too big for all bar the 550/650 and need reducing on the 400/470/450. although unproven, i expect that the 41mm (DL) will add power and that will apply to nearly all the models.
the camshaft has proven the major restriction so far.
regards
Taffy
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