MotoGP’s 850s and the Eternal Cry of “Too Fast”
The 800s Fooled Everybody. Will the 850s?
by Kevin Cameron
Friday, August 7, 2026
As motorcycle race tire grip improves with continuous development, corner speeds rise. This means that when a rider falls, bike and rider slide and tumble farther. Therefore a background chant of “Too fast, too fast…” can always be heard. When the 2007 displacement reduction from 990 to 800 cc was under discussion, Valentino Rossi joined on the side of “Too fast.”
The new bikes were introduced at the post-Valencia test in 2006. Immediately the new 800 Ducati was—at least on a lap-time basis—competitive with the 990s.
I walked down to where Yamaha had set up sound recording equipment near the end of the straight. They were analyzing the exhaust pulse frequency to determine the revs their rivals were turning. In past times, team managers have been known to carry musician’s pitch pipes for this purpose.
Because the new rules imposed no limits on bore or stroke, Ducati had built a large-bore, short-stroke engine, turning much higher revs. The large bore made room for valves large enough to fill and empty the cylinders at those higher revs. The short stroke reduced piston acceleration at any given rpm in direct proportion.
Many people are intuitively sure that a longer stroke must increase torque, but in a situation in which displacement is fixed, as the stroke is made longer, the piston area against which combustion pressure acts becomes smaller in direct proportion. Torque cannot increase.
Only an increase in combustion pressure can do that.
What is different in the planned drop from 1000 cc to 850 for next year is that Dorna have set an upper limit of 75 mm for bore diameter. That means that the stroke will be 48 mm instead of the previous 48.5 (bore and stroke in the present formula are 81 X 48.5).
With a stroke fixed by rule, the upper limit on rpm is set by piston fatigue cracking. Each rider in MotoGP for 2027 is allocated six sealed engines which must complete 20 races. If the number of races is increased to 21 or 22, engine allocation will be seven.
Much stronger piston material has been used in the past – so-called dispersed-phase aluminum. It had roughly twice the hot-strength of conventional alloys, but cost $10,000 to 20,000 per piston. The FIM banned it on the basis that it can be considered a composite.
With variable ride height banned from 2027, its ability to allow higher rates of acceleration and braking before wheel-lift occurs will no longer be in play.
The above are the reasons why the 850 formula is much less likely to be a repeat of the previous 800 formula – i.e. become quickly competitive with the previous. On the other hand, Marc Marquez has expressed the idea that the new bikes will be a bit lighter (nine pounds) and more maneuverable (less aero) than the old, and could surprise us.
The new bikes were introduced at the post-Valencia test in 2006. Immediately the new 800 Ducati was—at least on a lap-time basis—competitive with the 990s.
I walked down to where Yamaha had set up sound recording equipment near the end of the straight. They were analyzing the exhaust pulse frequency to determine the revs their rivals were turning. In past times, team managers have been known to carry musician’s pitch pipes for this purpose.
Because the new rules imposed no limits on bore or stroke, Ducati had built a large-bore, short-stroke engine, turning much higher revs. The large bore made room for valves large enough to fill and empty the cylinders at those higher revs. The short stroke reduced piston acceleration at any given rpm in direct proportion.
Many people are intuitively sure that a longer stroke must increase torque, but in a situation in which displacement is fixed, as the stroke is made longer, the piston area against which combustion pressure acts becomes smaller in direct proportion. Torque cannot increase.
Only an increase in combustion pressure can do that.
What is different in the planned drop from 1000 cc to 850 for next year is that Dorna have set an upper limit of 75 mm for bore diameter. That means that the stroke will be 48 mm instead of the previous 48.5 (bore and stroke in the present formula are 81 X 48.5).
With a stroke fixed by rule, the upper limit on rpm is set by piston fatigue cracking. Each rider in MotoGP for 2027 is allocated six sealed engines which must complete 20 races. If the number of races is increased to 21 or 22, engine allocation will be seven.
Much stronger piston material has been used in the past – so-called dispersed-phase aluminum. It had roughly twice the hot-strength of conventional alloys, but cost $10,000 to 20,000 per piston. The FIM banned it on the basis that it can be considered a composite.
With variable ride height banned from 2027, its ability to allow higher rates of acceleration and braking before wheel-lift occurs will no longer be in play.
The above are the reasons why the 850 formula is much less likely to be a repeat of the previous 800 formula – i.e. become quickly competitive with the previous. On the other hand, Marc Marquez has expressed the idea that the new bikes will be a bit lighter (nine pounds) and more maneuverable (less aero) than the old, and could surprise us.
— ends —
