I just got an email back from Daihatsu regarding redline on our little trucks. According to them, the EB engine's valves will start to float at 5800 rpm. Therefore, they recommended setting a redline on any aftermarket tach at 5500 rpm.
Hmm. Just got a Tack in mine.. Been running it up to a little over 7000rpm down the highway for over 100 miles now with No valve float or any other problems.
the eb is the 550cc engine....the newer 660cc engine is redlined at around 7000....daihatsu even lists the power and torque curves for the 660cc to 7000 so I would assume it was designed to rev that high
Oh.......me thinks thou doth rev. too highly sire .....but I can find nothing anywhere that states that emphatically ....so ..hmmm...not sure
Did some diggin on the specs... 550 / 660 have same stroke just bigger bore for the 660 so the bottom end should be fine . So as long as you don't get valve float then it should wind right on up there. Will keep you posted.. When I get some rings and bearings scared up, I will pull it down and check the factory balancing etc. before I "race prep " the bottom end. If I can Find a set of forged Pistons I will probably do a Full build on this little gem and see what it is capable of hehe..
Update Got over 1000 Miles on it now Most at highway speeds (60 - 65 mph) and 6800 to 7400 rpm. did a 3 hrs strait run the other day too. Will probably be doing it again tomorrow too. Still running strong !