I like to call this video the Erik Cromer show

[cosp600rr]

Here is another one from the trackday. Its got a few more mra members in it. I hope you enjoy.

http://media.putfile.com/Trackday-with-MRA-members

[cosp600rr]

As I am watching and listening to these videos it brings up questions that I have never thought of before.

When down shifting is it possible to over rev the motor and do damage to it. I wonder if I should be waiting to down shiftuntil I have been on the brakes for a bit so the rpms wont go as high. I notice it mostly when I go into turn 9. Maybe I down shift to soon.

Some thoughts on this from some of you motor savvy people would be nice.

[rybo]

Mat,

Short answer is yes, it is VERY possible to over rev the motor by downshifting. The forces are the same as over revving it on the gas, but the rev limiter doesn't work when the wheel is driving the motor.

Slipper clutch helps, as does waiting a smidge longer (time on the brakes) to get ground speed down before completing the downshift.

Now, I'll leave it to the motor experts to say how much over rev is built into engine design to prevent you from grenading that thing...

s

[cosp600rr]

From the sound of the video does it sound like I am over reving it on the down shifts?

[cromer611]

Erik Cromer show?


and no your revs dont sound too high to me. but maybe im doin the same thing so im used to hearing it : (

[cromer611]

man, i look hella slow in 6a and 6b. i know my gearing has alot to do with it. time to shorten it up : P

[cosp600rr]

are you sure its the gearing and not your right hand? :lol:

[cosp600rr]

I thought about passing you twice and it looks like James did too. Its not a great place to pass though and it just being a trackday. Raceday I might have stuffed it in.

[cromer611]

its gearing along with my right hand for the first time out this season : )
im only 1 tooth down in the front and barely get into 6th before turn 1 : (

[cosp600rr]

I haven't even been using 6th. I think I should thought as I am winding it out pretty high.

[Jon]

What make/model camera are you using?

[cosp600rr]

go pro hero wide angle lens. You can get them at vickery motorsports or superbikestore.net
Tell eather one of them that Mat sent you.

[cosp600rr]

any of the motor builders in the house have any thoughts on this. Not saying you guys dont know what you are talking about just want to get some more opinions

[marty]

no clue if it is the same on the new fangle FI bikes, but on a carbed bike, you can cause a lean condition by having the motor spinning at a high rpm and a closed throttle. i wouldn't take my word on it though, just a thought. probably best to wait til ben or the like chimes in.

[cosp600rr]

Ben your motor sense has been requested. Do you have any thoughts on this.

[cromer611]

what about your high rpm bog. what was that anyway?

[cosp600rr]

are you talking about when I was on the straight and the rpms changed and I said what the heck was that in the video. It dropped out of 5th gear into 4th and I pulled it back up real fast. It does that every once in a while if I dont pull the shifter all the way. Thats what happens when I get lazy. I dont know if this is nurmal or not. I hope its not a sign of something bad.

[cu260r6]

I don't think you're risking much of an overrev from downshifting. My data recorder says I lose 18.5-19.5mph per second for the first 2.6 seconds immediately after rolling off the throttle entering T1 at Pueblo. Even if I roll off and promptly start grabbing downshifts the aero drag and engine braking has already slowed me enough to permit a downshift without overreving the engine. The gap from 6-5th is pretty small, but unless you're right against the limiter in second and downshift into first right after rolling off the throttle I don't think you'll damage anything.

[nude]

Take a look at this video of Jason Pridmore.

http://video.google.com/videoplay?docid=-3771749678223260079

If you are braking as you are downshifting then chances are that you will not over-rev the motor. Can you ruin a motor by over-revving it with the tire - Yes. I spun a crank bearing at pueblo on an older race bike when I accidentally grabbed a double down shift and let the clutch out.

Nude