MOTOBRICK.COM

TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: K1300S on December 25, 2017, 06:35:59 PM

Title: rev limiter whack?
Post by: K1300S on December 25, 2017, 06:35:59 PM
so i was out for a little christmas eve errand running on the K75S.  well,  after the errands i did a little fun riding in case the weather made it the last ride of the year.  did a few redline runs in first and second gears.


first gear...engine flattened out at about 7200 rpm.  seemed like it was cutting out.


second gear....pulled strong all the way to 8500 rpm.


huh?  any thoughts on why no full redline pull in first gear?
Title: Re: rev limiter whack?
Post by: Laitch on December 26, 2017, 11:02:23 AM
I've never had the bike up to or past redline. What happens to performance when the rev-limiter kicks in? Is it like what happened in 1st at 7200?
Title: Re: rev limiter whack?
Post by: Inge K. on December 26, 2017, 04:30:17 PM
The rev limiter is managed by the ignition ECU which don't receive any info about which gear or bike speed.
So it should make no difference which gear you use.
Title: Re: rev limiter whack?
Post by: Chaos on December 26, 2017, 05:54:41 PM
massive g forces from acceleration in 1st gear forces gas to back of tank starving engine.  In 2nd gear g force not so much.  Are the tires inflated with Nitrogen?
Title: Re: rev limiter whack?
Post by: K1300S on December 26, 2017, 06:00:15 PM
Quote from: Inge K. on December 26, 2017, 04:30:17 PM
The rev limiter is managed by the ignition ECU which don't receive any info about which gear or bike speed.
So it should make no difference which gear you use.
yes...bad title to my thread.  ECU doesn't care what gear on these old bikes.  the 7200rpm + stumble in 1st gear is odd...not like the ignition cut out with the rev limiter.


Quote from: Chaos on December 26, 2017, 05:54:41 PM
massive g forces from acceleration in 1st gear forces gas to back of tank starving engine.  In 2nd gear g force not so much.  Are the tires inflated with Nitrogen?

LOL!!!! I wish that was the issue!!
Title: Re: rev limiter whack?
Post by: Inge K. on December 26, 2017, 06:10:08 PM
These old rockets accelerate so lightning fast that the tacho can't follow in first gear.  :yes