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Discussion Starter #1
I'm just wondering if anyone has removed the clutch operated cut out switch that prevents you from starting the bike in gear unless the clutch is pulled in.

I'm asking this because I have an issue with my 2020 gen 3 race bike that I'm currently setting up .
As part of the race strip down I removed the switch from the perch and initially left the two wires that had previously been connected to the switch separated. But when I run the bike up on the race stand I noticed the idle speed would increase when I put the bike in neutral. Hmmm... So I thought I'd try joining the wires together and hey presto the high idle speed in neutral issue was gone. However... today I road tested the bike (on a private road of course!) and when I came to a halt the idle speed was pulsing rhythmically between 1000 and 1500 RPM. Also the bike was popping badly on decel which it never did before. I discovered that by cycling the key on and off it would reset something and the idle speed would be normal again until I started riding again. This has got me scratching my head even more than before.

The only hunch I have is that it is related to the extra ECU complexities of the 'Low RPM assist' function that the Gen 3 model has. I've already had issues getting around the complexities of the 'Easy start' function the Gen 3 bike has. This was solved by increasing my Lithium battery rating from 180CCA to 300CCA to satisfy the requirements of the ECU.

I'm asking here first because the switch wires are now buried in the loom (but labeled) so not easily accessible.
 

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We're running the clutch switch disconnected but the wiring is still there, we don't have either of those issues though. When it's in gear the revs jump up to about 1500, but in neutral it's around 1000.
 

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Discussion Starter #3
OK, so the opposite condition of what I had the first time with the revs rising in the neutral position. This was with the wires apart, which would (or should) be the same as the stock set up with the switch in the open position but interestingly it never did the rev change thing in stock set up. Do you still have the left hand switch block in place and that loom plugged in (the yellow plug connector)?

I'm wondering now if maybe I have that rev rising thing around the wrong way as it was two weeks ago that I did that job. Regardless I will hack back into the loom again tomorrow and separate the two switch wires that I soldered together.
 

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Discussion Starter #4
Normal service has resumed after re-fitting the clutch switch. I decided just to refit it rather than leave the circuit in the open position and get the rev rise every time you put it in gear when the RPM assist function kicks in.
My dyno tuner said he’s seen ECU related issues with gixxers too when the clutch switch is removed. Reckons it’s a bit of Suzuki thing.
 

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Yeah, we tested today with it as well. There was definitely a lot more popping during decel when the clutch switch is plugged in, and the rpm sits lower when in gear.

I've heard the same thing from my dyno guy about the GSXRs. Might try it out in the next month.
 

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On the Gen 2 bikes, the clutch switch widens the injector pulse when the clutch lever is pulled, the forum's electrical guru TeeRiver did a video that clearly demonstrates this. The effect of this is richening the mixture when the throttle is shut on deceleration, to help stop the engine cutting out. Of course, the motor will still run, but not as smoothly.

I don't know if the Gen 3 bikes do this, in addition to the low-rpm assist function too.

A quirk of the Gen 3 is that the ECU allows the motor to produce slightly more power and torque (2 or 3 more lb-ft from 5,000rpm upwards and 3bhp at 8,000rpm) in the midrange in 5th & 6th gear than in the lower gears.

Video with dyno charts here:
 
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