To Synch or not to synch (first thread). Been reading, thinking and tinkering until now.

Hi guys.

Bought myself a 2011 White VFR back in May this year with 7,000ks on the clock and been following/joined VFRworld soon after. Had a few different bikes over the past 20 years, but the VFR is by far the best all rounder. Had it on my bucket list to buy one.

Anyway, I've read lots and tried a few things. A truly great forum!

As I commute everyday in traffic it didn't take long for the PAIR to get blocked off and the flapper removed. Reason being was the jerkiness or very sensitive throttle in stop start traffic. I found I was feathering the clutch to smooth out some of this and around low speed corners. Nothing bad but more annoying than anything. I could hear the PAIR openning and closing all the time too, so it had to go.

I really noticed a difference with the above mods, but there was a lingering small issue with the initial throttle where the engine revs would cycle up and down about 500 revs. In the trade its called a surging throttle. Ie. The ECU is in a loop to correct an issue.

Which lead me to doing the throttle body synch. I'd arranged some vacuum gauges from a mate and was about to do this. BUT... Step one in the workshop manual and every post is "adjust idle to 1,200 +- 100" etc. So I did this as the revs were around 1,100 rpm. I am just using the VFR tachometer as I've read that it is very accurate.

The idle screw is very touchy and I adjusted to bang on 1,200. I decided to take it for a ride before pulling things apart and there is now a very smooth transition with the throttle, no surging and I'm finding through low speed corners I don't need to touch the clutch. Problem gone.

So my observation or question is, how much of the synching is really the problem out there or is it just a case of not having the correct idle speed? Think about it. Why the importance of setting the idle at 1,200 +- 100 rpm. Seems very particular to me and why have a very accessible idle adjustment screw? Maybe the ECU can't handle the revs outside of this range and tries to compensate...

My last EFI Suzuki had no idle adjustment. Anyway, problem solved without getting into the bowels of the motor.

I've no doubt there are some genuine cases where synching is required, but maybe just get the idle bang on 1,200 might solve a lot of problems. The local bike shop I've been going to for years wouldn't even do the synching as he reckoned all EFI bikes are touchy and it was a waste of my money.

BTW some other observations and mods I've done.


The cooling system does not get enough air through it at 60km/hr and less. I fitted a fan override switch and flick it on about 5mins into the 30 minute commute. Keeps temps low before they get too much heat sink. Fitted one on my last bike too. Keeps everything cooler for longer.

Givi box came with the bike. I bought some yellow and red LEDs and resistors and fitted my own indicator and brake lights into the Givi spaces. Cost me around $15 all up and I used bright LEDs. Had to remember ohms law but that is another story.

Tinted Double bubble screen from flea-bay. Someone in China for $30. Good quality and made a big difference for wind noise at speed. Looks a lot better than standard.

Aftermarket look alike mirrors again from flea-bay China. The ball on the stem is smaller so I can move the mirrors in closer and still get good vision. The Honda ones just stick out in the breeze too much for me and not good for lane filtering.

Pilot 4 tyres. Trust me they are worth the extra money. The bike had the original tyres when I bought it and they were buggered. The bike goes through corners on rails. No chicken strips on the edge of the tyres. My first bike without chicken strips.

That'll do for now. Photo below after cleaning the spark plugs to Mt Glorious.

 

I wouldn't bother with a throttle body sync on a relatively brand new bike unless you did all the mods and it was still surging bad. With only a few thousand miles on the butterflies and bores, there really hasn't been enough time to cause any considerable wear, so there won't be much to correct, unless it left the factory on a monday and someone at honda botched it. I am curious as to why, with all the surging, you didn't delete the o2 sensors as the first mod.

 

Beautiful white bike!

You seem like a hands on guy and the starter valve synch is not a horrible procedure. Just like you proactively pulled the plugs for cleaning, I suggest you continue to do the synch as well. There is a pressure differential among the four cylinders, and it is tuneable, so we tune it.

I do not understand mechanics blowing off a standard maintenance item. I can tell you this, in my work when another IT group tells us, "We cannot do that" I immediately translate that to, "I do not want to do that." This rule has proven to be pretty robust. Everything is doable. The logic programmers can write is infinite. So why would someone say "that cannot be done?" The answer is some combination of laziness and fear of learning something new.

Why 1200 RPM for idle? There is a minimum smooth idle for any engine. On the high side, if the idle is exceeded then gas is just being wasted. So I think that it is smart to specify a concise idle speed, independent of everything else.

 

Blowing future off maintenance that doesn't need to be done for another 16,000-32000 miles lol. Its a brand new bike. Delete the o2 sensors if its still surging. Takes five minutes. If its still surging after that look into a power commander and or go through with the sync if you've got time.

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I should have explained "Cleaning the spark plugs...."

It's what you say to the police officer when he says "is there any reason you were speeding?"

"Yep, it was running rough so I was riding it hard to clean the spark plugs" I doubt you could use that excuse these days but could on the really old aircooled bikes I used to have.

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Can't means won't

 

I've no idea why synching needs to happen at a very defined rpm; the whole purpose is to match the air being bled through the starter valves so the same amount reaches the cylinders (or prescribed different amounts on a 5th gen!) and you'd have thought that would be independent of precise rpm, but I suppose if it was too high then maybe the starter valves would be further open (from the idle adjuster) and not provide enough adjustment range, and too low risks stalling the motor.

Synching the valves should give you a more stable idle but I don't think it would make a lot of difference to the surging, particularly if setting the idle has made the problem disappear.

 

Ahhh Mt Glorious

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Looks like the cafe on a quiet day. Haha. Last few times I've been there was a very strong Police presence.

 

Yeah last time I was there they had their own shade tent

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Hi guys.

Out of shear curiosity I hooked up some gauges and found number 2 and 3 were out by about 25mm or 1 inch of mercury. Adjusted them all bang onto number 4. Throttle transition is a bit smoother through corners and traffic but I did notice a fair bit more bottom end grunt and can now potter around a lower revs than before. When I turn the bike around on my driveway now, it has enough grunt to not even apply the throttle. Driveway has a slope too.

Didn't transform the bike. Just made a great bike even better.

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Very good, thank you for reporting back.

 

Love happy endings - Good Job!

 

Thanks, YOuve inspired me to take on the task.

 

The more I ride the more I'm impressed with what a little fine tuning has done. Less feathering the clutch and at idle there is no vibration through the seat.


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Sync'd up the '04 this past Saturday. Amazed at what the difference is. Like Rusty posted, nice improvement on bottom and off idle.
Best hour of fiddlin' time spent on it so far.

 

Before I give back the gauges to my friend, I thought I'd check my syncing from the other week and see if anything had changed. Also, I hooked the gauges up in reverse to be sure they are all the same accuracy. Turns out the gauges were pretty close and I spent a lot more time this time getting each cylinder exactly the same. They weren't out much and I'm talking the width of the needle on the gauges.

I am so impressed with how the smooth the idle is now on the bike, I just had to do the glass of water on the fuel tank test. See video. Would have to be the smoothest idling bike I have had in over 25 years of various bikes. [video=youtube_share;SjtlGPB_EA0]http://youtu.be/SjtlGPB_EA0[/video]

 

Wow Nice and smooth, so is your paint factory with white wheels Too.

 

Wow, impressive. Got Lint coming over tomarrow to check both bikes with his gauges....think I'll try the glass before and after.
Always loved that color scheme. ...is the white a pearl like the new 8g?

 

Thanks. That's what I thought too. All factory white. Pearl white.

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