Ninja 650 mid range surge

[Shilouette]

Pretty new to this road bike thing, although competent, I'm no expert. I've recently brought a 2010 ninja 650. This is a Lams approved bike, to which it has a shunt in the wiring harness to prevent full mapping of the ECU and a throttle stop screw, which has been removed prior to me purchasing the bike. The shunt in the harness under the seat is still in place. The only other modification that I can see is a Leo Vince slip on. Most of my commuting is around town, and I'm finding in 2nd and 3rd gears the bike has a tendency to hunt/ surge at the nice usable range of 3000 to 3800 rpm. Bike has only done 3000klms and is in pristine condition. I've changed oil and filter because bike sat for 2 years unused. Apart from this annoying surge....I love the thing...could it be the fuel map shunt needs to be removed? Could it be the slip on over scavenging at certain rpms. Or is it just the nature of the beast? I've also gone so far as to check chain tension and all appears well. Any ideas? Thanks.

[dilligaf]

I had a nonlams ER6 and never ran it much below 4000rpm. Are you using 91 or 95 ron petrol. Mine went better on 91.
ECU stuff is probably for mechanics and dealers. Where are you based? There are a few good mechanics around.

[Shilouette]

I've been using 98 octane premium but I have heard they may be better with lower octane fuel. Some say this is for compliance in other countries where fuel quality is an issue. I asked the dealer and he said to use premium to avoid detonation. I'm in regional Victoria so good advice is hard to find but I did locate a workshop in Melbourne and the mechanic there sounded pretty genuine. I think it might be worth a ride down to see what he thinks. It's not a huge deal but for a near new bike it just seems a bit annoying.

[tim]

You wanna sort it asap would piss me off. Good luck

[fireyrob]

I dont know how a motor can run 'better' on a lower octane fuel? Octane is a measure of compression the fuel can take before detonation. If your bike is made to run on 91 the higher octane shouldnt make a difference should it? If its made for 95 then yeah the 91 might make it ping but it could be ok should you have no choice???

Some 98 octane fuel have additives to reach that octane level. Others are refined to reach it.

The 98's have cleaners etc to prevent carbon build up inside the motor. Thus probably why mechanics recommend them.

If your bike is surging I dont think you can blame the fuel type. Must be something mechanical going on :/

[Shilouette]

I wasn't actually blaming the fuel type just suggesting it may not be compatible with the restricted fuel mapping shunt. I agree you should always run the best or highest octane fuel available I doubt fuel is the issue ,and I doubt it's a mechanical problem from my experience with cars I think it's an electronic or sensor type issue. I can Replicate the rpm at higher speeds and it's not an issue. So I believe it's more load/ speed/ mixture related. Thanks all for the input. Il let you know what the outcome is. Cheers.

[Six Addict]

I dont know how a motor can run 'better' on a lower octane fuel? Octane is a measure of compression the fuel can take before detonation. If your bike is made to run on 91 the higher octane shouldnt make a difference should it? If its made for 95 then yeah the 91 might make it ping but it could be ok should you have no choice???

Some 98 octane fuel have additives to reach that octane level. Others are refined to reach it.

The 98's have cleaners etc to prevent carbon build up inside the motor. Thus probably why mechanics recommend them.

If your bike is surging I dont think you can blame the fuel type. Must be something mechanical going on :/

it may not run better, but its a waste of money... the sticker on your tank should tell you the minimum required RON... your bike will be designed with this fuel in mind. even my fancy-arsed new ducati is recommended to run 95... so thats what i put in it

[bonester]

ER6n can even run on E10. Injected so it can adjust to different fuels. I wouldn't run E10, but I run 91 in my three and they run ok. They all stall when they are cold too. Bastards

[Gosling1]

.....I dont know how a motor can run 'better' on a lower octane fuel? Octane is a measure of compression the fuel can take before detonation. If your bike is made to run on 91 the higher octane shouldnt make a difference should it?.......

Running 98 in a motor designed to work fine on 91 - is a total waste of money. The ER6 motors don't have knock sensors, so the use of a higher-octane fuel is essentially pointless.

I know from experience that nearly all my older bikes - designed to run on Standard fuel, work and run best on 91 octane. I tried 98 a couple of times in the 650 but it made the bike harder to start. It ran OK but was just a bitch to get going on 98. On 91 - it would start easily and run just as well as it did on 98, so it was pointless to spend more money on 98.

I reckon run a few tanks of 91 through your ER6 and see how it feels on that fuel. My guess is that it will work a lot better. You may still end up needing to remove the ECU by-pass thing to get it fueling 100% though.

[fireyrob]

I totally agree using 98 in a motor designed to use 91 is a waste. I just dont see how it could run 'better' on either fuel. Thats what I was referring too. My 03 zeddy was designed to use 91 and thats what I use. Locally though all the servo's rushed to E10 so premium is my choice. But alas starting yeah I could see that being an issue with a carby.

[Shilouette]

Ok. Today's mission was to get on top of the surge. Filled to the brim with premium 98. Removed ECU restrictor shunt. Ride bike. Through town there was no noticeable difference in the surge. Proceeded to ride about 150 Kay's that included freeway , high and low speed corners and hills. By the time I came back into town, surge was gone. I suspect removing the shunt was the key but it also needed various drive cycles to remap the ECU. I know with cars this kind of issue can take several weeks because the fuel mapping, spark advance, sensor feedbacks all need many drive cycles to reset. I'm guessing removing the shunt and taking the bike for a good run was all that was required in this case. Thanks to all for the input and advice and I'll be keeping an eye out for that little surge in future but fir now. Problem solvered!

[dilligaf]

Mine ran better on 91. I think it was as it then ran at higher revs and it just liked it there. Might be just ECU tricks on the older ones.
It felt "fat" on 95 and 98 but nice and peaky on 91. I also had a good mechanic tuning it.

[Nelso]

I dont know how a motor can run 'better' on a lower octane fuel? Octane is a measure of compression the fuel can take before detonation. If your bike is made to run on 91 the higher octane shouldnt make a difference should it? If its made for 95 then yeah the 91 might make it ping but it could be ok should you have no choice???

Some 98 octane fuel have additives to reach that octane level. Others are refined to reach it.

The 98's have cleaners etc to prevent carbon build up inside the motor. Thus probably why mechanics recommend them.

If your bike is surging I dont think you can blame the fuel type. Must be something mechanical going on :/

The higher octane is harder to detonate, which is why you need them in higher compression engines. The lower octane fuels apparently detonate easier and (according to some sources) have a faster flamefront, which is why they theoretically should work better in engines running less compression. I don't know if you could realistically feel the difference though.

[tim]

I remember the GS500 liked 95 more than 98, can't remember exactly what it did but remember was better on 95.

[fireyrob]

Oh Interesting! Thanks Nelso