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Discussion Starter #1
I've been reading these forums for a few months now and I think I'd better introduce myself, seeing as I have a 910R of my own (thanks to Mick De V). The bike is amazing, everything I'm after. In the past month or so of owning it I've put 4000km on it though twisty roads and doing chores around town.
:brutale:

There is one problem I'm having though. Once the bike is hot, say above 90*C, it surges. The RPM goes up and down in waves and being forced to use the clutch to keep upright on low speed turns.
On a cool day it sits around 87*C and feels smooth. If I stop and let it heat up for any amount of time it reverts to surging. The surge is also noticeable at idle.

I had a good search and these sort of problems are usually solved with tuning, but that has already been done with the Microtec and a good amount of dyno time.

My first thoughs before I discovered the issue is heat related were to look at the TPS. If anybody can point me in the right direction that would be great.

Cheers :)
 

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Welcome Alex.
Sounds like a bit of a heat / map related issue, the ECU changes the mapping once the temp goes over a pre-determined temp, this could be your issue. It might be a temp compensating issue in the mapping and only a dyno tuner will find this.
What fuel are you running, should be a 95 if that is what they used to tune the bike with, and is your fans coming on?
The TPS is not adjustable on your bike, and is the round little black thing on the r/h side of your throttle bodies.
You will see it illustrated in the workshop manuals which you can download from my website.
 

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Discussion Starter #3
Thanks Donsy,
The bike is tuned for 98, which I always use.
Fans are coming on at 95*C
Yeah, when I said TPS I was thinking throttle bodies.:rolleyes: Do you think it is worthwhile checking before I spend the $$$ at the shop? I have all the tools to check them.
 

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Throttle body balancing will not change between a hot and cold bike, if they're out, it will affect the bike at all temps if you know what I meant Alex ?

Have you got access to your Microtec, if you do then set the fans to come on at 90*C and see if that will help.

Do you know how old the plugs are ?

There is another wild stab, if all else fails.
A battery running low or a weak battery will affect the running of the bike when the fans come on, this is often solved by replacing the battery obviously, but sometimes it can be something as little as replacing the battery mains cables as some guys have discovered.

http://www.mvagusta.net/forum/showthread.php?t=102666
 

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It really is a chasing game ,Donsy is spot on ,You can if you so desire is to sync the throttle bodies in a different manner ,by memory never touch the 2 throttle bodies on the tps side ,ever. the other 2 on the other side can be adjusted with the screw in the middle ,with a gauge you can get them closed at the precise point,basically lh and rh throttle bodies being perfect when closed.if you do this mark all reference points.Better to take the bodies off the bike when doing this.Then hold them up to a light and you will see how crappy they are.Be warned do at your on peril.

Also you could sync the throttle bodies using a good carbtune.

also you could let more air into the bike at idle by adjusting the air bleed valves ,say 1 turn out wich should increase your idle rpm.

With the microtec Chris from X-bikes is the guru,maybe send him a Pm .

I would do as Donsy suggested first.

I am only suggesting certain options here and no responsibility taken as i am running Pc5 and running a different bike.
what coolant are you using, I just use water and 25 percent anti corrosion solution.Water is your best coolant.

cheers eddy
 

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Discussion Starter #6
The plugs are iridium and have ~16k on them.
The battery is sitting at 12.7v.
I'll contact Microtec and get the software. I already have the CAN to USB adapter.
 

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The plugs are iridium and have ~16k on them.
The battery is sitting at 12.7v.
I'll contact Microtec and get the software. I already have the CAN to USB adapter.
Recon those plugs are old.
Don't bother with Microtec, you'll be wasting your time.
Contact Chris (X81 here on the forum) or the guys who did the install for Mick, he might still have the disc/CD ?
http://www.mvagusta.net/forum/member.php?u=3979
 

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Discussion Starter #8
Eddy, Donsy, thanks for the help. At least I've got some direction now.

I'll keep you posted after I check these things out.
 

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A question: Does it surge throughout the rev range, or only 4k and below?
 

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Discussion Starter #10 (Edited)
I notice it less above 5.5k, though the other day I was maintaining about 7k through a corner when things started to get choppy. Below 5ish its more noticable and feels as though for a fraction of a second power drops, like losing spark I guess.
 

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I have the software , pm me for a link to it.

Have you asked Mick if this was always a problem or is it something new ?
 

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I have the software , pm me for a link to it.

Have you asked Mick if this was always a problem or is it something new ?
This had not been a problem for me, Alex. At least not since the fan was set to kick in at 95C. Truth be told I rarely rode the Brute in stop/start traffic in the last three years, so it did not often reach 95C. The fan coming on is very likely the cause of the surging.

My advice is to contact Dominic at Protech in Port Macquarie who was the last man to fine-tune the microtec mapping, on Chris (XBikes)'s instructions. As mentioned to you when you picked up the bike, I only did an oil and oil filter change at the end of December; if you've put on 4,000km since then, with a fair few short town trips, the bike will surely benefit from a good service and tune.

And yes, new spark plugs can make a difference.

Cheers mate.
 

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Discussion Starter #13
Hey Mick!
Yeah the bike ran fine for me for a while so I figured there wasn't any problems for you. Today I changed the fan to kick in at a lower temperature so I could gt a better idea how it infuenced the bike. RPM drops a bit but thats expected I guess. I like it at 95*C.
Had a play with the throttle linearization and I think I've fixed it.

Ill post the changes I've once I'm sure she's running 100%

By the way, LOVING this bike.:f4:

This had not been a problem for me, Alex. At least not since the fan was set to kick in at 95C. Truth be told I rarely rode the Brute in stop/start traffic in the last three years, so it did not often reach 95C. The fan coming on is very likely the cause of the surging.

My advice is to contact Dominic at Protech in Port Macquarie who was the last man to fine-tune the microtec mapping, on Chris (XBikes)'s instructions. As mentioned to you when you picked up the bike, I only did an oil and oil filter change at the end of December; if you've put on 4,000km since then, with a fair few short town trips, the bike will surely benefit from a good service and tune.

And yes, new spark plugs can make a difference.

Cheers mate.
 

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Hey Mick!
Yeah the bike ran fine for me for a while so I figured there wasn't any problems for you. Today I changed the fan to kick in at a lower temperature so I could gt a better idea how it infuenced the bike. RPM drops a bit but thats expected I guess. I like it at 95*C.
Had a play with the throttle linearization and I think I've fixed it.

Ill post the changes I've once I'm sure she's running 100%

By the way, LOVING this bike.:f4:
That's good news, Alex.
And i'm very happy you LOVE the Brute :)
Check your pm, i've copied you and old email exchange with Dominic and Chris
 

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Discussion Starter #15
Just a quick update incase anybody is curious as to how things are going.
I've installed an O2 sensor and low throttle openings have an AFR or about 10.3! Just throwing fuel and carbon out the exhaust for no reason :crazyeyes

I've leaned it off a bit to the point where the stuttering has stopped and over the next week I'll have datalogging set up and continue to lean the bike out to a more acceptable 13.3.
Once things are smooth at crusing speeds I'll take the rest of the tune.:f4:
 
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