Benelli Forum banner
1 - 18 of 18 Posts

·
Registered
Joined
·
209 Posts
Discussion Starter · #1 ·
Nuts, on my way to work in heavy traffic when I stalled the bike for the second time. I'd previously upped the idle to 1500 so wasn't expecting the stalls. Tried to restart and the battery would barely turn the bike over. Powered off and on several times, same results. Walked to work, rang the shop and a transport company. Walked back to the bike, transport van turned up and just for fun I tried again. Vrrrrrm, started no problem. Turned it off and on several times, started every time. Grr! Cost me a $20 call out and an hour and a half of time. :mad: :mad: :mad: :mad: :mad:

Anyone got an update on solving this ? It must be something getting too hot and packing it in.

ciao
Derek
 

·
I'm firing on three
Joined
·
611 Posts
Derek, what year is your TNT?...... 04 & 05 bikes have hot starting problems, :( improved greatly by larger battery cables, latest ECU map and the modified starter assembly. Also as per my posts over the last year moving the thermistor (air sensor) away from its present position in the airbox will make a significant difference.
My 05 TNT was a nightmare having done the mods above it reduced the hot starting problem by about 95%. Short term if it does it again leave it for 2 or 3mins then try it again but don’t touch the throttle until it starts to fire up.
Indecently the starter mod was a warranty mod by Benelli.
 

·
Super Moderator
Joined
·
7,779 Posts
Terry, It's not just the 04 and 05 models that have this problem. I had a test ride on a new Cafe Racer last year and it done the same thing :mad: :mad: :mad:

After leaving it for around 20 mins I tried it again and it bursts into life like nothing was wrong!!!!
 

·
Registered
Joined
·
19 Posts
Had this problem twice, 1st by leaving it running while looking for garage key, 2nd in Leeds when the fan was on. Found it best to only stop for fuel after 3 or 4 minutes easy riding, then it starts. :doh: :doh: I'm in for a services next month, so will be asking for ALL mods to be done. So anywhere i can find out what's for free would be a good help to my pocket. :clap:
 

·
Registered
Joined
·
209 Posts
Discussion Starter · #5 ·
In this case it's an '07 Cafe Racer with only 700ks on it. I've also noticed that the idle is getting lumpier and lumpier. Every now and then you hear it "miss", causing the revs to drop a couple of hundred or so for a second before coming back up. There is also a solid "knock" you can feel through the frame when this happens. My guess is it's missing the timing on a cylinder or something like that. I think that is when the engine would stall if at the factory idle setting. It's due for it's 1st service in a few weeks so maybe that will improve things.

You'd think after 100+ years of development, getting a petrol engine to idle smoothly would not be an issue.

ciao
Derek
 

·
Senior Member
Joined
·
463 Posts
Mine occasionally has the same symptons(miss and a knocking sound) although the knock seems to come from the engine, its done it from new but luckily hasnt made it stall, it was a bit worrying at first but the engines done7000 mls now so i tend to forget about it.
 

·
Registered
Joined
·
209 Posts
Discussion Starter · #7 ·
Yeah, I've been wondering what it's doing to the engine. The concern is that it puts strain on the internals. I'd be interested ot know just what's going on though. Miss timing on sparks seems likely, but caused by what ? Perhaps I should get some sort of data logger installed and dump off the results.

Could this be a glitch in the computer, or the Matrix - who knows ? :doh:
 

·
I'm firing on three
Joined
·
611 Posts
I spent a bit of time last year on this problem and monitored signals from the TPS, THERMISTOR (air sensor) & STEPPER VALVE with the equipment I had it was hard to work out what the signal to the stepper was all about (in relation to the other sensors) but I got some interesting data from the other two particularly the thermistor………….. When the data is “crunched” by the ECU it then mods the fuel, ignition, stepper etc ……………..ECU’s are a form of computer (loosely speaking) and like computers some are quicker and more accurate at processing data than others, the sagem for example is a good unit but tends to process data incrementally less accurately than some other units on the market.
With the data I got it became obvious that the thermistor was sending inconsistent data to the ECU which I eventually realised was down to where it was positioned on the bike, so instead of constantly monitoring true ambient air coming into the airbox the heat from the engine fooled the thermistor into thinking the ambient air was hotter than it really was.
The result was the sudden “hiccup “at low revs and the bike stalling, I also think that the stepper valve (which is a bypass valve) is inconsistent due to its mechanical nature and this again affects the low rev band.
At the moment I am trying to get help/software to enable me to modifying the ignition settings On the walbro ECU fitted to my sport , this is because I am convinced that when the engine experiences the hot start problem retarding the ignition until the engine starts (reaching say 900rpm) will cure the problem, these are relatively high compression engines and this is a recognised problem with high comp engines. (Phew are you still awake)
:doh:
 

·
Registered
Joined
·
1,007 Posts
Regarding the fake dead battery - I've just had the new starter motor fitted to my 04 model and I've not had a problem starting when hot so far. I also fitted a larger battery before this, just for good measure.

I also experience the solid knock on tickover which can't be doing the bottom end much good. It started after I had the latest map installed in Feb this year - It was fine before. Hope there's a newer one which clears it

For the record, my particular disaster has been a porous casting on the head/barrel meaning its been off the road at Red Dog for 8 months.
There's a case for collating these failures to find their frequency against the year of manufacture - I was terrified by Benelli Dave's alternator shaft failure
 

·
Registered
Joined
·
736 Posts
I have never to date had a battery failure since I fitted a genuine Yuasa battery! Now I`ve said it I probably have one!!!!:doh:
I cant remember the battery number off the top of my head but I`m sure someone will provide the info.
 

·
Registered
Joined
·
209 Posts
Discussion Starter · #12 ·
Further on from this :) I was talking about the FDB issue with a dinner guest the other night and he mentioned that some time ago Holden had the same problem with the same issue with one of their cars. Apparently the the starter motor was too close to the main engine block and copped a lot of heat when the engine was running. After a while it would get so hot that the resistance in the motor wiring increased to a point where battery could not supply enough juice to turn it. Apparently this happens with electrical motors when they get hot.

Holden's fix was to put some heat shield between the main block and the starter motor so it didn't get too hot.

Opinions please - do people think that the issue with the FDB's could actually be the same thing, the starter getting too hot, thereby increasing the resistance of the internal wiring it it, and therefore refusing to turn over ?

It's an interesting theory and certainly fits the symptoms.

:D :D :D :D
 

·
Registered
Joined
·
1,007 Posts
As I understood it, the problem with the starter IS heat related but specifically the starter motor shaft bearings tighten up through expansion. I've certainly fixed it in the past by throwing buckets of cold water over the starter but its embarrassing when you do it at the petrol station.
The new starter is around £250(?) and does seem to fix it. A battery upgrade will always help in marginal conditions but its not really the cause - If the bike starts 20 minutes later, it can't be a flat battery: Batteries don't "recover" charge to any significant degree
 

·
Senior Member
Joined
·
5,963 Posts
Opinions please - do people think that the issue with the FDB's could actually be the same thing, the starter getting too hot, thereby increasing the resistance of the internal wiring it it, and therefore refusing to turn over ?
Derek, you can prove your theory, or otherwise, by carrying around a multimeter. Measure the resistance when cold, and again when hot - and not starting. You might have to do this a few times after several starts, 'cos the brushes won't always find the same resistance point on the commutator.

Let us know what all your measurements are, and I'll calculate the currents. That should put it to bed, either way.
 

·
Registered
Joined
·
12 Posts
Regarding the fake dead battery - I've just had the new starter motor fitted to my 04 model and I've not had a problem starting when hot so far. I also fitted a larger battery before this, just for good measure.

I also experience the solid knock on tickover which can't be doing the bottom end much good. It started after I had the latest map installed in Feb this year - It was fine before. Hope there's a newer one which clears it

For the record, my particular disaster has been a porous casting on the head/barrel meaning its been off the road at Red Dog for 8 months.
There's a case for collating these failures to find their frequency against the year of manufacture - I was terrified by Benelli Dave's alternator shaft failure

Hi Pike

Why is it taking 8 months, at least, for them to repair your bike?

Have they given you a loan bike?:confused:
 

·
Registered
Joined
·
1,007 Posts
Hmm! I need to be careful here. I'll just say that I wasn't impressed by the speed of their repairs and an early misdiagnosis introduced delays too. However, I gather that other people think highly of Mitch & Co so I dunno.

I didn't buy the bike from Red Dog, so I didn't expect a loan bike

Anyway, its back on the road, which is the main thing
 

·
Registered
Joined
·
209 Posts
Discussion Starter · #17 ·
As I understood it, the problem with the starter IS heat related but specifically the starter motor shaft bearings tighten up through expansion. I've certainly fixed it in the past by throwing buckets of cold water over the starter but its embarrassing when you do it at the petrol station.
The new starter is around £250(?) and does seem to fix it. A battery upgrade will always help in marginal conditions but its not really the cause - If the bike starts 20 minutes later, it can't be a flat battery: Batteries don't "recover" charge to any significant degree
That's interesting. Is this new starter available under warranty ?
 

·
I'm firing on three
Joined
·
611 Posts
Further on from this :) I was talking about the FDB issue with a dinner guest the other night and he mentioned that some time ago Holden had the same problem with the same issue with one of their cars. Apparently the the starter motor was too close to the main engine block and copped a lot of heat when the engine was running. After a while it would get so hot that the resistance in the motor wiring increased to a point where battery could not supply enough juice to turn it. Apparently this happens with electrical motors when they get hot.

Holden's fix was to put some heat shield between the main block and the starter motor so it didn't get too hot.

Opinions please - do people think that the issue with the FDB's could actually be the same thing, the starter getting too hot, thereby increasing the resistance of the internal wiring it it, and therefore refusing to turn over ?

It's an interesting theory and certainly fits the symptoms.

:D :D :D :D
Drekka, you are right resistance values change when wire is heated, so any motor getting hot is not good for its performance; however I know that on the early TNT starters there is a bearing / armature tightening issue which causes binding, they have also changed the cranking ratio on the latest models, (like going up 3 teeth on the back sprocket where you get more initial torque) which has improved starting reliability, the upgrade on the starter was/is a warranty modification.
vtxbrit
 
1 - 18 of 18 Posts
Top