Symptoms of throttle bodies out if sync

[Saint aka ML]

What are the indicators of throttle bodies being out of sync?

[Dukedesmo]

Rough idle, possibly stalling at idle.

[Saint aka ML]

Ok not what I have well it stalls when cold at idle but for only first 2 - 3 minutes.

Ok in my case when I close the throttle it sometimes gives a feeling of it being stuck open about 3k rpm mark despite throttle cable being very loose now. I can correct that by blipping. Happens more often when I have fast idle on.

Also when engine gets warm-ish (past point where it stalls on idle with fast idle off so 2 3 minutes) and I still have fast idle on it will backfire from time to time via airbox kind off like misfire spark plug.
But that only happens if I do a constant low throttle where fuelling is ****. Fast idle off I can do constant low throttle no problem.
It will never misfire above 3k rpm (fast idle on or off, cold or warm) or when not touching throttle and just idling.

[Saint aka ML]

It does not sound electrical to me but rather one of throttle bodies is closing a bit more then other so it chokes one of the cylinders and if I have fast idle on throttle bodies are a bit more open in general couple that with one of them being even more up it drags the RPM up.

[Dukedesmo]

Backfiring through the intakes at low RPM sounds like it is running lean. I would go for a full TPS reset, TB balance & CO setting.

[Saint aka ML]

Backfiring through the intakes at low RPM sounds like it is running lean. I would go for a full TPS reset, TB balance & CO setting.

Ok will do. Was going to fit Termis anyhow soon so just need to get new air filter and will do all at one time.

[Capo]

Take it to Ray, he will sort it.

[bensley]

My M600 dark is doing the same, exactly the same, although it also doesn't run right sometimes when out on the road. Sometimes when you open the throttle it just makes more noise but doesn't go anywhere, no increase in speed, just a real deep throaty kind of roar.

I wasn't sure if this was just because I hadn't used it all winter but took it out for a bit today.

As a real novice could you please give me a bit more info on a TPS reset, TB balance and Co setting. As perhaps I need to look at this on my bike too.

When I told a friend today about the problem he suggested that perhaps the mix wasn't quite right.....

[Darren69]

Could possibly be an air leak somewhere in the induction syste which would cause lean running and higher revs even when throttle closed air is getting in. WD40 or similar can indicate that if you spray some on the air ways and the revs die.

[bensley]

Do you guys ever use a cleaning additive, spray or something similar to Sea Foam to clean stuff in and around these parts?

[Nickj]

My M600 dark is doing the same, exactly the same, although it also doesn't run right sometimes when out on the road. Sometimes when you open the throttle it just makes more noise but doesn't go anywhere, no increase in speed, just a real deep throaty kind of roar.

I wasn't sure if this was just because I hadn't used it all winter but took it out for a bit today.

As a real novice could you please give me a bit more info on a TPS reset, TB balance and Co setting. As perhaps I need to look at this on my bike too.

When I told a friend today about the problem he suggested that perhaps the mix wasn't quite right.....

If it's an IE then TPS etc is relevant, if it's a standard M600 then air filter, balance and float heights are peobably much more relevant.
M600 not picking up much just a lot of intake noise ... The noise is air being sucked into the air box, the not doing much might be that you need to be down a gear or more

[Darren69]

I think what Nickj meant to say is that 'If its an ie then you will have a TPS so it could be an issue' if not then it could be carbs but from what you say its typical of an air leak somewhere. Rubbers from throttle bodies cracked or from air box to carb throttle bodies?

[Saint aka ML]

Could possibly be an air leak somewhere in the induction syste which would cause lean running and higher revs even when throttle closed air is getting in. WD40 or similar can indicate that if you spray some on the air ways and the revs die.

Vertical cylinder intake manifold. Anyone got a spare that will fit 620/695 monster....

[Saint aka ML]

Bensley from your description I would start from checking if fuel filter is not blocked, if tank breather is not blocked, fuel hoses are not pinched, if you have fuel tap if that is not broken(ie valve inside closing a bit) and if carbs are clean.

You open throttle and more air goes in (roar, induction noise). However not enough petrol is delivered so bike fuelling turns lean, makes no power. Reason why you hear more induction noise is if it did get correct fuel & air it would start shifting so you would behaving more wind noise and less stress/vibration on engine/drive chain.

Your description sounds exactly like when I had fuelling issues.

After fuelling I would check if cdi unit/coils are not failing. Again you open throttle so more air gets in, more petrol gets in but spark misses few cycles so bike feels underpowered, noisy and vibrating. (cdi).

If coil spark is to weak and does not always ignite when more petrol and air is in. Does bike ever smell of petrol after that incident?

[gary tompkins]

is it based on m620 or 695?

the 695 had CATs built into cans and lambda sensors - fuelling is crap with CATs removed

[Saint aka ML]

is it based on m620 or 695?

the 695 had CATs built into cans and lambda sensors - fuelling is crap with CATs removed

m620 also has CATs in cans ... cheese sounds like Vietnamese restaurant here

I have headers from 695 so lambda sensor is there.

It is the inlet manifold as I completely forgot that when I was building it up I noticed one was damaged and made a fix with stretchy tape and that metal round thing for tightening stuff.

[slob]

Take it to Ray, he will sort it.

He's just had a look at mine and replaced an iffy TPS. It runs bloody lovely now.

[Dirty]

that metal round thing for tightening stuff.

Ah yes, a hammer! :)

[Saint aka ML]

Ok while changing belts had a look around and rubber between airbox and injector on left isde has slipped off the airbox side. Would explain why those occasional hissing/airbox back fire sounds sounded like coming from left.

We shell see. Bike is running bloody lean anyhow so mixture adjustment is in order, especially that I still did not change air filter or pipes.


On another note, how do you know that on your supposedly 6k miles, 2007 695 engine belts were never changed.....

Well the green marking paint still in place on all bolts and belt tensioners in exactly same spot as it was painted on.

Old belts still look ok after 7 years hehe.

[Saint aka ML]

Ah yes, a hammer! :)

My favourite tool but in this case no, it was hose clamp I was on about.

[Dirty]

Old belts still look ok after 7 years hehe.

Stick em on eBay. Actually no, I need a belt change, I'll have em off ya :mand:

My favourite tool but in this case no, it was hose clamp I was on about.

Meh amateur, pro would use the correct tool and that's, 99% of the time, a hammer, the other 1% it's a bigger hammer!

[Saint aka ML]

Well that was not my air leak crap.

[Darren69]

Hi, Did you sort your air leak issue? Sorry can't help much on the coil/spark plug issue, according to the bible which doesn't go into specific detail both bikes have Magnetti Marelli ignition with 45mm throttle bodies so I would hazard a guess that they are both the same, but it probably wouldn't hurt to put a pair of matching coils and ht caps on to help keep everthing in sync.

[Saint aka ML]

Well just change cable and plugs over. Bike is much smoother at lower RPM and yet to have that funny airbox misfire and covered about 80 miles today.

It could have been that one of the old plugs was failing and misfiring from time to time which would be more noticeable at low RPM slow movement. We shell see.