Idle Problem?

OK, so for the past few times i have used the GRiSO, the idle speed has dropped to 1000rpm when its been cold, almost as if the clutch is dragging, it only happens for a few seconds and then pops backup to 1250rpm, doesn't happen every time, but you feel the bike might stall with it in gear.

What should i check?

Valves. Immediately. Have they opened up?

Also sniff your oil. Any hint of a 'Burnt' smell?

If the valve clearances have opened up or the oil smells odd stop riding until you've checked the tappets.

Pete

Pete, i shall go and smell the oil, the bike is outside, i will need to ride it home though. What am i looking for on the tappets?

Thanks

Just smelled, the oil, smells like almost new oil it was changed 1800 miles ago, no burnt smell

Check the valve clearances. If they have opened up appreciably be suspicious.

As the tappets fail the valve lift and duration changes. This means the engine doesn't breathe like it is designed to. With the W5AM controller the amount of air being moved is judged by the position of the throttle butterfly and its density by the pressure sensor and ambient temp sensor.

If the tappets go out of whack, either by mis-adjustment or wear to the componentry the engine will pump differently. If it's wear then duration will be shorter and lift diminished which effectively means less air. That should mean that the engine will run rich and therefore the tick-over will be lower. BUT?

Idle speed is hard coded into the ECU as a target to be achieved. How this is done is by the use of an 'Air over idle' system that uses an air bleed valve known as a stepper motor. If the idle tries to drop it will pass more air to lean the mixture and increase the idle speed but it only does this at idle.

If you throttle off and come to a standstill the engine may, in the early stages of tappet failure, try and stall due to the mixture going overly rich. This will 'Panic' the stepper into over-compensating and slamming wide open causing the engine to idle high. After a couple of hundred cycles though the ECU will recognise this and close the stepper down again to stabilise the idle at, or as close as it can get, to its idle.

I'm not saying your tappets are fucked. Other things like dirty TB's will also create the same problem, but if it happens the first thing to do is check your valves. If they have opened up appreciably it's a red flag. Don't ride it until you've examined the tappets and if they are dodgy rollerise. There is no other alternative.

This may be a red herring. It may simply be a poor tune or dirty TB's but checking the valves is so easy it is cheap insurance and if the tappets are going west the quicker you catch it the lower the chance of complications.

Pete

Thanks Pete.

The bike has been rollerised 6000 miles and a year ago. I have just been out to start it, its 22C here and it starts and idles perfectly. I think the non idling is only when it is cold in the mornings, it was only 12C here when i came to work.

I will check the tappets tonight.

After starting it just now there is a distinct hesitation when you go to rev it from idle, this disappears when the bike warms up a little, maybe (hopefully) i just have some dirty TB's, recent full service 1800 miles ago. If i check the valvel clearances tonight and they are ok, is there anything else to look at before i drop it back to the shop?

Thanks in advance Pete.

Are the charcoal canister, valve & hoses still on the bike?

tocino wrote:

Are the charcoal canister, valve & hoses still on the bike?

So far as i am aware the bike is standard apart from the Termi exhaust and that it has has the roller tappets, new crank, cases and oil pump, because of the failure of the original tappets.

Could it be blocked?

It's possible - or the charcoal got saturated by gas (unlikely I'd think). After I performed the "cannister-ectomy" on mine it did idle better; but I wasn't experiencing your symptoms. You could remove yours and see if that changes anything, provided removing the canister is something you want / planned to do.

I don't think they have the charcoal canister in pommy land.

If it's been rollerised you don't need to worry about the tappets. Do check the clearances and balance the TB's and re-set the TPS and clear the trims. Do you know for sure that the TB's have been balanced correctly? Are both the air bleeds open by any chance?

Pete

Pete, i will re-set the TPS and clear the trims, don't have a TB balancer, so will acquire one, i assume at the last service they were balanced, but hey you never know. Will look at the air bleeds. Just got home and the bike idles perfectly when warm.

Might take a day or two to check, but will come back with some updates, really appreciate the help

I've often found that shops don't balance TB's. I have no idea why not but I have a sneaking suspicion they don't know how to in many cases or they may of messed with things that shouldn't of been messed with on a previous bike so it ran like a munter and therefore don't like to risk it again!

Checking the air bleeds is always a dead giveaway. If they are both open they either haven't been touched or the bike has been 'Tuned' by an idiot!

As has been said many times before the 8V is very sensitive to set up and it is so easy to do yourself with Guzzidiag and a Morgan Carbtune that it's insane to trust it to any shop you don't have 100% faith in. A fair amount of my time is spent in-fucking other shops fuck ups.

Pete

This continues to amaze me. I am a weekend mechanic AT BEST and learning how to do, checking valves and balancing throttle bodies was super easy and required very little time.

To me, it is dishonest to service a bike and not complete something so basic - that should have been done at the factory!

That said, best of luck in getting things running smoothly.

Do you know which map you are running? My 09 with termi pipe did exactly as you described until I bumped the co trim from 0 to + 3. At + 5 it will disappear altogether but I keep it at +3 and it only does it when it's really cold say below 45 f. My GRiSO has not yet been rollerized, and I have been running Beetle's fantastic map.

Thanks Lucian, i am hoping to have some time this evening to check everything over.

Currently the CO trim is set to 0.

So all checked, no movement at all from the tappets, air bleeds seem ok, tps set correctly, reset the learning and set CO2 to plus 4.

Will see what happens if i take it to work in the morning