Throttle Body balancing

Morgan Carbtune. 'Nuff said.

beetle wrote:

Morgan Carbtune. 'Nuff said.

I prefer the twin max.  It compares the amount of suck in each inlet port, and balances the differential.

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I had mine for over forty years.  Still going strong.

Well I've had my Carbtune since the Silurian Era. When I was riding 4 cylinder Suzuki's. Or was that the Pre-Cambrian Era?  


Nyer!  

beetle wrote:

Well I've had my Carbtune since the Silurian Era. When I was riding 4 cylinder Suzuki's. Or was that the Pre-Cambrian Era?  


Nyer!  

Am with you dude, am still trying to wrap my head around why people are using Power Commanders and Booster Plugs when they could be running a much better Beetle map

I got "offered" a booster plug when I purchased my V85 a few weeks back. Surprised at where the offer came from too.

Some disappointment in all that.

Had a carbtune since the cambrian (when i was employed spannering on T140s)  

it wore out.  the steel rods scratch in the tubes until the stiction becomes really F*%king frustrating.

Bought a pair of cheap dial gauges (Bourdon type) swapped them over to check calibration and speed of respnse (it turns out that A reads 4% higher than B) marked them with the variation and that is it done.

Having ridden my GRiSO around London for the past 10 days I am more aware of low rev fuelling glitches. Seems almost like it runs on 1 pot until 3/3500 rpm when it all smooths out. Anyway, looked on the BSD website (UK dyno tuner) who smoothed out my KTM990 years ago, and found that they have done a GRiSO:
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Think I'll give them a go, unless anyone has better suggestion?

Have you checked the plug caps aren't arcing to the rocker cover?

No, but I will! My description of the lumpy low down feeling as if its running on one not two is a slight exaggeration! Just that it all smooths out at 3/3500rpm and although I think I have the 068 Map it might be worth a trip to BSD to fine tune it. All these noises and lumpy running only being noticed as I am riding in the City for the past week and probably another week whilst my Vespa is off the road!

Are the throttle bodies balanced correctly? Is the tune correct? Also the 68S map was originally developed for the flat tappet motor. I've never run it in a roller bike. That might be a factor in low speed behaviour.

Thanks. Was serviced in 2019 at Twiggers in UK but hasn't done much since due to Lockdown, until recently. So throttle bodies should be balanced but I will check. Map is just what I understood from some distant memory but could be wrong - Ill check! I've just treated her to a full fresh tank of 'super unleaded' to avoid the E10 and at a cost of £1.53 a litre!

Mine came with PCV/Autotune (and a rat nest of associated wiring).   I excised those and replaced with Beetle map and thought that it ran better.  Fast forward many months, I was on a 4 hour ride and it seemed to get rough at the halfway point.  Only 4K, but fingers crossed and, after doing plugs and wires, and checking exhaust for big leak(s), going in to do the valves-balance-TPS reset.  Additional alternative device attached.  Costs a bit more but comes with fittings and hose, is from a small business and made in  [You must be registered and logged in to see this image.] , so that's what we do.  We'll see.  "Digi Sync", available in 2/4/6 configuraions.

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Does one also need to worship Cthulhu?

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I'm thinking "FSM", given its noodly appendages!
We'll see how tomorrow goes, I'm likely to invoke all of those and then some!

I used to think that I would eventually mature out of...then retire from....the "fix it 'til its good an broke" club.  However, I'm still rocking emeritus status.   I still enjoy the learning, but have some trepidation now at the first attempt at anything and truly hate the subsequent do-overs that seem to be inevitable now.  I was pretty decent at wrench stuff when I was young.  That's somehow gone.    /end vent.   [You must be registered and logged in to see this image.]

Yes maybe too hot on left cylinder. Will not idle below1400 rpm. Haven't gone to third tank refill yet. Mpg for second tank is 53 mpg. 3300 to 3500 is Sweet Zone! Rev limiter is set for 68 or 7000 tops. I have my Littman stethoscope from my working days. Mechanically I can adjust the closing of each throttle body closer then it is now. Then I will check the air bleed on both TBs. I will pop a valve cover and see if it's a roller engine plus valve adjustment check. Nothing radical on this part. Stay tuned. I took the day off to finally get to this part.

Gas tank is moved and now I get to make the next discoveries. I will try to use photos taken today and tomorrow. (picture=1000s of words. The "up side" is that I can fix this. With the advice and support here it's almost guaranteed. We can start with MG ORIGINAL spark plug wires. Both air beads are screwed up tight fully compressing those little springs. Nothing I have done changes the high idle...so far. Back to the section here on balancing. There is a throttle position sensor. There is also a four pin connector dangling with nothing to connect to. One of the photos I will send are the tiny connecting rods with a roller over the cam lobes!

The rev limiter is set in the map. The flashing triangle is simply a gear change indicator and can be changed in the 'Settings' menu.

The four pin plug is likely the lambda sensor plug. If it is disconnected and there isn't a 'Service' warning exhibited on the dash then the bike is running an open loop map.

Before attempting to adjust anything on the throttlebodies you will need to get cables and download Guzzidiag and acquire a manometer for balancing the TB's. The 1400 idle may just be the result of worn throttlebodies but make sure ALL the hoses and drains on the airbox are attached, undamaged and in the case of the drains, plugged and ensure the air filter is clean and NOT an aftermarket type like a K&N or BMC or the like.

tiny connecting rods with a roller over the cam lobes.
Sounds like a roller motor.

Thanks for the guidance Pete. You might want to refer to this mornings post in the "garage & busted knuckles section. I am out of time today but tomorrow I promise to go through my downloads for repair and replace. There are colored photos but right now it looks like there is more then just the entire airbox missing. The entire crankcase and gearbox venting has been altered and replaced. Tell me how to PM you as this is wild stuff and I took photos. I will ascertain that they have possibly the stepper motor removed andif the ECU shares the bracket with the airbox..all I have is the empty bracket. I will check this before posting or pm you if you tell me how. I called my message the "rabbit hole" for good reason. I will be back tomorrow with my autopsy results. BTW it is or has been converted to rollers. This alone causes more questions. I'M having fun with a look of disbelief and wonder of what's next? I do have a plan "B". I paid book value for a bike worth a couple grand less. Then another almost two grand to fly out and have to U Haul back because it was not nearly road worthy with no rear brake along with what I didn't know or went unanswered when I asked. I should have walked away. I can easily buy any of the used classified Grisos this is an intervention to fix what never should have happened to such a fine engineering example of a motorcycle.