Italian Tune Up

martymoose

martymoose

Hero member
Location
Sydney, Australia
Had an interesting diagnosis today in the workshop. 2019 truimph bonnieville T120, 8 valve verticle twin 1200cc. 9000km, had run on 98 octane. Presented with a pretty big knock, top end. The knock went quiet between the piston accelerating and decelerating, so I thought piston little end/ wrist pin issue.

Got the motor warm, and sprayed a heap of three bond super engine conditioner down the plug holes. Took it outside after it soaked in, and let rip, huge amount of carbon came out the back. Knock gone! Older owner had basically just putted around and carbon had built up till the piston was hitting it.

Ride fast, use 95 octane.
 
Thinking aloud, cuz I'm bored at my desk... A big build up of carbon could give a few effects to create knock.
> Bits of it might glow and create pre-ignition.
> A massive build up would increase the compression ratio, especially when you open the throttle wider than the owner fella and increase the volumetric efficiency of the cylinder filling.

Great to see you got a fix for the noise. Happy days.
 
Good tale, Marty. Never had that issue with either my motos or cars :cool:. In fact I systematically give the Skoda diesel max throttle to redline a few times in 2nd if it's been tootling around town too much. Older PD motor tends to accumulate a little residue on the turbo blades and wherever else and the DPF must be getting on (200,000km) because it'll leave a cloud of smoke behind. And, no, it wasn't a VW cheater - been checked and cleared.

Surprising how many vehicle owners think tootling is good for engines and revving the fukken things is damaging to engines.
 
Same story with my Merc E320 diesel - I give it the full berries every month or so, to clear it out. I tend to do it at night on a quiet road because the smoke screen laid behind me is really very bad. Following traffic would definitely not be able to see where they are going. First time it happened was by accident (racing a knobber) and I was amazed at the billowing clouds of grey shite in my mirror.
 
Andy said:
Why would 95 be better than 98 in this case?
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Depends on the local mix - the proportion of aromatics used to achieve the desired octane rating can make some fuels more prone to heavy carbon deposits.
Did you try the NPD 100 octane while you were in the South Island ? I've found it very good in race engines and it's available at the pump locally.

The Italian tune up reminds me of a shop in Christchurch back in the day. Well known for quick tunes on twostrokes.
It consisted of taking them out the back into the alley - and revving the tits off them for 5 minutes. This knocked the carbon off the edges of the exhaust ports and restored performance. Not so easy today with clean burning oils.
 
a good story and good tip!

back in the day (earlier engines) it was always 'a thing' to run the engine out when you could, especially for the plugs and I think appropriate for running in as well ...
 
I had a minor oil leak from the generator cover, ( '76 180° Triple) a few years/10,000 miles back.
After a particularly spirited ride back from the pub, with Nick and Clem, it had fixed itself and remains fixed.
 
PD as against CR, Cam :cool: ... Pompe Deuse vs Common Rail diesel, DPF - diesel particulate filter (removes soot from diesel exhaust). Dunno what NPD fuel is ...
 
NPD is just the company name for a locally owned chain of petrol stations.
No Greg I didn’t try their 100 option, although I have used the 98 from BP a couple of times when available, then kid myself that I can go faster 🤣
 
When we were kids my mate was into dirt bikes and got himself a Yamaha YZ465, which was an enormous step up at the time. After a while he thought he was getting used to it, then he cleaned huge amounts of carbon from the expansion chamber…
He gained very strong shoulders while he owned that bike!
 
Andy said:
NPD is just the company name for a locally owned chain of petrol stations.
No Greg I didn’t try their 100 option, although I have used the 98 from BP a couple of times when available, then kid myself that I can go faster 🤣
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Before NPD got set up, the BP 98 was the best available in the South Island. All the Post Classic race bikes I looked after were set up on it as you could go to the Burt without having to take your own fuel....But you still had to know where the BP station carrying it in Invercargill was.
 
Andy said:
When we were kids my mate was into dirt bikes and got himself a Yamaha YZ465, which was an enormous step up at the time. After a while he thought he was getting used to it, then he cleaned huge amounts of carbon from the expansion chamber…
He gained very strong shoulders while he owned that bike!
Click to expand...
We used to ride our RGV 250's and NSR250's on slicks , for track days to Pukekohe, and fill the bikes up with Avgas or at least we called it that, there was always a long line at that pump, at the gas station down the road from the track. , Im sure it was a BP. From Hamilton, we would go left at Huntly and take the back roads through Glen Murray to Tuakau and then into Pukekohe. We thought we were hero's, the ridding on road and track was great, especially the ride back, the stuff you do when you are 17 in the early 90's . Nothing quite like the smell of a two stroke running belray.
 
sideshow said:
We used to ride our RGV 250's and NSR250's on slicks , for track days to Pukekohe, and fill the bikes up with Avgas or at least we called it that, there was always a long line at that pump, at the gas station down the road from the track. , Im sure it was a BP. From Hamilton, we would go left at Huntly and take the back roads through Glen Murray to Tuakau and then into Pukekohe. We thought we were hero's, the ridding on road and track was great, especially the ride back, the stuff you do when you are 17 in the early 90's . Nothing quite like the smell of a two stroke running belray.
Click to expand...
Did you ever do nationals ? I was involved in a mass teardown of the whole 250 prod field at Levels toward the end of that era. Very interesting as it showed who were the good riders - on stock bikes - and the not so good on worked cheaters, LOL. Like Formula Ford, the cheaters paid good money to get from the back of the grid to the mid-field.
 
GregT said:
Did you ever do nationals ? I was involved in a mass teardown of the whole 250 prod field at Levels toward the end of that era. Very interesting as it showed who were the good riders - on stock bikes - and the not so good on worked cheaters, LOL. Like Formula Ford, the cheaters paid good money to get from the back of the grid to the mid-field.
Click to expand...
I didn't do nationals, I just did odd rounds, mostly Bay Park before it was closed, and the odd Pukekohe event, At that age money was a hard thing to come by as an apprentice, to get me much further. I loved the RGV's but I was a honda boy at heart, my favourite being the MC18 R5K, there was just something about that bike, it was the old Scobie honda prody bike. I went right through the NSR models up to a Mc28, but that couldn't be raced in production, but it was tricked up and could hold its own on the road against far bigger bikes.
I could never understand the cheaters in the production class, Its supposed to showcase the rider, but then I guess that is human nature to push things
 
at one time there was a set of gauges to lay on the cams of your 500 Laverda racer, so as to be sure and check that they had the stock profiles,
not used in the UK (errhem) thankfully, and I don't recall any 500 in my day ever beinbg stripped and getting the bore and stroke measured, (there were some 600's around in 500 proddy racing, but not inside mine)
CLEM
 
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