Dyno testing of my 501 engined 3 1/2

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julianharty
Posts: 478
Joined: 15 May 2016 16:34
Location: High Wycombe
Location: High Wycombe Area (Bucks)

Dyno testing of my 501 engined 3 1/2

Post by julianharty »

I've seen discussions of the exhausts, carbs, airboxes, etc. to get 501 engined 3 1/2's to behave. I've owned my 501 engine since it's youth in a 501 New York. NLM fitted it with their S/S 2-2 clone exhausts and standard airbox (with filters) into a 3 1/2 K1 frame about a decade ago and 2 years ago I replaced the exhausts with a tweaked set of the standard Excalibur exhaust system and have ridden it to Italy and back, to Cadwell and back, etc. perhaps 5,000+ miles in it's current guise.

Earlier this week I took it to PDQ in Taplow, Berkshire to check the power output and jetting. We found it ran best with the 120 mains I'd been using. We tried 130's, 125's and 115's. With the larger mains the fuelling was better (closer to the 13:1 the tester reckoned was ideal) but power dropped. With the 115's power was marginally down but he reckoned that was perhaps down to the heat of the bike at the end of the testing runs (of about 85 minutes overall). We settled on the 120's to protect the engine.

Peak torque is at just over 5000 rpm (5,230) at 31.38 ft-lbs
Peak power is at 7000 rpm (7,010) at 35.88 hp

He recommends I fit either a lambda sensor to both downpipes or a 1/8 bsp take off (as used by Aprilla's apparently) in the U bend so he could get a more accurate fuel/air reading (which was a problem throughout the test at the end of the Excalibur exhausts).

BTW the bike does an indicated 170+ kph quite easily and pulls extremely well with few fuelling problems. I seldom see 180 kph, it's maxed out at 170+.

In terms of general riding, It's a bit grumpy off idle. It's very pleasant otherwise, and I use the bike for everything from long distance (250+ mile runs) to commuting into C. London as well as shorter rides. Fuel consumption is in the mid 50's MPG perhaps up to 60+ MPG at times. It cruises very happily (where the law allows, etc) at an indicated 145 kmh. I do have a Givi clear handlebar fairing fitted and ride with Tomaselli adjustable clip-ons.

I hope this helps others. I'll test my 3 1/2 at some point, once I get it back together after it lost the rear head insert and the 2-1 downpipe got mangled.
MickeyMoto
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Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: Dyno testing of my 501 engined 3 1/2

Post by MickeyMoto »

My Excalibur 501 with Buso silencers uses 118s. I tried 120, 115 and 130. Slight stutter off idle, but a change to the idle jet (or whatever) will cure that. Mine will run to over 90, but feels it is running out of steam. I think this is a cam profile problem. Maybe the Excalibur exhaust setup is a great help. I am running standard 500 downpipes with the balance tube. The bike is brilliant around town as it pulls from 2k. On the open road, over 40 and top gear overtakes are possible. I made the mistake of using 500 gearing, but have reverted to Excalibur as the engine revs higher than the 478. The higher gearing blunted the performance. I agree with the fuel economy figures, too.
julianharty
Posts: 478
Joined: 15 May 2016 16:34
Location: High Wycombe
Location: High Wycombe Area (Bucks)

Re: Dyno testing of my 501 engined 3 1/2

Post by julianharty »

I went to the effort of fitting the Excalibur exhausts as my bike simply wouldn't reach 160 kph (100 mph) with the 2 into 2's. I'll try changing the pilot jets and also 118 mains. Thanks for the suggestion.

BTW I'm considering getting the excalibur tubing copied in S/S and adapted to fit better in a 3 1/2 frame. If you'd be interested in a set let me know. The exhausts exit differently so you'd need to change your silencers too though. Stuart @ NLM has many sets of the standard Sito ones, or we could try finding some less restrictive ones.
'It must be a .....'
Posts: 364
Joined: 12 Sep 2010 12:25

Re: Dyno testing of my 501 engined 3 1/2

Post by 'It must be a .....' »

Hi, I have a 500 Camel fitted with a 501 Coguaru engine (Ducati Electronica electrics and ignition).
After lots of messing about with filters, jets, exhaust (silencer flow is adjustable) etc to get it to run well and rev out; I settled on the standard 500 air box/filters and changed to 42 pilots jets (from 55) and 128 main jets (from 76).
It starts easily, runs well and once warmed up has quite a low tickover for a Morini, but I've always meant to experiment further using the 130/125/122 main jets I have; first I'll get some new X18 needles (2nd notch) as the current ones are past their best and I should have changed them ages ago.

With gearing have the opposite problem as I am using Camel 500 sprockets which doesn't really suit the engine, although the acceleration is fun.

Many thanks for your posts, Ian
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