Dyno questions

Beng, the chromate coating on Manx Norton electron crankcases was covered by a UK Ministry of Technology Specification (DTD934 I think). These days the process uses used in the aircraft industry vary according to the composition of the magnesium alloy. I cannot find a source of the old specification, years ago they were available from Australian DOD. And I do not know which magnesium alloy the old crankcases were made out of. My friend is talking to Bruce Verdon of TT Industries because he treats his magnesium gearbox cases, however it is not an ideal situation. - My friend could still end up with his crankcases looking like hessian bags. With baked on Castrol R, even acetone or MEK won't usually shift it. There is a product here called Yuk-Off, it is a graffiti remover and it is very effective . However it contains glycol ethers which can effect your balls. If the vapour from it even wafts over plastic parts, it unlocks the stresses, and the part falls to pieces. By the time I told my friend about it, it was all too late - the idiots had struck ! The guy who did that blasting could even be sued - there is a lot of anger involved.
 
Dances, I appreciate what John has posted and your comments are also correct if you live in a place which is not full of hicks. Most of our local machine shops are excellent, however other businesses are very suspect . They tend to make every post a winning post, and often fall short on detail. There is only one dyno near here, it is about 40 miles away in another town. I know our local superbike champion has used it, however he no longer does that so there must be a reason. I will definitely go and have a look at it, and if the operator looks sane I might take my bike there. However I know that I will have to keep the whole process under close scrutiny if I'm to get value. Dyno tuning is too close to my own profession, which I don't usually combine with motorcycle racing. I know the calibre of person who is needed to produce reliable data. The local schools around here do not produce them.
 
Beautiful piece of engineering work by JohnM!!! It made me smile, then when I thought of the cost, I winced.

John has a ton of research planned, and I wondered if he could get the same results at less cost than a dyno run.
Here is the nutshell of my musings....you guys can take it and run with it if you think you can make it work.

You have all seen the data loggers that road test vehicles tow. They are nothing more than a wheel revolution counter and timing device. Distance is obtained from Pi x Dia of wheel, instantaneous speed is Distance / time per rev, and acceleration is the speed change between two successive revs / time change over that interval.

Wheel rev can be obtained by mounting a cylindrical magnet in the wheel rim...use two 180 apart to preserve balance. A magnetic reed switch can be used to send a pulse to a PLC (programmable logic controller), and the PLC has internal programmable timers for timing. It would be helpful to have a handlebar mounted push button switch to use as an event marker. With a 12 v battery for power (might need two in series if the PLC requires 24 vdc), the whole package could be home built for less than $300 US.

The PLC will be logging elapsed time between wheel revs, and there will be a stream of data points in PLC memory that can be dumped into a computer and massaged to produce instantaneous speed and acceleration. Next, your bikes road speed per engine RPM can be worked into the software to produce instantaneous acceleration vs engine RPM.

If you then found a paved course over which you can do repetitive testing, engage top gear, and starting at low end RPM, then hit the event button and go WOT. Dump the data, massage it, and graph it. Next make your tuning changes and do it again, and compare results. You do not get actual torque or HP from this procedure, but if you get higher instantaneous acceleration over part of the rpm range, you are getting more torque.

You will need to perform repetitive runs with the combined weight of machine, man, and fuel within 1/4 pound (100 grams) and for this end you might want to ballast the bike with a 10 pound (5 kg) sandbag. That way you can let off weight should you gain it between runs.

Record ambient temperature, barometric pressure, wind speed and direction. These will allow "correction" factors to be worked in to the software.
 
texasSlick said:
If you then found a paved course over which you can do repetitive testing,.
Click to expand...

While this has some merit - seat of the pants, WITH datalogger - actually finding a 'paved course' suitable for this is not as easy as it sounds.
Some quiet roads out the back of Arkansas, or Texas, might work, but one stray cow or horse or dog - or car - could ruin your research program !
Not to mention the constabulary, who tend to take an interest in this sort of thing....
Lets see - unreg, unroadworthy, no mufflers, no insurance, no MOT, no lights, no blinkers, slick tires ?

Dyno hire for a run is probably a lot cheaper than hiring a racetrack ?
Or paying the fines.
Unless you can recommend a suitable road ?
 
Rohan said:
texasSlick said:
While this has some merit - seat of the pants, WITH datalogger - actually finding a 'paved course' suitable for this is not as easy as it sounds.

Dyno hire for a run is probably a lot cheaper than hiring a racetrack ?
Click to expand...
Click to expand...

Yes that is exactly the issue. I live in Wellington and there are no roads anywhere where I could do say 15 runs over a 6 hour period without a visit from the Police department! (Many years back the Velo did get run out in the Wairarapa countryside and a local friendly policeman turned up. By some miracle he was a bike nut and he just told the boys to go home and not come back or he would have to throw the book at them!!) Not something to ignore :)

The nearest track is 2 hours and even then you would need to hire it 100% which is way more expensive than the dyno.

From memory I have done about 5 dyno visits. Maybe an average of 15 20 runs per time - 4 to 6 hours at a cost of say US$ 350 a session. Sounds a lot but hp per $ is a lot less than most race parts.
 
I am aware of the issues regarding using public roads for testing. It should be possible to obtain permission from a private airstrip owner. We have plenty here in Texas, as well as some ranches having mile long paved roads. Of course, there will be some who live where there are none convenient. This may not be for those persons. Purchase an airman's map of your area. Private strips will be marked with a P or color coded. Then do some research to find the owner. Offer to pay for the privilege....

Also, there is nothing "seat of the pants", which I interpret as "subjective" 'about this scheme....the data logger will produce definitive , measurable , repetitive results, just not in torque or HP units. Who cares....you just want to know what tweaks will get you around the track faster.
 
Re your recent comment on things to test, In the Dunstall Norton engine tuning data, he comment that the 500 engine requires & goes better with smaller diameter exhaust pipe. When you think about it, it makes sense as each cylinder is 125cc smaller than the 750s. Bigger pipes on a 500 is not the way to go.

http://www.ebay.com/itm/Paul-Dunstall-N ... 2074wt_932


http://www.nortonownersclub.org/library

dustall-domiracer-bed-t11983.html?hilit=dustall

http://www.nortonownersclub.org/noc-cha ... tart:int=0
 
Tuning exhaust systems involves getting the exhaust pulses (frequency) and velocities in "tune" to best scavenge the cylinder and exhaust plumbing. Sometimes this is best achieved by using a smaller Dia. pipe to increase the velocities.

Wasn't there a Japanese mfgr who put a small Dia pipe inside a larger one? The mfgr knew the small Dia would be a better tune, but buyers (especially Americans) associate bigger pipes with power, and would have sneered at the dinky tubes.
 
Exactly which type of cylinder head are you using, has it got the inlet port carb bolt holes vertical or horizontal :?:
not that it matters that much :D
 
Bernhard said:
Re your recent comment on things to test, In the Dunstall Norton engine tuning data, he comment that the 500 engine requires & goes better with smaller diameter exhaust pipe. When you think about it, it makes sense as each cylinder is 125cc smaller than the 750s. Bigger pipes is not the way to go.

dustall-domiracer-bed-t11983.html?hilit=dustall

http://www.nortonownersclub.org/noc-cha ... tart:int=0
Click to expand...

Hi Bernhard,

Thanks for all those links. I had not seen several of them before.

I am aware of Dunstalls comments about header pipe diameter. I tested over 1.25, 1.5 and 1.625 in. OD. The answer is it depends. If you want absolute top end and are prepared to sacrifice the power band use shorter headers of small diameter. If you want to fill in bottom end you need very long headers. Mine are over 40 " long and most people recomend 32 " and shorter . If you use very long headers you need bigger diameters. Somewhere I have a spread sheet with a sumary of header lenght versus diameter versus width of power band.

This is clearly an area where my bike has not bothered to read the literature to see how it should behave. :) What can I say. I tested the pipe options carefully and I have reached a different conclusion from Dunstall.

Actaully there is a good reason why long headers work and it is discussed in Blairs text book - specfically in the chapter on tuning the G50.

Another area where I do not agree with him is the use of bellmouths and long inlet tract extentions. In his tuning book he says he did not find them useful. I found them very useful.

I could also point out that Dunstall would not have had the use of a modern dyno. Even Peter Williams was very interested in my results when I showed him. He said they did not have comparable test facilities in the Norton factory when he was there in the 1970s.

My head is a SS head. That is the casting used from 1962 on and very similar for all 500, 650, 750 and all Commando heads. Carb mounts are horizontal
 
About road testing bikes. I don't use public roads. I raced at Winton Motor Raceway near my current home in Benalla over a 12 year period when I was a kid. Much later and after my first marriage I came up here to work, and finally retired in the town. I started the Winton Motorcycle Club and I am still the Secretary. We have a bout 90 members , mostly involved in Motocross. Each Friday there are usually separate practice sessions on the bitumen for both cars and bikes, we also now have our own MX circuit as a starting point for the kids. It costs about $200 for any practice session on the bitumen, Fridays or 'Moto Ride Days' and that includes licence and insurance. There is always an ambulance and first aid person on stand by. I suggest that if you live anywhere near a race circuit, it is worth getting involved with the local bike club, or start one where there is not one already in existence . Winton Motor Race way is owned by the Benalla Auto Club and I have inveigled one of their committee members to become our motorcycle club President (he now runs the Moto Ride Days as an earner. ) Our motorcycle club has reciprocal rights agreement with the Benalla Auto Club members, - we use their office, computer and staff, and we meet each month in in their nice new warm air conditioned conference room. The whole thing is run as a well-controlled business although still not-for-profit. I think you will find that any race circuit owner is always interested in finding a new source of revenue, and supporting enthusiasts. All this motorcycle stuff depends on 'critical mass' for success, however petty jealousies can be destructive.
 
John, You mentioned tuning your cam advance, would you please tell me your inlet and exhaust opening points (at nil tappet clearance) if you feel you would not be giving too much away ?
 
Ok I just have a normal PW 3 cam and if you go here you will see the Mike Hemmings spec sheet that has been posted by someone whose name I have forgotten - sorry!



search.php?st=0&sk=t&sd=d&sr=posts&keywords=PW=3=settings&fid%5B%5D=1&start=600

This gives you the standard opening closing settings.

Now the PW 3 is a Commando cam (stroke 89 mm, rod lenght 5 7/8 in) and I have installed it in a 500 Dominator (stroke 72 mm, rod lenght 6 inch) So the rod stroke ratio is very different - 1.68 Commando 2.1 Dominator.

This means the piston is in a slightly different position in the stroke in a Commando or Dommie for the same degree of crank rotation. If you dont beleive this then please stop reading now :)

Which means do not use the same cam advance in a Commando as I used in the Dommie.

Beleive it or not my cam is installed 5 degree retarded. Most (all) engine tuners will advance a cam on a race bike over a street bike- say around 5 degree. On a Norton this can be done by remeshing the timing chain and timing gears. I have not found a reliable vernier yet and either just accept the approximate setting or these days I use one of my collection of about 5 cam sprockets which all have slightly different settings.

Which is along way of saying if your working on a Commando I cant help with advice on cam advance except to repeat what the books say.

John
 
John, I have also used a very short stroke 500cc motor, and I used very different cam timings. In my 850 motor I use the standard cam but advanced 12 degrees. With the two into one pipe, it works very well. The cam sprocket I use has three keyways, the other two I has broached randomly after softening the sprocket. I find I can usually get within two degrees of my timing objective. I recently bought a combat cam from Brett Wolfie, when I fit that I will advance it only 6 degrees to get the same inlet opening , slightly different closing. However I think the exhaust closing might be much better. At the moment the exhaust timing is about - open 94 deg.BBDC, closes 27 deg. ATDC, - however I've achieved an inlet opening of 65 deg. BTDC. The performance is excellent - loads of torque.
 
texasSlick said:
Also, there is nothing "seat of the pants", which I interpret as "subjective" 'about this scheme....the data logger will produce definitive , measurable , repetitive results, just not in torque or HP units. Who cares....you just want to know what tweaks will get you around the track faster.
Click to expand...

Perhaps seat of the pants wasn't the right phrase - would you prefer on-road real world-testing, bugs-an-all ?

What level of expense is involved in a sophisticated enough data logger here though ?
 
acotrel said:
In my 850 motor I use the standard cam but advanced 12 degrees.
Click to expand...

By coincidence if you go to my post of 28 July and look at the first plot labeled Exhaust options.

The dark blue line labeled original exhaust is my first run ever. It used a 4s cam installed straight up and a Campbell street type exhaust which was vey quiet. It has a nice smooth power curve and would be good for a street bike. About 34 bhp at rear wheel and for a 500 Norton street bike this would be a pretty good result.

The second pink line labeled Original Ad cam Hunt is exactly the same set up but with the 4 S cam advanced 13 degrees. It was supposed to be 6 degrees but I mixed up camshaft and crankshaft degrees !!! (I was just learnng ;-)

Above 6300 rpm they are identical

Around 5900 the advanced cam filled in a bit of a hole by about 1.5 to 2 bhp.

Around 5100- 5200 rpm the advanced cam gives an extra 4 bhp

But around 4400 and below there is reversion in the carb and bad megaphonitis. This is a very characteristic result with an over advanced cam even with a street exhaust. You dont need a megaphone to get megaphonitis if you try hard enough :). However you can tune a lot of this out with header and inlet modifications.

Step by step I built up the curve. You can usually get a big easy step win in PEAK hp with a good megaphone exhaust but it takes lots of work to then make the bike rideable especially with a 4 speed box. Thats the importent bit. The numbers on the dyno do not matter - just the improvement. You could put my bike on another machine and it might say 45 bhp. Another one 55 bhp. It just the change and the improvement in ridability that matters.
 
John, When I first rod e my short stroke 500cc Triumph it was fitted with 4 inch megaphones. It was extremely nasty and difficult t o ride. I made a two into one exhaust for it and after much modification of the pipe finally got de cent lap times out of the bike. When I built the Seeley Commando 850, I virtually went straight to a reasonable answer. The bike is superb to ride, and I am possibly somewhere near the optimum. However I am using methanol fuel through Mk2 Amal Carburettors fitted with Mikuni Needles and home made needle jets. From my Triumph 500 days, I have a head start there too. I'm using fairly rich Mikuni petrol needles, however there are twelve alternatives listed on the web for different applications, compared with three for MK2 Amals. I'm certain there is still opportunity for improvement.
 
John, When I first rod e my short stroke 500cc Triumph it was fitted with 4 inch megaphones. It was extremely nasty and difficult t o ride. I made a two into one exhaust for it and after much modification of the pipe finally got de cent lap times out of the bike. When I built the Seeley Commando 850, I virtually went straight to a reasonable answer. The bike is superb to ride, and I am possibly somewhere near the optimum. However I am using methanol fuel through Mk2 Amal Carburettors fitted with Mikuni Needles and home made needle jets. From my Triumph 500 days, I have a head start there too. I'm using fairly rich Mikuni petrol needles, however there are twenty alternatives listed on the web for different applications, compared with three for MK2 Amals. I'm certain there is still opportunity for improvement. From memory my current needles are 6dp6, the 6 series needles are used in VM round slide Mikuni carbs from 30mm to 38mm choke size. here is the list :

http://www.mikunioz.com/needles_numerical_list.htm
 
John, what fuel are you using and what are you permitted to use ? I'm sorry if my comments are old-fashioned, however my brother and I have been doing this stuff for a long time without the help of a dyno. I still have a problem relating throttle opening, fuel demand, and gearing for different circuits. I usually base my adjustments on improvements in performance around the three tight bends and short straights at the back of Winton Motor Raceway. If I can get around there really fast, I know I will be OK in races on that circuit even if I lose a bit at the ends of the longer straights.
 
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