K & L Dynamometer

[Jack Gifford]

Drag chute won't do?

[Koncretekid]

Tom, one tip the manuals never tell you with this type dyno is to never use the bike's brakes to slow it down after a run, it will fry the brakes in seconds.  Lots of Dynojet operators have learned this lesson the hard way.

This dyno has no brake!  Allowing it to slow down on its own takes about 3 minutes, which incidentally is how I performed the coast down test to determine rear wheel, chain, and bearing drag.  As a result, I have to use the bikes brake to slow it down as gently as I can.  So if the rear brakes wear out, I don't really need them anyway.

Also, it is imperative to tie the bike down in both directions... And don't try to bump start the motor from the speed after the run.

Like transporting a bike in a trailer or on a truck, I always tie the bike down with 4 straps.  On the rear wheel, the tie downs don't want to be too tight and the tire pressure needs to be at the upper limit of their rating to prevent excessive drag.

Tom could you take the Yam to another Dyno get some results then fiddle with the software to replicate it.
Good advice on overrun from the roller you will need to be careful with the BSA gearbox,i usually pull the clutch and use the dyno's brake to slow down then select neutral once stopped.

Andy, I could test one of the bikes on another dyno, but the dyno guy I used before (Dan Dunn) has left the area. By using the Yamaha factory rating, I should get some "happy horsepower" numbers anyway.  And as for not downshifting while the wheel is spinning, I think I've already learned the dangers of that - - twice! Remember my infamous transmission swap at Bonneville last year?

Drag chute won't do?

Good idea Jack.  But I haven't figured out how to get the dyno moving fast enough to make that work!  Although the wheel did slow down a bit faster when the tail end of one of the tie-down straps got caught in the rear wheel.

Tom

[Koncretekid]

Latest update on the old Dyno is shown in the following photo.  It shows the new brake shoe I've added as well as the polyurethane capped starting wheel on the starter motor.  Both features work well so I'll be able to save some brakes on the old bikes.  The brake shoe is custom made with dual 3/16" steel supports which were radius'd on a CNC mill to get the exact radius I wanted.  I then had a piece of 1/8" plate rolled to fit and welded the supports to the shoe.  The brake lining I picked up on Ebay as sold for old tractors thru which we drilled  a dozen holes, counterbored for rivet heads, and fitted to the shoe.  The lever mechanism is self energizing and is welded to a piece of tubing with bushings so it operates separately from the starter with which it shares the shaft. The pedal is not shown here but protrudes up thru the floor of the Dyno adjacent to the right side of the bike, same as the starter pedal does on the left side.

Hopefully I'll get a couple of bikes on the Dyno this week.

[RidgeRunner]

     Looking good!   

     Nothing like being able to gather data at your own pace in house when you want to.

                   Ed

[Koncretekid]

Thanks, Ed, but unfortunately, the dyno is in Colorado and my race bikes are now in Nova Scotia!  It's getting tougher to make the long drive between places.

Hope to see you in Loring where I'll be bringing the B50/ 600cc with the new rear suspension and a longer tail, as well as a new untested B25 (250 BSA/Triumph).

Tom

[RidgeRunner]

Tom,

     My 4 mile drive between work places suddenly looks much better to me now!

     We're currently getting the head back together with a better cam and valve springs to match.  Still far from being a bullet but along with some other changes it's no longer a 'yard engine.  Planning on being back in July to see just how many steps we can climb the speed ladder.  Looking forward to checking out your new old iron, stealing tech, and picking your brain again.

                     Ed

     

     

[Koncretekid]

A short video filmed with my I-phone showing a dyno run with my BSA B50 Tracker project.  I didn't have the hold down straps tight enough which is why the tire slipped upon starting.  Quality with the I phone is poor, but it shows how it works. Performance Trends dyno hardware and software recorded a maximum horsepower of 37, but that is only comparable to my other bikes which showed as follows: BSA B44, JE piston +.020", electronic ignition, otherwise stock = 28 hp
BSA B50 SS, JE piston + .020", points ignition, otherwise stock = 31 hp
BSA B50 Land Speed Bike, punched out to 600cc, Megacycle cam and much, much more = 64 hp
This bike, BSA B50, +.020" JE piston, 32mm Amal carb, electronic ignition,  Sifton HT cam, ported and dual plugged head = 37 hp


https://www.youtube.com/watch?v=ShaNig9EpB8

Tom

[Koncretekid]

I've updated the old K&L dyno significantly with the addition of Performance Trends Datamite  hardware and software, a new computer, and a full enclosure.

[Koncretekid]

Computer doesn't like my attachments so I'll try again.

[Koncretekid]

More photos: The exhaust flows into a 4" diameter truck muffler and then into one of those rubber garage hoses.  I'd like to add a stack to get the noise directed more upward.  We've got several horse farms within a half mile, so I have to be careful.  Luckily, the immediate neighbors are all gearheads! I've also added a "leaf blower" at the front aimed at the motor for cooling.

[Koncretekid]

And more, no more than 500 KB per post. The fan bought on eBay as "surplus" was new and powerful enough for about 9 air changes per minute.  Window in the back causes about a 10mph wind to flow thru.  Side window came from local recycle facility and is triple glazed.

[Koncretekid]

And finally, the starter, made from a Dodge reduction gear starter and a polyurethane wheel is actuated by a foot pedal on the left.  The brake shoe is fitted to the dyno wheel and lined with brake shoe material riveted on.  It is operated from a pedal at the right of the operator.  Before I had this brake in place, I burned up the rear disc brake on my APS bike as well as ruining the disc.

Also the view on the dyno room empty.

[Peter Jack]

That's a really nice installation Tom. 

Pete

[Rex Schimmer]

Tom,
That dyno is really nice!!! and serious! Looking at the numbers on your various bikes the 600 is really impressive. I live in Northern Cal and near Petaluma and Duke and I have our engine done by Engine Dynamics. The owner there is Mike Crowther who happens to have been the engineer at Triumph back in England that ran their research and dyno facility. They are probably the most expert at doing motorcycle head work in the US. They have done a number of research/development projects with the likes of Honda and KTM to name a few so if you ever need head work on your B50s you might consider them. They did the head on our 1000 cc Kawasaki and it is impressive.  They have done a number of the 450s that are run on the flat track circuit and are getting 75+ hp from them.

Which meet are you planning to run this year? Duke and I are planning to do both Speed Week and the World of Speed.

Rex

[Koncretekid]

Rex,

World of Speed - -thanks for the advice and complements

Tom