ESE's works engine tuner

[husaberg]

Ha, was going to use his bike as an example. Rear brake lever was made from Perspex.

Plenty of ally discs in Buckets. Use organic pads.

for years the 50/80 and 125 gp bikes used alloy disc rotors Zanzani?


Harry hunt sold ones in the states
The first i remember was the MV racers in the 70's
they were i believe plasma sparayed but you could i assume do one these days out of MMC

[husaberg]

Kawasaki had plasma sprayed aluminium disks on their racebikes years ago. (pre carbon age) No idea how well they worked. Bro-in-law made an aluminium rear disk for one of Bruce Ansteys TZ250 as it only had to work for scrutineering, he never used the rear during races.

Ha, was going to use his bike as an example. Rear brake lever was made from Perspex.

Plenty of ally discs in Buckets. Use organic pads.

for years the 50/80 and 125 gp bikes used alloy disc rotors Zanzani?


Harry hunt sold ones in the states
The first i remember was the MV racers in the 70's
they were i believe plasma sprayed but you could i assume do one these days out of MMC

[katinas]

And remember, it´s a 201m racebike, not a trackbike that is running lap after lap after lap.

Yes, I forget that this is for drag race, so suspension less important than weight.
Another good option for rear could be the very light 16.5 front magnesium wheels. I use few 16.5 front wheels for rear, just made brake disc and sprocket adapter, whose shape allows little torsional movement (add photos).
A superb brake discs, could be made from car clutch flywheel disc. Stopping power of this special iron material is amazing. Disc can be made small in diameter and therefore much lighter while maintaining efficiency of bigger steel disc. One down side is rust.
Two other photos, rear ventilated iron disc made from Honda CBX 550 inner type brake adapted to CBR 600 lightened rear wheel 17x4.5. But material is not as good as from car clutch flywheel.

Some Honda NR/NS/NSR front forks tubes were made from carbon fiber with outside layer of thin chromed aluminium tube.

[pete376403]

A superb brake discs, could be made from car clutch flywheel disc. Stopping power of this special iron material is amazing. Disc can be made small in diameter and therefore much lighter while maintaining efficiency of bigger steel disc. One down side is rust..

A friend bought a write-off BMW K100 which required new discs. He had a couple made from LandRover flywheels - worked very well, although, as you say, always a light coat of rust in the morning - wiped off with the first application of brakes. (helped that he had access to a big lathe)

[ken seeber]

Wile we're on the topic of lightweight disc rotors, here's one that we do for karts:

https://www.kiwibiker.co.nz/forums/s...post1130999910

[TZ350]

.


Blue line was the first cut Red line after some carb adjustments.

I had machined away the inside faces of the crank wheels as much as possible. I wanted to get as much crankcase volume as I could and with the wider space between the wheels I hoped it would reduce wind-age on the conrod as it passed between the cheeks of the flywheels. Also the big end oiling should be improved as it is completely un-shrouded now.

A lot of the counter balance had been machined away. No idea what the B/F was now or what it should be so I just tried it as is. The vibration is so bad at 9,000 rpm I had to throttle off. 9k was about 105 mph on the dyno. The aim is to be able to run on out to 10k which looks to be about 115mph.



Ok. Re balancing the F81M 250 crank. Eight 14mm x 16mm slugs of Tungsten (99%).

Done one side, now have to swap over and do the other side. Looking for a 55% balance factor.

This engine vibrated real bad at 9,000 plus rpm. I am looking for a useful power spread from 7500, to 10,500 rpm. With the peak at 9,500.

The ignitions soft limiter is set at 10,500 and hard limiter at 11,000. But the limiter does nothing if the mixture goes leanish as then it runs away like a glow plug engine. On the occasions that it did this, I saw 12,000 plus before I could get my hand over the carb bell mouth and drown the engine into submission. Frightening.

[TZ350]

2Stroke Stuffing eureka moment.

[TZ350]

.


All this re balancing palaver started because I machined away the inside faces of the crank for better B/E oiling, less windage on the rod squeezing through the original narrow gap between the wheels and more crankcase volume.



The original idea was to drill a size for size hole and hold the slug in with JB Weld. With the excess JB squishing out the 3,5mm pilot holes that were drilled right thru the crank cheek.



52% balance factor was achieved with seven slugs of Tungsten. I had calculated 6,5 slugs but I guess on the finished job there was some air space behind the slugs.



It turns out that the old drill cut slightly undersize so the slugs were a press fit and I did not need the J B Weld.

Seven slugs in total. Four one side three the other. I wonder if this will set up a rocking couple? And would it matter?

[Vannik]

A cautionary tale about crank balancing (I know it is 4T but still relevant):

https://www.youtube.com/watch?v=_RvNt8qWMgc&t=633s

[F5 Dave]

Lordy, I think I aged a month waiting for that dude getting to the point. First Tshirt adds, then talk talk talk.

Rob I think all this palaver actually started when you asked a mild trail bike engine to rev higher than its intended 4-6000 range. Unavoidable.

Looking forward to progress.

[peewee]

CR1000

excellent but why they dont put nitro in there .maybe scared ?

[wobbly]

Rob - I have rebalanced many cranks with Mallory using a press fit - twice one slug has moved.
Its easy to TIG two small spots opposite each other , just fusion weld the two materials together , never had an issue since.

[TZ350]

Rob - I have rebalanced many cranks with Mallory using a press fit - twice one slug has moved. Its easy to TIG two small spots opposite each other , just fusion weld the two materials together , never had an issue since.

Yes, off to Machine Parts Welding tomorrow, to stich weld the seven Tungsten slugs.

[karter444]

Hi Wobbly,
Was wondering if you could answer a couple of questions , that may be of interest to others as well .

1. If you were running 100cc direct drive air cooled reed and rotary engines and your main concern was looking after the engine and extending engine life , what type of oil would you recommend ie either a castor based oil like castrol R or a fully synthetic and why .

2. Why is it that TM have designed the head and insert on the kz engine to have no coolant flow directly over the insert , I havnt seen this on other engines . I imagine the risk of deto would be reduced if the insert had direct water cooling . If the head and insert were machined to allow coolant flow over the insert would the jetting need to be adjusted leaner to achieve the same egt and if so are you just back to the same situation where you are still one jet away from deto to achieve max performance .

cheers Richard

[Ocean1]

Yes, off to Machine Parts Welding tomorrow, to stich weld the seven Tungsten slugs.

I'll be real interested to hear how that goes, even using a laser the melting temp difference is huge...