.................*NICK BRAMLEY'S 186CC ENGINE*.............

Hi All,

Some info on Nick's race engine!

http://postimg.org/image/jnoxz05zh/

Hi All,

As I learn image hosting the subject practise will focus on Nick's race motor of 2014!.................

Cheers!...........Rex

Thank you for that Rex,
                                 Scaling that port against the 64mm piston there seems little time/angle area and even less blow-down, could be the reason that the engine is a modest rever? Can you offer us any more technical specifications. Is Nick remaining as the works rider for 2015, living here in the wilds of Somerset, little news filters through of the outside world!

Trevor

Hi Trevor,

Thank you for your interest in Nick's 186cc engine!

It is a privilege to work with Nick and a lot of the results were down to his vast two stroke knowledge!

More photos!

https://2img.net/h/s6.postimg.cc/62cmctykx/GEORGE_TODD_BILLET_HEAD_MACHINED_AND_SAND_BLASTE.jpg

https://2img.net/h/s6.postimg.cc/bzbwfwqc1/CYLINDER_PHOTO_9.jpg

https://2img.net/h/s6.postimg.cc/vv7vvg7dd/PISTON_CROWN_LOWER_COMP_3_Q_6_NJ_260_MAIN_2_MALL.jpg


Owing to Debb having health issues since January 13th, my time here is restricted, but Nick thought this might help with ideas for fellow enthusiasts!

Cheers for now!..............Rex

hello rex,
nice pictures, are you building this one new or we are seeing the 2014 motor?

was good  talk to you the other day, you mentioned my photos of the new spare engine, heres a few other pictures from other angles etc
these were taken before the hone had finished the dia and before a final smoothing in the transfers and inlet exhaust too,

Morning Dan,

Good Day!

I like the look of your cylinder and am looking forward to how it performs!

The engineering is excellent!...................

The photos of Nick's engine are from the 2014 race/development motor!

The basic concept started in 2012 as a step up from the Mick Grant Trials cylinder to test some ideas and achieve a modest

performance, i.e. 20Bhp at the rear wheel.

After that result on the dyno Nick did the race testing to get more data!

https://2img.net/h/s6.postimg.cc/5e3rtvzv5/BANTAM_MARK_2_ROAD_PIPE_CHALKIE_RUN.jpg

Debb's health issues have moved the goalposts somewhat so now we are working on some solutions to help more with our

learning!

It might be that the Bantam won't be satisfied until it can fly with the Eagle!............

Cheers.............Rex

rex,
an interesting graph, good low rpm figures, seems an opposite from how mine feels,
i've found a localish dyno man the other day and having spoken to him i feel i'll be happy going there,
itll be maybe better for me than a trackday as i'll not be wearing tyres and using life up on the bike as a whole,

i hope to make it there before the mallory meet but so far i'm pleased with the new one , starting is easy and it rev's and falls with a nice sound, looking forward to see what it'll do, this barrel has been a chance to try a few different things namely wide transfers (46mm) and a new exhaust height ,

once its on the dyno i'll video it and post on here with a few figures.

on another note , debb seemed in good sorts the other day on the phone , hope all goes well , glad she's on the mend .

Hi Dan,

Thanks for your interest in Debb! I will pass on your wishes!...................

Good to get your information! Looking forward to your results!

During this morning's tea break I am practicing more engine photo posting!..............

Here goes............

https://2img.net/h/s6.postimg.cc/opudhljdd/BANTAM_20_BHP_CON_ROD_KIT.jpg

https://2img.net/h/s6.postimg.cc/kyksva5ox/BANTAM_20_BHP_CRANKSHAFT_6.jpg

https://2img.net/h/s6.postimg.cc/azzu8sw9d/BANTAM_20_BHP_CRANKSHAFT_7.jpg

https://2img.net/h/s6.postimg.cc/s5mhr5glt/BANTAM_20_BHP_CRANKSHAFT_8.jpg

https://2img.net/h/s6.postimg.cc/3vdfm0zm9/BANTAM_20_BHP_CRANKSHAFT_4.jpg

https://2img.net/h/s6.postimg.cc/t6mqg9xld/BANTAM_20_BHP_CRANKSHAFT_3.jpg

Now back to work...............Have a Good Day All!...........

Rex

Not criticism just observation of the dyno curve shape...
... I take it the "DIN Smoothing" means results are corrected to a known DIN Norm ....

Must be heart warming to have 10horsepower (at 5000rpm) at the rear wheel with a Bantam (nearly 190cc, of course). It is the dip at 8000rpm that has me perplexed. I can understand a four stroke engine having such (The racing Jag did...) with bvariable valve-timing and wonder what causes such a drop off and recovery from 8 to 8.5k rpm in a two-stroke....

Can someone explain that please?

Lovely pictures Rex & Nick -- looks as if it must sound good too.

Cherrs!

JayBee nursing an Envy-Eruption...

A very useful statistic to compare different engine performance is to calculate the relative BMEP (psi). As peak power is extrapolated from peak torque it is with that figure these calculations were made, and Rex`s power graph from the dyno that shows peak torque at 14.3ft/lbs. As transmission losses from crank to rear wheel are commonly taken as 12%, the torque figure must reflect that and the revised number is 16.1ft/lbs. peak power of 20.8hp therefore jumps to 23.3hp.
The standard formula for BMEP is given as: T x (constant) 1.283 / capacity in ltrs.
Inserting our numbers for this we get: 16.1x1.238/.186= 107.2psi, converting to BAR means dividing that number by 14.5 and gives: 7.4 BAR from 186cc.
As the highest BMEP is at the point of max torque and coincides with the peak of volumetric efficiency it become a good indicator of relative engine performance.
To provide some context to this isolated number, the 500cc Manx Norton of the mid 50s achieved 14bar at just over 7000rpm and the 125 Aprilia of 2007 achieved 16bar at 13,250rpm. My w/c 125 engine comes in at just under 9bar at 10,500rpm!
7.4bar speaks for itself, the engine ran out of breath at 7750rpm and power dropped away as revs carried on, perhaps an earlier miss-match somewhere chimed in at 8700rpm held 18hp till 9000 and dropped away again.
Ignition timing can play a big role in engine performance and I notice a faint indicator of 1.1 mm-14*btdc is shown? Running a static set up does no one any favors and 14* is very much a compromise that suites neither bottom nor top end of the rev scale.
This post has revealed two very fine big Bantam engines with some similarities and differences. Great credit is due to both Dan and Rex for their creations and being magnanimous enough to share their concepts and engineering secrets with us all.

Trevor

Hi Trevor,

Thank you for that Great explanation of potential on Nick's 186cc engine!

Before the official opening hours of the shop, I can make time for a couple more photos!...

https://2img.net/h/s6.postimg.cc/xfwyyxo41/NICK_NEW_ENGINE_A_MAY_2014_2.jpg

https://2img.net/h/s6.postimg.cc/5q0dxzz9t/MOTOR_WITH_TAPER_BORED_VM32_RIGHT_VIEW_AT_MALLOR.jpg

https://2img.net/h/s6.postimg.cc/uurebeyq9/MOTOR_IGNITION_STATOR_AT_MALLORY_JUNE_14_2014.jpg

Debb is in full time recovery at the moment so now is a Great time for me to develop extra skills........

Cheers and Have a Great Day!...............Rex

interesting about the timing, I set mine at 0.070" static, I have a ducati energia type, and having put the strobe light on it I does as the rule say move 4 degrees , by 3500rpm , on the normal engine it'll rev to 10000 no problem and I have a max revs recall on the counter and some times it'll peak at 11500 or so, my new spare engine has bigger flywheels 4 7/16 " so I guess it'll be getting less rev.

Wonderful pictures Rex ...

Makes me wish I got into tuning instead of habba-a-dabba-doo racing.

Cheers with envy!

JayBee...

Be careful what you wish for Dan, revving your engine to 11,500. At that speed the upward inertia loading at tdc is around 1373kg(3,028lbs), not so bad in the other downward direction at 856kg. Going bang at that speed loading will total the engine! Bit of an educated guess at the reciprocating weights, even so we are in the right ball park.
You may get less revs with the larger diameter crank discs, but what you will get is a higher inertia crank working at a larger radius of gyration! That may be good or not, it depends what operating conditions you are seeking riding at the circuits you compete at.

Rex, good photos and it`s nice to see a mixture of traditional features and the modern, even down to the brass plate advising contact breaker points setting? Yours is probably the most original looking engine out there and I guess sits well with the other commercial interests of trials and road bikes.

Trevor

yes Trevor, scary init !

Hi Trevor,

Thank you for your comments on our mix of old and new!

This project has turned out to be a Great teacher.................. !


https://2img.net/h/s6.postimg.cc/67vjduoup/NICK_NEW_ENGINE_H_MAY_2014_2.jpg

https://2img.net/h/s6.postimg.cc/xwi6ldbv5/BANTAM_20_BHP_POST_RACE_EXHAUST_COLOUR.jpg

https://2img.net/h/s6.postimg.cc/6aff0osi9/DYNO_DAY_AT_CHALKIE_SEPT_17_2014_1.jpg

https://2img.net/h/s6.postimg.cc/o6ze2k4lt/NICKS_BIKE_5.jpg

https://2img.net/h/s6.postimg.cc/d4ub44aj5/NICKS_BIKE_LEFT_VIEW_2_DYNO_DAY_13_JUNE_2014.jpg

By the way John, a Great friend of yours--AB has been an avid Mentor for us!

Cheers!.........Rex

Rex,
More nice pictures, you`re spoiling us. That exhaust pipe is an object lesson in design, manufacture and installation. Take note every one, no excuses for high level, serpentine pipes that so many use, and that compromise efficiency.

Trevor

the front part is impressive, i like the whole thing but that part in particular !

Hi Dan,

Thank you!

Andy Bacon makes a cracking job!.......................

Tea break time so more photos (Technical)!!

https://2img.net/h/s6.postimg.cc/64k3gkcwh/PORT_MOULDS_RACE_CYLINDER_1.jpg

https://2img.net/h/s6.postimg.cc/yipj0g0gh/PORT_MOULDS_RACE_CYLINDER_2.jpg

https://2img.net/h/s6.postimg.cc/pwm9fuogh/PORT_MOULDS_RACE_CYLINDER_3.jpg

https://2img.net/h/s6.postimg.cc/jwyic73o1/PORT_MOULDS_RACE_CYLINDER_4.jpg

Wishing all of you a Great Time in the workshop!................  

Rex

That exhaust pipe is a beautifully made thing, but I would have some misgivings about the angle of bank it will permit. The ones I used "back in the day" were similarly positioned but quite a bit smaller. I had no problem with cornering clearance, but tyres back then did not grip like those in use today. It will be interesting to see how it works out for the rider.

I hope my fears prove to be groundless - hey that's a good pun!

All the best,

John C. - Emeritus Professor, College of Old Farts.

i think the photos are old one from last year john, and apart from cadwell    I know It touched down there

Hi John,

Good Morning

Good to have your input!

Nick did experience cornering limitations from the pipe as you you predicted!

https://2img.net/h/s6.postimg.cc/65c4ae24x/NICK_PIPE_4_2.jpg

https://2img.net/h/s6.postimg.cc/k0aesuwk1/NICK_PIPE_4_1.jpg

I did wonder if the old 19" wheel size would give benefits.............

What do you think?

All the Best!

Rex

Good morning, Rex,

Ouch! That was a hefty wallop. It's good to know my eyes were not deceiving me. No doubt 19" wheels would help, but only if suitable racing tyres are available in that size.

As an aside, once upon a time at Cadwell, I had both tyres let go simultaneously on the long right hander approaching the Gooseneck. The bike dropped onto the exhaust system, which threw it back upright again! It must have looked like a spectacular "save", but was just dumb luck. Terry B. could not believe it when I told him we needed more cornering clearance! He looked at the flat on the chamber, and stood there shaking his head, until I explained what had happened.

Rex:
I see Nick has the same problem as me, with the "Sprinter" pipe !

My proposed solution is to follow Captain Bain's example and use a Bushman front frame loop, which puts the engine some 2" higher.
In the meantime , I am getting some new engine mounts made to lift up the engine in D7 Road frame.

19" tyres not really a viable auction, unless you want huge tyres.

I really like the plain classic looking Bantam !

Keep up the good work