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Re: RS Winter Project [message #285313 is a reply to message #285244] Thu, 07 August 2014 20:36 Go to previous messageGo to next message
Pipe is currently offline  Pipe   United Kingdom
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(22) Giacomo Agostini
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As you know, running leaded again.

Everything looks mint!

The Sunaco fuel i bough turned out sour ... i found out some real bad stuff on it ... so forced since to find an air field selling Shell Avgas which is a great life line ... cheap too, relatively.

No detonation from 7 sessions = roughly 140 miles = half the piston life.

Time to tweak the jets down and push that BHP graph up Laugh

[Updated on: Thu, 07 August 2014 20:44]

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Re: RS Winter Project [message #285321 is a reply to message #285313] Thu, 07 August 2014 22:39 Go to previous messageGo to next message
Kermit is currently offline  Kermit   United Kingdom
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Not quite quite following the no detonation = half piston life think

Compared to....?
Re: RS Winter Project [message #285323 is a reply to message #285321] Fri, 08 August 2014 07:29 Go to previous messageGo to next message
Kakugo is currently offline  Kakugo   Italy
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(18) Geoff Duke
Kermit wrote on Thu, 07 August 2014 23:39
Not quite quite following the no detonation = half piston life think

Compared to....?


The pistons' lifespan is 280 hours.
Re: RS Winter Project [message #285324 is a reply to message #285323] Fri, 08 August 2014 07:33 Go to previous messageGo to next message
Quazi is currently offline  Quazi   United Kingdom
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(22) Giacomo Agostini
Kakugo wrote on Fri, 08 August 2014 07:29
Kermit wrote on Thu, 07 August 2014 23:39
Not quite quite following the no detonation = half piston life think

Compared to....?


The pistons' lifespan is 280 hours.



Bargain! Wink
Re: RS Winter Project [message #285325 is a reply to message #285324] Fri, 08 August 2014 10:58 Go to previous messageGo to next message
Kakugo is currently offline  Kakugo   Italy
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Quazi wrote on Fri, 08 August 2014 08:33
Kakugo wrote on Fri, 08 August 2014 07:29
Kermit wrote on Thu, 07 August 2014 23:39
Not quite quite following the no detonation = half piston life think

Compared to....?


The pistons' lifespan is 280 hours.



Bargain! Wink


At that price, surely! Laugh
Re: RS Winter Project [message #285331 is a reply to message #285325] Fri, 08 August 2014 20:34 Go to previous messageGo to next message
Pipe is currently offline  Pipe   United Kingdom
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14 x 20 minute sessions = 280 minutes! = 4.67 Hours

Re: RS Winter Project [message #285332 is a reply to message #285331] Fri, 08 August 2014 22:29 Go to previous messageGo to next message
Pipe is currently offline  Pipe   United Kingdom
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This is all estimated.

I do need for my own benefit need to work out the crank and piston actual mileage this year.

I will post results tomorrow.

My gut feeling is this bike cost about £4 per mile or £100 per 25 mile session based on a session being 20 minutes on a 2.5 mile track = 25 miles.

It's a HRC GP Bike....

As for detonation ....

It can damage pistons, heads, cylinders through collateral damage and more importantly ... The Crank Main Bearings ..... Which are not repairable or serviceable on the RS.

Once they have seized they are scrap and so are many other parts in that scenario. It's a major rebuild and at least crank case welding.

[Updated on: Fri, 08 August 2014 22:41]

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Re: RS Winter Project [message #285333 is a reply to message #285332] Fri, 08 August 2014 22:55 Go to previous messageGo to next message
Pipe is currently offline  Pipe   United Kingdom
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One other thing for tonight.

You must be aware that this bike is like nothing else you have ridden in your life.

Jan Freeman had a taste of a 125 so she probably knows more than most.

It has taken me 4 years to learn how to ride it, treat it and look after it.

It very much forces home just how good the bikes are that the best riders in the world have available to them and then again ... it's a very humbling experience that your 20-30 seconds a lap off what they achieve ... and it's mainly all achieved in the corners Laugh eek

The experience has totally opened my eyes.

[Updated on: Fri, 08 August 2014 22:56]

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Re: RS Winter Project [message #285342 is a reply to message #285331] Sat, 09 August 2014 09:15 Go to previous messageGo to next message
Kakugo is currently offline  Kakugo   Italy
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Pipe wrote on Fri, 08 August 2014 21:34
14 x 20 minute sessions = 280 minutes! = 4.67 Hours



I was overoptimistic... though many Chinese engines don't last that long. Laugh
Re: RS Winter Project [message #285367 is a reply to message #284614] Mon, 11 August 2014 23:25 Go to previous messageGo to next message
Kermit is currently offline  Kermit   United Kingdom
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I have been reading up on Karts and noticed this which caught my eye - maybe HRC don't know jack about buiding engines RollEyes if the bhp figures quoted are about right as I'd have thought 250cc and twin cylinder 2 strokes built for racing would all produce similar amounts think

http://en.wikipedia.org/wiki/Superkart - Division 1 section is the one I'm looking at as division 2 seem to produce similar/a touch less to your RS but I'm curious to know what makes the difference between D1 and D2 engines

More tech info on Formula E (which is D1's old name) which does mention Honda RS and Yamaha TZ engines being some of the engines used http://www.250superkarts.com/ABOUT250RACING.htm

Then again, it gives you something to aim for...one day Cool

Pipe wrote on Sun, 09 March 2014 21:02
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[Updated on: Mon, 11 August 2014 23:32]

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Re: RS Winter Project [message #285377 is a reply to message #285367] Wed, 13 August 2014 08:34 Go to previous messageGo to next message
Pipe is currently offline  Pipe   United Kingdom
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There are a number of things to mention here.
D1 engines are twin cylinder so that's the direct comparison realistically with my graph.
D2 engines are single cylinder and probably motocross engines, doubt you will ever see a 250 motocross engine with 62bhp.

Now here is why and I have noticed this before in the data given for various two stroke oils, take a look at this:

http://www.wp-motorsport.co.uk/res/HTX-909_uk.pdf

Note the rev ceiling, now look at this:

http://www.elf-racing.de/PDF/HTX976.pdf

Note the rev ceiling!

I use 976+. Now back to my graph, which is not showing rpm, but mine is tuned to make all of its power before 13,000 rpm which gives better torque lower down the rev range so you can drive harder off the apex of corners. (More about this later on)

Bikes need this as their apex speed will be much lower than a cart so you need the torque. Carts will need less torque because they will carry more speed so you can then tune them to make more BHP by raising the rev ceiling.

Same for motocross engines, they don't need and are not tuned for ultimate BHP, torque is much more important to that particular discipline.

So onto the other factors as two strokes are things that are influenced by many things.

[Updated on: Wed, 13 August 2014 08:35]

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Re: RS Winter Project [message #285381 is a reply to message #285377] Wed, 13 August 2014 08:53 Go to previous messageGo to next message
Pipe is currently offline  Pipe   United Kingdom
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Part 2 ..... As I am typing on an iPad and didn't want to loose everything I have typed with a 'session timed out' Laugh

Back to the graph: dyno run 016 175/180

Jetting, This is where you gain or loose 10bhp, depending how brave you are eek

There is definitely more to be had here, but how safe do you play? The leaner you go the more power you get and the trade off is seizure and reduced piston/ring life. It would be interesting to find out how frequently they replace the top end on the carts ... They have to be revving higher to make the extra power so the poor old pistons and specifically rings, are doing more work in a leaner and hotter environment.

I don't know how accurate this is but if a cart throws a piston it's probably less likely the driver will be spat into the air but on a bike, if it seizes when you are on the edge of the tyre then there is only really going to be one result Laugh

Time to go to work now so part three and four will have to wait Get your coat
Re: RS Winter Project [message #285383 is a reply to message #285381] Wed, 13 August 2014 15:34 Go to previous messageGo to next message
Kermit is currently offline  Kermit   United Kingdom
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Doh, never thought to consider that bhp is a result of torque and rpm and that Karts might well sacrifice the former for the later

And yes, I guess an engine blow up us the result over overly lean mix [in the pursuit of ultimate power) is probably a fair bit less scary on 4 wheels than 2 Thumbs Up

Re: RS Winter Project [message #285411 is a reply to message #272121] Thu, 14 August 2014 20:00 Go to previous messageGo to next message
Kakugo is currently offline  Kakugo   Italy
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Cannot offer much except with my experience with power equipment which stretches back quite a fair bit.
These engines are not as stressed as those used on a kart, but work in far more punishing conditions: poor oil, often way too lean to keep them environmental friendly, not much in the way of cooling etc.
On Japanese engines (including Dolmar) seizures or crippled bearings are rarely if ever heard of even when the engine has run hundreds of hours on chips oil. Immensely impressive, then people ask me why I am in awe of Japanese engineering.
On German engines (meaning Stihl and AS Motor) these mishaps are known but still happen at more than acceptable service intervals. I suspect the main reason is lubrication but I won't delve there otherwise this will devolve in an oil thread.

Now, many chainsaw engines find their way into RC airplanes, where they are invariably tuned for performances. Japanese engines (chiefly Zenoah) seem to be able to absorb whatever you can throw at them, but with a caveat: you still need to run them at 2% premix. The Japanese seem to have perfected the art of running engines on that premix percentage with minimal (if any) reliability concerns when it comes to oil grade. JASO FD is always the best choice (and very competitively priced) but you can throw at them that overpriced excuse Stihl sells as oil and they will gobble it up with no issue.

My point is that reliability on two stroke engines is a very fine line between F/A ratio and premix percentage.
HRC probably ran their bikes as lean and with as little oil as possible to get them through the racing weekend: after all their bikes are serviced by the best technicians in the world and for Honda rebuilding an engine every weekend is less than pocket change. I am ready to bet a shilling they knew exactly how to squeeze the last hp out of their engines by running it in such a way it would seize if run five extra laps. eek
Re: RS Winter Project [message #285412 is a reply to message #285411] Thu, 14 August 2014 23:25 Go to previous messageGo to next message
Pipe is currently offline  Pipe   United Kingdom
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I haven't finished yet Mauro Laugh

Now look at the length of a cart expansion chamber and of my RS Laugh

[Updated on: Thu, 14 August 2014 23:28]

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Re: RS Winter Project [message #285452 is a reply to message #285412] Tue, 19 August 2014 19:51 Go to previous messageGo to next message
Pipe is currently offline  Pipe   United Kingdom
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Part 3.

Back to it then after a busy week or so.

There is something definitely very different about the exhaust pipes on those carts to the ones on bikes.

They are very short and don't seem to have an expansion chamber followed by a narrow exit pipe.

This is used to block the exhaust port with pressure pulses when the inlet transfer ports are filling the cylinder so i don't quite know whats going on there with those cart pipes as on the bikes, a good set of well designed spannies make a lot of difference.

Maybe this is directly related to the rev ceiling .... needs more investigation me thinks.



[Updated on: Tue, 19 August 2014 19:54]

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Re: RS Winter Project [message #285453 is a reply to message #285452] Tue, 19 August 2014 19:53 Go to previous messageGo to next message
Pipe is currently offline  Pipe   United Kingdom
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Part 3 then.

Re: RS Winter Project [message #285454 is a reply to message #285453] Tue, 19 August 2014 20:28 Go to previous messageGo to next message
Pipe is currently offline  Pipe   United Kingdom
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Part 4 ..

Just spent ages writing about reed valves VS disc valves and it timed out.

So in summary, if carts run disc valve designs (the motor suppliers i have not heard of) ... they will win on the dyno for ultimate BHP but midrange will suffer ... Back to the two requirements of the engines i guess.
Re: RS Winter Project [message #285455 is a reply to message #285454] Tue, 19 August 2014 20:53 Go to previous messageGo to next message
Pipe is currently offline  Pipe   United Kingdom
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Part 5 ... Dynos and Wrap up.

Dynos are strange things and so are numbers from them, calibration/type and all sorts of variables effect the output on a graph.

It's only really relevant if you are changing things and using the same dyno ... which i will be doing.

Then you get a comparison of the change you have made to see if it's positive or negative.

Crank power from the RS at the moment is 87 (RE; Clive Padgett) from a dyno reading a rear wheel BHP of 79.

The works HRC bikes and the Aprillias are reported to have been well over 100? Crank? Rear Wheel? ...... who will ever know?

There is no better 'dyno' than the seat of your pants ..... and mine is currently the best it's ever been, it's massively quick for a 250 and i can't use the bike to its potential because i am 20 seconds slower around Donington than Jorge Lorenzo, on an Aprillia (he holds the lap record on a 250) and i probably only have 10-15 bhp less BHP if your talking crank power Laugh

I love the experience of it all though, its totally addictive. I am living the MGP dream and understanding more about just how very good those riders are and how very good the kit is that they get to ride ...

Its a level of understanding above watching them on TV and thinking ... they are fast.

[Updated on: Tue, 19 August 2014 21:08]

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Re: RS Winter Project [message #285456 is a reply to message #285455] Tue, 19 August 2014 22:27 Go to previous messageGo to previous message
gone2 is currently offline  gone2   Netherlands
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One other small item Pipe...they don't mind falling off, or wrecking the bike. That's worth 20 seconds a lap, I'd say.

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