ESE's works engine tuner

[wobbly]

MC21 deck dimension = 30.1mm

[2T Institute]

Has anyone experiences overhauling the Aprilia RS250 / Suzuki RGV crank? Mine needs a rebuild because of too much play at the right conrod.
I want to fit 110mm long TZ250 rods instead of the 105mm series.
1. Is it a good idea to convert the Crank to Washers at the low end? Is it even possible without milling of the crank web on the inside?

Happy to say I was the first to build a long rod rgv/rs engine, conrods can be bottom guided no machining needed

[husaberg]

Anyone have piston dimensions for a nsr250r mc21?

Looking for wrist pin to timing edge of piston crown please. Thanks!

Pretty sure they are on this site
http://edetuckracing.blogspot.co.nz/...5-pistons.html
here is his site as well
http://nsr250.freeforums.org/

here is plenty of piston, rings and conrod information anyway not related to the NSR250.
http://www.mitaka.co.uk/pistons.htm
http://www.wossnerpistons.com/produc...rcycle-pistons
http://www.pvlsverige.se/vrm/index/index22.html
http://www.tkrj.co.jp/product/m-piston-kit.html
http://www.mingyang-group.2u.com.tw/...Motorcycle.pdf
http://www.con-rod.com.tw/motorcycle-connecting-rod.htm
http://www.google.co.nz/url?sa=t&rct...MVppLeMVAqjHUA
http://www.mxcomposites.com/con_rod.php
http://www.connectingrod.com.tw/ktm.htm
http://www.pro-x.com/downloads/Technical.pdf
http://www.kevinbreedonracing.co.uk/...ts_conrods.asp
http://www.connectingrod.com.tw/honda.htm
http://www.samarin.nl/webshop/index....ewCat&catId=32
http://dl.dropbox.com/u/399336/Pictu...ted/HotRod.pdf
http://www.kingrod.com.tw/products.p...t&pc_parent=22
http://www.crankshaftparts.com/index...7_93&limit=100
http://shop.atlanticmotoplex.ca/prod...catalogId=2016
http://jjmachineryonline.com/snowmob...onnecting-rods
http://www.scooter-center.com/scoweb...y2=CAT&lang=en
http://www.bansheedepot.com/products.asp?cat=17
http://http://www.samarin.net/?productos

[Flettner]

come on then Flettner, lets have it. spill the beans,,,,

I'm a bit gun shy to say anything, it is interesting what you learn doing odd ball (dumb) stuff though. I'm sure Ryger wasn't a complete hoax, this high pressure transfer is interesting and being able to present the super homogenized (and heated) fuel air up into the head around the spark plug (with normal fuel air mixture further down the cylinder) might have the answer. Being able to adjust the compression on the fly (as in the beam engine) has a huge benefit for controlling HCCI timing. Ignition still started with the spark plug but shortly after (with the right conditions) HCCI occurs. Well that's the theory anyway. Isn't it ironic that squish may no longer be a good thing. Real work keeps getting in the way though bugger it!

[Tim Ey]

conrods can be bottom guided no machining needed

Well that is what I call lovely news Thanks a lot!

[jonny quest]

Great links Husaberg! Thank you!

Deck height is 23mm on NSR250 piston.

Wobbly, you must have given me the deck height of a NSR125. They're 30mm

[jonny quest]

What is meant by conrods can be bottom guided?

[breezy]

I'm a bit gun shy to say anything, it is interesting what you learn doing odd ball (dumb) stuff though. I'm sure Ryger wasn't a complete hoax, this high pressure transfer is interesting and being able to present the super homogenized (and heated) fuel air up into the head around the spark plug (with normal fuel air mixture further down the cylinder) might have the answer. Being able to adjust the compression on the fly (as in the beam engine) has a huge benefit for controlling HCCI timing. Ignition still started with the spark plug but shortly after (with the right conditions) HCCI occurs. Well that's the theory anyway. Isn't it ironic that squish may no longer be a good thing. Real work keeps getting in the way though bugger it!

maybe" true" hcci is still a dream away, but maybe new ideas of better si combustion will come from the hcci challenge..... still interested why your hcci test engine suddenly screamed to high rpm before it died...

[wobbly]

I have MC18 and MC21 pistons here, they both measure 22.6mm from the pin to the timing edge, checked with a vernier and a height gauge.
The pin is 15 dia so the deck height is 22.6 + 7.5 = 30.1.
This is also mentioned here, when we were looking at RM125 piston fitment.
http://edetuckracing.blogspot.co.nz/...5-pistons.html

Bottom guided rods are the " norm " and have silver plated washers each side of the thrust faces , with a clearance between 0.6 and 0.8mm.

[jonny quest]

My bad Wobbly. I looked at drawings from link Husayn provided.

I trust you.

I have a MC21, and wanted to do a +2mm to the stock cylinders. I want to use cast pistons, and pistons readily available in the USA. The RM and KX125 pistons are probably my best choice.

This will only be a commuter, not a track day bike. I don't want EX timing any higher than it already is, maybe even a bit lower than stock. Worried if I have to cut bottom of cylinders 1mm, it will mess up all the port floors for what I want to do.

I haven't taken motor apart yet, just general Web searches to get an idea of it's configuration. From what I've found, it's really an oddball motor. Not many part choices for how many they've made over the years

[TZ350]

Some terminology.



In the good old days the "Compression Height" was the distance from the center of the pin to the top edge of the piston. Excluding any sort of combustion chamber filling piston dome pop up.

A four stroke piston dome pop up is mostly about boosting the compression ratio by filling up space in the combustion chamber.



Some call the "Deck Height" the distance between the top edge of the piston and the block deck. The Deck Height can be positive or negative. It is negative if the piston edge protrudes above the block. The block or piston are machined to get the Deck Height required. I guess if it was a two stroke, we would call it "Setting the Squish".



But with all terminology you have to be a little careful about what others mean because the engine block "Deck Height" could also be the distance between the center of the main journals and the top of the block.

[oldjohnno]

So I've been thinking that what I really need is a thermodynamicist, and when I stumbled upon this interview I couldn't help but feel my prayers were answered. I mean, as two stroke builders we're all familiar with concepts like angle/area and so on, but this woman takes us much further with things like heat angles and the circle of hotness. Watch, listen and be in awe.

[WilDun]

So I've been thinking that what I really need is a thermodynamicist, and when I stumbled upon this interview

Either I'm on the way out and my brain is dying or something has gone wrong with the kids of today, they speak a different language, but they obviously have an exceptional understanding of things - much greater than mine!
One thing I do understand though, is that someone with that degree of wisdom must be kept out of the workshop at all times!

[husaberg]

So I've been thinking that what I really need is a thermodynamicist, and when I stumbled upon this interview I couldn't help but feel my prayers were answered. I mean, as two stroke builders we're all familiar with concepts like angle/area and so on, but this woman takes us much further with things like heat angles and the circle of hotness. Watch, listen and be in awe.
https://www.youtube.com/watch?v=bbjGdgtscDA

Either I'm on the way out and my brain is dying or something has gone wrong with the kids of today, they speak a different language, but they obviously have an exceptional understanding of things - much greater than mine!
One thing I do understand though, is that someone with that degree of wisdom must be kept out of the workshop at all times!

Not really the thread for this, but this is the best explanation of how it works

[richban]

After 3 years of slow development, the NSR300 finally is getting what it wants. Proper pipes. Many thanks Wobbly for the engmod help and pipe design. Also thanks Sketchy for the CAD help. Now its time to roll and weld. If I do a good job I will post the finished pipe pics. No pressure.