exhaust port

some very true words being spoken there,

ive read many books, and ive dun all the sums but i just cant use a dremmel for shit.

its so frustrating as ive got quite a few maps ive calculated and i wanna try but everytime ive tried to lay a map on to a barrel its never the right shape. lol,
just wanna try one, den improve it, try again etc but last time i tried i some how ended with triangle inlets and a exhaust 8 degress out from where i wanted it! lol

 

ok so last weekend I took the motor apart. I didn't have a dremel so I used a chisel and a hammer. I put everything back together but now it won't start...Why?????
cratch: :wallbash:











hahaha...na just joking. It's done. just got to tune the tranny. used to pull between 6 and 7 k...but now pulls from 7 to 8 k. Top RPM is still same though....hmmmmm?

 

hahahah! relax...chisel never came out!
But results stated above are true.

 

Hey man....don't have the measurements on me....using different computer and can't get to it everyday...thats why i haven't posted much lately.

I have a porting programme here...actually a few :rofl:
I'll hook you up with the measurements hopefully by the weekend. Cos i want to put them in my programmes and see what i get compared to you.

 

yeah got limited resouurces at the moment...will have a little bit of 'tin' at the end of the month to spend...working as barman at the moment.

You still want the bore and stroke? doubt so without the rest.

I got a LV ZX at home....but i reckon its for a 50cc....the header is the same diameter as stock (round about) and it doesn't give performance....is it cos of the restrictor in the cone? there isn't one in the header,
Thanks

 

yeah I agree...bigger isn't always better when it comes to 2 strokes.... But it seems abnormally small and abnormally long (the header) compared to all the other 100cc pipes.

When my PRD pipe was on it performed at it's best....but gradually got worse and worse....the got the ZX and was the worst...even with the tuned tranny, So whipped the PRD back on. Unfortunately the only picture I have is on another scooter site, so won't be able to show you.

I got jennings book on expansion chambers at home....labelled

DO YOU REALLY WANT TO KNOW ABOUT EXPANSION CHAMBERS.........

and basically made me even more confused.

Does the silenser have anything to do with performance? maybe increasing pressure or something allowing crisper pressure wave? Cos the pipe isn't performing well with the sort and fat ZX silencer on...hmmmm

 

http://www.bigscale-trucks.be/image/mot ... _usa_3.jpg

reading this at the moment
http://images.google.co.za/imgres?imgur ... l%26sa%3DN

yeah i get what you saying...oh the ZX stinger was wank thin....compared to my pipe.

 

Iv heard it's a bitch to make cos of the wood rollers you have to make first...just thinking about it is making me want to leave it. But the pipe and the cylinder must work in conjunction with one another and parts here are scarce.

Seriously thinking about a 70cc. What all would have to be changed in a 100cc to make it a 70cc?

 

Reading this thread with intrest and if you want Dylan I can send you a spec sheet (scan it an email it) of a pipe design for your current specs.
How you build it is up to you
Id need specific info tho:

Bore
Stroke
Conrod length
Gudeon pin offset (height above or below the centre line of the piston)
Exhaust port height (over all)
Exhaust port height from the top of the port to TDC
Exhaust port duration or degrees it opens ATDC
Effective exhaust port diameter (actual port in the cylinder wall)
Effective exhaust port diameter (opening at the manifold)
Length ot the exhaust tract (from piston face to manifold)
Required operating RPM
Max RPM peak power.


After crunching the numbers this will produce a pipe that`ll work well for the specs provided.
Affecting matters will be the quality of construction,cone matching (not easy to roll cones whose edges match perfectly, i know ive hand built over 30 now)
and material although it`s always easier to build them out of low carbon mild steel simply because it`s easier to work with and is the perfect material for resonant pipes that ...resonate a lot (read vibrate).

 

WOW...that'll be first prize hey!
Iv'e sent you a PM...
Really appreciate it

 

Not gonna build it for him Minor just going to crunch the numbers and send him the specs to build to, it`s a challange so it`s a freebie and you never know I might wind up in a bar in S. Africa one day and need a drink