DT125R ARCHIVE

Members Login
Username 
 
Password 
    Remember Me  
DT125R Forum -> Tuning -> crankcase tuning...
Post Info TOPIC: crankcase tuning...
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
RE: crankcase tuning...
Permalink  
 

ARGH!!! more reading and brain warping biggrin wicked that nev,cheers. its already answered my questions on boost port angles... then raised one about boyesen ports???? biggrin also found this company for porting programs

http://www.porting-programs.com/



__________________

money killed everything....
NEV


Guru

Status: Offline
Posts: 2515
Date:
Permalink  
 

Lol, thats why I just gave the engine to Cornish motorcycles mate, and said do your magic, came back, re-bored, ported and gas flowed, and without the headaches. ended up with a lighter wallet mind.
Fair play to ya though, for having a go at it yoursen like.

__________________

 
mr karnage


Guru

Status: Offline
Posts: 439
Date:
Permalink  
 

the dark arts of engine tuning

__________________

red 1990 dtr - http://dt125r.activeboard.com/t45695405/red-1990-dtr/
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

well it was all decided when i got my mates dt off him and it had a 3bn cylinder and head,on its last rebore.... they were junk anyways so no loss apart from my time (and headaches,tourettes and sleeplessness lol) to be honest though,my 4dl crankcases and 4fu head will be goin to mick abbey biggrin



__________________

money killed everything....
NEV


Guru

Status: Offline
Posts: 2515
Date:
Permalink  
 

Theres actually a forum with all the technical info, could benefit from mate, not 100% but I think theres a small charge to join it.

http://www.macdizzy.com/forums/index.php



__________________

 
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

be well worth a look fella,cheers biggrin



__________________

money killed everything....
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

got a little more done on the cylinder today

aiming to make it like the sp on the bottom

and match the ports through.... i don't think the boost ports are viable though? think i'd hit the water jacket 1st?



__________________

money killed everything....
NORFE


DTR Trusted Engine Builder

Status: Offline
Posts: 1723
Date:
Permalink  
 

whats the sp barrel off???

looks like a good setup for a std barrel smile



__________________
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

they come off the tzr 4dl sp model fella. meant to make 33 hp at the rear wheel confuse still looking for a belgarda 4dl engine though,33 hp at the crank as standard (4he if its a swiss model) rare as rocking horse poop though....



__________________

money killed everything....
NEV


Guru

Status: Offline
Posts: 2515
Date:
Permalink  
 

Am sure the SP was a higher bhp Dave, the ones marked 'P' were 33bhp, I was on about this to someone the other day, I wish I'd bookmarked it now, but read that the 'SP' was near to 38bhp

__________________

 
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

that would make more sense nev. hard to find actual figures for it though,they're as rare as the bike lol even the belgarda's are getting rare now disbelief  33 hp in a dt could be a lot of fun biggrin



__________________

money killed everything....
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

right so i got on with a bit more on the top end i'm doin (ruining biggrin) cut the front skirts a touch and opened up the ports

opened them up as much as i dare (same with cutting the front and rear skirts)widened the transfers a touch,widened the rear transfer a touch and matched all the heights (3/8 of a mill difference as they were) raised the exhaust port by almost a mill in the middle and changed its shape a touch biggrin

 

and then i got brave and cut in COUGH *boost ports* COUGH

lots of tidying up to do lol good job i've got a sense of humour,i'll need it when i try to get this to run biggrin my moneys on a full 8 seconds before it blows the rings,piston and most the crank out its exhaust..... any advances?



__________________

money killed everything....
Seanyftw


Guru

Status: Offline
Posts: 928
Date:
Permalink  
 

Whatever you do, make sure you film it :D


__________________

Sig.jpg  gHnbADQ.gif  401587_10152319640490591_758222196_n.jpg

       Then                                                                                                                             Now
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

yer boi! youtube gold that 1 lol if i can find someone i dont like to look down the exhaust when i fire it up....BANG £250 from you've been framed lol biggrin



__________________

money killed everything....
NORFE


DTR Trusted Engine Builder

Status: Offline
Posts: 1723
Date:
Permalink  
 

looking well mate

u want to get it sand blasted when its all done all over the barrel/ports,then get it bored over size, that bit from the boost port to the ex port looks rough lol

there a **** when them cutting bits grab and shoot off where they shunt.be good to no how difrent it runs

have u matched the pv to the boost ports aswel



__________________
mr karnage


Guru

Status: Offline
Posts: 439
Date:
Permalink  
 

you can use oil and grinding stones to get it all smooth

use plenty of oil to stop it shattering

__________________

red 1990 dtr - http://dt125r.activeboard.com/t45695405/red-1990-dtr/
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

NORFE wrote:

looking well mate

u want to get it sand blasted when its all done all over the barrel/ports,then get it bored over size, that bit from the boost port to the ex port looks rough lol

there a **** when them cutting bits grab and shoot off where they shunt.be good to no how difrent it runs

have u matched the pv to the boost ports aswel

 got the power valve to do next... slipping/grabbing bits...frustrated.gifgood job its got one more oversize biggrin hadn't thought about sand blasting it,will look into it. i'm thinking bout doing a standard barrel with boost ports just to see how it changes,this one 1st though... i'll give the oil and grinding stones a look karnage,cheers! 



__________________

money killed everything....
mr karnage


Guru

Status: Offline
Posts: 439
Date:
Permalink  
 

did you get that right angle dremel bit?

__________________

red 1990 dtr - http://dt125r.activeboard.com/t45695405/red-1990-dtr/
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

yeah i got one BUT its a bit big lol i'll post a pic up tomorrow so you can see what i mean. i've found the flexi shaft easier to use,just me though biggrin



__________________

money killed everything....
GADGET


Guru

Status: Offline
Posts: 1332
Date:
Permalink  
 

Would the power valve need grooves all the way round or do the boost ports only open at a certain rpm range ??? Coz they will only be inline with the exhaust at full chat,or wherever you've placed them!

__________________
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

i did wonder where there best range would be lol think its best at full chat. did toy with the idea of curving the ports around the powervalve,but the pics i've seen say not...

but all this is really my best guess and just an experiment lol



__________________

money killed everything....
the only way is YAMAHA DTR


Guru

Status: Offline
Posts: 1290
Date:
Permalink  
 

on my wr200 barrel the PV boost ports line up when the valve is fully open



__________________

 

 
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

cheers mate! that takes away the guess work lol would make sense for the exhaust port would get bigger AND wider at full pelt biggrin



__________________

money killed everything....
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

well i got the power valve done smile

and a couple of views from inside

its smiling biggrin

i think before i get it blasted an re-bored to its last oversize,i'll try it on my off road dt lol bit impatient plus dont wanna waste cash if its just gonna blow it out its ass biggrin



__________________

money killed everything....
mr karnage


Guru

Status: Offline
Posts: 439
Date:
Permalink  
 

youve done a good job there

__________________

red 1990 dtr - http://dt125r.activeboard.com/t45695405/red-1990-dtr/
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

i'm well happy for a 1st attempt lol i'll be even happier if it runs properly biggrin then it'll be on to the crankcases again...



__________________

money killed everything....
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

just thought,i'll need to dyno it if it runs. does anyone know of one near ipswich? 



__________________

money killed everything....
NEV


Guru

Status: Offline
Posts: 2515
Date:
Permalink  
 

Dunno Dave, but make sure they test two stroke bikes, as there a few round here but 4t only.

__________________

 
FunkeyMunkeyDavid


Guru

Status: Offline
Posts: 802
Date:
Permalink  
 

well finally got one side of the crankcases done!!!

polished inside and sprayed outside too

if this engine works it'll turn into a build thread for my q plater biggrin 



__________________

money killed everything....
mr karnage


Guru

Status: Offline
Posts: 439
Date:
Permalink  
 

mate, did you manage to get a pic of that right angle bit

__________________

red 1990 dtr - http://dt125r.activeboard.com/t45695405/red-1990-dtr/
«First  <  1 2 3 4  >  Last»  | Page of 4  sorted by
Quick Reply

Please log in to post quick replies.
DT125R Forum -> Tuning -> crankcase tuning...
Tweet this page Post to Digg Post to Del.icio.us


Create your own FREE Forum
Report Abuse 		Powered by ActiveBoard