micron expansion chambers

bluesmokebilly · micron expansion chambers

Hi just joined the forum, i have a KH 250 1976 and a s3 also 1976 which i will be rebuilding over the next few months , i hope . The Kh is up and running and will use as blue print for s3 build thought it would make life a bit easier , i have rebuilt a suzuki ts 250 a few years ago and recently just completed a nut and bolt rebuild of a AJS 500 twin model 20 1958 .So this will be my first triple .........can`t wait , i must say this is an excellent forum. i`m putting a set of micron pipes on the KH just to excite the neighbours a little and from what i`ve been reading i should stick with original air intake system and try 82.5 main jets , what do you think ?I will post some pictures of the bikes over the weekend . I have an excess of parts and will offer them up on the forum when i know for sure what i need , many thanks

simonh

its a good start but depending on the engine, 85's and 90's could be better.

I had a slightly tuned 250 that was running 92.5's (i think)

will make it balk at 3/4 throttle if their too big, have to try and see!

and welcome mate 8)

bluesmokebilly

Cheers have some 85`s so will give them a try as well , and leave the air box as standard ?

simonh

yeh just make sure your air filters clean and no leaks on the inlet rubbers. no leaks on carbs to inlet stubs. If you like make the intake bigger on the airbox

The Wolfman

You're just too good to those neighbours Billy. :D

simonh

bluesmokebilly

Went to Boxhill last Sunday ,on the way guy pulls up by traffic lights , giving me the thumbs up and saying i could smell the bike way back down the road and said it was like going back to the seventies lots of interest at Boxhill as well , so money back already fantastic .

The Wolfman

Just try following thirty or forty two strokes.... :D

bluesmokebilly

I`ll be there at some point , I have now fitted the 85 main jets and changed the spark plugs to 9`s as there were 7`s in there , took for test run ,checked plugs nice light brownish deposits , however it`s a bit boggy low down so checked needle heights ,thinking i`ll lift them up a bit , but already on lowest notch , any ideas ??? many thanks Billy

180kid

on my 250 with pipes, gone up a size on the pilots too and have 72' S1 slides, with different cutaway, pods too, and the needle if remember is at one up from bottom,.... :wink:

bluesmokebilly

Cheers , will look at pilots and move up a bit

bluesmokebilly

Have now fitted bigger pilots at 22.5 with main 85`s still not right looked at plug appear to show to rich mixture , wet and black ,when to bike does pick up it flys , but as i say still got problems around 1/4 to 1/3 throttle , sorry to go on guys but any suggestions would be great , most advice is to keep main original air box , but do you think K&N`S would be an idea or am i just getting a little lost on this ???

scouse

ok
if you fit the standard pipes back on (assuming you have fitted the microns)
put the jetting back to standard and see what it runs like

if it is still boggy (compared to what ?) then check the timing and make sure the carbs are clean

the microns sound louder but the bike is quicker with standard pipes

when I fitted my microns, no jetting alterations where needed as they are a performance step down as opposed to a performance step up

they are just lighter and louder

Gary T

bluesmokebilly

Cheers Gary , you know i was starting to look at the bike and thinking put it back to standard as the sound of the standard pipes is sweet anyway , it`s fitted with Boyer system so timing should be ok , maybe the standard pipes are coked up a bit ,many thanks

bluesmokebilly

Well well, took out air filter and noticed it had been crushed , so i think engine struggling for air , went down the road minus air filter , good grief!!! now jetted as S3 .......................Risk of explosion !!!

180kid