dpro 160 mikuni problem

[nickv1980]

mikuni 30mm carb
needle on the bottom clip with a washer underneath it ( so i need a richer pilot ?? ) no idea whats in it atm sorry but runs great

Fuel screw out 2 turns from closed

revs crisp and clean from idle to full throttle with quick blips

Goes like a cut snake with hard acceleration from idle to flat out and very smooth no surging at all

ONE PROBLEM even before i started fine tuning it when you pull up the idle dips and sometimes stalls ... mainly when you just putt around in first and clutch in quickly to stop , it wont tend to do it when you've given it a hard run through all the gears and stop... ive got the idle set decently high too .... why or what could cause this ?? im really happy with the tune i dont want to touch it ive got it that good ! Could it be float level ???

 

[DHZ_XR8cing]

Could be float level.
I would be checking the clutch adjustment to make sure the clutch aint grabbing and making it stall.

 

[sean01]

id be checking fuel mixture screw..

needle height has nothing to do with pilot..

 

[nickv1980]

okay ill have a go at all 3 items and see how i go ive actualy got the clutch adjusted so it engages at 3/4 out so i think either float level and fuel mix ....

@ Sean01..... i tried the mixture screw at 1-1/2 at 2 and 2-1/2 it seems to idle better and run better at 2 but the idle dipping issue was apparent at all settings mentioned and never changed ...

Also how do i know if the fuel level in the bowl is spot on ?

 

[sean01]

poorly tuned mixture/pilot circuit will result in funny idle quality. some times they will take ages to return to idle some times they will drop below idle speed and then try and pick up but resulting in stalling first.. turn your idle speed up and see what happens..

also make sure the air cleaner is clean and doesnt have too much oil on it, also make sure the carb is spotless inside and that the slide doesnt have sign's of dirt scratches on it..

then also theres valve clearances and spark plug to check..

if your cant tune it 100%, tune it so that it responds good at the throttle your most likely to use.. ie: half to full or if doing mx tracks 1/4 to 3/4

 

[nickv1980]

Okay cheers mate ... valves are set at 0.003 and 0.004 respectively air filter is clean and ive tried with and without same results .....

The throttle response through out the whole rev range is freakin awsome plenty of power and great pull all the way to redline , its a wheelie monster in 1st and 2nd im hanging over the handle bars to keep it on the ground alot better now than the stock tune it came with anyway.

As for the idle issue has been the same since the first time i started her .

Bikes only got 2 hours on it so it might all settle down hopefully or ill get over it and buy a flatside 26mm oko instead lol no more burning the crappers out of my hands trying to turn the darn fuel screw !! freakin mikuni design ......

 

[sean01]

yep, just ride it lol

 

[SnItChY]

air leak ??

 

[nickv1980]

air leak ??

could be but ive checked all gaskets there all good and every things tight as.

Float level is 21mm from gasket base to bottom of float when carbs on its side with the float tab just touching the needle so its all shweeet according to a miki spec sheet i dug up on the net gotta love google !!!

Umm okay now slow jet is a 20 and main is 100

im guessing the main could be a tad bigger due to the needle clip position being right on the bottom with an extra washer under it so it runs spot on ??? correct me if im wrong im relearning what i used to know years ago its been ages but im enjoying it none the less

Blown out all the jets cleaned everything

Ive managed to make a flexi screw driver and dial in the fuel screw my fingers no longer get burnt grrrr but its pritty spot on at 2 turns from closed thats where she idles up at her highest strongest....

Guess what its still a piece of garbage lol buying an oko tomorrow 26mm mani and uni from ken and a heap of jets so i can play with a decent carb sorry to all the miki lovers out there im just over it :hache:

 

[Hellbound]

Have you fitted the oko yet mate and did you get the result you were after with it?

 

[sean01]

could be but ive checked all gaskets there all good and every things tight as.

Float level is 21mm from gasket base to bottom of float when carbs on its side with the float tab just touching the needle so its all shweeet according to a miki spec sheet i dug up on the net gotta love google !!!

Umm okay now slow jet is a 20 and main is 100

im guessing the main could be a tad bigger due to the needle clip position being right on the bottom with an extra washer under it so it runs spot on ??? correct me if im wrong im relearning what i used to know years ago its been ages but im enjoying it none the less

Blown out all the jets cleaned everything

Ive managed to make a flexi screw driver and dial in the fuel screw my fingers no longer get burnt grrrr but its pritty spot on at 2 turns from closed thats where she idles up at her highest strongest....

Guess what its still a piece of garbage lol buying an oko tomorrow 26mm mani and uni from ken and a heap of jets so i can play with a decent carb sorry to all the miki lovers out there im just over it :hache:

needle really has nothing to do with main jet..
needle controls 1/4 to 3/4 throttle and main jet only controls wide open..

BUT a 100 miki main is on the lower side of the scale for a 160..

 

[nickv1980]

Update : buying an oko flatside today to tinker with i ended up getting the miki not to bad all round running the original jets : 20 slow 100 main needle on bottom clip with washer shim to raise it up a tad more and 1-1/2 turns out on the fuel screw.

Idles decent , smooth transition from idle upward and revs out to the limiter nice and quickly in top gear .

Took a bit of work but its tuned fairly good for a 160cc / 150cc ...

Once i set up the flatside im going to sell the miki and filter if anyones interested its done less than two hours work on the bike. finally running nicely