Microns and running like a dog!

[mudmover]

Since owning an LC ive wanted the original micron look /sound.....Fortunately one of our forum chums supplied a set which I got rechromed and they are like brand new!!

The pipes have now been fitted and of course are loud BUT I like them lots depsite menacing looks from the law and ramblers.

The problem is that my bike is now running like a dog....Between 5.5-7K the bike splutters terrible and everybody keeps telling me she's not running right. She is also set up with KN type filters but is standard. Apart from this bike starts/ runs real tidy.

Anybody know where I can take bike to get sorted?? I'm not mechanically minded ...I live near Severn Bridge

[lcowner]

what mains jet are u running?premix?i had same setup and ran with those filters,standard mains het is 220 but i had to go to 270 mains to stop the same hastle u are having .......

[mudmover]

I believe that it has 210 jets from reading dyno report....these were set up with lomas style pipes. Also it has power valve crabs with foam filters. The guy who set it up told me he was very conservative with 40hp at wheel...is it easy to change jets? I've run out of cash so I've got to fix......I cannot believe how much $$$ the rd had sucked up!

[bare]

Seriously?? Take the K& N filters off and then throw them as far away as you can possibly manage.
CRAP is a charitable descriptor for those Horrid things.. Lose them.. today!.
Re-Fit an oem Airbox with STOCK jettings then come back and ask :-)

[mudmover]

OK many thanks for that...has anybody got the complete set up to replace KN airfilters with original set up?

Will also post in wanted section...

Cheers
MM

[lcowner]

cheapest ad quickest starting point is change the mains jets,very simply:
remove filters
remove the clips holding on the carbs onto the reed blocks
remove oil pump lines
screw off top of carb
once on the bench
there are 4 posi screws at bottom of carb take these out to remove the bowl
u will see the mains get in middle(think its a size8 spanner to remove these
check what size they are (its staped onto th base of jets)
and rejet!!!
take it slowly and if its 220 mains ur running go up to 240 maybe and then refit the carbs and try bike on the road
always do a plug chop when u make any changes to the carbs

[mudmover]

I guess thats not quite so painful to change jets....

What sizes should i get from norbo to start with....i can set they only 2.50 a set so its not so bad

[Norbo]

is it a 250 or 350 and the carbs are they power jet or 31K .

[mudmover]

ur...urm...the carbs are off a 350 power valve and its a 350....
Cheers
MM

[mudmover]

Norb, can you let us know on the jets..cheers
Max

[stuboy]

Bottom line is throw the Microns away or put up with it !!!!
I have tried for hours messing with carb jet sizes and settings and can only make it worse.
In all honesty I have never know anyone with Microns fitted with no dead spot issues !!
Also make sure you dont run lean unless you have a good collection of pistons.
Microns are only good for two things
1= sounding good
2= making sure you always have to be above 7k !!!
The only way through the dead spot is the gearbox.
Allspeeds were far better developed for the Elsie and still enable you to blow the enging up.

[mudmover]

the guy who set the bike up for me is now saying to reduce jet sizes....Its already on 210's......I'm completely confused with all of this...I just want to ride the bloody thing.....I previously had a lomas pipe fitted and it did run better with a smaller flat spot

[lcowner]

std settings are:std 4lo settings are:
350LC 4L0
Main jet 220
Air jet 0.8
Clip from top 3
Pilot jet 22.5
Air screw 1.5 turns out
flote hight 1.0mm

the settngs i had with my microns on near unuf setup as urs where:
these are my settings now:
main jet 260
needles stamped 5k1
air jet .8
clip from top 3(middle clip)
pilot jet 22.5
air screw 1.75 turns out
float height approx 1mm

hope this helps but carb stup is all about small steps and is slightly different on all bikes but i found with the mains on 220 it was bgging down.and always do a plug chop its the only sure way of knowing what way ur engine is working

[K.B]

microns are good pipes ! Use the standard airbox and standard jetting but do a few plug chops. You may have to adjust the needles . I have microns on my LC an it has no flat spot just clean crisp power with a strong powerband.
Get rid of the K&N filters .

[billy]

FYI I once tried the stock LC reeds and I got a terrible flatspot at 5-6K rpm. I quickly changed back to the boyesen reeds and the flat spot was GONE. I also think it sounds very strange to run 210 mains if using aftermarket pipes. Shouldn't you generally go UP in size!?

[stanlc7189]

I'll echo what's already been said. DITCH THE K&Ns and go back to standard air box etc. Problem will be solved and you can enjoy the excellent Microns without the splutter.

[mogster]

Microns with stock jetting ..................... never . powervalve carbs non power jet try 260 and work from there .

[stuboy]

Try Alspeeds job done and it will sound the same !!

[midlifecrisisrd]

Sept 8, 2011 20:49:10 GMT 1 billy said:

FYI I once tried the stock LC reeds and I got a terrible flatspot at 5-6K rpm. I quickly changed back to the boyesen reeds and the flat spot was GONE. I also think it sounds very strange to run 210 mains if using aftermarket pipes. Shouldn't you generally go UP in size!?

If carbs are 31k then 210 with filters very weak so doubt this is the set up.

May be 1ua carbs that run 185 mains standard.

If you look on the side of the carb on the slide housing it will have a code, starting either 4L1/4Lo/31k/1UA/4CE

That will give a better idea of what jetting should be.

Steve