I have a 2008 LS650 with ~900 miles. When I got it, it ran sluggish so I performed the spacer mod (shaved it to about 1/3) and adjusted the air mix screw to the best of my ability. With my limited motorcycle experience, I did fair and it ran a lot better than it did when I bought it (at 400 miles). I was concerned I may not perform a rejet properly so I let the dealership do it while they were doing my initial service and I think they did me fair (I really hate to pay for things I really could do if I struggled through it).

Anyhow, I got it back and I have to admit it runs a lot better than it even did after my mods, but the one thing the mechanic (an older experienced guy) said is that I shouldn't have done the spacer mod and along with the rejet, he had to replace the spacer to stock.  Fair enough I guess.

The bike runs great as far as I would say for my limited experience with motorcycles considering this is my first and I have ~450 miles in the saddle. One thing I have noticed (maybe being over analyzing) is that when I am cruising on the interior streets at around 40mph in 4th gear, if I let it slow to ~35mph, it seems like the bike starts to bog and I have to get in the throttle or downshift to get the RPMs back up.  Do I need to back out the air mix screw to allow more fuel in at this minimal throttle level because as I understand it, the white spacer controls the mid-range, and the air mix screw controls the first 1/8 or so of the throttle which is where I think I am when I experience this.

OR...am I just a sissy and not running the bike at high enough RPMs and I need to go change my panties and get in the gas harder? Maybe I am just not used to letting that little engine run at higher RPMs because I think I am tearing it up.

Routy wrote on 08/30/12 at 19:33:42:


Sorry, it wasn't me that you asked before, but thanks for asking!

Before the rejet, YES, it only ran decent on half-choke. You guessed that one!

After the dealership work, (I asked that he correct the choke issue which was probably why the rejet) it now runs pretty good on no choke after warm. If I run it on half-choke now, which I don't need to, I think it spices it up a little but I will have to confirm this after the storm blows over...I haven't been riding all week.

So, it sounds like what I am thinking is not incorrect...that the spacer mod was helping.  And maybe with the rejet removing 2/3 might have been too much, but maybe I consider getting back in there and taking 1/3 off and testing it out, and worst case I order another spacer and have it handy if my tinkering makes matters worse instead of better?

I'm not an ingenious mechanic and want to give the old timers some credit for their knowledge and experience and don't want to ruin my new bike, but I guess that's why we are all here asking what we ask?  

A #4 teflon washer from Ace hardware is 2/3 of stock...

Jetting is a funky thing... it's easy to fool yourself, one way or the other...
You can test the main jet easy... See my tuning tips in the Tech Section...
Idle,.. without an O2 tester is just hunting for a smooth idle between 1 and 3 turns out on the mix...
The mid-range stuff is nuts... ...
I just try to average the mods from the idle and WFO main test...
If you like to fiddle with your toy,.. just play around with different options...
If you just want it over with,... average the main and idle mods, or don't even bother...  it ain't that important...
Your bike ain't working hard in it's happy place...

In general,... err on the side of rich on the main... and lean in the mid and idle...
That way,.. you'll have the safety at full throttle,.. but good mpg's...

The biggest mistake newbies make is overdoing, and over worrying...
More isn't better, or faster,.... and it just wastes gas...
Unless you go leaner than stock,.. you won't hurt the engine...
...and  if you make mods to intake or exhaust,.. and it runs crappy after,.. it generally needs a bit more fuel...

If you don't like to fool around... don't...
If you want to play with your toy,... make small changes, and be critical in your analysis... more isn't automatically better...
Faster bikes run slightly lean... although, slightly rich is easier on components...
But, it's all slight... going to extremes, just makes for a turd runner...

Mainly,.. I'm saying, don't worry... If it seems okay,.. it is okay...
Badly jetted bikes really let you know...

There are tons of bikes,.. (mostly Harleys)... out there, that are radically modded to run like cr@p...
It's so pitiful to see a "100hp" modded custom 30k bike,.. that can't out run a stock Savage...
...

I ranted...
Sorry,.. half asleep,.. mild heat stroke...
It's not a tumour!... ...

PS... I've been trying get rid of a rattle in my water bottle for 2 weeks...
Still can't figure it out... (no, I can't ditch the bottle)...
That confession,.. may influence the credibility of my previous rant... ...

stewmills wrote on 08/30/12 at 19:07:51:



Stew,

It may just be me, but I try not to run mine (see signature block) below 40 mph in 4th gear.  And, if I DO find myself in 4th when going slower than 40 mph, I definitely downshift to 3rd if I need to gain speed, or if I hit an uphill grade (even a slight one).

JMO.....

Stew,

Mine was a barn find, too (back in the day).  Had been sitting for a year with only 70 miles on it.

I dipped the carb and she was good to go.  I fooled around with the spacer some, but ended up putting it back in, as I was fouling plugs.

Routy wrote on 09/02/12 at 06:49:09:


Yes, that's very similar.  Since the rejet it runs pretty smooth.  Before the rejet it had surging, etc. when loafing, which 1 click on the choke would fix (for the most part).

I plan to try maybe a 1/3 shave of the spacer and see if that little bit trims out the wee little bit I still think I feel.