Rejet without removing carbs, can it be done? And mixture issue

piresito · February 15, 2012, 04:27:32 AM

Hi all,
Having my bike running great now, I have to mess with it, can't pass without creating a problem...

So, is it possible to change the main jets without removing the carbs from the bike?
Like, removing float bowls, the floats a unscrewing the jets and screw the new ones? It seems simple, but I don't see anyone doing it this way, there must be a reason...
BTW, um switching the 115 jets with 125 ones, stock bike.

Second, the mixture screws doesn't sit in the same position when fully closed. One of the has more 1/4 turn when fully closed. This is something to care about or is it normal?
There is some mismatch in the spark plug color as seen here:

Regards,

Tombstones81 · February 15, 2012, 05:43:49 AM

Yes u can change the jets without removing the carbs fully.

Just take out the air box, loosen the clamps on the engine side of the carbs.
pull the carbs off and turn it upside down and get busy.

but dont forget to drain the carbs of fuel!

and yes one side looks to be richer then the other
or leaner then the other, whichever way u want to look at it.
doesnt look like its by very much.

(edit)
and yes the mixture screws not being perfectly lined up with eachother is fine.
mine are the same way.
when fully closed, they are not both lined up the same way.

just make sure you turn them out the same amount is all.

piresito · February 15, 2012, 08:17:15 AM

Quote from: Tombstones81 on February 15, 2012, 05:43:49 AM
Yes u can change the jets without removing the carbs fully.

Just take out the air box, loosen the clamps on the engine side of the carbs.
pull the carbs off and turn it upside down and get busy.

but dont forget to drain the carbs of fuel!

and yes one side looks to be richer then the other
or leaner then the other, whichever way u want to look at it.
doesnt look like its by very much.

(edit)
and yes the mixture screws not being perfectly lined up with eachother is fine.
mine are the same way.
when fully closed, they are not both lined up the same way.

just make sure you turn them out the same amount is all.

Thank you for your reply!

My intention is to switch the jets without taking anything out of the bike, not even the seat. Just acessing them from the float bowls. Is there a reason to not do it? (appart from the tight space)

Is this mismatch in the plugs something that I should do something about? Maybe compensate with mixture screws?
I found out when syncing the carbs, that as soon as I gave throttle one of the carbs started sucking more thank the other, but they would stay equivalent at idle...

Funderb · February 15, 2012, 12:14:07 PM

It can be done, but its going to be a total PITA, and you'll probably strip the bowl screw heads out. And then the jets too...
But go for it.

With the right tools and a careful hand you may be able to do it.

haha! forgot about the filter!

bombsquad83 · February 15, 2012, 02:50:25 PM

I woulndn't try this without removing the carbs from the bike. The space is way too tight and the access too small for you to get the right angle on your screwdrivers. You will end up regretting it if/when you strip out a jet or a screw because you couldn't see it, use the right tool, or apply torque properly.

I'm not saying this to discourage you. I know it's a pain to take the tank up and airbox out. I'm trying to save you from much much greater headaches caused by trying to shortcut a job.

The Buddha · February 15, 2012, 02:53:27 PM

Once you remove the float bowl phillips head screws and replace them wiht allen headed bolts that are not cranked down to 30,000 lb-ft you can remove them with what I call a handle spinner and an allen socket fitted onto it.

I routinely do it on GS'es that have the airbox, I also have done it on kawi eliminators, 4 carbs, I could do 1, 3 and 4 in 5 mins flat and take 20 for #2 alone as well as lose 30-40 bolts only to have them splattered along the driveway and street as I start and ride away. True story.

Cool.
Buddha.

bombsquad83 · February 15, 2012, 02:56:32 PM

Quote from: The Buddha on February 15, 2012, 02:53:27 PM
Once you remove the float bowl phillips head screws and replace them wiht allen headed bolts that are not cranked down to 30,000 lb-ft you can remove them with what I call a handle spinner and an allen socket fitted onto it.

I routinely do it on GS'es that have the airbox, I also have done it on kawi eliminators, 4 carbs, I could do 1, 3 and 4 in 5 mins flat and take 20 for #2 alone as well as lose 30-40 bolts only to have them splattered along the driveway and street as I start and ride away. True story.

Cool.
Buddha.

Don't get me wrong Buddha, I'm sure you can do this. The key is though that you have done it before 100 times and you had allen head bolts on your bowls. If you have those horrible original JIS screws and no experience, I would say there is a good chance of causing more problems than it's worth.

piresito · February 15, 2012, 04:17:40 PM

Quote from: The Buddha on February 15, 2012, 02:53:27 PM
Once you remove the float bowl phillips head screws and replace them wiht allen headed bolts that are not cranked down to 30,000 lb-ft you can remove them with what I call a handle spinner and an allen socket fitted onto it.

I routinely do it on GS'es that have the airbox, I also have done it on kawi eliminators, 4 carbs, I could do 1, 3 and 4 in 5 mins flat and take 20 for #2 alone as well as lose 30-40 bolts only to have them splattered along the driveway and street as I start and ride away. True story.

Cool.
Buddha.

After all you found them...

The genes of doing it the right way went to my big brother, so I have this thing for shortcuts...and trouble...

I have a ratchet angled screwdriver and the bit that I used when I took them of the bike two weeks ago. I remember that I didn't applied too much force in them and put some lube in thread. Anyway, thanks for the warning, now if I feel one screw skipping I wont even try a 2nd run, carbs will come out and that's it. If successful, more time to ride it!

And about the mismatch in the spark plugs color, is something to worry about or is it normal?
The sync behavior is normal (as soon as I rev it a bit from the 1750rpm, one side pulls more than the other)?

piresito · February 20, 2012, 03:30:28 AM

I ended up taking the carbs out, I tried to unscrew one of those float bowls weird-headed screws and felt it stripping from the beggining...replaced those with allen screws. Still having issues syncing carbs, I've eyeball sync them in my hand, then on the bike they were very out sync. Now I know why there is fuel injection...

Good news, now I can hit 190 Km/h, around 118 mph! She is a bullet!!

BaltimoreGS · February 20, 2012, 04:48:30 AM

Quote from: piresito on February 20, 2012, 03:30:28 AM
Still having issues syncing carbs, I've eyeball sync them in my hand, then on the bike they were very out sync. Now I know why there is fuel injection...

Sorry to kill your fuel injection chubby but throttle bodies have to be synched too.

-Jessie

piresito · February 20, 2012, 05:34:43 AM

Really?!

I hate single-cylinder bikes...it's my fate then, isn't it?!

werase643 · February 20, 2012, 06:59:45 AM

home made synch sticks or a pair of vacuum gauges from horrible freight will get you synched up quickly. by sight only works for buddah

piresito · February 20, 2012, 08:09:42 AM

Quote from: werase643 on February 20, 2012, 06:59:45 AM
home made synch sticks or a pair of vacuum gauges from horrible freight will get you synched up quickly. by sight only works for buddah

That's the way I found out they were out of sync, I forgot to mention in my post...

I guess I will forget about it so I actually ride more than service...

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Rejet without removing carbs, can it be done? And mixture issue