2004 Carb jetting help

[offtosleep]

I have been bitten by the Blaster bug and completely lost my mind. I ended up picking up another 2004 Blaster this weekend. Purchased it from the original owner (this thing darn near looks like it rolled off the showroom floor). Anyways, it was his daughters. He told me it was stock except the exhaust and filter, but didn't know exactly what he had added (brand wise). From what I can tell, he put on a FMF Gold Series Fatty expansion chamber and FMF Powercore II silencer. The filter appears to be a K&N, the snorkel for the filter box has been removed and the lid has been fitted with filtered inserts. I haven't found any other changes.

It runs fine now and I haven't ridden it much at all. However, when I asked if it had been rejetted for the mods, he said "no." I pulled the carb off and the the main jet is a 230. Where I live and ride is 3500 ft above sea level. Its Arizona so its hot and dry!

I am not going to ride it until I do a leak test, compression test, and then I'll do a plug chop depending on the feedback of the jets once I get them installed.

So, what jet do I need to put in it? I know the 230 is too small.

 

[offtosleep]

Btw, I will be keeping the oil injection

 

[Awk08]

buy ...290/270/260
start large and work down plug chopping to perfection

 

[offtosleep]

Just ordered a jet set from www.jetsrus.com. Should be 5-10 days and then I'll post up my results

 

[offtosleep]

Okay gang, I got the jets in from JetsRUs. I started with a 290 (in their OEM equivalent). Tore the carb down, placed the jet. While the carb was out, I did a leak down test and it held 6 psi for 10 min with only 0.5 psi drop (5.5psi at the 10 min mark). I warmed the motor up for about 10 min and then went to my straight away/run area. I put in a brand new plug and rode WOT to 6th gear and held it for 15 seconds and shut her down. Replaced the plug and rode home.

Here are the results:







Whats the verdict?

BTW, the end of the plug was dry as a bone with no signs of fouling.

 

[Blaaster]

My thoughts would favour a #300 main, if the float level is set correctly.

 

[offtosleep]

Did it again with a 300 and same results. Went to a 320 and the smoke ring is actually getting lighter (more faint). I don't really have anything other than a 3 mile straight away near my house. I've been hold the rear brake one and going WOT I'm 6th gear for 10 seconds. Should I try WOT with the brake on for 15-20 seconds?

I'm expecting it to show rich here soon. I don't have a jet higher than 320.

 

[Blaaster]

10 secs is usually ample as long as the motor is pulling strong.

I always load up the motor with the brakes, both front and rear.

If it needs a #320 main with your mods then that little drop in the leak test could be causing a problem.

Did you flex the carby boot well when you tested it as sometimes they crack and only really leak under vibration.

 

[offtosleep]

Confused as hell!

Okay, here are some pics with the various jets. I've run out of jets (320 is the biggest I have).

Results:

 

[Herpderplol]

Must be a leak, they shouldnt look identical

 

[offtosleep]

10 secs is usually ample as long as the motor is pulling strong.

I always load up the motor with the brakes, both front and rear.

If it needs a #320 main with your mods then that little drop in the leak test could be causing a problem.

Did you flex the carby boot well when you tested it as sometimes they crack and only really leak under vibration.

I'll try the leak test again and wiggle the carb/intake boot. BTW, using a Motion Pro kit for the leak down. The the drop was only 0.5psi and then it held, and held, and held, and held.

 

[offtosleep]

Must be a leak, they shouldnt look identical

But where? I don't know what more to do than a leak test. Should I let it idle and spray carb cleaner around to see if the idle picks up a bit?

 

[Herpderplol]

But where? I don't know what more to do than a leak test. Should I let it idle and spray carb cleaner around to see if the idle picks up a bit?

NO!

Start a leak test again like normal.
Get soapy water in a spray bottle and spray a little in areas it COULD leak

 

[offtosleep]

Just went outside and started the bike. Sprayed carb cleaner all around the carb while wiggling it. NO CHANGE in idle speed what so ever.

 

[offtosleep]

NO!

Start a leak test again like normal.
Get soapy water in a spray bottle and spray a little in areas it COULD leak

I will do as you are telling me, but just speaking out loud here again....if its on the intake side, there should be a vacuum. If there's a vacuum, shouldn't the carb cleaner work?

 

[Herpderplol]

Just went outside and started the bike. Sprayed carb cleaner all around the carb while wiggling it. NO CHANGE in idle speed what so ever.

Thats not going to work, it wont seal anything, just might suck in a tiny bit, or just bubble out if the leak is there (probably not if it held for 6 min...)... And carb cleaner is flammable, so i suggest you clean your engine really good

 

[offtosleep]

Thats not going to work, it wont seal anything, just bubble out if the leak is there (probably not if it held for 6 min...)... And carb cleaner is flammable, so i suggest you clean your engine really good

I'm not trying to "seal" anything with the carb cleaner, only isolate a leak.

I realize the car cleaner is flammable. The motor is a clean as the day it rolled off the assembly line.

 

[offtosleep]

Is there anyway I'm doing the plug chop run incorrectly? I go through the gears WOT and hold in 6th. When I use the the brake, I'm bogging the motor, but still holding the throttle wide open. Not sure how much I should bog the motor.

 

[offtosleep]

Another thing I thought about/noticed was that I was moving the right direction until I switched to the 320 jet (OEM equivalent....not genuine Mikuni). Should I get more jets (genuine Mikuni) and start fresh?

 

[Herpderplol]

Thats might be worth a shot I:I