| Author |
Message |
    
Medioxcore
| | Posted on Thursday, January 16, 2014 - 10:19 am: | 
|
Hey guys. I'm new to this forum and Buells. I just bought a 2003 Blast. It has a lot of mileage, but I got it for $600. When I initially looked at it, the guy selling got it running for about 2 minutes and then it died. I talked him down from his asking price due to it not running properly. Once my buddy (who has two blasts) and I got it home, we changed das boot and added some vital fluids. Now, I can get it to start after a few tries, but unless I roll the throttle it stalls. It won't idle at all. I'm also getting backfires and black puffs of smoke from both the carb and exhaust. I should also mention that it has the Vance and Hines exhaust. We know it's running a bit rich, due to the spark plug being black. We just couldn't get to the fuel mixture screw. Does anyone here have any ideas? |
Andersonhdj
| | Posted on Thursday, January 16, 2014 - 03:50 pm: |
|
First post this in the blast section , if you have'nt already.
Secondly , if the plug is fouled there's no way she'll idle decently , is the plug a shiny black color on the porcelain insulator?
If my guess is right there's no way short of sandblasting you're going to get that plug clean , fit a new plug
If the mixture is off she'll continue to destroy plugs , the other thing is quality of spark , anything less than a strong blue spark is going to affect your plug burn.
Your mixture screw only affects slow running normally. On some bikes, Yamaha's in particular the slow running screws are often sealed off with a plug which means they should not be touched, ever!
My point being , your carb is like as not quite worn if it's a high mileage motor and no amount of fettling with the mixture screw is going to cure the problem permanently without replacing some bits in the fuel circuit.
On CV carbs most commonly , the needle and nozzle wear out , leading to an over rich idle mixture.
A question i often ask is have you actually been able to ride her?
Sometimes all it takes is a good ride to burn a plug clean and discover where you're actually at.
You've replaced the boot , check the airfilter , fit a clean plug and ride her round the block , then you'll know where you're at.
(Message edited by andersonhdj on January 16, 2014)
(Message edited by andersonhdj on January 16, 2014) |
Medioxcore
| | Posted on Saturday, January 18, 2014 - 01:44 pm: |
|
Well, I didn't drill the plug out, it was already done. The porcelain of the spark plug is still white, but the threaded end where the spark generates is black. A lot of the black comes off with a rag, but it's still there. When it does start, I can ride it for about a minute, then it dies. |
Andersonhdj
| | Posted on Saturday, January 18, 2014 - 04:30 pm: |
|
Sorry , but , what are you talking about? Drill the plug out????
The porcelain part i am referring to , is at the spark gap end , and if it won't come clean you'll have to replace the plug .
Make sure you get the correct heat range,etc.
It has become carbonised making the spark weak to non existent.
Effectively it's become short circuited
The top half of the plug , the white porcelain part has no bearing here other than the number it bears and the quality of the gas seal between it and the metal threaded body. |
Britchri10
| | Posted on Sunday, January 19, 2014 - 08:09 am: |
|
The Blast carb has the air/fuel ratio adjuster sealed off by a metal "plug". In order to access the adjuster you remove the plug, normally w/a drill bit. You can then adjust the idle.
Make sure that the spring and washer are a) There & b) intact/not damaged and installed correctly.
I can't remember the exact # of turns to achieve a good idle (I sold my Blast a couple of years ago) but adjusting the idle screw will make the bike idle better.
DO NOT GIVE THE CARB A GOOD CLEANING BY TAKING IT APART! (Thanks Gearheaderiko)
as stated: check the plug & replace if necessary. Check spark. Check/adjust idle speed. Check boot.
After all that, if she still won't run, go to the Blast section for further advice.
It could be any number of problems. The secret is to only make one change at a time in order to rule out non-issues.
Good luck,
Chris C |
Andersonhdj
| | Posted on Sunday, January 19, 2014 - 04:44 pm: |
|
quote:The Blast carb has the air/fuel ratio adjuster sealed off by a metal "plug". In order to access the adjuster you remove the plug, normally w/a drill bit. You can then adjust the idle.
My apologies, i did'nt know the Blast had a sealed mixture screw though i did refer to others that have , and he did'nt specify what plug he was referring to, spark plug or blanking plug.
This is normally something i would not do, for any reason as the change in mixture is almost always down to wear , aside from the obvious change in atmospheric conditions if that were applicable , but then this is a single cyl machine so i guess it does'nt really matter.
On multi's it's an absolute no-no without the correct diagnostic equipment and even then can be a pain in the rear.
General rule of thumb on a healthy motor is 1.5 to 1.75 turns out but can vary.
Set the screw at 1.5 , fit a new plug , start her up and get her warmed up.
The idea is to adjust the screw to achieve a stable idle, so you turn the screw out till the idle drops then back in again till the idle drops yet again then back the screw out to get a good idle, sorta like halfway between the extremes.
I must admit to having no experience with the Blast but my experience comes from 45 yrs of wrenching bikes from Bees'a to Zundaps.
(Message edited by andersonhdj on January 19, 2014) |
Britchri10
| | Posted on Sunday, January 19, 2014 - 07:49 pm: |
|
Removing the plug is a common procedure from the Blast board. I took mine out and installed a "thumbscrew" adjuster.
I wouldn't do it on a twin/multi-carb set-up for the reasons you stated but on the Blast it's generally fine.
It's all just a question of "fine tuning" the idle. |
Medioxcore
| | Posted on Monday, January 20, 2014 - 02:51 am: |
|
Thanks guys. I put a new spark plug in, and it started right up, but then died. I adjusted the mixture screw and got it to a sloppy idle and kinda fine tuned it from there. So, she idles now. But I can't ride her. I tried, but it sputtered out when I rolled the throttle. I guess it's time to get some new jets. |
Andersonhdj
| | Posted on Monday, January 20, 2014 - 03:43 am: |
|
No , first diagnose , check out the plug and see what color it is , if it's carbonised again , you need to check spark , with a clean plug , if the spark is strong and blue , then look at worn needle and nozzle in the carb.
After thought , if the plug is clean and ok , check the carb diaphragm for pinholes or tears , if the diaphragm cannot react to the depression of pressure then the piston won't lift and allow fuel to enter the induction system and she obviously , then will die when you open the throttle.
(Message edited by andersonhdj on January 20, 2014) |
Blake
| | Posted on Monday, January 20, 2014 - 09:22 am: |
|
Weak spark due to old spark plug wire is another possibility.
Also, the auto enrichener may be malfunctioning. |
Klallement
| | Posted on Monday, January 20, 2014 - 08:21 pm: |
|
I have a 2001 Blast.It has ran fine and then i parked it in the garage 2 days ago and I went out to ride tonight.I went to fire it up it backfired a little no it won't hit a lick.
It ran fine before now nothing.Help!!!!!!!!!!! |
Britchri10
| | Posted on Monday, January 20, 2014 - 08:28 pm: |
|
Check that the boot is still on the carb'. Oftentimes a backfire will unseat it.
Also: was the kickstand up? There is a cut out switch on the kickstand if you pull away w/the stand down (You probably know this already) |
|
Troubleshooting (Poor Starting/Running/Handling/Ride Issues) »
Archive through June 11, 2014 »
Blast won't start/idle