'01 Blaster Issues... Low end bogging, dies and wont start after an hour...

Dc2ProductionS

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Dec 18, 2014
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Hey guys...Newbie on the forums here. Picked up an '01 Blaster from a friend for cheap to beat up on. Have been riding it and loving it even though it does need a little bit of work.

It has a FMF Power Core II on it and is a pre-mix setup. Other than that, idk anything about any work to the engine or whatnot. It does look like it has an upgraded air filter and sock on it? Few things that need to be addressed are: Twist throttle... Dont like it. I ride in dense woods and just a little bit of whiskey on that throttle and your gonna end up in trouble. Plus on a couple sharp turns we have on the track we made, and me being a bigger guy, keeping my elbow in to still be able to twist my wrist to power out of the turn is a PITA. It also has slack in the line before it really pulls the motor. I ordered a thumb setup and a new throttle cable. Will be here this weekend to get installed. There was no headlight or rear grab bar, I ordered both of those and they are going on as well. Since I got the thumb throttle, I also got some new grips for the handles while I was at it.

The plastic are a little beat, but I plan on beating the hell out of this thing, not taking pictures of it. If its been sitting overnight, even in cold NY sitting outside, it starts up on the 3rd kick. Little idle adjustment, and its ready to go once shes warmed up. And heres where I run into my first problem. In the low end of the gears, its pretty bogged down. It goes... it seems like its struggling a little bit but once you get higher into the RPM's in picks up, and offff you go. Bang. Blaster. Rips through all 6 no problem.....but if you get back down into the low end, its a little bogged down. After a few minutes of riding, you get used to it and are able to stay in the power range if you can maneuver the twist throttle enough. My friend said the spark plug prob needs to be changed, so I had already ordered a new one and it came in two days ago. The wire looks good and shows no signs of having any issues.

After about and hour of riding, and you shut it off, it doesnt want to start again. Even after numerous starts and stops. At one point (a little over an hour) when you shut it off, it doesnt want ot start. And if it DOES start, it only runs for a few seconds and boggs out. Then after that sequence it will backfire on a kick or two, but it wont start. Really confused as to what is causing this. Tried to let it sit for 20 minutes and cool down, only kicked over and bogged right back out after a few seconds. After that, I put it away and let it sit for the next day as I worked all day and night. Came home, the day after that, and everything was fine. Kicked over on 3rd kick, ran fine (same low end prob) and once in powerband she was good to go.

My plan is to change the spark plug and clean out carb. Hopefully this will get her running a little better in the low end and gives me a little more power. It could also be the slack in the throttle that is hurting the low end. With the new cable and thumb throttle I should be able to adjust is tension nice.

If there's anything else i should check for or replace, let me know!! Thanks for the help in advance!
 
Welcome to BF !


i'd start with the basics.....
compression and leakdown tests and report findings.
good fuel flow to carb ?
good strong blue spark ?
does the choke on/off effect it starting ?
clean air filter, inspect reeds for cracks/chips,
check if vent/hose on fuel cap is flowing freely (loosen cap to see if that breaks the vapor lock)
pull petcock to check filter screens for cloggage

properly clean the carb:
http://www.blasterforum.com/threads/how-to-clean-your-carbureutor.254/

while your in there, check/adjust float height:
http://www.blasterforum.com/threads/float-heights-and-how-to-adjust-them.50565/

check and write down main jet & needle clip setting, and report to us, (although they have nothing to do with starting)

adjust airscrew/pilot jetting
http://www.blasterforum.com/threads/adjusting-your-airscrew-pilot-jet.51060/

then we'll move on to possible electrical causes.
 
Awk,

Thank you so much for your response! I will def check into those things and report back.

I assume I can perform compression test same as with a car?

I'll have to find out more about the main jet & needle clip settings so I make sure I get it right.

Thanks again!
 
awk said it all:)
do you have lid on airbox or off?
fmf pipe and silencer?
you deff got your work cutout
did you or someone tap/drill an idle screw on carb

welcome:)
 
Awk,

Thank you so much for your response! I will def check into those things and report back.

I assume I can perform compression test same as with a car?

I'll have to find out more about the main jet & needle clip settings so I make sure I get it right.

Thanks again!


yep, same compression tester as a car, be sure the sealing o-ring is good, screw it in tight, with throttle held wide open, kick it until the needle stops.

i'm pretty sure this video will explain the how and where's of checking jetting and cleaning your carb
 
Definitely check that jetting, some people don't know to up it for mods, and even fewer know how to get it right on. Sounds like your filter has a cover (hopefully not an actual sock) so I'm gonna guess your running with the lid off. Main jet should be around 300 depending on the temp there. Definitely check the floats and get them set right, just a little off can throw everything off. And everything else Awk said as well, you'll learn around here we demand leak testing, its very important as well!! Btw welcome!!
 
Wow you guys are awesome. I plan on tearing into it tonight for a bit. Hopefully I can borrow a leak down and compression tester from the auto parts store. Im having my friend who works at the local Recreation Vehicle shop come over and assist. Lets hope there is nothing major and she can be running like a top soon enough!

Thanks again for the responses and help. Very appreciated.
 
Wow you guys are awesome. I plan on tearing into it tonight for a bit. Hopefully I can borrow a leak down and compression tester from the auto parts store. Im having my friend who works at the local Recreation Vehicle shop come over and assist. Lets hope there is nothing major and she can be running like a top soon enough!

Thanks again for the responses and help. Very appreciated.

i've never seen any auto parts store have the correct leakdown tester for a 2 stroke.
motion pro sales one commercially, but it's big $
you've got 2 other choices, build one yourself, or message me :)

http://www.blasterforum.com/threads/build-and-use-a-leakdown-tester.10663/

http://www.blasterforum.com/threads/leakdown-testers.55015/


Any ideas as to why it might be dying and not starting after an hour or so of riding it?

sounds heat related to me ?
check all electrical connections, especially the plug wire and boot, and ground to bare frame at the coil
get that compression checked and report back
float height/fuel level would show itself quicker than an hour
 
Here's a few pics of her....

Os9nx3N.jpg


zJLxfTe.jpg
 
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Here's a few pics of her....

whatever you did there with imgur did not work, the pics didn't show until i hit reply to the post, then they showed in that reply box, so i downloaded and re-uploaded them into an edit of your post ?
did you cop/paste the .IMG code for forums ?
posting the URL only works for youtube videos

try the forums upload system.......
http://www.blasterforum.com/threads/how-to-post-pics-on-this-new-forum-layout.57951/


the blaster looks like a solid foundation to build off of :)
 
that is deffinetly not a stock carb.....what is it??
that may be 1 of your problems..does not look modded enough for the need for a huge carb:)perhaps im wrong but from image to me,, it looks not stock???
but you know more about it then meo_O click image to expand

mmmmk 1 1.png
 
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i'd start with the basics.....
compression and leakdown tests and report findings.
good fuel flow to carb ?
good strong blue spark ?
does the choke on/off effect it starting ?
clean air filter, inspect reeds for cracks/chips,
check if vent/hose on fuel cap is flowing freely (loosen cap to see if that breaks the vapor lock)
pull petcock to check filter screens for cloggage

check and write down main jet & needle clip setting, and report to us, (although they have nothing to do with starting)

adjust airscrew/pilot jetting

- Compression tester was unavailable to be borrowed from Auto Parts store. :( My friend is going to bring one home from work this week so we can check it over holiday break.
- Good constant flow to carb
- Spark is good
- Choke on/off does effect. With ON, start much easier from cold.
- Cleaned Air Filter and Sock.
- Put a brand new Vent hose on
- Petcock flow was smooth and no leaks upon turning valve on and off.

The main jet setting is 165 and the other is 55... ?? I have seen that the stock jet is 230? Idk why it would be so low? It seems if you have mods like a intake with no box, and a bigger carb, and exhaust, (as i do) you should use a HIGHER jetting? 260, 280?

My friend who was helping me was adjusting the airscrew when we put everything back together and was getting the idle set and clean rev's.


do you have lid on airbox or off?
fmf pipe and silencer?
you deff got your work cutout
did you or someone tap/drill an idle screw on carb

- Lid and box removed I believe. The intake is a K&N with a cover sock on it and is exposed?
- Nothing has been tapped or drilled on the carb

Definitely check that jetting, some people don't know to up it for mods, and even fewer know how to get it right on. Sounds like your filter has a cover (hopefully not an actual sock) so I'm gonna guess your running with the lid off. Main jet should be around 300 depending on the temp there. Definitely check the floats and get them set right, just a little off can throw everything off. And everything else Awk said as well, you'll learn around here we demand leak testing, its very important as well!! Btw welcome!!

Main jet is at 165?? Secondary is 55. Idk why it would be that low. Stock Ive read is 230. What is the stock secondary? Temps in NY currently are in the high 20's-low 30's. Floats are all good and set. MY buddy took apart the whole carb and reassembled.

Is the fuel tank breather free of obstruction?
If it is blocked it may stop delivery of fuel.

The flow of fuel going from tank to carb is unrestricted. Smooth strong flow.



I know I said I wasnt going to worry about how she looked, but my bored Saturday night got the best of me!! So heres her new look.

IMG_8197.JPG


IMG_8202.JPG

IMG_8217.JPG


Really happy with how it came out for now. We disassembled the carb and found those jet settings. Here is a pic of them.

IMG_8183.JPG


Floats and valves and ports were all cleaned and checked. New spark plug. Swapped out slacky twist throttle for OEM thumb unit and adjusted the throttle, tightened up a small exhaust leak, and made a new mixture of gas for it and drained out the old. She started right up on the second kick after reassembly and sounds much better than before. It is still a bit boggy down low, but with the adjusted thumb throttle, and Im assuming the plug and cleaning, the top end is super smooth and gobbs of power. Once you hit powerband its gone. All the way through 6th. Im prob gonna get a stock jet (230) and an upgraded jet (260?) and see what those do. I need to know what I should up the secondary to as well though. Any ideas??

Heres a pic of the track we have been making and a little video I put together of us trying to tear it up a little. :p:D

IMG_8249.JPG




Anxious to hear what you guys think from those settings and what Ive reported back. Thanks in advance fellas!
 
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The main jet setting is 165 and the other is 55... ?? I have seen that the stock jet is 230? Idk why it would be so low? It seems if you have mods like a intake with no box, and a bigger carb, and exhaust, (as i do) you should use a HIGHER jetting? 260, 280?
Main jet is at 165?? Secondary is 55. Idk why it would be that low. Stock Ive read is 230. What is the stock secondary?

Im prob gonna get a stock jet (230) and an upgraded jet (260?) and see what those do. I need to know what I should up the secondary to as well though. Any ideas??





the 55/160 jetting suggests thats a keihin carb, not a stock mikuni which takes the 230-300+ jetting your seeing.
the mikuni 230+ jets cannot be used in a keihin carb

see here and read down for answers to this same issue...
http://www.blasterforum.com/threads/sputtering-and-bogging.60699/page-2#post-757249


we need to know what size keihin that is to suggest jetting for it
for keihins, 42-50 pilots and 145-155 mains are usually a good starting points for jetting,
along with a dgh or cel needle <(a must have)
 
the 55/160 jetting suggests thats a keihin carb, not a stock mikuni which takes the 230-300+ jetting your seeing.
the mikuni 230+ jets cannot be used in a keihin carb

see here and read down for answers to this same issue...
http://www.blasterforum.com/threads/sputtering-and-bogging.60699/page-2#post-757249

we need to know what size keihin that is to suggest jetting for it
for keihins, 42-50 pilots and 145-155 mains are usually a good starting points for jetting,
along with a dgh or cel needle <(a must have)

It is def a Keihin carb. I saw that stamped on the side of it when we were cleaning it. I understand now that getting those jets would be useless! Thank you! Idk about anything dgh or cel needles? :eek:

I was actually JUST reading through that thread. Not knowing whats done to the motor seems to put me in a guessing game. Do I get a stock carb? Hmmmm.... It feels like it might have been a race quad? bc when its pinned, it eats up every second of it.
 
well, i can see the pics now ?
Looking good !
dig that old school helmet :)


definately a keihin carb
 
It is def a Keihin carb. I saw that stamped on the side of it when we were cleaning it. I understand now that getting those jets would be useless! Thank you! Idk about anything dgh or cel needles? :eek:

I was actually JUST reading through that thread. Not knowing whats done to the motor seems to put me in a guessing game. Do I get a stock carb? Hmmmm.... It feels like it might have been a race quad? bc when its pinned, it eats up every second of it.


the stock 26mm carb will easily handle modified engines up to around the 30+hp range.

90% of riding is between 1/4 -3/4 throttle, which the needle controls.
if wide open runs good and thats all you do, don't fool with it.

but here's the needles if you want, I run a DGH @ 1800'+ elevation
others @ sea level run CEL's
both are adjustable with needle clip settings to probably overlap and cover a wide range of elevations.
choose based on your elevation

DGH
http://www.ebay.com/itm/Keihin-Jet-...Parts_Accessories&hash=item2edad0ded2&vxp=mtr

CEL
http://www.ebay.com/itm/Keihin-Jet-...Parts_Accessories&hash=item2ed8d677c9&vxp=mtr




edit:
from this in your first post, i'd get a new needle for that carb.

It has a FMF Power Core II on it and is a pre-mix setup. Other than that, idk anything about any work to the engine or whatnot. It does look like it has an upgraded air filter and sock on it? Few things that need to be addressed are: Twist throttle... Dont like it. I ride in dense woods and just a little bit of whiskey on that throttle and your gonna end up in trouble. Plus on a couple sharp turns we have on the track we made, and me being a bigger guy, keeping my elbow in to still be able to twist my wrist to power out of the turn is a PITA. It also has slack in the line before it really pulls the motor. I ordered a thumb setup and a new throttle cable. Will be here this weekend to get installed.

if it is indeed a 34mm,
which it does appear from the choke knob and lack of idle screw (?)

with that pipe and not knowing any other internal mods (ported ?),
and the way you say it runs wide open, i'd say it's tuneable.
if it's a 28mm carb....GREAT !
but the riding you describe in the tight woods will benefit greatly from a new needle