Bike bogging waaay down when in high RPM's


binaryterror

Member
Jun 17, 2007
20
0
My KX100 was working PERFECTLY last saturday. well, yesterday i started it up, and as soon as i hit high rmp's, the thing would bog down super low and almost stall, and then when i shifted down to 1st, it would kinda ok again.

the only change i made from then to now was i cleaned the air filter.

the only thing i can think of is that it was pretty hot last weekend, and now it is kinda cool outside. so maybe itsw the temp?

it honestly seems like its getting way to much fuel at high rpms because its turning the plugs black, but i dont understand!!! i didnt change a single thing from last saturday, and it does this to me all the sudden!

any suggestions?
 

binaryterror

Member
Jun 17, 2007
20
0
i was just riding it and it works fine in the majority of the throttle range, but as soon as i hit the probably last 1/4 of the throttle, it just bogs, and almost stalls until i let ther throttle go.
 

binaryterror

Member
Jun 17, 2007
20
0
Thats what I was thinking. I bought some Seafoam and have been running it through my bike for like 45 mins riding it. It has been getting better, but as soon as I hit that one spot in the last bit of the throttle, it just like stops cycling. I am going to ride it tomorrow again with the Seafoam to see if that can clear anything out.
 

IndyMX

Crash Test Dummy
~SPONSOR~
Jul 18, 2006
5,547
2
Amo, IN
Don't use Seafoam... Take the main jet out, blow air thru it...

It took longer for me to type this than it would have to just do it.
 

binaryterror

Member
Jun 17, 2007
20
0
I actually think there might be too much oil in my gas. I put my hand behind the exhaust and there were little specks of oil all of my hand. Plus it is blowing out alot more smoke than normal. I was using like 38:1, but could something have happened to it to make it go bad?
 

Micahdawg

Member
Feb 2, 2001
503
0
Few things I can think of that would cause bog:

Bad gas
Too rich main jet.
Fouling plug.
Powervalve problem (if a KX100 even has one)
Very low compression.

In my experience, being too lean hasn't cause a bog like being too rich will. I've run my bike on the lean/crisp side and never had significant bogging. Can't imagine how lean you would have to be to get a hard bog like that.
 

quintwatson

Member
Jan 22, 2006
30
0
Binary - I agree with Indy. You need to pop open that carb. A buddy had a similar problem on his 250 and the main jet had actually fallen out into the float bowl! Ran awful at anything past 1/4 throttle.. Don't mess with oil ratios until you check the main jet.
 

binaryterror

Member
Jun 17, 2007
20
0
Well, I bought some new gas and drained all of the old stuff. The new gas I am using is 40:1, and it is almost getting worse now. Basically anything past 1/4th throttle now just bogs.

I can clearly notice that it DOES smoke more than normal. When the bike was working fine, it would smoke a good amount until the bike got warmed up, and then there wouldnt really be any visible smoke. Well now, there is CONSTANTLY a smoke trail behind me...
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
Yep,now do a leak down test and get back in the morn'in! SUCK UP 320 BUCKS AND DO A COMPLETE ENGINE REBUILD Choice is yours! Bt quit using the frigg'in outboard motor products and think about what the hell you have ! Then go from there,not some place in between,convenient for you!
 

IndyMX

Crash Test Dummy
~SPONSOR~
Jul 18, 2006
5,547
2
Amo, IN
It's a Leak Down Test.. and it involves putting pressure into the cylinder and watching gauge over time to see if it leaks off the pressure.

Don't worry so much about that right now. First priority should be to remove the main jet from your carb and clean it.

You need a 17 mm wrench to remove the cap from the bottom of the float bowl and a 6 mm socket to remove the jet.
 

_JOE_

~SPONSOR~
May 10, 2007
4,697
3
Ok, I may be goin out on a limb here, but you said you cleaned the air filter. Did you saturate the filter in oil? Maybe its sucking a bunch of oil at high rpm? You said its turning plugs black and blowing oil out. Just a thought. But as suggested, check the main and a leakdown test is a good idea from time to time.
 

binaryterror

Member
Jun 17, 2007
20
0
I did put oil on the airfilter, but I dont think I put so much that it is the problem.

What should I clean the main jet with? I dont have any carb cleaner. can I soak it in something?
 

CHR!S

Member
Jun 30, 2006
293
0
binaryterror said:
I did put oil on the airfilter, but I dont think I put so much that it is the problem.

What should I clean the main jet with? I dont have any carb cleaner. can I soak it in something?

You can blow it out with air, or you could also use brake cleaner. i guess you could try and push it out with a toothpick if its big and you can see it.
 

Moparman1539

Member
Sep 9, 2006
804
0
Clean the gas off put your mouth on it and BLOW! if you have a basketball air needle you can use a bicycle pump.. Or like CHR!S said.. use brake cleaner or wd-40 might work...

But the main jet is probably your problem...
 

Micahdawg

Member
Feb 2, 2001
503
0
A can of carb cleaner or brake cleaner and that little plastic tube that comes with the can usually works really well. Just spray through until it comes out nice and even.
 

2strokerfun

Member
May 19, 2006
1,500
1
binaryterror said:
i dont have an air compressor or anything like that, so i guess I will just look at it, and it I see anything then ill pick it out.

Get one of those cans of computer-cleaner air. They work really well for blowing out carb parts after cleaning, if you don't have an air compressor. It's like having a mini compressor for $5.
 


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