Carbuerator.

[jcm2792]

I have an 01 blaster. with a mikuni carb on it. right when i start it it just idles really high but the slide is all the way down. i cleaned the carb and still the same thing. I need a new carb and thumb throttle with cable. If you can help please lemme know. Thanks.

 

[sheeblast]

you might have an air leak or you are running super lean jetting. but i am leaning toward air leak.
check for an air leak. either build a leakdown tester or buy one and follow the instructions on how to do a leakdown test. there is a thread in the DIY section, search for it.

 

[brandoz28]

sounds like an air leak to me too leakdown as he said^^^^^

 

[jcm2792]

So If i have an air leak this would cause my engine to run at pretty much full throttle and the slide is all the way down. I would still like to replace the carb. Anyone have one?

 

[brandoz28]

yes it will. find your air leak before buying a carb, or she's gonna be blowin up

 

[jcm2792]

Alright. Ill read up on the threads. thanks for the help.

 

[jcm2792]

Alright i tore the carb apart cleaned it really well. put it all back together. Still idles high but when adjusting air/fuel screw it calmed down a little and if i put my hand over the intake for the carb it calms down. Im no pro but Im still leaning towards the carb. Im still confused on the air leak option. Could someone go a little more in depth?

 

[royalt67]

Putting your hand over the intake and "calming it down" is a sure sign that the guys are right about an air leak (2-strokes rev uncontrolably when lean at idle). You cut the air going in, but it runs better, therefore you are getting air in from somewhere else. Common leak locations are carb boot, reed gaskets, base gasket, and crank seals. A leak tester pressurizes what should be a sealed system, allowing you to figure out where the extra air is getting in.

It is possible to do all sorts of things carb wise to mask the problem, but you will still have a leak that will only get worse.

 

[TechBlaster]

Alright i tore the carb apart cleaned it really well. put it all back together. Still idles high but when adjusting air/fuel screw it calmed down a little and if i put my hand over the intake for the carb it calms down. Im no pro but Im still leaning towards the carb. Im still confused on the air leak option. Could someone go a little more in depth?

Air = Lean
To lean out is to add air.

If your bike is pitching the revs with no throttle applied it is lean, dangerously lean. If no changes were made to jetting, etc and it just started doing this, you have an air leak.

As you stated when you cover the carb intake with your hand, you are cutting down the air intake volume to the engine, and the idle calms down, due to it flattening out to a more stable mixture. Take your hand off, and back up on the revs/dangerously air/leaned out.

Point is, as stated a few times above, you, my friend, have an air leak. Where is it coming from? That needs to be investigated. A leak down test will tell the tale, HoleShotMan and can help ya out with a tester, PM him for more info. Check possibly the intake side of the carb, reed cage, gaskets etc??? That is where i would go first. Inspect gaskets, possible try some permatex gasket maker to see if this helps calm it down, etc.

BUT, careful there bro, don't run it too much or as Brando says, Boom-Bah!!!!


Edit: as i hit post I saw royal posted very similar info, so it is a no brainer, and fact Royal and I are hunting down the same trail, great minds think alike!!! I:I

 

[brandoz28]

is the cap on the top of the carb tightening down all the way? and is the little rubber gasket still there?


a leakdown test is definitely in order, that's a bad air leak and it will hurt it sooner or later

 

[LOCSTA]

WARNING! WARNING! WARNING! You have an air leak. Find it now and don't ride it anymore till it's fixed or you will be replacing your top end.

I repeat do not ride the bike till you find and fix the leak.

LEAN = FRIED

 

[LOCSTA]

Here's the link to Holeshotmans leakdown tester. I have one and it works great. Very nice setup.

http://www.blasterforum.com/sale-18/leak-down-testers-28728/

 

[jcm2792]

Alright i did have an air leak where the reeds go into the cylinder. so i had it running good yesturday but today i tried starting it and i couldnt get it started. yesturday i sprayed some starter fluid in it and she ran fine all day but something is obviously wrong if i have to spray fluid to start it. Any ideas? seems like one thing after another

 

[brandoz28]

have you checked the compression?


what do the reeds look like?


is fuel getting to the cylinder?

 

[jcm2792]

Like i said she will fire right up if i hit it with some starter fluid. so its getting gas compression seems fine cause it ran fine yesterday. What are reeds supposed to look like. im not too familiar with them.

 

[brandoz28]

they shouldn't be chipped/warped, they should sit flat


and you really shouldn't use starting fluid, that's like running with no premix


have you put a compression gauge on it? if not, you won't know if its good or not

 

[jcm2792]

Havent put a compression gauge on it. ill try to pick one up tomorrow. needs to be between like 100-125?

 

[royalt67]

I believe 125 is what the book says. 100 is tired but it should still start ok.

 

[jcm2792]

1 thing after another. I put a new plug in and she started up fine. rode it for like 10 min. put it on the trailer was gonna go to the woods started it to make sure she was gonna start ran for a few seconds then heard a loud bang and the motor is now seized! where do i start. Thanks for all the help

 

[hudack]

well from reading threw the thread real fast that air leak did a toll on your pistion and then that starting fluid didnt help im thinking the air leak was your main cause for this