Engine performance issue.

TROJANMAN2014

Member
Mar 21, 2012
18
1
40
nebraska
Hey everyone,
I got something that has me stumped. I rebuilt the top end of my blaster (for the second time) this time I decided to delete the oil pump and just mix my own gas. Well now it won't idle quite right. It's got balls of steel at wot and just cruising but at idle it does this weird sort of gurgle or hiccup. I've put a new plug in it cleaned out the carb the gas is great running a 32:1 mix. What am I missing here??? Can't seem to post the video on here so here is the link to YouTube where I posted it.
2000 Yamaha blaster gurgle/hiccup at idle.:
 
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I hate to be a proverbial parrot, but you need to leak test the motor. Sounds like you have a lean bog.
 
I hate to be a proverbial parrot, but you need to leak test the motor. Sounds like you have a lean bog.

I hate to be a proverbial parrot, but you need to leak test the motor. Sounds like you have a lean bog.
Well I might look like a jackass here haha. but leak test as in similar to doing so on a carb on a v8? As spraying carb cleaner around the intake and waiting for a bog? Or are you talking about like a compression leakage test? Again sorry if I'm making a fool of myself. I'm used to working on cars not quads.....
 
Sounds like a lean bog to me also.
A leak test is done to find any air leaks in the motor either by a leaky seal, head, base, and or intake gasket. Lean conditions seize motors or worse.

You would either need to build your own leakdown tester or you can buy one also.

Also, have you heat cycled and re torqued the head and base nuts? And on a new rebuild how long has it been since rebuild that you are running WOT and for how long?

Carb cleaned well and float height set correctly?
 
Sounds like a lean bog to me also.
A leak test is done to find any air leaks in the motor either by a leaky seal, head, base, and or intake gasket. Lean conditions seize motors or worse.

You would either need to build your own leakdown tester or you can buy one also.

Also, have you heat cycled and re torqued the head and base nuts? And on a new rebuild how long has it been since rebuild that you are running WOT and for how long?

Carb cleaned well and float height set correctly?
Yeah I hear cycled it 3 times retorqued and ran it at 1/4 throttle then 1/2 throttle then 3/4 throttle and then a wot pull and let it cool in between those. I had done that last weekend. I pulled cylinder off today everything looks good to me. All gaskets are new. Could it be a problem with the reeds or reed cage? And how would I make my own tester?
 
scooby_ruh_roh-100273465-orig.jpg


Now you'll never know where the air leak was.
 
Looks like I'm headin to the homodepot tomorrow! I was figuring maybe I could use my leak tester that I use at work (sadly enough I'm a auto tech(still in school currently) learning as I go) so thanks everyone for being helpful!!!!
 
2 strokes are like new born baby's. They need a little care, a little nurturing, diaper changing and some love. Eventually they grow into something you can be proud of. Something thing you can show off to others and gloat about...lol
 
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Looks like I'm headin to the homodepot tomorrow! I was figuring maybe I could use my leak tester that I use at work (sadly enough I'm a auto tech(still in school currently) learning as I go) so thanks everyone for being helpful!!!!
No you cannot use an auto leakdown tester. those are make to check for leaks on valves and/or rings ~75+ psi

the tester you are building is for testing seals and gaskets. ~5-8 psi

if you use the auto tester, you will definitely blow out your crank seals!
 
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Update: I made a leak tester tested it and found the reed cage was leaking. I used rtv to deal it off. Let it cure for 24 hrs and rode it. It ran great!.... Untill it warmed up and went back to what it sounded like I'm the video. and I noticed now at idle if I just barely push the throttle it will die. Should I test again and see if anything else is leaking? Try another plug? Where all could it be leaking from?
 
Step 1 leak test
Step 2 locate leak
Step 3 Repair found leak
Step 4 Retest to see if repair was successful and if there are any more leaks
 
Step 1 leak test
Step 2 locate leak
Step 3 Repair found leak
Step 4 Retest to see if repair was successful and if there are any more leaks
Well I fixed the reed cage. but now found the exhaust flange is leaking. Is it possible for it to be warped? And has anyone out a gasket on it from a car to stop a leak?
 
Uh, the exhaust flange shouldn't even be on there when leak testing. It should be capped off with a plate
 
Uh, the exhaust flange shouldn't even be on there when leak testing. It should be capped off with a plate


Right ok, so I cheated the test a bit cause I suspected my flange to be leaking. So I capped it off at the end of the expansion chamber and behold my flange is indeed leaking
 
sounds terrible.!!!
air screw setting?
free flowing gas from tank to carb?
spark plug type?
is your silencer even on in the video?
pics/video in the day time lol...

never mind i saw your other post saying you cut the silencer somewheres
 
sounds terrible.!!!
air screw setting?
free flowing gas from tank to carb?
spark plug type?
is your silencer even on in the video?
pics/video in the day time lol...

never mind i saw your other post saying you cut the silencer somewheres

Alright well. Before anyone jumps on my case for this! It ran fine before I rebuilt it.... But I had made a "silencer" consisting of a 2.5" pipe adapted to the 1" so no real silencing happening. And yes I'm sure it's not great for it and what not I get that no need to explain that. But I know for a fact it has ran with the pipe I made for 4 years not. the only thing I changed this time was the expansion pipe which I bought off eBay used.....
 
I do a leak test with my exhaust flange installed. Saves me from buying exhaust gaskets and is easier to remove and do a leak test. . It also lets me know if my flange is leaking as well..


^^^ and like stated, you can have more than 1 leak. Fix the one you noticed first and then retest. You could have no more or you could have a few more. There is no way of knowing until you test again.