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Old 12-27-2009, 08:40 PM   #1
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Default front engine bearing

I was breaking down my engine (jxBo1A), it has a little less then 2 gallons.

Anyway, when i took the back plate off then put it back on, when i did it made a hissing sound in the front bearing. I know some leakage is going to happen on front bearings, but how much? When i turn the crank it was smooth. When i turned the bearing with my finger i could feel some resistance in the balls. I want to say it felt gritty, but i don't think so.

Also, when i took the button head off and the piston out, there was alot of deposits on the piston head. I could also push the piston right below the ring mark. I know it's an O.S. so it loses metal pinch after a gallon.

For you seasoned racers, how much of this is normal?

byrons 30% btw. Does this sound like a normal rate of wear?

i have more P/S and do not need it yet, but it's looking like 4 or 5 gallons on that P/S.

man, electric is starting to look good.
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Old 12-27-2009, 08:48 PM   #2
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That hissing sound was just the air inside your engine being exerted displacing the volume of the backplate. As long as your not having tuning problems, and you don't have a puddle of oil under your engine, don't worry about the front bearing. However, you said you thought it felt gritty. I would definitely check that out. Also discoloration on the piston is normal How To Clean Carbon Deposits On The Piston Head?
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Old 12-27-2009, 08:52 PM   #3
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That hissing sound was just the air inside your engine being exerted displacing the volume of the backplate. As long as your not having tuning problems, and you don't have a puddle of oil under your engine, don't worry about the front bearing. However, you said you thought it felt gritty. I would definitely check that out. Also discoloration on the piston is normal, do a search and you'll find a few threads on that.
I wound't say gritty, it's more like i can feel the balls rolling around. Anyway, what do i do? pull the seal?

I knew the backplate was pushing the air out. Just never really paid attention to it i guess. Would a leaky bearing cause it to run cold?
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Old 12-27-2009, 08:54 PM   #4
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I wound't say gritty, it's more like i can feel the balls rolling around. Anyway, what do i do? pull the seal?

I knew the backplate was pushing the air out. Just never really paid attention to it i guess. Would a leaky bearing cause it to run cold?
if your having to question the bearing replace it. and a leaking bearing would run hot because its causing an air leak. whats your temps, what engine?
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Old 12-27-2009, 09:08 PM   #5
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if your having to question the bearing replace it. and a leaking bearing would run hot because its causing an air leak. whats your temps, what engine?
ninja, 2 gallons.

i have leaned it out all i can and it reads 160 on the side 140 on the head and 220 at the manifold. Runs and sounds great, lean it anymore and my engine will fry. I have it now 2 1/4 out on the HSN and 3 turns out on the LSN (or a full turn and a half in from flush). Idle gap is hair thin. Midrange at the factory setting.

Has a trail of smoke and thats about it. No big puffs of smoke, the engine doens't really load up either.

when i got a good tune i richened it a couple hours to be on the safe side, but when i do the temps drop to almost 130. Like i said, that is the temp on the head. If i take it on the back of the engine by the manifold it's over 200.

but this doesn't make sense because i have taken temps of the head at 200.

p3 plug btw. It's been about 60 degrees outside.
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Old 12-27-2009, 09:10 PM   #6
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Am i using to much ARO?

I also preheat my engine.
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Old 12-27-2009, 09:12 PM   #7
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ninja, 2 gallons.

i have leaned it out all i can and it reads 160 on the side and 220 at the manifold. Runs and sounds great, lean it anymore and my engine will fry. I have it now 2 1/4 out on the HSN and 3 turns out on the LSN (or a full turn and a half in from flush). Idle gap is hair thin. Midrange at the factory setting.

Has a trail of smoke and thats about it. No big puffs of smoke, the engine doens't really load up either.

when i got a good tune i richened it a couple hours to be on the safe side, but when i do the temps drop to almost 130. Like i said, that is the temp on the head. If i take it on the back of the engine by the manifold it's over 200.

but this doesn't make sense because i have taken temps of the head at 200.

p3 plug btw. It's been about 60 degrees outside.

are you taking the temp at the glow plug? not the side or manifold, ON TOP of the head where you put the gp in?

if so and you have a consistent trail of smoke, no lean bog then dont worry about temps.
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Old 12-27-2009, 09:12 PM   #8
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Change to a smaller head shim, that will put the heat on your engine head, not your pipe.
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Old 12-27-2009, 09:16 PM   #9
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Change to a smaller head shim, that will put the heat on your engine head, not your pipe.
i have the silver one that came with it, and one copper shim. The copper shim is as thin as they get. I am running 30% so i have to have 1 right? some people put 2 shims with 30%.
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Old 12-27-2009, 09:20 PM   #10
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I'm not familiar with those engines, so maybe someone else can chime in and tell you what shim to use. Here's some info about where i'm coming from . .
hot pipe..cool head
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Old 12-27-2009, 09:22 PM   #11
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keep the stock shim in there. no need to put the copper one in
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Old 12-27-2009, 09:30 PM   #12
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would to much after run oil make it run colder? I so put a bit much i think.
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Old 12-27-2009, 09:43 PM   #13
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If your mid range is still factory settings and you leaned out the top, you have a bad tune. The needles need to be tuned together, to get the proper tune. You are surely fat on the bottom. your temps are also too cold.
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Old 12-27-2009, 09:54 PM   #14
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plugs already dry. Guess i could richen the top a couple hours then the top will be at almost break in settings.

I will lean the bottom a couple more hours. ttyl.
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Old 12-27-2009, 09:56 PM   #15
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If your mid range is still factory settings and you leaned out the top, you have a bad tune. The needles need to be tuned together, to get the proper tune. You are surely fat on the bottom. your temps are also too cold.
that is very true james,

we dont really know where he is getting his temps though because he takes them all over the engine.

the only temp you need is right on the glowplug witch should be right around 190-230

if its around 50 degrees it will be cooler on the engine as it has cooler air running over it.

if its 100 degrees the engine is going to read in the 220-240 range

the ninja motor can run all day long at those temps...

dont tune to temp btw if its making some good smoke all around and running fine and making all the jumps on the track with out much effort then leave it alone.
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