[atvrcr500]

Ok, I have a '04 RC with about 19000 miles on her. Was running perfect and was out of town for about 2 weeks and she didn't want to idle properly when I started it back up. While riding it seemed down on power a little. Ran a compression check and the readings were 90 in the front and 160 in the rear.
I was told that valve clearance can cause the low compression reading so I ran the valves. Intakes were .006 on both and the exhaust were .012 and .010.
My question is the one valve that is out of tolerance by .002 cause the low compression reading. I do not race the bike, it does occasionally a track day but normally I'm the one at the back of the pack. I use them to hone my riding skills.
It is rode everyday regardless of weather and I mean -4 and I'm still riding as long as there is no snow or ice.
Any help would be greatly apperciated. As I'm frustrated :banghead

 

[johnyisthedevil]

nope, start looking elsewhere. a leak down test is the next step.

 

[finnishkid]

hows the gas, fpr, fuel pump and everything else related to fuel. thats what i would be looking at.

 

[RVTMAVERICK]

Hey Buddy atvrcr500

When I first started reading your problem, My first thought was You had a Spark Plug crappin' out on You...

BUT then You talk about a Compression Test and getting ONLY 90psi in front cylinder! I'm sure I don't need to tell you, this SUCKS = Not GOOD!

My 1st Question to You is,... when You did the "Compression test", was it with the engine WARM, Hot or Cold?

2nd: When the engine was turning over, was the Throttle held WIDE Open both times from the start to end of the engine cranking over or? Very Very Important bro!

Peace Jeff

 

[ZeroGara]

I would change the oil and while doing so take the plug off and spray some CRC/WD40 in the cylinder and turn the engine over while you are doing so.
Then when you are ready to start it up turn it by button whith the plug off to throw the excess lubricant out.
Inspect the oil you took out carefully and if too dark (bad boy) filter it through a clean cloth and see if you find any signs of metal.
Start it up and go for a ride.

US gas is full of chemical crap and when you mix different brands some of those may crystalize around the rings and cause them to stick.

By the way, what does your plug look like, dry, black, oily, gray?

2 weeks is not significant as a period of sitting around but it may be enough to make an existing problem worse. The MX 450s run a quart of oil and it must be changed every race or 4-5 hours of practice. Are you running a power commander, pipes, etc? If the mixture is richer than optimal for the riding you do the oil has more to clean than a fine tuned bike.

 

[ZeroGara]

Senario 2

There was gas in the cylinder, too much to compress, and you fired it up and the rod is damaged.

 

[DesperateSP2]

I suggest a leakdown test. You don't need to take it to the shop or buy a new one: if you have a (decent) air compressor you can build one yourself.
Here are the instructions: Building and Using a Cylinder Leakdown Tester
Tip: you don't need an EGA, just do it when you can hear the noise of air escaping.

 

[Trace]

US gas is full of chemical crap and when you mix different brands some of those may crystalize around the rings and cause them to stick.

That is simply not true, and I'm betting that you have absolutely "Zero" data to validate that statement other than what someone else may have mistakenly told you. Please don't go around making up nonsense like that, and don't ask others to buy into your Big Oil Company Conspiracy Theories.

That chemical crap in there is called g-a-s-o-l-i-n-e, and it's been full of good, explosive "crap" for the past 100 years.

As your signature mentions....it's best to avoid ignorance.

 

[ZeroGara]

Trace

Have you lived outside the US? Long enough to clean carburators there?

Ok, especially in the South East US but also in general there is methanol and ethanol in the gas (all explosive stuff) but there is also less explosive stuff in there as well. Gas is not the same from 7-11, Citgo, Chevron, BP etc. What comes out your nearest refinery is gas mixed with a blend of ethanol and sometimes methanol. Then each brand adds its own unique blends of additives. Some companies don't even add any. Some of those additives are not compatible with each other.
An other problem this gas has is due to organic substances being in it, it attracts bacteria that grows into your tank, your carb.bowls or anywhere gas and oxygen is present.
On the other hand I have left or found a bike sitting for years here in Europe and it showed non of that nonsense that builds up in the US. That is enough data for me!
Look at DJ maps for any bike, they are different from US than they are for Europe. That should be enough data for you, if it is all 100% pure explosive stuff what is the difference?
It will not be the first time something mulfunctions in the RC ECU and it squirts gas like crazy, and the front cylinder is almost flat with any left over gas running right up to the rings. Just a tiny bit of build up in the ring groove and you have ring that is not performing.

Why are you surprised that you have corn oil in your gas I have no idea. Buy CITGO, it has no corn oil in it

 

[ZeroGara]

and don't ask others to buy into your Big Oil Company Conspiracy Theories.

That chemical crap in there is called g-a-s-o-l-i-n-e, and it's been full of good, explosive "crap" for the past 100 years.

Which oil company are you working for? BP maybe? They should throw you out of Florida!

 

[Trace]

Some of those additives are not compatible with each other.

This is simply not true. Not true. And if it was true, how did you determine that the result is the formation of "crystals" on piston rings? Why isn't it the formation of some odd varnish or resin or something, which would make more sense? Because you're spouting alarmist conspiracy nonsense that is not true.

An other problem this gas has is due to organic substances being in it, it attracts bacteria that grows into your tank, your carb.bowls or anywhere gas and oxygen is present.

Not true. Diesel supports the growth of algae in certain conditions. But gasoline does not support bacteria. Or algae, for that matter.

What you are seeing is what I have been seeing in fuel bowls since I was a teenage newbie racer in 1971...the typical formation of gums, resins and varnish from being exposed to air. Modern oxygenated gasoline, with their higher levels of aromatics (that chemical crap) do go bad much faster than gas from the old days. But ultimately, it's the same thing that's been going on since the Model T Ford. No crystals or other conspiracy issues are at play. It's the same-old-same-old of "bad gas".

Look at DJ maps for any bike, they are different from US than they are for Europe. That should be enough data for you, if it is all 100% pure explosive stuff what is the difference?

Sorry, that is no "data" whatsoever. The DynoJet maps are different because of one very simple reason: different OEM fueling requirements due to specific USA EPA (there's your conspriacy right there--the damn EPA!) mandates on emissions allowances and/or cat-converter requirements vs. those of other countries. And your example of "map data" has absolutely zero relationship to the heat value or the additives in USA gas vs. Europe gas vs. India gas vs. Australia gas vs Japan gas. No relationship. Zero, ZeroGara.

It will not be the first time something mulfunctions in the RC ECU and it squirts gas like crazy, and the front cylinder is almost flat with any left over gas running right up to the rings.

Does anyone here know if this actually happens, this failure of the ECU or the injector in a shut-down, cold motor that allows a significant quantity of gas to "squirt like crazy" into the cold chamber and then cause problems? And it has to be a cold motor, because if it were hot and doing the squirt thing, the gas would vaporize away and there would be no leftover raw gas to magically crystalize and seize your rings, correct? How does the ECU continue to squirt gas with the key turned off? And why does this only affect the forward "lay flat" cylinder? Won't "squirting like crazy" fill the rear cylinder with loathsome USA gas and crystalize the rings, too?

Anyway, your gasoline chemical crapcrystal conspiracy is nonsense. And if there was even a grain of truth to your nonsense, what would you have someone do about it. Buy Citgo? Oh....now I see the truth! You're part of the Citgo Conspiracy. snopes.com: Citgo / Petro Express

 

[Trace]

Which oil company are you working for? BP maybe? They should throw you out of Florida!

And why did you have to say something like that? You would just love to find a Big Oil Conspiracy going on here in Florida, wouldn't you? Someone knowledgeable like me debunks your Big Oil misinformation and you think I must be working for them huh? You need to watch out for black helicopters!

And "they" should throw me out? Who is "they"? Do "they" have the black helicopters, or is it your frightened co-conspirators here in Florida that I should be wary of?

I don't work for an oil company, Zero. Sorry to burst your conspiracy bubble. But "zero" is indeed a good name for you! :woot:

 

[ZeroGara]

I think your reaction is of political nature and not on how scientific my statements are. So I am not going to feed into your frenzy, not here anyway.

My association of FL and BP and your vigorous defense is related to the largest ecological disaster recorded by Big Oil.

My father used to carry gasoline in tankers out of Savannah before you were born (unless you were already old in 71) back when there weren't as many refineries in the world to produce gas locally, so I've heard stories about how gas was and how it is now.

I am not a chemist, but I do accept some of your statements as true but they do not invalidate the fact of crap building up. There are thousands of posts relating to malfunctions of the FI.ECU causing flooding and wet plugs, whether pressure regulator related or electrical.

Are you saying all gas sold in the US is 100% dynosaur oil distilled? How do you get your variable octane rating without lead? Are all companies using the same additives? What's the difference between 87 and 93 gas?
Is it impossible for 2 organic substances to react and form crystals? What is common between sugar and aspirin?

Tell us professor!

PS They are the people who live along the gulf coast of NW Florida. Who said anything about a conspiracy, it is the competition and marketing among them that makes them use these additives. How can SUNOCO have 95 gas and 4 other grades in areas where all brands are getting their gas out of the same refinery?

PS2 Stick to the subject and get your head out of the trenches my signature threw you in.

PS3 I have seen scratching and wear on Nikasil surfaces that were researched well. You don't happen to have a TZ750d do you?

 

[Trace]

I think your reaction is of political nature and not on how scientific my statements are.

Wait...let me get this straight. You say I'm political and you're somehow scientific? Wow. WOW!

Okay. I can't think of anything to say that can possibly top that delusion. You win.

 

[SubSailor]

On the subject of crystal formation in the fuel system, back in '83 (the previous economic recession) the economy was about as bad as today and bike sales were in the toilet.
I was working at a Yamaha/Kawasaki dealer and we had bikes in the crates for quite some time, like over a year or two.
When the bike was finally sold, we found the bike wouldn't start or idle due to deposits in the carbs from left over fuel during the factory test run.
We had to remove and disassemble every carb on every bike sold to try and clean the pilot jets and other parts.
When we removed the float bowls, we did find what looked like green salt in the float bowls from the old fuel.
Eventually Yamaha developed their fuel system cleaner which helped dissolve the deposits.

 

[Trace]

When we removed the float bowls, we did find what looked like green salt in the float bowls from the old fuel.

Yep, seen that plenty of times in carbs that have been allowed to go dry, long ago and sometimes today on the few carbed engines that are out there now (like pressure washers and such). That is varnish scale (not quite crystaline formations, but looks pretty close) and I "think" the greenish tinge was from the copper/brass in the carb and fuel system. This does indeed happen in forgotten fuel bowls. I just got a pressure washer running for a pal who didn't know to run it dry (or drain the carb and tank) when done washing last summer and there was greenish varnish goo in there. Gas goes bad really fast. It went bad really fast in 1971, and it goes faster now what with oxygenated aromatics in there. Drain your lawnmower!!!

But that scenario a far cry from "incompatible chemical crap that forms crystals in the gas and siezes the rings in the front cylinder". There are no crystal formations in my (or anyone else's) gas tanks!


I'll bow out now and leave the science to Zero.

 

[ZeroGara]

For the shake of returning to the subject, whether crystal or varnish goo "what's the formula for goo Doc?" is this crap formation able to get rings to stick, mixed with carbon deposits?

FI engines return warm fuel into the tank, you must have noticed your tank getting warmer in warm days especially if it is not full. This causes frothing in the tank and the heating and cooling of the tank and fuel together with the tank's ability to breathe, is a source of moisture. This is a condition where crap can grow in the dry parts of the tank and then contaminate the fuel sloshing beneath it. Whether any of this stuff makes it through to the engine or is caught up in the filter I can't call, especially with Trace around analyzing every word I say.

We don't have a response of whether the plug was dry or wet, and whether fuel was going into the cylinder. A dry cylinder will not have sufficient compression.

 

[Trace]

especially with Trace around analyzing every word I say.

When you originally spouted about "chemical crap in US gas is incompatible and causes crystals" or whatever, I thought it best to challenge your contention right away, before someone else reads it and believes it as The Truth.

When you fought back at me when I challenged you, you mentioned that your father used to be involved in tanker operations [ "My father used to carry gasoline in tankers out of Savannah before you were born" ]. At that point I realized that you had no factual knowledge of gasoline other than how to burn it in a motor vehicle. Although I'm sure your father was a fine fellow (ships's captain, deck hand, port operations guy, petro-chemical engineer...what?), hauling gasoline out of Savannah before I was born (1955) has zero to do with your possible factual knowledge of incompatible chemical crap in modern US gasoline. Period. It makes your argument less and less believable. Thus I pronounced it "nonsense".

If this gasoline issue is your opinion (or Big Oil Conspiracy Fear), that's fine. You're entitled to it. But so others here wouldn't simply swallow what you said as The Truth and start worrying about mixing gasoline (which everyone in the world does every day, BTW, with no crystals being formed), I felt it necessary to analyze and attempt to debunk everything you said. Somebody had to do it!

 

[ZeroGara]

The reason I mentioned my father hauling gas as a captain is that I grew up listening to stories about fuels, where they came from, what they did with them, and how the industry changed. Among those stories were facts that are you will not find on record on the internet or wikileaks, like in the 70s how millions of tons of fuel was being imported in the US from the soviet union with fake papers so even customs agents couldn't relate the fuel burned in the US coming from there. No conspiracy, just marketing! More than 70% of the fuel used in the US today for transportation needs comes from Venezuela.

Anyway, here are some sources of the evils of ethanol and methanol in your engine, why is this more prevalent in the US, and why no engine manufacturer in the world recommends those as fuels!
Gasoline - Definition

"Alcohols, including ethanol, are corrosive and attract water. Flex-fuel vehicles have special components to cope with those drawbacks without damage. The EPA's decision to seek comment was in response to a petition filed March 6 by Growth Energy, which is a consortium of ethanol interests.
To approve the change, the EPA would have to be convinced that higher levels of ethanol would neither create more tailpipe emissions nor harm vehicles' anti-pollution hardware." EPA begins discussion on boosting ethanol content in gas to 15% - USATODAY.com

"All Fuel Additives & Fuel System Treatment Products, that contain alcohol, should be avoided or used with caution with E10 gas.​

​

E10 gas containing alcohol over the legal limit of 10%, often results from the engine owners, ​

unknowingly adding gas treatment products containing alcohol to their fuel tanks.​

Since ethanol is an excellent cleanser, solvent, water absorber, degreaser and more - It's not surprising that these products would contain alcohol or chemicals with the exact same chemical properties of ethanol.


Desiccants, like alcohol, also have a strong affinity for moisture and will absorb relatively large amounts of water from the atmosphere, forming a liquid solution. Deliquescent salts include calcium chloride, magnesium chloride, zinc chloride, Carnallite and sodium hydroxide. "Marine Fuel Additives, Gas System Treatments and Ethanol E10.