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Discussion Starter · #1 ·
I pulled the motor out of the bike today. I took the top end apart and the piston and the cylinder walls look fine. No scratches or anything. The wall looks shiny and smooth. I couldn't feel any scratches either.

However, the valves are covered in carbon buildup. It is so thick I can't scratch it off with my fingernail. Could this be causing the smoke? Or what? The bike smoked blue and used oil before I tore it apart.



p.s....Always bring friends when pulling a motor. It was pretty hard for me to do it by myself. But, I got er did!
 

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Too rich? My V-twin would smoke when it was running rich
 

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Discussion Starter · #3 ·
I have 2 1.5" snorkels. Plug was a good brown color. I don't think I was running rich. The bike did get a bit of water in the head. Rich is usually black smoke. My bike was shooting out blue smoke like no tomorrow. I'm sick of worrying with this thing...

Thanks for the reply.
 

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Valve Seals Valve guides are a cause of oil huffin....
 

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yep i was thinking valve seals also letting some oil blowby. i would rehone the cylinder a bit before you reinstall to scuff up the shineyness just incase.
 

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Leaking valve guide seals typically don't let by much oil (not enough to notice a change in your oil level) and the few drops burns off quickly after startup and the smoking stops. If your bike was making blue smoke the entire time it was running, and burning enough oil for you to notice the level go down it is getting pasts the piston rings. This can be due to: an out of round bore, worn rings, or scored cylinder walls (which you don't have). Did you have a chance to run a wet/dry compression test before teardown? Most likely you will need an overbore piston and rings, and have your cylinder bored to match the piston by a reputable machine shop. Good luck.
 

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Pull the rings of the piston and do a ring end gap measurement. You will most likely find your problem there.
 

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Discussion Starter · #8 ·
I pulled the top ring off and did an end gap measurement. I followed my SM so i'm sure I did it right. The end gap is about twice as big as it should be inside the sleeve. Also, my crankshaft has a bit of side to side play. Is that normal?
 

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Discussion Starter · #10 ·
The connecting rod has a bit of side to side play. Is this normal?

I have my entire top end tore apart. I have horrible carbon/oil buildup on the intake and exhaust valves. I also have buildup on the back of the exhaust valves. Does this mean I need new valve guides? The sm says that I have to replace the seals too.

I also have to buy all of those tools that the sm says I need to measure everything. I just don't know what all I need to do to it since I tore it apart before anyone metioned a compression test. Where can I purchase the micrometers and everything needed? Do parts stores carry them? If so, how much do the tools cost?

Are there any write ups on rebuilding these motors? I'd like to read all I can about them so that I understand everything better. Thanks
 

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boy oh boy...........in kinda of a pickle i see. sorry by the way i thought it was a vtwin.
as far as the rods, i would think a bit of play but not excessive but i don't know the "tollarances" of the 500.
deposits will come off, wire wheel, light air sander wheel, ect
where the valve seets or the taper part seals when closed how does that look? chipped or gummed up? hard to say much more without seeing/being there. haven't seen any writeups on rebuilding in the 2.5 years i have been on here. hopefully someone will come along and provide more insite, good luck.
 

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Discussion Starter · #12 ·
I am going to go and buy the measuring tools and measure everything in the bike and replace whatever isn't in spec. I figure that should get me back on track.

Thanks for your help.
 

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<div class='quotetop'>QUOTE (tuck05 @ May 7 2007, 12:57 AM) <{POST_SNAPBACK}></div>
The end gap is about twice as big as it should be inside the sleeve. Also, my crankshaft has a bit of side to side play. Is that normal?[/b]
Did I understand correctly that the ring gap is twice as big as the manual says it should be???? If so, many where you losing power and oil!!! If you can get the bore measured and find it to be within tolerance than it was just the rings being worn out. As for the carbon buildup, just clean it off with some cleaner and a wire brush. Might be the kind of gas you are using.... I know a few guys that use some fuel additive every once in awhile to clean up the cylinder....
 

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Discussion Starter · #14 ·
The rings are square on the end and I did not see any writing on the ring ends. The rings in the pics in the manual are sorta L shaped with writing. I am wondering if the previous owner has ever put new rings in it. Maybe he also had the timing wrong b/c the bike has always ran WAY too rich. Stock with 693 miles is when I bought it. It would blow out a lot of black smoke all the time.

I am gonna buy some more tools and check everything in it, clean up the valves, put in new valve guides and seals, and probably have it bored .20 over or so and put in a new piston and rings.

Honestly, I have almost talked myself into just getting a new bike and fixing this one over time and using it as a back up bike. What do you guys think?
 

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Timing has no affect/effect on if a bike/atv runs rich. The only thing that affects that is the carb settings like size of the jets...etc.... If you can afford a new ATV that's always the best upgrade!!!!
 

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Timing has no affect/effect on if a bike/atv runs rich. The only thing that affects that is the carb settings like size of the jets...etc.... If you can afford a new ATV that's always the best upgrade!!!!
 

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Timing has no affect/effect on if a bike/atv runs rich. The only thing that affects that is the carb settings like size of the jets...etc.... If you can afford a new ATV that's always the best upgrade!!!!
 

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Discussion Starter · #18 ·
Yeah. I'd love to have a new one. I like my current bike but it has SRA with 11" or so of GC. I get hung up in every good rut I go in. I hate it.

I may just get this one running and see what a dealer would give me for it on a trade in. I still have a lot of work to do to this one though.
 

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The play you talk about in the connecting rod is normal. The piston is a floating design and some play is normal due to the imprecise fit of the piston pin to the circlips. Chances are if you are on a budget you can just get a set of rings. High Compression pistons are avalible and improve performance. The reason you rings are so worn is because of dirty air coming in the cylinder. Make sure you have a good air filter.
 

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If it has always run too rich, you could have been washing down the cylinder wall with raw fuel. If you haven't noticed a large amount of fuel in your oil, then that might not be the case. Just thinking out loud, that's all.

Have seen overfueling cause havoc on cylinder walls and rings.
 
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