running on 3 cylinders....

ok guys this does not seem to be my week, everything with the bike just seems to be falling apart!!!:crazy:

I was pulling out of my driveway and got on the throttle pretty good, about midway through third the bike just seemed to lose power all of a sudden. I pulled into a nearby parking lot and checked it out, the leftside exhaust pipe was not putting out as much exhaust as usual.. so i took it home and let it cool off for my second test. I started the engine and felt the header pipes, the left front when sitting on it (cylinder #2 I believe) was cold. So no combustion in that cylinder, I took the plugs off and checked for spark both coming from the plug wire and replaced the plug with a good spare I had around the house. So I have spark.
A day before I had removed the air cleaner and cleaned it and put everything back together, but I had ridden it since then.

My thoughts are that it is possibly clogged fuel line/jet/something in the carb clogged...
any ideas or what to look for before I tear this thing apart tomorrow????

 

Given the model, my first move would be to check compression just to calm my fears.Please do not get me wrong, I love the 500. But to lose one hole would make my butt pucker.Would need to know just to sleep again.

 

Clean fuel filter screens on missing cylinder.

Fuel tank debris, rust, crap , flakes, drek naturally settles against downhill carbs on left side.

 

Whats the easiest way to check the compression on these bikes??

Thanks for the quick reply man!!!

 

Thanks!! this is what I was thinking as well, but I did not know about the downhill left side, it makes sense though as much as it sits on the kickstand!! I try to always put it on the center stand but that doesnt always happen
where exactly are these screens? are they inside the carbs? like the diaphram or are they before?
Thanks a ton!!

do i need to install an in line fuel filter coming from the tank before it reaches any of the carbs or does the one in the tank do a good enough job??

 

FILTER screens are located just above float needle seats, which must be removed for access.

 

Yeah, it sounds like a clogged carburetor screen. Same thing happened to me on my '86 500. Same cylinder even. After cleaning (looked like paint flakes) I put two filters in line (one for each set). I was concerned about putting filters on gravity fed carbs but it hasn't affected the bikes performance one whit. Why Honda would omit something as critical as a fuel filter is beyond understanding. Especially when pulling and re-installing the carbs is such a freaking task. The only protection between the carbs and the tank is a ridiculous little screen on the petcock. I strongly recommend installing a filter the moment you get the beast home after purchase. The last thing I wanted to do was spend my weekend with a Chilton's Guide learning how to pull carburetors!

Good luck with it.

 

Thank you for the post. What brand of in-line filter are you using? Do you have a few photos of the install? Thx!

 

As described ,the failure would make me want to check compression first. If its ok then at least you know it is an easy fix and not to expensive and a quick easy thing to check on the 500.

 

would dropping a valve not have a bad clanging sound? or at least a tick? when it happend there were no odd noises of any kind. I am heading up to the auto parts store now to get a compression tester, if that checks out looks like Ill be pulling carbs today!! Luckily im off all week this week! This would suck to be a weekend job...

 

ok guys.. checked the compression today and did not get a reading at all on that cylinder...checked the others and they have a low compression around 7 kg but this was on a cold engine so maybe that will rise when its warmed up??

Anyways, what do I do now? Ive never had to replace anything this major before but am willing to try and tackel the challenge. I realize there are alot of factors.. like how much damage is done but can anyone give me a price range of how much this will cost to fix? all I have is $300 at the moment to throw at it.
would yall reccomend taking to to a shop or is it possible to tackle myself? I would like to try it, but if it requires a lot of skill and specific tools then a shop would probably be the best option..
If Im doing it myself, what all parts do I need to go ahead and order??

Also can someone tell me what exactly happend to drop the valve? spring crack and lose tension on the valve or what?

Thanks

 

Not great news,,,the spec's show 12 +/- 2 kg/cm2, so you definitely have low compression readings (besides the one reading '0' of course). As a first step - after cracking open your copy of the Factory Shop Manual - I think you'll need to remove the cylinder head covers and inspect what is going on in there, re. the valve springs & adjustment. As you may have read, the springs are the Achilles' heal to this engine's design and unfortunately they are NLA.

 

That sucks, would have rather been wrong on this one. You will need to remove the head and inspect the damage.

 

It's an old bike, now worn out.

Put the past behind you, you've paid your dues, now look for a good gen 2, 3, or 4.

You'll have more mechanical issues as long as you ride that bike, so find a newer one.

 

If I had the money for a newer model I would get one, but being a college student I am alittle low on funds...

A guy at the honda shop suggested it could just be a valve that stuck open, is this a possibility? I am going to tear it down and see tomorrow, can all the valve work be done with the engine in the frame?
Also does anyone know of where I can get better aftermarket valve springs from besides stock ones at bike bandit?

Thanks

ps. I will try and post up some pics of the valves and what I see, as to I do not really know what I am looking for besides a cracked spring or completely missing valve lol

I am going to look at a $100 parts bike this weekend I hope and if all goes well I might have a good set of valves/springs an all

 

Thanks man!!! I really am not in a hurry to get it fixed, I will be back at school next week and away from the bike except for on occasional weekends till school ends in may. So I can probably hold out for a cheap motor, I am limited by money however, I can really only spend about $300 tops for everything, and I had really rather keep it under $200.
Online bike bandit says that they have the springs, they are about 5 and 6 bucks a piece. I havent actually called them yet to see if they have them on hand though. I am going to take the motor out and check it tomorrow.
I will let you know about the head!! thanks for the help!!