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Last ditch post for my 98 450ES not running

17K views 276 replies 21 participants last post by  trailridr 
#1 ·
I have made a few posts trying to get my 98 450ES running and about at my wits end. Here's where I am:
1) getting good blue spark while cranking
2) carb rebuilt and ultra soaked twice, still won't fire
3) fuel coming out the fuel line and carb getting fuel
4) pulled the valve cover and lined up the T on compression stroke, valves very close to .006
5) sprayed a little fuel in the plug hole put plug back in and it popped
6) tried again and put my hand over the carb intake and blew fuel back out onto my hand with some pressure

Some have mentioned a timing issue but if the valves line up with the T mark at .006 the timing should be OK right? If timing was bad the T and valves wouldn't be correct I would think.

Have heard CDI might be bad not sure if that would allow spark but at the wrong time. I am kinda frustrated to say the least...any ideas would be appreciated, I can give more details if necessary.
 
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#2 ·
That sounds like a classic CDI failure — will pop initially but not run.

Are you using the service manual diagnostics?

Ok if it was me I’d pull the CDI and bake it in the oven at no more than 180F for at least two hours. Let it cool completely!!! then reinstall. Don’t rush the cool down.
 
#5 ·
That sounds like a classic CDI failure – will pop initially but not run.

Are you using the service manual diagnostics?

Ok if it was me I’d pull the CDI and bake it in the oven at no more than 180F for at least two hours. Let it cool completely!!! then reinstall. Don’t rush the cool down.
Only way to get it to pop is putting a squirt into the plug hole. Other than that nothing even if I spray into the carb intake. I'll try to figure out how to remove, prolly have to take the front apart.
 
#7 ·
CDI is housed upfront held in place by a rubber boot, plugs in on the left hand side on top of the main square frame rails. I’d remove the front fender, be a hell of a lot easier.
 
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#8 · (Edited)
OK front fender removed to make easy access to the CDI. Oh my very dirty up there. Does it just slide out of the rubber boot or does the boot come apart? If it just slides out I will probably have to remove the connector first, don't want to stretch the wires...
 
#9 ·
Just slides out of the boot, it will be stuck though with the years of crud trapped in there. Wet it with a sponge and water, always works for me.
 
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#11 ·
I know you have NO compression tester... but humour me...

Plug the spark plug hole and crank motor. If you have compression of any kind it should blow past your finger ect... I understand some may think I'm crazy but you can tell IF you have good or weak compression...
 
#13 ·
I had to take the fender off of mine yesterday yeah a muddy mess under there.
I made a bucket of hot soapy water and used a rag and bottle brush. I have a few sizes.

Try not to get the connectors wet, you can wet the rag and wipe off the connectors.

The CDI has these little connector locks that you have to pull open, then pull off the connector. Since it’s dirty might not want to come off at first so be gentle. Hit the connectors with some electrical contact cleaner and use a plumber acid brush to clean off/out the connections. Then with a clean brush apply a thin layer of permatex dielectric grease to the contacts. This will seal out water and make the CDI easier to disco.

Ok once you do that. Just plug it back in and see if just cleaning the connectors solved your problem
 
#17 ·
OK trying to answer to some of the latest posts:
1) @wheeler--put my finger over the plug hole and cranked a few times, pushed my finger off pretty strongly.
2) @Goober--got the CDI removed and connectors off and cleaned with contact cleaner, installed but still no love
3) @Chalkymon--oil level good and pretty new, no other smells
4) @ktriebol--did check valves yesterday and with T lined up on compression pretty much had .006 on both valves
5) @ATC4ever--no fuel coming out exhaust, but am getting air flow from engine
checked plug wire up to the coil, no rubbing or bare wire
yes have tried 2 plugs

I tried to get the wires off the ignition coil but they seem stuck pretty good. They should just pull off right? And yes I agree just because getting spark on the plug doesn't mean it's good.

I again tried some carb cleaner in the plug hole and it kinda pops but doesn't really run, fuel is on.
 
#19 ·
The CDI should be a plastic tub with sealant. Yup lay the CDI in the oven with the sealant side up. The circuit board is laying at the base of and inside the tub.

So what you’re trying to do is drive off any moisture, perhaps relieve any sealant tension on the board. It might only last a day or maybe a year—maybe will help you prove CDI is bad.
 
#20 · (Edited)
Got it laying on my wood stove right now, low fire going but nice and warm....

Ever tested the ignition coil? I don't think I can just use my voltmeter. Trying to get the leads off but seem stuck and don't want to get too crazy and break something. It doesn't look like there are any clips, just slide on.+
 
#23 ·
4) @ktriebol--did check valves yesterday and with T lined up on compression pretty much had .006 on both valves

bcsman, I saw that you checked valve clearance in your earlier post. I wasn't referring to that when I asked you if you were sure that the valve timing is correct. What I mean by correct valve timing is that the camshaft must be timed correctly to the crankshaft. If the timing chain is off one or more teeth, the valve timing is incorrect. Correct setting of valve timing is explained in the service manual.
 
#24 ·
4) @ktriebol--did check valves yesterday and with T lined up on compression pretty much had .006 on both valves

bcsman, I saw that you checked valve clearance in your earlier post. I wasn't referring to that when I asked you if you were sure that the valve timing is correct. What I mean by correct valve timing is that the camshaft must be timed correctly to the crankshaft. If the timing chain is off one or more teeth, the valve timing is incorrect. Correct setting of valve timing is explained in the service manual.
Oh sorry no I haven't checked that, I think I need to tear more of the engine apart to check.
 
#25 ·
I had my cam chain off 1 tooth. Quad ran but never right. Once I fixed it it was a new machine. So if that’s off your .006 will not really be that at TDC...
 
#30 ·
I'm going out on a major limb here so I hope you'll take my comments in the spirit in which they are offered.
I read back through all your threads to be sure I understand where you are at this point. I know you listed, in this thread, what you've done so far, but that still does not sort it out in my simple brain. Here are my questions:

1. You added a new fuel line without a filter. Are you sure the fuel line is the correct size per the manual?

2. After adding the new fuel line did you fill the tank adequately to check the fuel flow in both the On and Reserve positions? I don't see where you were ever able to get good flow in "On". Maybe you did and did not post about it.

3. You say there is no problem with the fuel flow from the tank to the carb but you are basing this only on the fact that the plug is wet and, I think, you said you had fuel in the bowl of the carb on one occasion. This only proves fuel got to the carb at some point but doesn't mean you have a good constant flow.
Also, you said you thought fuel flow was good because you blew air through the petcock. Sorry, but air from the outside into the tank may just push any debris back into the tank and it will settle again against the petcock filter. AND, that petcock filter just slides on and you may have knocked it off when you flew air through it.

4. Are you positive your fuel selection knob is in "ON' and not Reserve or somewhere in between. My On position is about 1/2 inch past the On position. You mentioned several times that you did not have much fuel in the tank. Are you cheaping out because you don't want to waste fuel? LOL. Fill that puppy up at least 1/3 of a tank. You'd be amazed how much gas needs to be in the tank to crank it.

4. As @shadetree mentioned, be sure you gas cap is sealing and that the vent tube is not stopped up.

I'll throw in #5 for the entertainment value. Part of my job here is to make you laugh.

5. Are you sure, really sure, the kill switch is off. Flip that switch back and fourth a few times and be sure it comes to rest in the centered position. It's fooled me more than once.

Sorry for asking all these things but I can't get past the fuel delivery issue. I hate to see you trying all these things when you may not need to.
 
#33 ·
I'm going out on a major limb here so I hope you'll take my comments in the spirit in which they are offered.
I read back through all your threads to be sure I understand where you are at this point. I know you listed, in this thread, what you've done so far, but that still does not sort it out in my simple brain. Here are my questions:

1. You added a new fuel line without a filter. Are you sure the fuel line is the correct size per the manual?

2. After adding the new fuel line did you fill the tank adequately to check the fuel flow in both the On and Reserve positions? I don't see where you were ever able to get good flow in "On". Maybe you did and did not post about it.

3. You say there is no problem with the fuel flow from the tank to the carb but you are basing this only on the fact that the plug is wet and, I think, you said you had fuel in the bowl of the carb on one occasion. This only proves fuel got to the carb at some point but doesn't mean you have a good constant flow.
Also, you said you thought fuel flow was good because you blew air through the petcock. Sorry, but air from the outside into the tank may just push any debris back into the tank and it will settle again against the petcock filter. AND, that petcock filter just slides on and you may have knocked it off when you flew air through it.

4. Are you positive your fuel selection knob is in "ON' and not Reserve or somewhere in between. My On position is about 1/2 inch past the On position. You mentioned several times that you did not have much fuel in the tank. Are you cheaping out because you don't want to waste fuel? LOL. Fill that puppy up at least 1/3 of a tank. You'd be amazed how much gas needs to be in the tank to crank it.

4. As @shadetree mentioned, be sure you gas cap is sealing and that the vent tube is not stopped up.

I'll throw in #5 for the entertainment value. Part of my job here is to make you laugh.

5. Are you sure, really sure, the kill switch is off. Flip that switch back and fourth a few times and be sure it comes to rest in the centered position. It's fooled me more than once.

Sorry for asking all these things but I can't get past the fuel delivery issue. I hate to see you trying all these things when you may not need to.
Thanks for taking time to read thru, yes a mixed up jumbled up mess on my part with the storyline. I have been all over the place going from one possible problem to another. As I have received advise from many posters, I have tried to track that angle down and has led me down many paths. At this point I truly don't believe it is a fuel issue and yes I did put more fuel in the tank and get good flow in the ON position. Yesterday when messing around after cranking the plug was pretty wet. My main bone of contention is I am getting blowback from the carb intake and from all I have ascertained it means timing or valves. Gonna do a little more today but it probably is going to the shop as I don't have knowledge to tear the engine if that is the issue.

Only other issue could be weak spark but also don't have a peak voltage tester to check and parts to expensive to just swap.
 
#31 ·
@ GirlsRideToo... IF the kill switch was off... NO Spark... crank it over all day & won’t fire. I believe he said good spark with plug removed.
 
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#39 ·
Well finally heard from the shop where I took my Honda. They have been pretty busy working on snowmobiles here in Michigan and I said there wasn't a rush. He said compression is 140 and timing is fine, but the valves are in sad shape. If they rebuild the upper engine with valves, guides, etc he said it will be around $1000. With everything I observed in trying to troubleshoot this makes the most sense. Sounds kinda pricey but I'm sure at $85 an hour for labor it is reasonable. Any thoughts from those that have helped me on this problem??
 
#46 ·
OK got to talk to the mechanic today, he's been off sick for a few days. He explained what he has done and what he anticipates is still wrong with it. It has had the head off and valves lapped, alot of carbon. The piston and cylinder look very good. He was able to inspect the cam and said it also looks in very good shape. After putting the head back on it did fire a little better but still not starting and pushing fuel out the carb intake. He did an initial leak down test and was around 20%, not where it should be. After the valve lap it tested at 4-5% so said valves working well now. He said valve timing is perfect and said without pulling the front cover off thinks the timing chain and cam are also lined up. His best guess is a problem in the back of the engine, maybe woodruff key has broken or stator or pulse generator bad. He also said he checked spark and it is very strong. He really feels it isn't sending the spark when it needs to. I'm gonna bring it home when they figure out what I owe for what they have done and gonna give this a shot myself. So first thing I will do is remove the pull start and get access to the flywheel. It's pretty cold here in Michigan so may not get at it right away.

Does any of this make sense to those here with alot of Honda experience? Figure it should be easier to check the back end, I won't have to remove the motor to do that will I?? Depending on what I find there I may have to take the front end apart. Is this a good plan of attack with what has been done already?
 
#47 ·
i aint got a lot of experience with working on honda atv's. that said, pushing fuel out the carb intake makes no sense, with a rear engine problem, or any engine problem i can think of at this moment...
 
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