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Back for more advise on my 98 450ES, blowing smoke

15K views 160 replies 16 participants last post by  shadetree 
#1 · (Edited)
OK need some more advise, she is now blowing smoke out the muffler. It has been running swell since the timing chain replacement and had her out last couple weeks pulling some logs for cutting. She did a great job. A couple days ago I was helping my son pull some brush out that was overgrown and on one pull I looked back and had smoke behind me. It is the whitish I guess blue smoke. Still seems to run fine and doesn't smoke right away when starting until I give her some throttle or slight load. I have tried adjusting the carb with no success. I pulled the plug and it was wet and pretty cruddy looking. The air filter is clean and no fuel in that area which is good. I am now going out to check the valves, but probably figure it is something worse. After I check valves where should I start? I surprised myself with the timing chain replacement and would like to do what is needed this time also. I will post results from the valves later.


Also the color of smoke, if it was fuel related would it not be a darker blackish color? This much lighter in color....Fun times....


Update: valves are good at .006, so any ideas much appreciated....
 
#116 ·
I've found it easiest to sit the cylinder in my lap, compress the rings with my fingers, and get the piston up into the cylinder. Then I slowly push the cylinder back out until the wrist pin hole is clear. It's VERY precise placement to get it there without pulling the piston out too far where the rings clear the cylinder and pop out, but if you get it just right you can then slide the cylinder and piston together down over the studs and slide the wrist pin in and push the cylinder down over the piston.

That works on a 500 and 420. Didn't work on my buddies Rincon so I just cussed and fought it for hours before I finally got it in place. That one I had to put the piston on the crank and try pinching the rings together and then push the cylinder down over the ring. An extra set of hands would probably have made it much easier.

You need oil, oil and more oil on piston and cylinder walls.
 
#117 ·
So have the engine all assembled and ready for installation, hopefully tomorrow. Have a neighbor thats gonna help, yea I know if I was a real guy I wouldn't need help!! It's a little heavier going back in as the cylinder and head were removed when we took it out. But figured I would prefer being buttoned up so nothing can enter or fall in. As with this whole project I will take it slow and easy and try to remember where all the parts lying around go back. Many thanks to a couple guys, you know who you are, to give pointers and advise.
 
#120 ·
If I might make a suggestion, these things go back in the frame much easier with the head off. I put the cylinder on the piston/ bottom end, then put the motor in the frame, then put the head and valve cover on.

You can get it in there with the head and valve cover on, it just requires turning the motor just right to get it in there.

Probably be easier since you will have help. I do them solo.
 
#119 ·
I've been following the progress super excited to read how it turns out. As I have a 2004 450s that I've rehabbed most of the chassis. And need to rebuild the engine. Working on the parts list now. Thanks to everyone thats contributed for all the great info and tips awesome site.
 
#132 ·
Well guys and gals the day has finally arrived, my 450ES lives to fight another war!! Only had one hiccup this morning, when I hooked fuel up to the carb it was leaking out the overflow as fast as it could. I figured the float was stuck so removed the carb, lo and behold somebody had left the drain screw at the bottom open. Closed the screw, put everything back together and with a little coaxing fired up. I started out with short run times and have graduated to driving around up and down shifting. So far I have had no problems, it really runs quieter than before. I have a couple things to play with and adjust, putting it into reverse I need to pull back hard on the brake lever. So after a couple months of fiddling and farting around I can say she lives!! Also after a couple days will put the front parts back together to make it look like a Foreman. Many thanks for all the advise for helping me thru my first tear down and rebuild. And especially to my friends who held my hand and wouldn't let me get depressed, again you know who you are......
 

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#142 ·
when was the last time, you had new plugs? just saying, that ya done so much work, if you got older plugs in there, ya might get a bad impression, of the problem...
 
#145 ·
That plug shows a fuel-rich condition.

I would check the operation of the choke plunger first. Make sure the choke cable allows the plunger to fully seat all of the way down in the bore and the return spring is putting sufficient pressure on the plunger to hold it down in the bore.

If that cable adjustment and return spring is fine, pull the plunger out for an inspection. The tip should have a short pointed needle on it, there should be a flat rubber seal filling the bottom diameter of the plunger. You may see a ring-shaped depression in that flat seal where it contacts and seals the end of the plunger to the bottom of the bore. There should be a lipped seal around the body of the plunger in good condition with the sharp lip facing the top of the plunger, so that the seal lip prevents air from entering around the plunger from the top.

Lubricate the plunger and lipped seal lightly using silicone o-ring grease (or dielectric grease can be used if you haven't any o-ring grease) when you put it back together. Let us know what you find.
 
#146 ·
So determined the pic of the plug was not very good and wasn't fuel rich. Pretty sure my carb and choke plunger are working ok. After some consultation it was determined I had not been doing a decent job breaking the engine in. I have been babying it too much, so I took it for a 45 minute ride and gave it a harder workout. Lots of up and downshifting and putting a load on the engine. I needed to heat the oil and the engine up to a better operating temp. And by golly after warming up the sluggish acceleration was not there anymore, very responsive. I need to do another one to get it broken in, then I will change oil and filter.
 
#150 ·
Your carb may be lean on the idle circuit. Here are my reasons for thinking this. First, two and a half turns out on the idle enrichment is a little more than usual. Not the "main" as you called it earlier. Second, you said you used it much harder than before which means you were on the needle and main circuits much more than before and that cleaned up the spark plug. Third, you said it runs better when "hot". A lean engine runs much better when hot than lean. I may be wrong but I'd clean the carb again when I got the time and this time pay a little closer attention to the "complete" idle circuit when cleaning. We can help you with the little details of this circuit if need be. A second valve adjustment may be in order at this time too. Valves can tighten or loosen a little after a rebuild.
 
#151 ·
So today I was just taking a look at the engine and noticed a small amount of oil on the spark plug side of the cylinder fins. I grabbed a 14mm wrench and the 3 nuts that are exposed to hold the head on were somewhat loose. I thought well better pull the valve cover and check the other 3 also. They were not as loose but tightened all 6 again. Figured while in there might as well check the valve clearance and they were tight, I couldn't stick the feeler in when TDC on compression. So I adjusted those a tad wider so the feeler was snug at .006. Also tightened the two 13mm exhaust nuts while apart.

I guess I used the wrong name when talking about the initial carb adjustment. According to the service manual it's called the pilot screw and default when setting is 2 5/8 turns out from being lightly seated. AFAIK this is the only adjustment available on the carb except for idle. I'm not sure what you mean by idle enrichment??? I just pulled the plug again today and it looks the same as everytime I have looked at it. The pic I took was what it looked like before I ran it harder, looks the same today.
 
#153 · (Edited)
The idle enrichment screw is the screw you adjusted to 2 and 5/8ths. It allows more fuel in in the circuit at idle to about 1/8th throttle. The slow jet does too but it is "fixed" so it needs to be replaced to a different size to adjust. Other adjustments are the needle clip position. It raises or lowers the "tapered" needle into the "emulsion tube" It is most effective from about 1/4 to 5/8 throttle. On machines with many miles the taper can wear itself smaller and make it rich. The needle goes into a "holder" or "jet" called a "needle jet". It's hole can wear at the same rate as the needle causing a rich condition. Most people don't bother with this but it is a factor on high mileage engines. About 15 or 20 years ago a friend of mine who is an excellant mechanic was stumped because his high mileage Goldwing ran good but had worse and worse fuel economy. I suggested replacing the needles and holders.....which he did and said that fixed it.
 
#152 ·
If those are the bolts that hold the head in place they should be torqued to a specific value as stated in the service manual if they are over or under tightened it will effect the sealing of the cylinder head and rocker arm to valve clearance i believe it's 29 ft lbs but please check the service book for the exact measurement and sequence.
 
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#155 ·
gotta ask !, why didn't you install a brand new shindy carb rebuild kit when you rebuilt the engine ???????..lol. I always ( on my projects ) replace/rebuild the carb with a shindy carb rebuild kit...ALWAYS !!.
 
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#156 ·
His carb is in great condition. Turns out the sluggish acceleration issue was nothing more than a cold motor due to the initial rings seating sessions being terminated way too early. AKA... a bit of over-cautious-ness protecting the rings from overheating in the new bore.... but just a smidgen of overdoing that. :)

The spark plug looks perfect, motor is a very strong and responsive runner, the rings are now fully seated, breakin oil & filter has been changed, Wiseco head gasket retorqued as required and the valve lash readjusted to spec. Its ready to be put to work, light duty short towing beginning right away then progressively heavier.
@bcsman performed admirably while building his 1st Honda motor in my opinion. I for one, am very impressed with his thorough efforts! I've tried dropping a couple subtle hints... but he didn't bite, so it looks like he won't sell it to me. :)
 
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