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Post by kawman on Feb 5, 2012 14:04:20 GMT -6
1986 good compression, good ignition timing, good spark, fuel to carbs. Backfires when attempting start. It did this once before and changing fuel out fixed the problem. But not this time.
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Post by Blaine on Feb 5, 2012 15:13:58 GMT -6
1986 good compression, good ignition timing, good spark, fuel to carbs. Backfires when attempting start. It did this once before and changing fuel out fixed the problem. But not this time. Welcome to the forum.Have you done a valve adjustment? These engines need a good valve adjustment every 5000 miles.
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Post by 454guy on Feb 5, 2012 15:32:17 GMT -6
I had the same problem and needed new spark plugs they where sparking but not good. Spray a little starter fluid in the hole where the spark goes in that will get it started too good luck!
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Post by mattsunn on Feb 5, 2012 18:11:17 GMT -6
+1 on the valve adjustment. It's surprising just how much a good running 454 depends on properly adjusted valves. Moreso than any other bike I've ever owned. And I've owned a lotta bikes.
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Post by eaglerider on Feb 5, 2012 19:09:55 GMT -6
I have made that point for years......just don't get it that it seems like that is the last thing anyone wants to do. Then when they finaly do, they find out that adjusting thevalves good, most times works wonders, and makes the 454 come "alive"
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Post by wanchesenative on Feb 5, 2012 20:41:34 GMT -6
I think it has something to do with the thought of tearing down the top of the motor. At least for me, it is kinda intimidating for a "not-so" mechanic like myself. I know in my mind I can do it but as they say, "dreading it is worse than doing it."
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Post by mattsunn on Feb 5, 2012 21:12:14 GMT -6
I think it has something to do with the thought of tearing down the top of the motor. At least for me, it is kinda intimidating for a "not-so" mechanic like myself. I know in my mind I can do it but as they say, "dreading it is worse than doing it." The adjustment itself is easy. All the stuff you need to disassemble to get to them is a PITA.
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Post by kawman on Feb 6, 2012 8:49:18 GMT -6
Uh, good compression. How can the valves be out of adjustment and still have 160 psi cold compression in each cylinder?
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Post by eaglerider on Feb 6, 2012 9:10:04 GMT -6
The valves on the 454 tend to tighten up, stopping fuel from getting into the combustion chamber. Loose valves do not close correctly, causing compression loss. U can have good compression, but if the intake valves stay closed, no fuel can get into the combustion chambeer, to fire the engine.
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Post by kawman on Feb 6, 2012 11:23:17 GMT -6
Uh, if the intake valve stayed closed wouldn't the lack of intake air to be compressed just make the piston free run within the cylinder
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Post by zekkfett on Feb 6, 2012 12:03:21 GMT -6
Trust us when we ALL tell you, the valve adjustment will make a WORLD of difference.
On the opposite end of what Eagle said, as the valves get longer, they may not close completely; depending on how long it has been since the valves were last adjusted. You may be getting fuel and fire, but if one or more of the valves do not seat, you won't get the compression to fire.
When you compression tested it, it may have drawn in air, and it is compressing it, but you are probably getting leaking around the valves. If, as it is compressing, one of the exhaust valves is slightly open, all your compression will leak out of the exhaust. And possibly backfire. And it won't fire up. On the other side, on compression, if one of the intakes valves is slightly open, it will backfire out of the carb.
Listen to Eagle, he's full of the Kawi knowledge. Valve adjustment. As much as anyone hates it, it is a must on motorcycles.
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Post by mattsunn on Feb 6, 2012 13:40:52 GMT -6
1986 good compression, good ignition timing, good spark, fuel to carbs. Backfires when attempting start. It did this once before and changing fuel out fixed the problem. But not this time. You could also have clogged idle jets. Drop the float bowls and check 'em out.
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Post by kawman on Feb 6, 2012 15:31:50 GMT -6
(When you compression tested it, it may have drawn in air, and it is compressing it, but you are probably getting leaking around the valves. If, as it is compressing, one of the exhaust valves is slightly open, all your compression will leak out of the exhaust. And possibly backfire. And it won't fire up. On the other side, on compression, if one of the intakes valves is slightly open, it will backfire out of the carb.)How can there be good, I repeat, how can there posssibly be good compression if as you say above? ? Read more: ltd454.proboards.com/index.cgi?board=general&action=display&thread=3373#ixzz1ldiMyE6Y
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Post by Bearded Biker on Feb 6, 2012 18:40:22 GMT -6
ive put 22,000 miles on my bike since i bought it. its a good sign that you need a valve adjustment. i went through the same thing.
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Post by zekkfett on Feb 6, 2012 22:18:07 GMT -6
In all actuality, most (90%) of compression testers only show MAXIMUM compression, most won't really show a leakdown. With a small leak, you will get the compression up, but it cannot sustain it.
Valves as they age get LONGER, which is why if you adjust the valves to the loose side, you can go a bit longer without adjusting them again.
Your valve adjuster nuts might have been loose from the last person that attempted to adjust the valves. Either way, the valves are most likely either too loose or too tight. Which means they are slightly open on intake and compression, or not opening at all.
Backfire is either a carb issue, or you're losing compression somewhere. Or it is escaping. Valve adjustment will get it firing right up.
Good luck.
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Post by kawman on Feb 7, 2012 20:56:50 GMT -6
Eagle Rider,
You were absolutely right, one intake valve's adjustment screw and lock nut were completely off the lifter mechanism. And as luck would have it I was able to retrieve both the screw and lock nut with my small pocket magnet, they were just laying there underneath the cam. And with two intake valves per cylinder one valve opening would give a good reading. I stand corrected.
Kawman
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Post by zekkfett on Feb 7, 2012 21:16:09 GMT -6
Did you get her running?
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Post by 454guy on Feb 7, 2012 23:27:56 GMT -6
I also adjusted my valves and it runs a lot better !
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Post by eaglerider on Feb 8, 2012 6:25:53 GMT -6
Good going, guys.....glad things are lookin up for you!
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Post by kawman on Feb 24, 2012 9:09:37 GMT -6
Zekkfett, It's been a while since I looked at the forum, but yeah it runs just fine. And thanks for all the input from everyone.
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Post by moosinatrix on Oct 4, 2013 2:11:52 GMT -6
Hi I recently have been having issues with my bike cold starting it started getting hard to start, steadily got worse until the, only way you, could start it cold was to push start it and now it won't even do that.
I started with the obvious check for good spark , got that. Went through the carbs, got fuel.
Found this thread so I did the valve adjustment. Every single valve was open at least .3 or .4 mm. knowing this im shrouded I was getting it to push off.
I did the adjustment and the symptoms are better but still won't fire up. I haven't had the energy nor courage to try pushing again. When I try to crank it I get nothing unless I choke it. When I choke it, it will fire as im cranking but will not actually run. My brain is racked. Tomorrow I'm gonna clean the plugs and gap them. When I checked for spark I just logged for a flash and said good 'nuff. Given that every issue with my bike I googled,i found the answer here, I thought I would gather yalls input. Thank you
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Post by Blaine on Oct 4, 2013 5:28:27 GMT -6
Hi I recently have been having issues with my bike cold starting it started getting hard to start, steadily got worse until the, only way you, could start it cold was to push start it and now it won't even do that. I started with the obvious check for good spark , got that. Went through the carbs, got fuel. Found this thread so I did the valve adjustment. Every single valve was open at least .3 or .4 mm. knowing this im shrouded I was getting it to push off. I did the adjustment and the symptoms are better but still won't fire up. I haven't had the energy nor courage to try pushing again. When I try to crank it I get nothing unless I choke it. When I choke it, it will fire as im cranking but will not actually run. My brain is racked. Tomorrow I'm gonna clean the plugs and gap them. When I checked for spark I just logged for a flash and said good 'nuff. Given that every issue with my bike I googled,i found the answer here, I thought I would gather yalls input. Thank you Welcome to the forum.Clean & gap your plugs as you stated & See what happens.Report back & we can go from there.
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Post by moosinatrix on Oct 4, 2013 16:12:24 GMT -6
Well cleaning and gapping got her running had some valve noise went to get oil our of garage, and it has died. Tried to crank and it just free spinning. pull the valve cover and cylinder 2 intake adjustments loosened up one completely fell out into the middle and broke my timing chain.... I'm an, idiot for not making sure they were tight. I'm tempted to drag it across the scales... From what,i can gather, you, have to split the case and practically rebuild entire engine just to do the chain. I can't even afford the chain.
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Post by moosinatrix on Oct 4, 2013 16:17:30 GMT -6
Might start parting it out so if anyone, is interested in any parts txt me 936,433,2393 bike is complete, all original with 23k mi on it.
Ps if anyone can hook me up with, discount parts and walk me through replacing the, chain I might go that direction
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mr340
New Member
Posts: 47
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Post by mr340 on Oct 4, 2013 17:23:40 GMT -6
Where are you located? I have a complete '86 motor that just turned 17k.
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Post by moosinatrix on Oct 4, 2013 19:30:46 GMT -6
Livingston Texas. How much for a motor?
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gonzo
Junior Member
For the 1st time ever I don't like the snow
Posts: 215
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Post by gonzo on Oct 4, 2013 19:54:21 GMT -6
If you can find the end of the chain you might be able to tie with wire a new broken chain and using the old one pull it through. $79 for a new chain is a better than loosing the whole bike. But tearing the enging apart becomes expensive. I'm doing that now, crud.
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Post by moosinatrix on Oct 4, 2013 20:12:13 GMT -6
I can pull it through, but it isn't like the new chain has a master link
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mr340
New Member
Posts: 47
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Post by mr340 on Oct 5, 2013 3:13:51 GMT -6
Livingston Texas. How much for a motor? Shipping will probably be more that the motor, but if you are interested i would like $225 for the motor and shipping is up to you. I'm in New Jersey.
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Post by eaglerider on Oct 5, 2013 5:45:41 GMT -6
How far is Livingston from San Antonio? I have the bottom half of an engine with good chain, etc, no starter, flywheel, etc. You could put your jugs, head, and other parts from your engine on it....come get it for $100.00. Let me know if you want it, so I can remove it from the frame.
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