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XX Motor problems


bajjer9

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So I am driving down the interstate when i hear a loud pop noise then what sounds like an exhaust leak. I take the plastic off and check and there is no leak at the exhaust. I remove the tank and the airbox to discover the number one sparkplug had come out. No biggie I thought and I went to the honda shop for new plugs, she needed them anyway. I put number one plug in and it spins and spins and spins.

So now I am stuck with about 500lbs of junk...Can you repair threads in an aluminum head? Do I have to replace the whole head? What are my options aside from lighting the damned thing on fire?!

I guess I shouldnt be too upset she gave me 90k miles....

I dont suppose anyone has a spare head lieing around?....sigh

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So I am driving down the interstate when i hear a loud pop noise then what sounds like an exhaust leak. I take the plastic off and check and there is no leak at the exhaust. I remove the tank and the airbox to discover the number one piston had come out. No biggie I thought and I went to the honda shop for new plugs, she needed them anyway. I put number one plug in and it spins and spins and spins.

So now I am stuck with about 500lbs of junk...Can you repair threads in an aluminum head? Do I have to replace the whole head? What are my options aside from lighting the damned thing on fire?!

I guess I shouldnt be too upset she gave me 90k miles....

I dont suppose anyone has a spare head lieing around?....sigh

I think you meant spark plug, not piston :icon_whistle: IF it was a piston, then it would be junk

You need to have a helicoil insert or similar installed, get a mechanic who has done this before. It would be best to take the head off because there will be some debris in the cyclinder from drillling and tapping. But many people do it with the head on.

This is why it is important to use anti-sieze for steel threads in aluminum holes. Also overtorquing is often a cause of thread damage.

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I'll bet you meant to say that your "plug" - not your "piston" had come out...

I'd speculate that you could do a Heli-Coil repair... of course that would entail removing the head to do it right. If you want to chance it, without removing the head, there is an old trick... (screw up any part of it and you'll have to remove the head anyway).

Remove all spark plugs... remove key.... and/or disconnect battery (at least that'll eliminate any chance of an electrical snafu...)

Bring the affeced cylinder's piston to TDC (or slightly before), saturate a round cotton patch (slightly larger diameter than the piston) with a good quality grease. Insert the patch through the buggered hole and use thin bent wires (i.e., coat hanger) to smooth it out on the piston (a bore light and a length of fiber optic will come in handy to assess your work). Tap the appropriate new threads for the Heli-coil; the chips will fall onto the patch and adhere to the grease. You can try to press the chips into the grease a bit if you like with your wire tool, so they'll stick better. Here's the tricky part - using your custom wire tool(s) try to fold the edges of the patch over to the center, the grease will stick to itself... 3-4 opposing folds ought to do it. Now the trick is to remove the folded patch without dumping the chips back into the cylinder - a simple spring-clawed pick up tool works well... although it can be done with some deft manipulation of the wire tools. Install the Heli-coil per instructions. As double-check and a follow-up, take a shop vac and some fuel line (won't collapse under strong vacuum); use duct tape to connect the vac hose to the fuel line (be generous with the tape - it has to seal). Stick the fuel line into the cylinder and activate the vacuum - it should suck up any chips you may have missed with the patch. Rotate the motor just enough to drop the piston in the bore and inspect with the bore light & fiber optic... repeat vacuum trick as necessary. Re-install plugs, tank, etc... and test.

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Just a side note ; I did my first plug change yesterday on my 01 (37,000k) I noticed that 2 of the 4 plugs were fairly loose. They were installed at the factory.... :icon_think:

So were they installed wrong at the factory, or did they back off alittle over time.

Just wondering if this is a potential problem spot?

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There is another option. MAC tools makes a thread chaser device. Let me explain. Basically it's a tap that taps from inside out by using an expanding head. What you do is stick this in the spark plug hole, tighten the head down which expands the end of the tube out making the tap actually tap from inside the motor out. This way it starts in clean threads and works it's way out to the bad ones. I'm pretty sure it also has a magnetic tip to catch any shavings that fall as well, so it should be safe. Of course, if all the threads are gone this won't help much, but if only the outer ones are toast it will solve the problem. It'd be worth a shot doing that before pulling the head off and helicoiling it. I think the tool is around $30 or $40.

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The head is aluminium and non magnetic. I actually sell the expanding spark plug tap but I dont think it will help in this case.

If the plug just spins it would indicate a significant loss of thread and you will not get the hole any smaller with the tap. The best way to fix it is to remove the head. I dont think you have a hope in hell of working through a small hole recessed in the head and spreading a rag to catch the filings. I can see where it would work just not on this application.

If you want to try with the head on use lots of grease on the tap and remove it after each turn or so to clean off the swarf and then regrease it and continue. When you fit the thread insert you have to break of the tang that lets you screw in the insert, dont drop it.

Then use a mighty vac and a thin hose to suck out any debris.

Good luck

JohnS

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James,

I have a spare cylinder head. It's off a 97.

LMK if you decide to go that route.

J.

J

Mine is a 97 so I might be interested...how much do you want for it? Is it bare? The more I think about it the more I think I will replace it or have it removed and repaired by a pro. My brother said they weld up the hole then tap it with a machine. Another head would be the best thing in my opinion

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With the head off, it would be a simple matter for any competent machinest to install a Timecert or helicoil in the head. I would be very wary of anyone who suggests welding up the hole and then remachining. The valve seats are way too close to the sparkplug hole for any of that. Both of the above mentioned systems come in varying lengths and you should get one that provides full thread engagement. One thing to be wary of when drilling the oversized hole to accomodate the insert is the sealing ring on the spark plug will now be operating with a reduced area. A flanged device will really help in this. A really good machinest could fashion an insert with a flange on the top and the proper internal thread, machine the head such that the flange was at the original height/location and then do a proper install.

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I was just reading this and I can't decide if aluminum shavings from doing a helicoil tap would be a problem if left in the cylinder.

I have done this with a tap and put grease on it to hold the fillings. Just take it a few turns and pull it out and clean and re grease and go some more. Even if some got in the cylinder they would either burn or go out with the first few explosions.

The only thing that would be a problem is the tang on the helicoil when you break it off and I think it is magnetic. Might be stainless so check. Be sure to lock tight with permanent lock tight and let it dry good.

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A Heli-Coil insert is stainless steel and actually stronger than the original threads, so don't hesitate to use one.

While the threads can be cut without removing the head (no drilling is required), it may be difficult to do on an engine with such a deep and narrow spark plug well, not to mention you can't get a clear sight on the plug threads without removing the engine.

My vote is to remove the cylinder head, and while it's off, carefully inspect the rest of the threads as I'm sure you don't want to do this twice :icon_eek:

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informative thread. I have two thoughts in regards this.

First, Heli-Coil with the head in place, it's quick.

Second, If the bike is in great shape why not do it right? Pull the head and take it to the machine shop.

I have helicoiled the plug threads on bikes with the head in place but I always knew there would be a chance of a piece of filing fouling the plug, creating a hot spot and burning a hole in the piston, jamming a ring or destroying a valve seat.

I was lucky until I stripped a plug hole on a CB750F, helicoiled it like the others I had done. Then one day afterwards it ran kinda crummy so I pulled the head and found a valve seat burned, all I could figure was a piece of the metal filing causing a hot spot there or holding the valve open just enough to creat a jet of hot gas at that spot, cam was fine....go fiqure.

So how lucky do ya feel??

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If this redneck can drop the engine you can!

Five bolts and boom, on the floor it goes!

:icon_eek:

JK, a floor jack under it helps along with having a buddy there to help steady it. I had mine out in a matter a a few hours and back in almost as easy. I just removed the airbox, unplugged it from the harness and throttle/choke cables, unhooked the radiator and oil cooler lines, removed sprocket cover and moved chain out of the way and unbolted it.

Really about that easy.

Reinstalled it in about the same amount of time.

Do a pair valve kit and change your plugs while it is out. :icon_wink:

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Do a pair valve kit and change your plugs while it is out. :icon_wink:

pair valve?

IMO, the drop the engine method is the easiest to do.

James,

I'll drop my service tool in the box with the head. This is the socket for the locknuts which hold the rear engine mount bolts.

J.

Thanks J. I guess I am gonna end up doing this myself despite my uneasiness...anyone have any other tips?

I am thinking at least carb removal (haha I will do the factory jet kit i have had for two years!!)...

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Let me know when you want to tackle this and I'll load up the toolboxes and everything I can think of in the trailer and head your way. Make sure it's a weekend that I'm off though, or we'll be stuck to a Sunday thing.

I've seen posts of this PAIR valve thing before, but have no idea what or where it is. Bajjer is 97 and I'm 99 and I don't think either one of us have whatever this thing is. Best I can figure out it's an exhaust thing, but neither one of us are 50 state legal. Hell, I'm only 1 state legal!!

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Let me know when you want to tackle this and I'll load up the toolboxes and everything I can think of in the trailer and head your way. Make sure it's a weekend that I'm off though, or we'll be stuck to a Sunday thing.

I've seen posts of this PAIR valve thing before, but have no idea what or where it is. Bajjer is 97 and I'm 99 and I don't think either one of us have whatever this thing is. Best I can figure out it's an exhaust thing, but neither one of us are 50 state legal. Hell, I'm only 1 state legal!!

sounds good Jeff once i gather up all the materials needed I will get with ya to work something out. I am going to order head gasket & valve cover gasket...anything else I might need?

can someone elaborate what the pair valve thing is? I never paid much attention to it because I thought it was an FI thing...If carbed bird has one why remove it?

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If the spark plug tube seals come separate I would order those as well. But you will need to get the exhaust gaskets, as those are definitely not reusable. Also need to have coolant and oil on standby along with a new oil filter. Wet/dry shop vac with a small attachment would help too, because no matter what you do, coolant will go everywhere.

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