Jump to content
Sign in to follow this  

NX650 piston gone....

Recommended Posts

well today i was driving my NX650 to work which i just got last friday and all is gong well nice and smooth and all of a sudden the engine seems to skip a beat in a really funny way so i keep going taking it kinda easy from there and notice a loss of power so some 10 more miles down the road all of a sudden it does it again and quits on me so i coast to the side of the freeway and notice that there is very little compression when i hit the starter. then after that the starter locked up. so after 3 hrs on the side of the road i got the bike home and tore it apart... i thought it was the timing chain at first by how it reacted but after i took off the clutch cover i saw that everything was fine except for huge chunks of aluminum all around in it. so i kept on going deeper adn pulled the head off and Bam there's the problem.

1233123_635407789845548_277812237_o.jpg

chunks of aluminum must of got in the gears so im going to split the case but now the problem i got are the damned cylinder bolts. im using a 6 point socket and and their so tight that i only got one loose. the head is stripping on the other 3 bolts. 

any ideas on how to get the bolts out?

now that iv gone this far im gonna rebuild the whole thing. ill post pics and keep a log of it. :]

Edited by Bajavwracer

Share this post


Link to post
Share on other sites

Not really but sort of....I'd locate an impact driver with a decent long extension on it (if such a thing exists) and start giving them some banging..Might pay to fill the holes with some sort of bolt freeing stuff (CRC or whatever) and leave them for a couple of days prior to the impact driver attack..That fails try heating the hole shabang up with a gas torch and get the impact driver into action again or use a large metal dolly  and hammer to try and break the frozen bolts free from the dross there stuck in..Then attack with the socket set or impact driver with socket extension..

 

Sadly lacking impact drivers with decent extensions and decent interchangable parts that go in them..The large ones you get 4 heads and all they do is philips or slot screws..totally inadequate,,as well as them not being able to take the smaller sized fittings..heads too big,,small fittings won't go in ..Money to be made with a decently tooled impact driver set..Needless to say I've never seen one in any tool shop or hardware store setup correctly with the right bits to satisfy my needs,,hence the :blah:

Edited by Horri

Share this post


Link to post
Share on other sites

Not really but sort of....I'd locate an impact driver with a decent long extension on it (if such a thing exists) and start giving them some banging..Might pay to fill the holes with some sort of bolt freeing stuff (CRC or whatever) and leave them for a couple of days prior to the impact driver attack..That fails try heating the hole shabang up with a gas torch and get the impact driver into action again or use a large metal dolly  and hammer to try and break the frozen bolts free from the dross there stuck in..Then attack with the socket set or impact driver with socket extension..

 

Sadly lacking impact drivers with decent extensions and decent interchangable parts that go in them..The large ones you get 4 heads and all they do is philips or slot screws..totally inadequate,,as well as them not being able to take the smaller sized fittings..heads too big,,small fittings won't go in ..Money to be made with a decently tooled impact driver set..Needless to say I've never seen one in any tool shop or hardware store setup correctly with the right bits to satisfy my needs,,hence the :blah:

Horri,

 

I have two impact drivers where the end comes off that holds the Phillips and straight screwdriver bits.  Underneath the holder is a 1/2" socket adapter.

Share this post


Link to post
Share on other sites

well today i was driving my NX650 to work which i just got last friday and all is gong well nice and smooth and all of a sudden the engine seems to skip a beat in a really funny way so i keep going taking it kinda easy from there and notice a loss of power so some 10 more miles down the road all of a sudden it does it again and quits on me so i coast to the side of the freeway and notice that there is very little compression when i hit the starter. then after that the starter locked up. so after 3 hrs on the side of the road i got the bike home and tore it apart... i thought it was the timing chain at first by how it reacted but after i took off the clutch cover i saw that everything was fine except for huge chunks of aluminum all around in it. so i kept on going deeper adn pulled the head off and Bam there's the problem.

1233123_635407789845548_277812237_o.jpg

chunks of aluminum must of got in the gears so im going to split the case but now the problem i got are the damned cylinder bolts. im using a 6 point socket and and their so tight that i only got one loose. the head is stripping on the other 3 bolts. 

any ideas on how to get the bolts out?

now that iv gone this far im gonna rebuild the whole thing. ill post pics and keep a log of it. :]

Was it running lean? 

Share this post


Link to post
Share on other sites

Horri,

 

I have two impact drivers where the end comes off that holds the Phillips and straight screwdriver bits.  Underneath the holder is a 1/2" socket adapter.

 

 

Holy heck Quint,,I never thought of pulling the head off the things,,shows my mechanical know how up that does. :banghead: ...Point taken..I still think they don't come with enough options though..Small bits should be able to go in a large driver and for the life of me I haven't seen a driver around yet which takes the large bits and the small. Maybe there is a 5 sided adapter you can buy that fits the large driver end and allows you to use the smaller bits,,my question is why isn't it in the set with the large bits and large driver..I shouldn't have to go hunting for one,,Anyway,,rant done..Should I once again be barking up the wrong tree and you have a solution don't hesitate to tell me about it..I'm sick of going to hardware shops and trying to figure out how I can use all the variety of smaller sized bits in my large impact driver..

Edited by Horri

Share this post


Link to post
Share on other sites

Holy heck Quint,,I never thought of pulling the head off the things,,shows my mechanical know how up that does. :banghead: ...Point taken..I still think they don't come with enough options though..Small bits should be able to go in a large driver and for the life of me I haven't seen a driver around yet which takes the large bits and the small.Maybe there is just an adapter you can buy,,my question is why isn't it in the set with the large bits and  large driver..

I don't know...Maybe the smaller bits can't withstand the torque needed to break loose some of the fasteners...Probably a liability issue with the manufacturer. 

Share this post


Link to post
Share on other sites

Ooo...I had a cylinder head bolt strip the hex part before trying to take it out. It cost me $90usd at a tap and die specialty place to remove. In hindsight i wish i tried to weld another nut to it. Nice new hex nut to wrench on and the heat from tacking the nut on should loosen things up nicely. A pro mechanic fromCanada told me that Snap On flank drive sockets can remove stripped heads sometimes. I tried that to no avail.

Edited by notoriousE-R-I-C

Share this post


Link to post
Share on other sites

Didn't seem to be running lean. only 16K miles on the Odo. i dunno what the hell happened. I wanna kill the guy who sold me the bike because i don't think he ever maintained it properly. on the other hand yes i do got a impact driver with decent extensions and a 1/2" drive i used it but it didn't really work. that was before i soaked the screws in WD40. im gonna soak it in some more and give it a try again with the impact driver. now my concern is how had can you hit the thing? i don't wanna crack the poor block.

Share this post


Link to post
Share on other sites

We can't really tell you how hard you can hit the impact driver..Best I can say is firmly so you get a sort of nice ring sound coming off the bolt..Plainly don't use sledge hammer tactics on it,,Short firm ringing raps..same as you'd do with the hammer and dolly if you soften it up with that first..Dolly and hammers the way to go at the start then move to the impact driver..Try not to wreck the bolt head...With the impact driver get it positioned and twist the head of the driver so the spring inside it is already under full load on the bolts head so when you hit the head the power comes on immediately and doesn't have to do it's twisting thing on the bolts head before it gets purchase..It'll flog out the head of the bolt even more if it's bouncing around as you hit the head..tight and under tension then hit it..

Edited by Horri

Share this post


Link to post
Share on other sites

My guess is a bad backfire a pre-detonation that cracked that cast piston.

 

I'd use something better than WD-40 for getting under the heads. I like PB blaster and I believe Sea Foam creeping lube(if I remember that name right). WD doesn't creep its way under things as much. I think I remember another rumor of heating bolts up and melting beeswax on them to break free. Either that or was it on toast? 

 

I put a touch of anti sieze or ARP assembly lube under the heads when reinstalling so this doesn't get so bad in the future.

Edited by jjktmrider

Share this post


Link to post
Share on other sites

Well finally got it all apart. I took a new 12mm socket that had a good sharp bite and that did the trick. There was aluminum everywhere scattered in the case. I got most of it cleaned up. Inside it seems everything is fine. There was a bit of aluminum smoshed between some of the gears and sprockets but the bearings seem fine and there's nothing out of spec. It does seem thought that this engine got kinda hot once because the rod looks discoloured. The rod bearings have no play and feel great. Also.. Is the piston supposed to be concave in? I don't think so.. Any tips for removing the fly wheel without the puller?

20130921_153559.jpg

20130921_143232.jpg

Share this post


Link to post
Share on other sites

That discoloration on the rod is normal heat treating done by Honda. That piston couldn't handle what was asked of it :naughty: . Now whether it was just a bad piston or pre det. is the million dollar question. What kind of gas are you using?

You don't need to pull the flywheel. Just need a new piston and rings, size to be determined by measuring the bore. I had a 2 stroke motor eat a piston skirt sometime in its life, I bought it brand new and when I rebuilt it I found half the skirt gone but no chunk, just some smears.

Edited by jjktmrider

Share this post


Link to post
Share on other sites

Yea i guess I gonna do that. I'm going to go ahead and change the timing chain and a few odds and ends too now that I got the engine apart. As for gas I use premium 91 octane always. Also regarding gas, I dunno in other states but here in California the fuel pumps have one hose for all the grades so if I get the premium and the guy before me got regular I'm gettingt a hose full of the regular before the premium comes out. What do you guys do to work around this?

PS attached is a pic of some of the junk that came out of the block

20130921_143241.jpg

Edited by Bajavwracer

Share this post


Link to post
Share on other sites

Most of our pumps(locally anyway) have three hoses, one for each grade so no issues there. I don't think there is enough in the hose to have too much of an effect on octane but I can't say for sure. The only other thin would be to buy a bottle of an octane booster and put a splash in each tank full. I have a local source for several types of race gas and have a 5gal can of it , put about a 1/2 gal of 100 octane to a tankfull of . I can get 113 if I wanted to but more pricey. I love the smell of race fuel in the morning. :smirk: If you get a Wiseco forged piston you should have no issues with the normal 91, I think it may have been a one time event or the previous owner had gone cheap with the last tankfulls and got 85.

 

You definitely need to flush the block out good somehow. I have a part cleaner that I can really flush things good with.

Edited by jjktmrider

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×