1998 superhawk. Something blew on the highway
Administrator
MotoGP
Joined: Apr 2006
Posts: 4,402
From: Kempner, TX
Took the carb and airbox off, which btw all of those hoses are so tight i cant even imagine how im going to reconnect them back to the bottom of the carb and airbox.
first thing i notice is that any deep18 mm socket wrench i can find anywhere wont fit in to grab the plug. Walls are too thick which is ridiculous honestly because they arent even thick to begin with. 17 mm doesnt fit the plug. Trying to pull the plugs because turning the crank with no compression is helpful. Can also just inspect them while im in here.
Now im realizing at this point, the rear plug is loose enough to turn with needle nose pliers on the top of the plug. In a momment of clarity i think to myself, my entire problem could be the power loss was yhe plug vibrating loose. I was either on one cyilnder or it was still firing but had enough compression loss to make it feel like one cyilnder. Next thought, is it loose enough for my valve tap sound to actually be that plug shaking in the slot? It wiggles very slightly.
screws in airbox are worn, so all of this has definitely been pulled before. So im hoping the CCT has already heen replaced, ill find out and check the timing anyways.
Not sure if the vid really sounds like it could beone cyilnder, sounds like theyre both firing to me but the power the bike currently has is definitely consistent withone cylinder.
Anyone have any advice on getting my plugs out trying to find a tool local today. Also any advice on reconnecting the carb and airbox? Everything is so damned tight i really cant inagine my hands getting under anything to fit hoses on anywhere. Thats actually got me concerned. The socket issue eith the spark plug is definitely ridiculous to be honest. Autozone ans homedepot had nothing that would work for it. Im going to check out harbo freight. I read on the forums a tool that screws into the boot threading i believe? I cant seem to find this.
first thing i notice is that any deep18 mm socket wrench i can find anywhere wont fit in to grab the plug. Walls are too thick which is ridiculous honestly because they arent even thick to begin with. 17 mm doesnt fit the plug. Trying to pull the plugs because turning the crank with no compression is helpful. Can also just inspect them while im in here.
Now im realizing at this point, the rear plug is loose enough to turn with needle nose pliers on the top of the plug. In a momment of clarity i think to myself, my entire problem could be the power loss was yhe plug vibrating loose. I was either on one cyilnder or it was still firing but had enough compression loss to make it feel like one cyilnder. Next thought, is it loose enough for my valve tap sound to actually be that plug shaking in the slot? It wiggles very slightly.
screws in airbox are worn, so all of this has definitely been pulled before. So im hoping the CCT has already heen replaced, ill find out and check the timing anyways.
Not sure if the vid really sounds like it could beone cyilnder, sounds like theyre both firing to me but the power the bike currently has is definitely consistent withone cylinder.
Anyone have any advice on getting my plugs out trying to find a tool local today. Also any advice on reconnecting the carb and airbox? Everything is so damned tight i really cant inagine my hands getting under anything to fit hoses on anywhere. Thats actually got me concerned. The socket issue eith the spark plug is definitely ridiculous to be honest. Autozone ans homedepot had nothing that would work for it. Im going to check out harbo freight. I read on the forums a tool that screws into the boot threading i believe? I cant seem to find this.
Senior Member
SuperBike
Joined: Sep 2008
Posts: 1,707
From: Essex, UK
Borrow a small child with ickle hands to reattach the airbox to the hose.
Seriously - it can be done with gynecological dexterity if you work out in your head what you want your fingers to perform - with practice.
As mentioned VTR toolkit originally with the bike will have the socket, or any auto tool shop should have one.
https://www.ebay.co.uk/itm/Under-Sea...c/401383332728
Seriously - it can be done with gynecological dexterity if you work out in your head what you want your fingers to perform - with practice.
As mentioned VTR toolkit originally with the bike will have the socket, or any auto tool shop should have one.
https://www.ebay.co.uk/itm/Under-Sea...c/401383332728
Senior Member
Superstock
Joined: Sep 2013
Posts: 460
From: Costa Mesa, CA
All of my (3) 18mm spark plug sockets have thinner walls than my 6 and 12 point 18mm deep sockets. All the plug sockets fit fine, plus, they have that nifty rubber collar that grips the plug making easier to extract. If the plug is loose, not only are you losing a little compression, having a bit of a rattle but the plug is not grounded properly causing weak spark and/or misfiring. Just a thought from an old man.
Thread Starter
Junior Member
Squid
Joined: Feb 2018
Posts: 18
Honestly everything looks fine. Valves arent bent, or if they are i cant eyeball it. The lines match up. Not sure how far it has to be off to be out of alignment but judging by the teeth size on the gear it cant even be a tooth off distance wise.
im putting it back together and hoping it was just a loose spark plug rattling.
the crank did become difficult to turn at one point. But no vibrations/roughness/sounds. It rotated smoothly other than one part of each 360 being really hard to turn. Im thinking thats normal?
im putting it back together and hoping it was just a loose spark plug rattling.
the crank did become difficult to turn at one point. But no vibrations/roughness/sounds. It rotated smoothly other than one part of each 360 being really hard to turn. Im thinking thats normal?
Administrator
MotoGP
Joined: Apr 2006
Posts: 4,402
From: Kempner, TX
I think it sounds perfectly fine......for a 3 cylinder diesel motor in my friends sail boat..but it sounds very wrong for a gas VTR V twin.
It could be a cam chain slapping because its loose, it could be a rod bearing bad...might be a valve contacting the piston..but something is wrong Id say...
The valve cover gaskets are reusable for many years and R&R, the only place they need help sealing is at the half moon area on the site, and you need just the slightest smear of RTV to make them seal.
With that much RTV used, Id bet you have some on the inside already or soon to be falling off and going places RTV is not suppose to be..
That motor needs some TLC and a good Mech to diagnose the issue.
Reading your thread, I'm not sure if you ever did finish checking the cam timing? Cam chain tension? outside visual signs of a bent valve (very large valve clearances)
It could be a cam chain slapping because its loose, it could be a rod bearing bad...might be a valve contacting the piston..but something is wrong Id say...
The valve cover gaskets are reusable for many years and R&R, the only place they need help sealing is at the half moon area on the site, and you need just the slightest smear of RTV to make them seal.
With that much RTV used, Id bet you have some on the inside already or soon to be falling off and going places RTV is not suppose to be..
That motor needs some TLC and a good Mech to diagnose the issue.
Reading your thread, I'm not sure if you ever did finish checking the cam timing? Cam chain tension? outside visual signs of a bent valve (very large valve clearances)
Thread Starter
Junior Member
Squid
Joined: Feb 2018
Posts: 18
I just ran a straight edge across the top and checked the timing marks. It LOOKs fine . I say that because it was an eye ball measurement. Everything lined up. The valves looked fine . The front cyilnder was almost impossible to really see though. I didn't check the chain tension. However if in going to do that or takes thede covers off again. Im honestly probably going to just drop the motor out. For the effort that goes into taking the carb and airbox off, i may as well and have the proper working room with my hands to actually do something to that front cyilnder.
also if the chain tensions perfect then I'm going to presumably just break doen the engineand check the crank bearings? Is there anything in the side crankcase covers that could do that?
Can the carb be ruled out? I cant think of any part of the carb that would sound like that.
also if the chain tensions perfect then I'm going to presumably just break doen the engineand check the crank bearings? Is there anything in the side crankcase covers that could do that?
Can the carb be ruled out? I cant think of any part of the carb that would sound like that.
Administrator
MotoGP
Joined: Apr 2006
Posts: 4,402
From: Kempner, TX
I'm a big believer in, pulling something, taking something apart, removing something vice trying to work around "stuff" , but dropping the motor to check valves and cam timing is not something even I would do. ...lol
I can not think of anything in the side case that would make that repetitive, timed with revolutions tapping sound.
\I have had leaking exhaust gaskets make some nasty "tapping" sounds though and I suppose the audio I'm hearing on this side of a computer may be different then how it sounds there, but it dos not sound like a bad exhaust leak..
If it were in my shop, Id check the valve clearance (you did not really confirm you did that, just said they are "fine") Your looking for a bigger then spec gap.
I would put the piston at BDC and use a video probe in the cylinder and check for the "ring of death" it is a contact pattern you find on the outer rim or the piston top when a rod bearing is worn. I would also look for any indications of piston to valve strike. Though you will find that clearance gap before that if the valve is hitting the piston.
I would check the cam chain tension (which you may have done???) to ensure it is not that which is slapping and making noise (again, does not sound that way, but audio can be confusing across a computer vs in person ) If all of that was inconclusive.....If the bike was mine, the motor would come apart (before it comes apart in use)
If it was a customers, Id suggest the same and leave it to them......
I might be missing an obvious source of the noise, or mis internet diagnosing it..as noises often are..... perhaps a second opinion from a local trusted mechanic
I can not think of anything in the side case that would make that repetitive, timed with revolutions tapping sound.
\I have had leaking exhaust gaskets make some nasty "tapping" sounds though and I suppose the audio I'm hearing on this side of a computer may be different then how it sounds there, but it dos not sound like a bad exhaust leak..
If it were in my shop, Id check the valve clearance (you did not really confirm you did that, just said they are "fine") Your looking for a bigger then spec gap.
I would put the piston at BDC and use a video probe in the cylinder and check for the "ring of death" it is a contact pattern you find on the outer rim or the piston top when a rod bearing is worn. I would also look for any indications of piston to valve strike. Though you will find that clearance gap before that if the valve is hitting the piston.
I would check the cam chain tension (which you may have done???) to ensure it is not that which is slapping and making noise (again, does not sound that way, but audio can be confusing across a computer vs in person ) If all of that was inconclusive.....If the bike was mine, the motor would come apart (before it comes apart in use)
If it was a customers, Id suggest the same and leave it to them......
I might be missing an obvious source of the noise, or mis internet diagnosing it..as noises often are..... perhaps a second opinion from a local trusted mechanic
Thread Starter
Junior Member
Squid
Joined: Feb 2018
Posts: 18
Yeah man after listening to some vids on YouTube of other vtrs. I dont think its bad bearings . It sounds like valve tap minus any sound of a chain slapping around but im going to pop the covers off and measure the vavles this time. For some reason i was thinking itd be more obvious, but its gotta be the vavles and maybe the cct.
Moderator
MotoGP
Joined: Jul 2007
Posts: 5,221
From: Gettysburg, Pa
Ya can't really tell if a valve is bent just by pulling the covers either. You said they "look fine" and were't bent but truth be told, how can you be sure?
We are just trying to help here.
Did you do a compression check? If they are bent, they aren't seating properly and that check should exploit an issue.
Bore scope would be awesome too.
It does sound like radically out of spec valve to me, but like E said, hard to tell from the audio.
We are just trying to help here.
Did you do a compression check? If they are bent, they aren't seating properly and that check should exploit an issue.
Bore scope would be awesome too.
It does sound like radically out of spec valve to me, but like E said, hard to tell from the audio.
Last edited by Wolverine; May 12, 2018 at 01:26 PM.
Administrator
MotoGP
Joined: Apr 2006
Posts: 4,402
From: Kempner, TX
If they are really larger, like 5mm, you have a bent valve. If they are just slightly larger , well did the last person in there mess up and set them loose? is the valve only a little bent? is there some anomaly going on and the hard face on the cam is wearing off and the clearance grew abnormally?
But yes, your right short of catastrophic failure, just measuring valve clearance is a good educated guess, a leak down test would confirm.
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