i dont ever post on here. my vfr has been so good to me the last 25k miles but i had to share. three days of riding two up here in the hill country of texas i was about a 1/4 mile from my truck and i hear and feel this loud popping and tapping. come to find out the spark plug had backed its way out and was jamming up and down damaging the threads on the head. this really sucks! i was on my way to san fransisco to ride northern california for two weeks before i get underway with the coast guard over seas.
any advice on either getting a new head or using a heli-coil?
Well, if you really wanted to, you could just pull the spark plug out, unhook the fuel injector for that cyclinder, and run your VFR on three cylinders... :blink:
HeliCoil is an option. You can also look at TimeSerts.
Anyway, how bad are the threads? Can you just clean them up using a tap?
I used a helicoil quite successfully on my snow blower for the spark plug. In fact, it was a kit specifically for repairing spark plug holes. I didn't even pull the head. I hooked a small hose to my shop vac and sucked out the shavings, then turned it over with out the plug in it. That blew out any remaining shavings. The snow blower was worth may be $100, not sure I would recommend this method for the VFR. I think I would pull the head to install the helicoil.
[image: View Post]ANDREW04VFR, on Nov 26 2008, 05:20 PM, said:
i dont ever post on here. my vfr has been so good to me the last 25k miles but i had to share. three days of riding two up here in the hill country of texas i was about a 1/4 mile from my truck and i hear and feel this loud popping and tapping. come to find out the spark plug had backed its way out and was jamming up and down damaging the threads on the head. this really sucks! i was on my way to san fransisco to ride northern california for two weeks before i get underway with the coast guard over seas.
any advice on either getting a new head or using a heli-coil?
[image: View Post]canib, on Nov 26 2008, 04:35 PM, said:
Dood, that sux!
I have not personally had to use heli-coil, but I have heard good things about it from two experienced mechanics.
In the very least it's cheaper than a new head.
Good luck!
i wish i could! the first four or five threads are gone. those time serts look really good. what size would i need to order? ive never really measured thread patterns or sizes?
[image: View Post]Conedodger, on Nov 26 2008, 03:54 PM, said:
I used a helicoil quite successfully on my snow blower for the spark plug. In fact, it was a kit specifically for repairing spark plug holes. I didn't even pull the head. I hooked a small hose to my shop vac and sucked out the shavings, then turned it over with out the plug in it. That blew out any remaining shavings. The snow blower was worth may be $100, not sure I would recommend this method for the VFR. I think I would pull the head to install the helicoil. http://www.acehardwa...128.html?ref=42
I would absolutely leave the head on. Use this kit, suck out the shavings with a small hose duct taped to a shop vac, then blow out any particles the vac doesn't get by cranking the motor with the plug out. Install plug. Ride. Enjoy. Your bike will be absolutely fine.
[image: View Post]ANDREW04VFR, on Nov 26 2008, 03:02 PM, said:
i wish i could! the first four or five threads are gone. those time serts look really good. what size would i need to order? ive never really measured thread patterns or sizes?
The 6th Gen uses an NGK spark plug, part number IMR9B-9H.
According to NGK:
Thread Diameter = 14mm
Reach = 19mm.
Hex Size = 13/16"
[image: View Post]magellan, on Nov 27 2008, 12:19 AM, said:
[image: View Post]Conedodger, on Nov 26 2008, 03:54 PM, said:
I used a helicoil quite successfully on my snow blower for the spark plug. In fact, it was a kit specifically for repairing spark plug holes. I didn't even pull the head. I hooked a small hose to my shop vac and sucked out the shavings, then turned it over with out the plug in it. That blew out any remaining shavings. The snow blower was worth may be $100, not sure I would recommend this method for the VFR. I think I would pull the head to install the helicoil. http://www.acehardwa...128.html?ref=42
I would absolutely leave the head on. Use this kit, suck out the shavings with a small hose duct taped to a shop vac, then blow out any particles the vac doesn't get by cranking the motor with the plug out. Install plug. Ride. Enjoy. Your bike will be absolutely fine.
And yes, I would do the same with my own bike.
I'd still be a little worried about shavings in the cylinder because the plug holes are so deep in in the head lobes that it's hard to really get at anything in there. I was wondering whether you can put the offending cylinder at TDC and try to push in a small peice of cotton rag or towel heavily coated in grease between the piston top and the sparplug hole with maybe a long hemostat, making sure that it spreads out enough under the sparkplug hole to catch all the shavings, do the helicoil bit and slowly/carefully pull the greasy rag back out with hopefully all of the shavings that fell into the cylinder. I would then back up the effort with the vacuum cleaner hose plus blow out any possible remnants with the piston as you described.
Heli-coil for sure. Way cheaper than a head. I've got one in cylinder #2 of my '79 GS850 cost my $30 canadian plus tax to have it put in, and never had a problem.
I have done the Heli-coil thing on a ZX-9 spark plug hole a few years back. I pulled the head to do it. Another option maybe to find a 14mm back tap. If you still have some threads this will clean them up. You put it in the hole, tighten wedge which expands the tap and then back it out starting from the clean/straight threads. They can work wonders. Hope this helps.
You got three options here.
1. Pull the head, and heli-coil. $$$$$ Price of everything involved.
2. Put a heli-coil in without remove the head. $$ Price of the heli-coil set.
3. Retap the threads to clean them up. $ Price of the tap set.
I would try option 3 first. Use a regular starting tap to chase the threads to clean them up. Chances are only the first 2 or 3 threads at the beginning are damaged. If doing this. Put lots of grease on the tap to catch the chips from the threads. Turn about 2 turns, remove to clean the tap and regrease and repete until you are through. Make sure the piston is at bottom dead center. You don't want to put the tap into the piston crown.
Options 2 and 3 involve drilling the hole a bit bigger. Then using the heli-coil tap to make new threads. Then installing the heli-coil insert, and breaking off the little tang on it. Option 2, you will get chips in the cylinder from drilling. Even if you use a shop vac and grease on the bit. If you do option 2. MAKE SURE THE PISTON IS AT BOTTOM DEAD CENTER. You don't want to drill a hole in the piston! And the inlet and exhaust valves are closed.
Been there, screwed that up, and got the stitches!
[image: View Post]ANDREW04VFR, on Nov 26 2008, 05:20 PM, said:
i dont ever post on here. my vfr has been so good to me the last 25k miles but i had to share. three days of riding two up here in the hill country of texas i was about a 1/4 mile from my truck and i hear and feel this loud popping and tapping. come to find out the spark plug had backed its way out and was jamming up and down damaging the threads on the head. this really sucks! i was on my way to san fransisco to ride northern california for two weeks before i get underway with the coast guard over seas.
any advice on either getting a new head or using a heli-coil?
If you try to clean up or retap the hole you can put some grease on the tap in the 4 relief areas where the tap has no threads,any small cuttings or debris stick to the grease and don't fall into the cylinder,still blow out and clean it afterwards to be sure
[image: View Post]Beck, on Nov 26 2008, 05:13 PM, said:
I'd still be a little worried about shavings in the cylinder because the plug holes are so deep in in the head lobes that it's hard to really get at anything in there. I was wondering whether you can put the offending cylinder at TDC and try to push in a small piece of cotton rag or towel heavily coated in grease between the piston top and the spark plug hole with maybe a long hemostat, making sure that it spreads out enough under the spark plug hole to catch all the shavings, do the heli-coil bit and slowly/carefully pull the greasy rag back out with hopefully all of the shavings that fell into the cylinder. I would then back up the effort with the vacuum cleaner hose plus blow out any possible remnants with the piston as you described.
This is a good idea. A piece of cotton cord coated in grease works too. The downside is, you have to make sure you have a hemostat that will get the cord back out, and you leave grease inside the combustion chamber, which will actually grab and hold shavings unless you pack the chamber right up to the bottom of the threads. Do that and you'll be golden.
[image: View Post]Beck, on Nov 26 2008, 04:13 PM, said:
[image: View Post]magellan, on Nov 27 2008, 12:19 AM, said:
[image: View Post]Conedodger, on Nov 26 2008, 03:54 PM, said:
I used a helicoil quite successfully on my snow blower for the spark plug. In fact, it was a kit specifically for repairing spark plug holes. I didn't even pull the head. I hooked a small hose to my shop vac and sucked out the shavings, then turned it over with out the plug in it. That blew out any remaining shavings. The snow blower was worth may be $100, not sure I would recommend this method for the VFR. I think I would pull the head to install the helicoil. http://www.acehardwa...128.html?ref=42
I would absolutely leave the head on. Use this kit, suck out the shavings with a small hose duct taped to a shop vac, then blow out any particles the vac doesn't get by cranking the motor with the plug out. Install plug. Ride. Enjoy. Your bike will be absolutely fine.
And yes, I would do the same with my own bike.
I'd still be a little worried about shavings in the cylinder because the plug holes are so deep in in the head lobes that it's hard to really get at anything in there. I was wondering whether you can put the offending cylinder at TDC and try to push in a small peice of cotton rag or towel heavily coated in grease between the piston top and the sparplug hole with maybe a long hemostat, making sure that it spreads out enough under the sparkplug hole to catch all the shavings, do the helicoil bit and slowly/carefully pull the greasy rag back out with hopefully all of the shavings that fell into the cylinder. I would then back up the effort with the vacuum cleaner hose plus blow out any possible remnants with the piston as you described.
Beck
95 VFR
I'd go with Magellan on this. If you have reservations doin it on your own, get a professional to take care of it for you. A really good mechanic like magellan.
I would re-tap the hole the same size. The threads may be fine. Just use the tap to smooth out thw threads and dont over tighten the plug. It's the absolute cheapest and easiest thing to try first, You can get the tool for cheap at any auto store. I've had threads that I thought were ruined. I cleaned up the threads and all is ok.
Dont worry much about saivings. Just grease the tap.
[image: View Post]ANDREW04VFR, on Nov 26 2008, 06:02 PM, said:
[image: View Post]canib, on Nov 26 2008, 04:35 PM, said:
Dood, that sux!
I have not personally had to use heli-coil, but I have heard good things about it from two experienced mechanics.
In the very least it's cheaper than a new head.
Good luck!
i wish i could! the first four or five threads are gone. those time serts look really good. what size would i need to order? ive never really measured thread patterns or sizes?
TimeSerts are a superior thread repair technology to Heli-coils because it's a solid bushing insert with a flanged top for perfect placement. I used to sell them to cylinder head repair shops in a previous lifetime.
[image: View Post]Darth Bling, on Nov 26 2008, 04:28 PM, said:
[image: View Post]ANDREW04VFR, on Nov 26 2008, 03:02 PM, said:
i wish i could! the first four or five threads are gone. those time serts look really good. what size would i need to order? ive never really measured thread patterns or sizes?
The 6th Gen uses an NGK spark plug, part number IMR9B-9H.
According to NGK:
Thread Diameter = 14mm
Reach = 19mm.
Hex Size = 13/16"
http://sparkplugs.co...p...5198&mfid=1
this is the correct specs on the plug. 3/4" of threads leaves lots of room for thread repair! chasing the threads may be difficult to get started straight in the bottom of a 5" hole, but certainly worth trying. chasing the threads will not cause a lot of debris so i would not use the rope trick or grease. any chip falls into the cylinder with grease on it won't be sucked up by a vacuum. suck out what you can with the vac and crank the motor a mite to blow out whats left. install a new plug to proper spec and RIDE! best of luck!
I've had to heli-coil a plug thread years ago. When I vacuumed the cylinder out, I got a lot of shavings out by using a small enough hose to actually stick it right down the hole, after hand cranking the motor over to open the intake valve so air can get into the cylinder. I took some smaller pvc pipe, then garden hose, and finally aquarium air hose, and put it all together with tons of duct tape wrapped around each joint. Pretty loose but it still pulled air hard into the aquarium hose. I just twisted and poked it all around the cylinder, since the hose had a natural curve in it and was very flexible.
Good luck!
End of thread · 22 posts recoveredWayback Machine snapshot 12 Apr 2010