| Author | Message | ||
     Onemanclan |
Ok, so I went to Harley and got plugs, synthetic, and a filter. Got home and realized they gave me the wrong parts...After I exchanged them I got to work. While putting in the rear plug the hole it goes into got threaded wrong and stripped the hole. My service manual speaks of a 'plug repair kit' for such a thing. Any other suggestions? How much is the kit? How in the world am I going to fix this? Thanks in advance for any info... | ||
| Hughlysses |
Dr. Greg, Dr. Greg, paging Dr. Greg...  You've got a pretty big job ahead of you. Basically you need to rotate the engine (see the service manual), pull the rear cylinder head, and install a Helicoil or Time-sert thread repair kit. Dr. Greg did this on his Uly and documented it thoroughly; do a search and you should find it without too much trouble. One alternative that MIGHT be worth trying is to use the thread repair compound that Locktite makes. Basically, you clean the hole, apply a release agent to the spark plug (that prevents the compound from adhering to it), coat the hole with the compound, and gently screw the spark plug into position with your hand. Let it cure, and then torque as required. IIRC, the stuff is claimed to be good for 100 ft-lbs. The worst that can happen is the stuff would fail on the road with you leaving you stranded. Still, it might be worth trying. | ||
| Rwcfrank |
An old trick to avoid removing the head is to drop the piston to bdc feed new clean cotton cord into the cylinder until it's full. bring the cylinder up in the bore slightly then use the helicole repair kit. Once your done catch the cotton cord with a pair of tweezers or hemostats and slowly pull it out. You will remove pretty much all of the debris. Crank the engine with the plugs out to push out whats left and viola, you saved your self much time and effort. | ||
| Electraglider_1997 |
American ingenuity at it's finest. | ||
| Reepicheep |
If you do that, make sure it is a narrow little rope. And be warned that the hole will make little snags of sharp metal that can make it hard to get it out. I almost killed a friends SV-650 trying a stunt like that... I thought we would have to split the cases. Pulling the head is safest, but if you do go into bodge mode (I might), make sure the drill bit depth can't cut the piston face. It would be easy to go too deep. And I would be more inclined to just do a lot of compressed air blowing, tube taped to a shop vac fishing, and engine degreaser spraying to clear out chips. Heavy grease on the drill bit with frequent wiping and regreasing will help capture a lot of chips as well. Still a $500 roll of the dice, but at least the chips would be aluminum.... | ||
| Mark_weiss |
Here's another procedure to re-thread a plug hole with the head in place: Turn the crank so that the exhaust valve is just slightly open. Stuff an air hose into the muffler, seal up as well as you can with rags and tape, run low pressure, 20 psi or so, so that there is air flow OUT of the plug hole. Use LOTS of grease on the drill and tap (holds chips) and work slowly. Air pressure will cause the grease to be pretty messy, but will prevent debris from falling into the cylinder. One more thought. How badly did you damage the threads? Would a thread chaser (special use square file) clean things up? With long thread plugs, it is rare that the whole hole is damaged. Mark SE AZ | ||
| Rwcfrank |
I would use an adjustable reemer and not a drill bit to enlarge the hole. If you must use a drill bit grind about 75% of the tip flat to avoid piston damage | ||
| Dr_greg |
Whew! I made it. Gotta rest a minute...just ran up the stairs after my "mechanisms" class. Well, dunno about the condition your hole is in, but mine was bad enough (I could slide the plug in and out) that I never considered an "in vivo" (I think that's the term) repair. Removing the head is not that difficult, if you take your time. Perhaps my experience will help you avoid a few of the "gotchas." I used a Time-Sert repair; got the kit from Jim Pendergrass at HIS WEBSITE. Since my engine had 55K miles on it, I also took the opportunity to "Time-Sert" the other head also, then installed new valve seals and gaskets throughout. Installing new base gaskets meant pulling the cylinders; I don't mind doing stuff like that but you probably don't want to. The Time-Sert fix is better than new, and is what I'd recommend. I could easily do it again over a weekend. If you do go this route, feel free to PM me with any questions (hell, I'll even give you my cell number); I'll be very happy to be an unpaid consultant. If you're going to Homecoming you can buy me a beer. --Doc | ||
| Bobbuell1961 |
Onemanclan,Doc, When you remove the head you relieve the tension on the base gasket, you are there, replace the gasket,too much work to go back and do it again. How many miles on the bike? It could be worth doing the valve seals, again your there. I recommend James metal base gaskets over stock paper. Bob | ||
| Xbimmer |
+1 to everything Bobbuell said. If you're getting into it that far do it all. I'm at 64K with a hot running engine, seepy gaskets, and a rattling lifter or two so I'll be seeing the guts of mine soon. I'll be doing Dr_greg's TimeSerts at the time as a preemptive procedure. | ||
| Xbimmer |
Oh yeah, James blue silicone intake seals while you're at it with easy access to the manifold. | ||
| Teeps |
Here's how I've fixed dozens of stripped plug holes; with the head on the engine. 1. bring the piston up on compression stroke near TDC. 2. fill the flutes of the tap full of grease. 3. cut the new threads a turn or two at a time. removing the tap after each new thread is cut to remove debris. 4. install the repair insert of choice. 5. (optional) rotate the crank to open the exhaust valve and blow out the cylinder with compressed air. 6. install the plug and admire your new found skill. | ||
| Dr_greg |
The OP has still not described the degree of thread damage, which is a major factor in the method of repair. --Doc | ||
| Onemanclan |
Hi guys...Thanks for the input. I'm not sure if I have the skill to undertake this repair. I may have to sell my Uly (I don't want to throw too much money at it). It only has 3500 miles on it. My wife and I had two kids right when I bought the bike and I can't ride it that often. What do you think this repair (unfinished) would do to the value of my bike? I'm going to have a couple of buddies read these posts and see what we can do....Thanks again! | ||
| Jlnance |
It only has 3500 miles on it. Oh that is so very tempting. | ||
| Towpro |
Find out what a dealer will charge you for the repair, then subtract that price from the value of the bike. But you are going to get beat up over it. "but I can't test ride the bike" will come up. | ||
| Mnrider |
Find a good shop in your area. I bet it could be repaired for 2-300 bucks. Like Teeps I've install lots of inserts with no problems. | ||
| Dr_greg |
If the thread damage is minimal, than I agree it can be fixed in situ. However, the repaired threads will not be as strong as the original. Some suspected that's why my plug was blown out. --Doc | ||
| Teeps |
Doc, If you are including the installation of a Heli-Coil or TimeSert ( http://www.timesert.com/ )in your statement about "repaired threads", I have to disagree. A permanent steel thread insert is many times stronger than the standard aluminum threads. | ||
| Dr_greg |
Yes, you're absolutely right. I plead a case of temporary dementia  due to my advanced age. For some reason I had a mental picture of simply chasing the damaged threads. But of course a Time-Sert (or similar Heli-Coil style steel insert) IS many times stronger. That's the repair I suggested (and used), except with head removal due the extent of my thread damage. Thanks for your understanding. I'm off to my therapist now.  --Doc | ||
| Glen |
how much would it cost to buy a new head? i used to throw crazy cash at my dirtbikes, having jugs sleeved ect. that was until, i found that a new jug cost half what i was paying to repair old stuff lol. | ||
| Xbimmer |
Heads retail for $370 each, for my '06. | ||
| Teeps |
Dr_greg Posted on Thursday, February 11, 2010 I plead a case of temporary dementia due to my advanced age. You're not alone...  |
