350x head problems

[350xtrike.rider]

soooooo.. horror story...

I go and check my oil and there is almost none in it. It ain't burning any so I check for leaks and sure enough there is a missing/broken bolt on the top of the cam cover under the oil cooler.
So I tear the engine out of the bike and proceed to EZ-out the broke bolt... Left hand drill bit.. then SNAP!!! the EZ-out snaps off in it.. get that mistake all cleaned up.

Then I order the stock hole size drill bit and tap. get it all drilled out straight.. stick the tap down taking 1/4 turns then breaking the chip off it half way down and... SNAP!!! no warning or anything the blasted tap snaps off at the end! :mad: Luckily it wasn't "stuck' and used the air compressor to blow the pieces out.

Then I set my drill press up for an over sized hole, drill it all out.. put an AMERICAN tap in it.. going smoothly down.. 1/4 turns then breaking the chip off.. almost to the bottom then it seizes! won't turn in or out or anything.

I ran wire down each side of the tap and there is a chip that won't come out. Tried the air compressor, that wire, everything I could think of to get the stupid chip out of there and nothing works! I do have a NOS 350 head but I was saving that for when I do a complete rebuild.

Any suggestions? Cuz I'm stumped.

[yaegerb]

Hmmmm, use the new head?

[86125m]

Well its no time like the present for a top end rebuild.

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[oscarmayer]

it sounds like your rushing the taping process and not using enough oil you should only be turning 1/2-1 ful turn then back out and then back in and out till smooth and then continue. every 2-3 turns I take it all the way out, blow off the tap, blow the chips out and start again. doing this keeps it from snapping off. it gets hot, sticks to the metal and snaps. if you spend some good coin, you can get a carbide or diamond tipped rotary tool ball head and slowly using a dremmel, cut the broken tap tip in half so it falls out of the grooves. this will let you remove it w/o any further damages, next you need to double check your depth. you only need to tat as far as the threads go with +2 threads as the stud stop will lock it.

option 2.
using a carbide drillbit, VERY slowly, drill out the hole to an even bigger sized bit. (Tap the hole using the "SLOW" method above I talked about) (12mm is probably EZiest for this). get a 12mmx1.25 tap. and a grade8 bolt. take the bolt to a machine ship and have them center drill and tap a hole in the bolt end for the stud and have them cut it off just slightly shorter than the stud section where it screws in.
when you get the bolt home drilled and ready, it is now a insert replacement. using green or red lock tight all over it, screw it in the 12mm hole you drilled and tapped and let it dry. you want to screw it in till it is just a hair below the surface of the head itself. Take some more lock tight and drop a drop or 2 on the insert you made with the head standing on end so it leaks into the threads more. let it stay that way for over night.
Now, your ready to screw in your stud. use "green" lock tight and screw the stud in till it stops. do not tighten hard, just till it stops and a tiny nudge. that is all it needs. let it sit for an hour or 2. your ready for final assembly of the engine. the good thing is the steel insert you created will not strop or pull out like some thread repair stuff can do.

good luck.

[oscarmayer]

Any updates?


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[350xtrike.rider]

Haven't had the time to mess with it yet. Been a busy week.

[350xtrike.rider]

I don't know how I'm going to get that stupid stuck tap out tho. I might just take the valve's off to get a better view of whats happening.

[oscarmayer]

I would honestly, take the top end off, and take it apart and have a machine shop properly remove it. not worth loosing a $350-$400 head to a bolt..

[350xtrike.rider]

Currently soaking all the bolts in blaster.
Here's the stuck tap. I think it might be broke in the bottom.



231229

[yaegerb]

why didn't you pull the rocker box cover to tap it? You are trying to tap it through the halves...interesting.

[350xtrike.rider]

why didn't you pull the rocker box cover to tap it? You are tapping it through to halves........

That was the plan. Then just drill out the top half. I can't pull the rocker box off cuz the bolts are rusted/stuck in. Now I see why this bolt was broke in the first place lol. My impact won't even break them loose. Guess I'll just soak them really good and try again tomorrow.

231230

[yaegerb]

I would invest in some Kroil oil. PB blaster is nice but second to kroil.

[oscarmayer]

I bet the tap is stuck in the top cover not the head.

You need to soak the engine in some sort of liquid penetrate.

I recommend this. (This will require the engine be fully dissembled when done except you will. It have to split the case halves. You will have to clean it very well though. )

Take a tub big enough to stop the entire engine in and out the engine into it ( take the stator side cover off first). Go buy some CLR by the gallon. You will probably need 3-5 gallons. Pour it into the tub with the engine in it. Let the engine sit for 24 hours.
Now take the engine out. Put it on a towel. Take a small ballpien hammer and smack the top of all the bolts with it. This sends a vibe ration shock that will help loosen the clamping of the corrosion to the bolt.
Now using a racket (not impact) loosen the bolts by hand. Good luck.
If they all come out, take both side covers off and remove the cylinder and piston. Take the case center left only. Clutch and flywheel need to be removed too.
Take a 5-gallon bucket and pour the CLR into it and save for future use.
Take the tub wash it out and put hot water in it. Use blue dawn soap. Take a scrub brush and clean that engine and soak it in the soapy water for at least an hour. Using hot water rinse the motor out and keep doing it till there are no soap water coming out of the center section.
Now use compressed air and blow as much of the water out that you can out of the center.
Take a big can of WD40 and spray the entire inside of the center area. Make sure to slowly turn the crank and sprocket gearing to turn the transmission so everything gets soaked in it.
Let it sit for an hour and pour any left overs out.
Start re-assembly. Put new seals and gaskets. Now is a good time to consider a piston upgrade. The head, have a machine shop do a valve job on it for you. Remember you may have I replace the valves as they may have lips from being worn. If they do they are to far gone to reuse.

Good luck.


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[Dirtcrasher]

The new Seafoam "Deep Creep" - works great like a Kroil as well.

I wondered, "why did he tap thru the clearance hole in the valve cover??." I know, you had other plans.

Anyhow, if anything has to be destroyed, don't ruin that head!! if you get tht cover off you should be able to grab that tap with something. Lube it up, go both ways slowly and easily.

Pretend your in Antarctica and you only get 1 chance to get this out; That's the frame of mind you want!

Try to grab the lower part of that tap (valve covers are cheap!!) turn it a smidge with oil, blast with air and repeat backwards. Keep blowing that hole lean!!

Good luck, should come out!

[350xtrike.rider]

GeeDangit! Tap snapped off just gonna throw it back together and calk/loctite sealant the leak. It's cheap I know but my patience is wearing thin. It'll blow up in the next year or two maybe then I'll completely rebuild it with the new head. It's exhaust stud threads are boogered up from the last owner, but he graciously included a NOS head when I bought it. Thanks for the help guys!

[yaegerb]

GeeDangit! Tap snapped off just gonna throw it back together and calk the leak. It's cheap I know but my patience is wearing thin. It'll blow up in the next year or two maybe then I'll completely rebuild it with the new head. It's exhaust stud threads are boogered up from the last owner, but he graciously included a NOS head when I bought it. Thanks for the help guys!

you serious clark?......

[oscarmayer]

350X heads are NOT cheap. they run starting at $350 minimum off ebay. you may think twice about that....

[DohcBikes]

86-89 trx350 head is a direct swap. They're much more available and much less costly.

[John Tice]

This is getting so complicated that it’s difficult to follow. Seems like you’ve got drills, taps etc broken off in the hole. My idea; heat the area with a torch warm enough to anneal the broken tools. You need an absolute rigid clamping so nothing can jump, jog around. Best bet; a vertical mill with proper clamping tools which won’t jump around. Your parts are annealed enough when they lose their magnetism; at this point the parts should be soft enough that they can be more easily removed. Using a center cut milling cutter you can plunge cut thru the broken parts.

As far as drills & taps go; you can use a taper tap, plug tap or gun tap to thread holes. The thread depth goes in % of thread depth. 50% to 75% threads.
The point is that there is a lot more to this than just going to a tool store to purchase drills & taps. Do you take this to a machine shop, I’d recommend it.
JT

[350xtrike.rider]

Got it all put back together. Cleaned the headers and exhaust port. Helped a ton, it had an insane amount of carbon build up.