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Kenner nurses a neglected 04F back to health

Started by Kenner, January 08, 2018, 10:52:41 PM

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The Buddha

Muriatic acid will eat aluminum and aluminum based alloys a lot faster than it will eat clean steel. It will eat rusted metal very very fast.
If your problem is that there is rust and heat that's gooped up in there and threads etc etc have shards of rusty metal preventing it from getting out, yea muriatic acid will get that eaten, but if you have cross thread type madness, you're gonna eat the aluminum fast.
On my first tank kreeming experience, I blew a hole in the petcock overnight trying to get rust out of the tank. Trust me, aluminum based alloy will go fast when you hit it with muriatic acid.
Cool.
Buddha.
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I run a business based on other people's junk.
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Kenner

#21
To save my pride I think I'm going to quit keeping score since the Yellow Bird is running up the score.

So turns out my acid trial didn't work out. It was probably due to using used acid from a dead old battery and not fresh new acid. I resorted to continuing to drill the studs out. I drilled them a tad oversize for an m8X1.25 but that was to clear out more of the corroded-in bolt from the holes. I started with a 17/64 (0.263) but then went up one size to 9/32 (0.281) .... according to the machinery handbook the hole should be 6.8mm (0.268") for this tap.

I then recut the threads with an m8X1.25 HSS tap. The studs will screw in, but the threads feel a little weak. I am at a crossroads on what to do next. Since I am changing the configuration to be studs instead of screws I have a few options. First, I could slather the studs in JB weld and then thread them into the holes and let it cure. Since the studs won't be spinning to put the exhaust back on this should work fine as it just needs to mostly resist the tensile force the nut will apply to the flange. I am tempted to go this route because if it doesn't work I can always drill it larger and add the insert, once drilled larger there is really no going back (easy to remove material but very difficult to put it back).

The second option is to drill it out larger for a threaded insert. I have a set of E-Z lock threaded inserts coming from Amazon, but I am deciding whether I want to use them. They have an m12X1.75 outer thread. This requires drilling a 10.8mm (0.425") hole and the threads themselves have a major diameter of 0.475". I am concerned going this route because of how large the holes need to be drilled and whether it will weaken the head or encroach into the exhaust chamber. It appears there is enough aluminum meat but it'll be close. Has anyone gone this route?

The third option would be to oversize the bolts to the next thread size which is m9X1.25. I am very reluctant to do this because I hate having mis-matched hardware. It always feels like such a hack job if you do it that way.

I did take the opportunity to check the valve clearances and the compression on the Yellow Bird this weekend.

Left Exhaust 0.003"               Right Exhaust 0.004"
Left Intake   0.002"               Right Intake   0.002"
Left Compression 120 psi       Right Compression 120 psi

(edit: now that I have the bike running I redid the compression test after getting the engine to full operating temperature.)
(Left Compression hot 128 psi       Right Compression hot 129 psi)

When I first measured the LI it was less than 0.0015 but unfortunately I didn't have a 0.001 feeler gauge (0.0015 was my smallest). The shim was stamped 245 and it measured 0.0966" with a micrometer. I pulled all the shims on my spare motor to see if one was small enough, but they were all too large at (0.105"X2 and 0.1104"X2). I resorted to sanding the shim down to 0.096" and reinstalled it. After that I could get my 0.002 feeler gauge under it which tells me it was just barely under my smallest feeler gauge so it was likely still within spec before the sanding. I will tell you that sanding 6 ten thousands of an inch off the shim took about 15-20 minutes. Those shims are made of hard material.

The compression is a little low according to the manual, but it also said to get the bike to operating temperature before performing the check. I did the check cold since the carbs are still off the bike waiting for rebuild kits.

Ken


Top pick -> Two inner threaded holes cleaned up after drilling out sheared screws.
Bottom pick -> Studs I will use to replace screws. These came from a 98-02 chevy cavalier exhaust manifold. I just happen to have a half dozen of them laying around from a repair I did on my natural gas cavalier.

mr72

Good job getting the bolts out! And ditto that sanding the shim, although if it were me I think I would not trust that I could sand it and have it remain flat within 0.001", I'd be afraid it'd rotate on me.

Your compression is low enough that it may cause you problems down the line. Heck, you have it apart this far, how hard is it to pull the head and jug, hone the cylinders and put in some rings?

Anyway, about your options on the exhaust studs, I agree with you that using the existing holes/threads is the least risky way to do it but I wouldn't use JB Weld because of a lot of reasons, not the least of which is that if you manage to get threads cut in it without it just flaking off it still only has 500F temperature rating which is not half of what I'd want for an exhaust stud. OTOH I think your existing threads are probably sufficient if you use a high-temp threadlocker. Loctite makes one rated for 650F and these guys have one rated to 2100F if you can find it. I'd probably just Amazon-Prime the Loctite and put the stud in with that, then make dang sure I never over-torqued it.

IMHO. And that's a heck of a lot easier than trying to fill and re-tap the hole. BTDT, never seen it work right, always more trouble than it was worth... well except one time when I packed a broken threaded hole in a magnesium bicycle fork (disc brake stud) with plastic steel putty and then drilled and tapped it like it was brand new material, but that's not a temperature sensitive application and I had the PSP on hand (it's very expensive, like $80). And that was an M5. Whole different animal. If you have salvageable threads then threadlocker seems like the way to go here.

If you had the head off this might be a good time to try aluminum brazing ... in theory you could just coat the threads and reduce the holes a little then re-tap, or use this method, which sounds dodgy but maybe if you chased the threads after.... Maybe when you have to take it all down again in a couple of months for a top end rebuild to fix that 120psi compression ;)

gregjet

#23
had a look ate that material and it looks the go actually. Attached video of a use and the joint is stringer than the base. For this job could be a real alternative. BTW alu-brite should clean the hole very well then wash it with lots of water before use. CAREFUL of alubrite as it contains Hydroflouric acid which makes the other halogen acids look like pussies and is not at all good for you skin and body. It will absorb straight through the skin. GLOVES! For the bolt coat it with moly( very thin) or teflon spray ( temp stable) and the bolt should turn out very easily.
https://www.youtube.com/watch?v=RCrixbXz4rc

Kenner

#24
I've been back at it in the garage. I decided instead of trying to hodge podge something together for the exhaust bolts that I would just repair them properly. I chose to go with a Time-Sert m8X1.25 kit for this repair. While Time-Sert is on the expensive end (the kit cost $73 US) in the end it was worth it. You get a fantastic repair that in this instance is stronger than the original because you are threading the studs in and out of a steel insert instead of aluminum threads (yes the insert is threaded into the aluminum threads, but once in it stays put and from my experience threads generally strip when tightening).

Another thing I like about the Time-Sert kit is that the inserts are very thin. They are only 0.372" diameter where an m8 bolt measures 0.307". The other inserts I was looking into were an m12X1.75 on the outer threads which has a diameter of 0.472" (these are much cheaper and can be installed with a normally available tap where the Time Sert tap size is non-standard). This means the holes would've been a tenth of an inch larger to fit the generic insert which would not have left much meat in the head. The reason the Time-Serts can be so thin is the inner and outer threads are synchronized so the peaks and valleys line up. (See picture below).

Next up is cleaning the carbs and installing the new bits from the K&L carb kits.

Top Pic: Time Sert cutout showing thread alignment.

2nd Pic: Time Sert Kit with drill, counterbore, tap, and installer (this is a thread rolling tap that forms the final threads on the bottom of the instert as it is installed)

3rd Pic: Holes prepped for install

4th Pic: Inserts installed

 

The Buddha

Why not helicoil ? There was no real need to do a timesert.
Cool.
Buddha.
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I run a business based on other people's junk.
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gregjet


Kenner

Y
Quote from: The Buddha on January 19, 2018, 01:12:55 PM
Why not helicoil ? There was no real need to do a timesert.
Cool.
Buddha.

I don't realy like helicoils. Once inserted they can be a little tricky to start the threads and I've had experience with them bending at the first coil. I prefer a solid insert. I chose Time Sert because they are thinner than most inserts and require a smaller hole. Once you own the kit the inserts are only a couple dollars each and this thread size is popular on motorcycles.

That being said a helicoil probably would have worked fine since I am changing to studs but since I didn't have a helicoil kit already I chose to pay more and get what I believe are a better product.

Ken

mr72

Not that you care, but IMHO, overkill is a great idea here. A solution that results in a reliable repair is a winner. Plus now you have the tools to do this kind of repair again in the future if need be. Total win.  :thumb:

The Buddha

Quote from: Kenner on January 20, 2018, 03:40:40 PM
Y
Quote from: The Buddha on January 19, 2018, 01:12:55 PM
Why not helicoil ? There was no real need to do a timesert.
Cool.
Buddha.

I don't realy like helicoils. Once inserted they can be a little tricky to start the threads and I've had experience with them bending at the first coil. I prefer a solid insert. I chose Time Sert because they are thinner than most inserts and require a smaller hole. Once you own the kit the inserts are only a couple dollars each and this thread size is popular on motorcycles.

That being said a helicoil probably would have worked fine since I am changing to studs but since I didn't have a helicoil kit already I chose to pay more and get what I believe are a better product.

Ken

One reason I love helicoils is that the wire they are made of are very very thin and hard as the dickens. Basically spring steel.
In any case its in place so you're good.
Cool.
Buddha.
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I run a business based on other people's junk.
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Kenner

Welcome back everybody!

The site has been crashed for a week or more so I haven't been able to post any updates. I have continued to make progress at a slow and steady pace since my last installment. I ordered a bunch of parts from a motorcycle recycler outfit based in Missouri (I am from Utah). I was able to swing a package deal since I bought a bunch of things at once. Namely, a seat, stock airbox, left hand controls, and exhaust (he cut the header and can apart to reduce shipping by $50 then I just welded them back together....I probably should have just paid the $50 though because I only have a Lincoln Tombstone 220V AC stick welder and it was tough to join the pipes together and make it look nice).

I have the header and seat installed. I took the front fairing off to repair a couple of cracks. I also removed the stock petcock since it is leaking. I purchased a crf250x petcock because it is plumbed similarly, but is not vacuum operated. This also allowed me to remove all the vacuum garbage from around the carbs. Trying to make this bike as simple as possible.

I painted the header with some inexpensive grill high heat paint. The paint looks good, but we'll see how durable it is. I first hit the header with a wire wheel in a cordless drill to clean off all the surface rust.

Kenner

Top pic: close up of painted header showing paint used.
Bottom pic: bike as it is today.

Kenner

If you recall from my earlier post I performed a compression test when the engine was cold and didn't have the carbs installed. The results were:

Left Compression 120 psi       Right Compression 120 psi

According to the Clymer manual the compression should be checked after getting the engine to full operating temperature. Now that I have it running I ran it up for about 10 minutes to heat it up and then redid the compression check.

Left Compression 68 psi       Right Compression 70 psi


WFT! Why would the compression be so much lower with a hot engine?

Then it dawned on me. Even though I was holding the throttle wide open the slide was not lifting since this is a CV carb and just cranking it over doesn't produce enough vacuum to raise the slide. I reached into the airbox and manually raised the slide while holding the throttle wide open and cranking it over. Then I got

Left Compression hot 128 psi       Right Compression hot 129 psi

That's more like it. Interesting to see the difference between hot and cold compression is about 8-9 psi. I didn't have an issue when the engine was cold because the carbs were not installed. Lesson learned.

Ken

Kenner

Update of tonight's work. I was able to get Yellow Bird's fuel lines replaced and I eliminated the vacuum petcock and instead replaced it with one from a CRF250X. I love how much simpler the new one is. I was able to make it fit quite nicely by sawing a small groove in the original petcock mounting plate. You can't see it in the picture below but on the back side of the petcock there is a small flange that needed a slot to seat in. When seated properly the petcock doesn't twist even though it is only held in with a single nut and bolt. I was able to start the bike up and give my youngest son (4) a ride around the block. It was really fun as the weather here lately has been much more spring-like than winter-like.

Still lots of odds and ends to complete but with the nice weather my garage time has been rather pleasant.

Ken

cbrfxr67

"Its something you take apart in 2-3 days and takes 10 years to go back together."
-buddha

gregjet

Standard fuel line system is a nightmare. looks like it was just tacked together...
Engineer: There I have finished the fuel lines
market exec: BUT you can't reach the tap and the needles and seats are crap.
Engineer: OH, OK here is a new one wit a vacuum shutoff
market exec: What about the reserve.
Engineer: OOps I forgot OK here is a tap you can reach with a vacuum shutoff and TWO lines leading into it . One from the revserve and one from the main. BTW the ends are different sizes now.
market exec: What about a prime when there is no fuel in the bowls and the vacuum isn't letting and fuel through.
Engineer: THERE satsified now.
market exec: But it now weighs more then the bike and needs an fluidics engineer to figure out how to connect it.
Engineer: That's OK put a section in the owners manual saying " if you need to connect the fuel hoses contact you dealer" that always works for a bit extra cash.

How did you block the other tank outlet? I turned down a brass plug and soldered it in one of the outlets. Brasss in getting really hard to find. Of course when I deconstructed the tank tap to solder it,  I found the rubber O ring was perished and now I have to find that right sizes fuel resistant O ring.

Most of the way through my fuel pump/shutoff mod.

Kenner

#35
Quote from: gregjet on February 07, 2018, 01:01:42 PM
How did you block the other tank outlet?

The easy way. I didn't block it off. The manual fuel tap I bought is designed similar to the GS500 one in that it accepts separate inlet lines for On and Res. This tap just allows me to get rid of the vaccuum lines and is only $30 to replace vs $100 for the stock unit. By much simpler I was referring to the petcock itself. I still have a mess of fuel lines hidden under the tank.

In the future I would consider a single tap out the bottom of the tank with only an On and Off, but this was the fast easy solution for now.

The picture above of my petcock was very poorly lit and a little out of focus so I'll try again when I have good daylight.

Ken

Below is a picture of the petcock I installed. It is from a CRF250X. Note the dual inlets and single outlet.

gregjet

Nice solution kenner.
Run the single line into a quick disconnect connector and you have the best line passive line solution I have seen so far.

I put the pump in to also see if it would help the fuel starvation problem at upper revs ( not that I get to use upper revs around the roads here). Also because it has a fuel shutoff when not powered.

mr72

It occurs to me that an electric fuel valve (aka fuel shut off solenoid) like this one would simplify and solve this problem very well without requiring vacuum.

Hook the electric shut off valve to the reserve tank line and plug the other tank outlet as gregjet did. Other end to the carb inlet. Cap the carb vacuum port forever.

Wire it to the keyed power source (on = open).

This would solve the prime problem.

Only real downside is you might leave the key on and if you have leaking float needles then you could flood the bike just like leaving it on PRI. I guess the other downside from a safety standpoint is that if the fuel line on the carb side were ever cut/disconnected/loose etc. then it would gush fuel as long as the key was on. Or if you lay the bike down it would run fuel out the overflow even if the engine wasn't running. This is no less safe than a manual petcock.

Next time I have to go fool with the carbs or if I have reason to take the tank off.

Kenner

I like the idea of a solenoid switched with the key. Super simple and nearly foolproof since I almost never leave my key on for  fear of running the battery down. Only drawback is loss of reserve which has saved my bacon on multiple occasions.

Ken

gregjet

#39
The shut off solenoid was my original idea , but I couldn't find one after a lot of searching ,that wasn't the size of a small planet. That, plus ebay has now stuffed it's search, so even if you search for Australian sites, you get US ones, and small items often cost a fraction of the freight cos,t so are economic. I end up buying nothing. Then after reading various posts on the forum I figured a fuel pump may solve a number of problems in one hit. The bonus was having the now spare air solenoid 12v wire and socket sitting in the right place to use.
BTW the size of the one you posted is pretty good but the pipe ID is only an 1/8" (3.2mm) . As there is only tank pressure behind it I may not have sufficient flow?

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