I may have missed it, but are you replacing the guide(s) and getting a valve job? Or maybe just trying to see how lapping goes?
Back from the depths of winter with an update.
Originally Dave, it was just seeing how lapping was going to go, and to replace one valve guide that was cracked. I had to drill out the old guide, but it got to a point where I was off a drill bit size by just a hair, so I couldn't remove the rest of the guide, and I certainly did not want to go over a size or else the head wouldn't be useable. I didn't know what to do next and I was getting hesitant to go further with that, which is when I stumbled upon a used head on eBay for $50. It had perfect fins and looked to be completely solid, so I went for it and bought it.
Turned out to be in pretty good shape. A lot more dirtier on the outside than mine was, but cosmetics are easily fixable. The inside was fairly decent, and turns out all of the studs were replaced at least in the past couple of years, so they almost look new. All threads are in great shape, no damage. So I went ahead and started to disassemble this head and look for issues. Since the first time my original top end was rebuilt by a shop, I have no internal comparison to make, but I could tell this head ran with ethanol fuel for a while. The exhaust valves were pretty ugly and took a while to clean, really caked stuff. I wish I took more pictures of the outside because it was pretty ugly, but here's a couple from the job. All valves, guides, and even seals seemed to be decent, so it was a really straightforward cleaning and lapping job. I bought Viton seals for it as well and put those on, and sprayed the head with a coat of VHT's Flat Aluminum Header paint.
So clean and pretty!
A glimpse of the work during a quick 400 grit sanding of the mating surface. It wasn't uneven really, but there was a tad bit of pitting from the corrosion you can see in the photo. After a nice cross cutting sand, the corrosion was still visible, but you can't feel it in the surface, even with a fingernail. So I didn't worry much, just not the prettiest surface, which is A ok in my book.
An old seal. I eventually cleaned out as much as possible on this head after soaking it in a 50/50 solution of Purple Power and water for a couple of days, since it's been so cold I was allowed to work inside the kitchen a couple of nights, so I grabbed some nail polish remover while I was in the house and started to clean up any hard to reach areas with cotton swabs. And yes, the alcohol content in nail polish remover does a really nice job of cleaning. I highly recommend it since it also does not have as strong of fumes as some of the typical solvents and cleaners.
Coming together. You can see I wasn't able to get the face of the exhaust valves to look completely smooth and new, but that seems to be of no issue. You can also see the array of tools and materials used, as well as the teddy bear sheet (which adds like 10 extra horsepower and a blessing to this build, of course.)
Very dirty exhaust port.
Very dirty intake valve. I wish I had remembered to take a photo of all 4 at once to compare to everyone the appearance of them. I could tell there was AFR issues in some valves, I think it was cylinders 2 & 3 that looked like they were running richer, which I believe could make sense if they were running a different intake style as 1 & 4 always get more air from the physics behind them, and likely the bike was tuned to the AFR of 1 & 4. Just a speculation I guess.
The cleanest valve!
Intake before:
After:
Nice and clean seat:
Nothing looks brand spanking new internally, nor am I using new oversized cool valve train components, but it was still exciting to see it come together
After cleaning up the valves and putting the new seals on, I went to reassemble and I noticed some of the retainers were more worn than others. I'm thinking at some point valve lash was incorrectly measured and maybe a couple of times it was ran a tad low on oil or there was some other oil issue. So I went ahead and swapped out the worn ones with good ones from my original head. It pays to have an extra after all.
Borrowed a leak down tester from work, and after working to about 4am, it was going to be ready to test the next morning. Quite frankly I was so tired that I didn't even realize how much the results we saw in that moment were going to matter. I had no idea how this was going to go.
1 & 2 were absolutely perfect. 3 was at about 20%, but that one is likely due to the fact that I kept spinning it over TDC by 10 degrees, every single time(it let air out through the exhaust port as well which is why I'm thinking there is no issue with the cylinder, but mainly user error
). 4 was a bit sad, because it showed results that need attention:
The good news is, absolutely none of this was leaking from the head. Which means that I finally solved the top end issue, once and for all. This was monumental for me!
The bad news is, this was crankcase pressure, so likely, I cracked a ring when placing the cylinder jug back on. I'm not really surprised since I had to do that twice, I probably cracked the ring the second time on and considering I used my hands to compress each ring, one at a time, and slowly lower the jug onto it going from side to side. I essentially was asking for a ring to fail, haha. So all in all, I am not upset. I actually was able to find a leak as well from the kickstarter area, which I referenced a few months ago when the kickstarter spring (at some unknown point in its life) kicked off the perch by the clutch basket and squeezed itself between the cover and the gasket. Now I know that it needs a little bit of RTV on that side and it should be good to go after. Quite frankly I'm happy that issue showed itself now and not when the bike was on the road and spilling oil every where!
I also used the rubber band trick as prevention when installing the valve cover on, and although I thought it would do little to nothing, it truly helped a lot more than expected and made installation a breeze. It only takes about a minute to put the rubber bands on as well so it's really not out of the way.
So, disassembly will be needed one more time, I'm going to wait until I can inspect the rings on 4 to order any parts or ring compressors. In the meantime, I did order an EK cam chain and master link, so I will need to break the old chain, break the new chain, remove a link, install chain with new master link and link tool. I know endless is always preferred but I didn't want to go down to the crankshaft and I think the advantage over master link will be negligible for a stock rebuild. All thoughts welcome on this however, if it's unanimous that this isn't the best chain brand or option, then I can still return it and swap it!
Right now it's just a waiting game, it's been single digits and diving into negatives for the past couple of days and weekends which is really upsetting since the next semester starts in two weeks. I really wanted to make some progress between now and then, but it's just too cold and I don't have a heater in the garage. I also know I make stupid mistakes when it's that cold, so I think it was a perfect time for an update.
I also made an electrical box about a month ago. It's pretty big because initially I was trying to fit a stock sized battery into it, but I've read that I'm going to need a lithium battery once it's running because of the extra CCA the electronic ignition is going to want along with a higher AMP per hour. This is fine because I had my eyes on a small Antigravity 8 cell anyways, so once I'm done with everything else I can modify the box further since the Antigravity battery reduces battery size pretty much in half. I was thinking about trimming an inch off the height and then creating a lip around the top of the box to give it a more refined finish look and feel, and hopefully save my fingers from getting cut on the rough edges haha. At that point everything will look so much more clean and tucked, even though it's still using original harness. After I get a season of riding time into this thing I would love to convert to a motogadget unit and create a new harness from scratch.
Thank you all for your support and telling me about similar instances many of you have had. I know I don't reply to most comments on here (I feel like it really lengthens posts an excessive amount, and I'm trying to keep it straightforward for anyone who reads this for any insight for whatever reason) but I read every single one and I try to respond to most of them in mass updates like this. Or, I hope that my updates help answer the previous question stated without having to reiterate it.
