got the R90 out in the sun

[Walking Eagle]

Snowbum has a tutorial on drilling mufflers for a better sound, and this "deep drill" is part of it. Can't find the link, but if you Google Snowbum, you'll easily find all his detailed articles.

Sadly, if you require pictures to understand instructions (vice words), Snowbum is not the guy for you. Fortunately, he uses many nice bright colors, sorta like Crayons, which helps when reading his long and quite specific instructions. He usually repeats the IMPORTANT stuff at least twice, a feature of his work that I appreciate.

Being a "non-trained" wrench, I read EVERYTHING I can get my hands on before I even think of doing a new job, but that's a personal thing. What I do next is READ EVERYTHING again. Then, after that, especially if I haven't done the job before -- I READ EVERYTHING again, and I'm not kidding. Yes, I'm old, but you may be surprised at all the details that you missed the on the first (or even second) reading. When I follow this discipline, I usually don't have parts left over after re-assembly -- and I take that for a good sign.

Walking Eagle

[8ninety8]

You are correct, it's been over twenty years when I drilled these, it wasn't easy, best left to qualified machinist.

[8ninety8]

Can't forget about these, two each side 180 degrees apart, cleaned up, made a little larger, should vacate moisture too. That about kicks the muffler dead horse down the line. Any more holes in these and they'll likely fall off. Also cleaned up 1st baffle holes with new 25" long bit. We're having some really scarey warm days.

[lmo1131]

We're having some really scarey warm days.

aka: Earthquake Weather out here...

[8ninety8]

Acrually thinking about gettin out shorts today, now that's scary, the partner wil be gettin out sunglasses.

[8ninety8]

Cylinders painted, got out rings, checked gaps, cleaned up pistons, checked where gap position should be, rings in with an oil film. Also drifted out pushrod tube rings to proper setting. Almost didn't use these rings, thought they may be problematic. A little tricky.

[Walking Eagle]

I noted that on the "other thread" that you apparently gave up on the Quickseat. I talked to a couple of mechanic friends, but they didn't know anything about it. Website wasn't much help.

Following your investigation, is it not worthy of consideration, or at least not worth $20? Possible damage to the 247? If you feel like reporting, let fly. Enjoying this thread, and I hope you keep it up.

Regards,

Walking Eagle

[8ninety8]

Skipping the powder stuff. Rings are getting pricey, but what the hey. Should work. Was ready to grind the gaps, but they were in spec. Didn't get any straight info on the powder either. Dry cylinders are dry enough.

Givem the throttle and see what happens. And then there is always next winter.

One tech squirts a shot of lite oil into the cylinder before start up, one completely dry, another a wipe. If you see me smokin down the road, let me know if it's blue or black. Just kidding. I go real sl-o-o-ow when it comes to this work. In no rush, thinking about a nice warm Sat. morning, no cars out, early, and can throttle it up and down for a few miles, or maybe a Sunday morning?

Tommorrow a bicycle ride to git my inner ear working. Thinking about what's next, is better than slapping it all together in one day, still thinking anerobic, or silicon base sealer? Or that gooey Hylomar?

[Walking Eagle]

The latest info from Oak is to use Loctite 510 Sealant. Everybody has their favorite, and many gurus probably still use Hylomar, which probably works just fine if properly applied. There is a LOT of "old" information out there, and Hylomar has been around a long time, which is one reason you see it recommended in so many places.

You probably won't find this product on a shelf. I ordered mine through a local Fastenal store, and it ran about $30 for enough to do many, many bikes IF it doesn't dry out once opened, as with Dreibond and probably others. There are less-expensive choices out there in your local auto supply store, and I know several excellent mechanics who swear by other products that cost under $10 a tube.

I'm not an expert on any of this stuff, by any means, but - like you - I never rush through a job, and I read everything I can get my eyes on.



Walking Eagle

[20774]

Tom Cutter just gave a nice treatise on gaskets and sealants. In it he stated the following:

------------------------------

BMW original recommendation was Hylomar SQ-32L Sealing compound.

Other sealants used by mechanics include:
- gray ThreeBond Liquid Gasket 1194 sealant
- other names for this include YamaBond 4 from Yamaha
- Suzuki offers the ThreeBond product in BLACK, under their "Sealant 1207B"
label
- Tom uses the Suzuzi 1207B on bikes with black-painted cylinders, and the ThreeBond 1194 for aluminum cylinders

----------------------------

I've heard Ted Porter say he uses Permatex Ultra Gray.

[8ninety8]

Thanx for the info. Got too many tubes of stuff around here. Need a fresh tube of the latest stuff. Went to bank, got four dollars, bought a can of rustoleum high temp paint, got out broom, and they're all done up fresh black, which will probably wear off in about one summer.

[typ181r90]

Thanx for the info. Got too many tubes of stuff around here. Need a fresh tube of the latest stuff. Went to bank, got four dollars, bought a can of rustoleum high temp paint, got out broom, and they're all done up fresh black, which will probably wear off in about one summer.

I used the rustoleum high heat spray on my valve covers and it held up tremendously, and that's without even prepping it properly. Once I'm ready to put my high compression pistons in I'll likely use the same spray on the cylinders.

Also, I sent you a PM but for some reason this forum won't let me send any out. Did you have to grind your valve pockets with the 336 cam using the 9.5:1 pistons? I've heard people say they've had to with smaller displacement engines and heard some people just put in the cam and go. I have the BMW TSB and they are sort of vague whether or not you have to insisting on testing for clearances on installation. I'm so anal I'm going to check all clearances when I finally decide to put the bike down for more than a few days at a time to install this stuff, but just want to know what your experiences with the cam were. The cam, pistons, cylinders, and dell'ortos are all on my shelf ready to go, but I just did the top end last year and have the bike tuned to perfection so I'm not really in any rush to take everything apart again

[8ninety8]

Had the same worry when I got the cam way back. Noting the warning, asked around and was told not to worry?, and ran it for 5K, but always wondered.

Thought about it again when someone ran a thread on valve/piston clearance. After disassembly this winter put putty on both sides of piston, reassembled, turned it over and showed about 2.5 mm clearance.

The first overbore pistons had a much deeper dish than the originals. The only way to know is to measure. A little hassle but worth the time. Don't know how close is too close and I don't know if one supplier's pistons are different from another. Don't know the exact difference in lift from 308 to 336. This is on a 900, don't know about 750. Don't know much.

Measuring will save a lot of cash the morning after. These parts are getting into the unobtainium price levels, a little care takes time, no rush.

So, no, didn't machine valve pockets, may have lucked out? Today I would definitely measure. Take care. Check it out. Ask around.

The cam in '87 cost 110 bucks. Pistons with rings and pins 160. Lifters 6, etc. Today?, may as well buy another bike. Good luck, and good night.

[8ninety8]

Here's the standard bore, left, with the first over, intake pockets. That's what I got when bought new pistons, a bigger pocket! And I didn't even know it at the time! Someone was looking out for 8ninety8. These are both 9.5 CR.

[typ181r90]

Here's the standard bore, left, with the first over, intake pockets. That's what I got when bought new pistons, a bigger pocket! And I didn't even know it at the time! Someone was looking out for 8ninety8. These are both 9.5 CR.

I have 2nd oversize and they look deep like the one on the right, maybe a little deeper even (but nothing like the stock one on the left). mine are also going into a 900. I don't have the installation sheet in front of me and it doesn't look like it's available online anymore but there is definitely a higher lift with the 336. I'll be measuring and measuring for sure once I finally decide to put the bike down (I ride through the winter so no downtime there), just wanted to see what your experiences were


EDIT:

336 cam lift = 10.68mm
308 = 9.4 mm