pidjones rat bike project - '79 CB750F

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Car mechanics just love RTV. I HATE it! The distribution, sale, and use of RTV should be regulated and require a license.
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[pidjones]

A good test this afternoon. Backed her out of the garage and hooked up to the aux fuel cell. Fired as soon as I touched the start button, and came off of the choke a lot faster than before. Reved up fast, not lethargic as before. All pipes are getting warm (~50F outside today)! Didn't bother with balancing carbs yet. #3 float must be sticking as it was overflowing (I put clear drain lines on this time). But it is firing on all 4 finally!

Holiday duties will be keeping me busy soon, so when I bring it in (have to leave it outside to air out so the wife doesn't complain as much about the exhaust smell) it will be pushed aside for a while to make room for getting the Hunley prepped for a show mid-January. Guess it is time to order a chain for it, too. Still won't be able to ride it as the tires are too old to even ride up my driveway, but at least it can be taken through the gears on the center stand.

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"Hunley"? You have a Civil War submarine? COOL!!!! I need pictures.
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Well,  she has spent some time under water by evidence in the belt cover area and in the #1 & 3 cylinders. So, I named her in honor and memory of the first successful military submarine. (I'm an old bubblehead).

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"L" cam holder is broken pretty badly. Could have been over-torqued, but I really suspect they just rammed in a too-long screw for the valve cover (only had a couple proper valve cover bolts when I bought it). Also, this is not the first holder to need replaced. As I looked at the others to see if they were damaged, I found a J in position for an F (far left end of intake cam). And yes, there is a J in the J position. Guess this one need to be Plastigage checked and also check oil hole alignment, too.

I was going to see what I could do to fix up the tail section on the seat as it seemed to have a lot of repair fiberglass under it. Turns out, almost the entire tail is packed with Bondo and fiberglass, which is all separating from the remaining ABS part which is the top part. Need to figure out what to do with it. I could just glue it back together with ABS cement, but it weights 3.4 pounds with all of this Bondo packed in it! Think I'll check forums and ebay for another. Cracked/broken doesn't matter as I can always glue with ABS cement and reinforce from below with fiberglass cloth, but all of the bottom/back of this one is missing.

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Good grief.
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Honestly, I need to stay away from this bike for a while. But, parts are supposed to be in this afternoon, so....  Good thing, too because I decided to check that J cap in an F position. They had jambed screws in the cross-drilled supply holes in the cap, and RTVed the bolt holes. And of course, broke one of the cap bolts off. I was able to remove the broken bit with little drama, then spent time picking out RTV.  Bolts are supposed to be included with the caps I bought, so hopefully things will get better.

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Swapped in new (used) F and L caps after first Plastgage testing them - both between .003 and .004 inch. Measured with both cylinders on respective side with lobes away from lifters. Final assesmbly with assembly lube on the bearing surfaces. New chain came in too, but it will wait for tomorrow or Monday for installation. Good weather forecast for next week, so hopefully there will be a chance to run it through the gears to make sure that is all fit.

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Chain is on!

Merry Christmas from East Tennessee! What a great gift it would be, if people would live in harmony - or at least tolerance of each other. Just how hard would it be?

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Merry Christmas to you to. We do not have "like" buttons here, but we do have these.
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[pidjones]

Rolled it out this morning, hooked up the aux fuel cell with ~ 1/2 liter real gasoline, and fired it up. Once warmed enough to take off the choke I ran it through all 5 gears (on center stand). Clutch engages/disengages well, all gears work and sound pretty good (chain is hitting the plastic chain guard some, so need to adjust that). Then shut it off and hooked up the mercury sticks (old MotionPro unit). Balanced the carbs, lowered idle, balanced again. Have not touched pilot screws - all set at 3 turns open. Aircut valves are disabled.

Guess the next thing other than fixing the seat rear cowl assembly is tires (ouch$$). Thinking maybe getting a bunch of wrecked Honda plastic from the dealer and gluing it together to patch the existing cowl assembly now that I've pried 3 pounds of Bondo off of it..

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Shinko tires are not too bad on price and really good tires. You should be riding soon.
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Had a set of Shinkos on my GL1800. @~5k miles the front developed blisters suddenly. I think they are fine on light sport bikes, but fear them on heavier bikes. The CB750 is right on the edge of light/heavy to me. Might go with Kendas or Duros. Not planning on high-dollar tires for it, as I hope to sell it to buy the next project. Have Duros on the GL1000, but haven't put many miles on it yet. I stay with a 'Stone on the front and darkside the rear on the GL1800 now.

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Ordered new Kenda 657s for the '79 CB750F rat bike. Not in a hurry for them, as it will be a couple months before decent riding weather, and I have a showw in a couple weeks to get the GL1000 ready for, plus rides scheduled for the GL1800 (weather permitting).

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Shook off the winter blues by showing my GL1000 "the Hunley" at the Knoxville Cabin Fever show this past weekend. She got 1st place Honda (admittedly, only three Hondas there).

The Kendas are mounted on the 750 and wheels back on. That's about as far as the weather and my health could take her this week. Came down with a cold that knocked me out until yesterday, when I went to the funeral of a high school classmate and then to see a cousin in a nursing home that is not doing well at all. I still need to drain the fuel from the tank into my waste gas jug to get rid of the fogging oil and storage spray grease that I'd put in the tank and never flushed out. I'm sure that is a major cause of the smoke that she displayed before, because she doesn't smoke on the auxiliary tank. The weather has turned its typical East Tennessee January/February crud. Maybe the middle of next week it will settle and I can at least try to ride around the neighborhood.

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I seen the Hunly on Instagram the other day and was trying to remember where I had heard of it. Good job.
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Made it to the 40s (F) today, so she was pulled out and given her first run. Only ~2 miles total in the adjacent subdivision and back around our house (not tagged or insured yet) revealed that the engine is getting better and better, the trans shifts fine (I just need to get used to it) at least up through 3rd. The problems; front brake is spongy but improving rapidly, rear brake feels firm but does nothing to slow me down, and there was a bit of a problem with the speedometer. Pretty happy with it overall. Guess now work on brakes, repair the speedo (I already have it apart), and go down to buy tags and register. Feels a bit different from the GoldWings that I've been riding the past 15 years or so.

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How fast were you going to break the needle off the speedometer?
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I don't plan to incriminate myself here. Anyway,  it is fixed now as well as the rear brake. Looks like a couple weeks before weather gets back to reasonable. I'm spoiled with the GL1800, 1500 Watt alternator, full fairing, and heated gear.

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Nice day Wednesday, so I took the CB750F for a loop over Norris Dam. Running great, I think. Accelerates much harder than my GoldWings but vibrates a lot more. Handles well. Everything mechanical that I could find wrong has been fixed except the speedometer error, which is ~ +10mph @ 55mph. She really smooths out at ~5000 RPM (~55 mph by GPS) all the way to ~7500 RPM - the highest speed I took her. Didn't have the GPS then, so I don't know how fast that was. I was wearing ear plugs, and above 55mph all that I could hear was the air intake and wind noise. So different than a GoldWing though! I like the ergonomics with these Euro handlebars. Only a little over 40 miles but the 66 year old body felt like I had done it on the GL1800. The original bars were identical to the GL1000 stock bars, and I always got stabbing back pains in 15 miles with them.

I guess she will go on Craigslist soon. She was always meant to be a winter project that I intend to get my investment back from, so I'll let her go for $1500. Not bad with it running well and new tires and chain, GL1000 front end, all sorted. I doubt anyone on here is interested but if you know of anyone wanting to do a custom CB750 but not needing to fix mechanicals - or someone that wants a "rat bike", let them know.

Oh, and that afternoon I took the GL1800 over the same loop, trying out the new GPS and front tire!