Author: grant

CB750F: Day 02

We couldn’t check the engine compression today, we need an adapter for the checker. Removed the spark plug from cylinder 2, Teacher said it is running lean (there is too much air in the air/fuel ratio of the mixture). Put fingertip on top of plug opening and tried starting it and it pushed my finger off and sucked it in, so the rings are allowing *some* compression. We need to remove the carburetors. Before class I did grab the service manual with the compression levels, and ordered printed copies, too from Helminc.com.

After pulling the plug out I realized there was crud all over in there, so I put the plug back in and shop-vac’d the top out first.
I wanted to remove the crash bars, they are not sporty. 3 bolts hold them on, all through the frame and one through the engine. The 2 on the top frame loosened easily, the one in the engine did not want to come out. Looked underneath to find that there were two bolts on the end. This was surprising. Teacher said the bolt was probably stripped, and that we might fix it later.
This makes it really difficult to get out. Jammed a screwdriver in there and turned it bit by bit for 1.5 hours and headed home. Teacher said mechanics is mostly about patience. I will print out directions for carb removal after talking to teacher about POR-15’ing the tank.

Working on the floor was really dirty, might have to dig out a lift and put it up there instead.

CB750F: Day 01

The bike was set up as a cruiser. That is too bad because it is a 1979 Honda CB750F which is a “supersport”. I removed the windshield and bagged the bolts.

Only 32K miles, that is nice. Supposedly the speedometer should go up to 160MPH, but only 150MPH is listed on this one.
I took the bike to school. Here is the “as is” profile:

I took the side panels off, they are black, not purple like the tank. The left side panel had the top most mount broken off and a large bolt glued in it’s place instead, which came off at some point. I wonder how I’ll fix that. I took off the license plate and bagged the bolts. It was interesting to learn that the set is bolted on, I bagged those bolts. Finally I removed the backrest, it was easy after removing the seat first, and bagged those bolts, which incidentally did not fit the rear mounts.
I removed the tail light assembly and labeled the wires first and found that there is a wire-harness. Teacher said to just replace the busted stalks.



The bike starts, runs, and stops, but Teacher checked and the 2nd cylinder is not firing (left to right looking forward sitting on bike, 1 to 4). Took the gas tank off. First turned the petcock to OFF. The fuel line was hard as a rock so teacher said just cut it, also there were heavy metal clamps on both the petcock and the distributor, so he said to be careful to protect the plastic part on the distributor, so I just cut the line in half and covered it up with a paper towel. The tank came right off, it was interesting to see how simple it was removed:

Tomorrow we’ll check the engine compression.

The New Patient: A 1979 Honda CB750F

Here is the new patient:

She is a patient because she will be patient as I learn how not to be scared to work on a bike and make all of the stupid mistakes that are to be expected.
It is a 1979 Honda CB750F.
A nice young man named Mitch sold it to me. It was the first time I had towed a trailer, that was interesting. Make sure you budget for tie downs, a hitch, and a trailer.

This is How Easy it is to Make Changes to DrRacket

DrRacket is open-source (LGPL) editor for Racket. Sometimes you want to make changes to it. For example today I wanted to enable online compilation on single-core machines. Here is how easy it is to do it:

  1. Assuming that DrRacket is already installed. This is a normal installation using the installer; you do not typically have to check out the Git repo to make changes.
  2. Asked Robby how to make the change. Robby is super everybody knows that, he explained the fix. The check for enabling the feature is in module-language.rkt. Here are the steps
  3. cd /opt/racket/5.3.1/collects/drracket/private/
sudo cp module-language.rkt module-language.rkt-ORG
# Made the change
# View it
diff module-language.rkt module-language.rkt-ORG
1329,1330c1329
<                    ;;(> (processor-count) 1))
<                    (> (processor-count) 0))
---
>                    (> (processor-count) 1))
1348,1349c1347
<                    ;;(> (processor-count) 1))
<                    (> (processor-count) 0))
---
>                    (> (processor-count) 1))
# Tell Racket to recompile that collection (aka library)
sudo raco setup -l drracket
# Restart DrRacket
  4. Now the online compilation indicator shows up and errors are automatically flagged.
  5. It works fine on a 1.6GHz Pentium with 2GB of RAM.

Hope this gave you a taste of how easily and quickly you can try new stuff out in DrRacket itself.
Here is how it looks with it turned on: