Faulty start problem of cold engine

I have been riding a 2006 Yamaha R1. It never had an engine problem for 12 years.

The R1 developed cold start problem around middle of March 2018. The symtom is when the engine is cold in ambient temperature, it fails to start the engine with own battery.  Jump start using a big car battery is required.  Once the engine starts, run about 10 to 15 minutes at idle, ignition is fine.

The mechanic at the bike shop told me replacement of three year old battery would fix it. So I replaced the old battery with new one. But new battery failed to start the engine also. Every time I went to a tour, I did jump start the R1 and have managed bike riding.

If the battery voltage is low, charging voltage drops below 14 V on the battery terminals.  The mechanic seemed not to understand it and suggested to replace the regulator. I could do that if the engine went dead while I was riding.  Genuine regulator from Yamaha is 340,000 KRW which is not cheap!

I asked to the mechanic what if new regulator wouldn’t fix the problem. His answer was to replace the generator next, which would cost probably over 400,000 KRW. In my head ‘then what’s next?’ I’ve known the mechanic for six years and did not want to develop bad relationship.

Few days ago I brought the R1 to a local bike center which a rider fixed his bike. The shop was small and owner has worked as a mechanic over three decades. We discussed about possible cause of the ignition problem of cold engine.

  • Valve clearance is out of the specification
  • Faulty starter motor
  • Faulty relay of starter motor
  • Generator or regulator unlikely

The mechanic suspected the starter motor and he would replace it with new one.   New starter motor and replacement of the starter motor relay fixed the cold ignition problem. The day before yesterday I went to the shop and picked up the R1. The mileage was 43,530 km.

I disassembled it to look inside. The inside was covered with black liquid. There was a broken piece of magnet.







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Pipe cloth hanger




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Convert a JPEG image to STL file

Start the Inkscape (0.92)

Select [File > Open] menu

Choose a JPEG image file and click.

On the pop-up window, choose the following values:

Image Import Type: Embed

Image DPI: From file

Image Rendering Mode: None

After the image is loaded, choose [Path > Trace Bitmap] menu

On the pop-up window, set Threshold to 0.5. Then press OK.

It will create a black trace on top of the image.

Select the black trace and choose [File > Save as] menu.

Type the file name, choose OpenSCAD DXF Output in the drop-down list.

Copy the dxf file to an OpenSCAD’s working directory.

Create a SCAD file and use linear_extrude() to load the DXF file.

linear_extrude(height = 3, center = true, convexity = 10)
import(file = "cloud3-logo-test.dxf");

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E3D Volcano hotend Slic3r settings

3D Printer: Original Prusa i3 MK2

Volcano nozzle: 0.8 mm

Slic3r:  Prusa Edition 1.39.1

To get the desired printing quality, I’ve played different settings of Slic3r.  The key of quality printing for Volcano hotend is to reduce the printing speed below 20 mm/s. Any value over 20 mm/s produces poor quality of printing. Retraction settings hardly makes any different.

Speed for print moves (mm/s)

Perimeters: 20
Small perimeters: 15
External perimeters: 50%
Infill: 30
Solid infill: 20
Top solid infill: 15
Support material: 30
Support material interface: 100%
Bridges: 40
Gap fill: 20

Speed for non-print moves
Travel: 130

First layer speed: 30

Acceleration control (advanced)
Perimeters: 0
Infill: 0
Bridge: 0
First layer: 0
Default: 0


Extrusion width (mm)
Default extrusion width: 0.9
First layer: 0.84
Perimeters: 0.9
External perimeters: 0.9
Infill: 1
Solid infill: 1
Top solid infill: 1
Support material: 0

Infill/perimeter overlap: 25%

Bridge flow ratio: 0.8



Filament: ABS
Temperature:  255 C degree
Printing speed:  20 mm/s
Retraction length: 1 mm



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This is why I ride a sportbike.

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Wear earplugs for motorcycle riding

Source: https://www.osha.gov/SLTC/noisehearingconservation/index.html#loud

Noise is measured in units of sound pressure levels called decibels, named after Alexander Graham Bell, using A-weighted sound levels (dBA). The A-weighted sound levels closely match the perception of loudness by the human ear. Decibels are measured on a logarithmic scale which means that a small change in the number of decibels results in a huge change in the amount of noise and the potential damage to a person’s hearing.

OSHA sets legal limits on noise exposure in the workplace. These limits are based on a worker’s time weighted average over an 8 hour day. With noise, OSHA’s permissible exposure limit (PEL) is 90 dBA for all workers for an 8 hour day. The OSHA standard uses a 5 dBA exchange rate. This means that when the noise level is increased by 5 dBA, the amount of time a person can be exposed to a certain noise level to receive the same dose is cut in half.

The National Institute for Occupational Safety and Health (NIOSH) has recommended that all worker exposures to noise should be controlled below a level equivalent to 85 dBA for eight hours to minimize occupational noise induced hearing loss. NIOSH has found that significant noise-induced hearing loss occurs at the exposure levels equivalent to the OSHA PEL based on updated information obtained from literature reviews. NIOSH also recommends a 3 dBA exchange rate so that every increase by 3 dBA doubles the amount of the noise and halves the recommended amount of exposure time.

Here’s an example: OSHA allows 8 hours of exposure to 90 dBA but only 2 hours of exposure to 100 dBA sound levels. NIOSH would recommend limiting the 8 hour exposure to less than 85 dBA. At 100 dBA, NIOSH recommends less than 15 minutes of exposure per day.


In 1981, OSHA implemented new requirements to protect all workers in general industry (e.g. the manufacturing and the service sectors) for employers to implement a Hearing Conservation Program where workers are exposed to a time weighted average noise level of 85 dBA or higher over an 8 hour work shift. Hearing Conservation Programs require employers to measure noise levels, provide free annual hearing exams and free hearing protection, provide training, and conduct evaluations of the adequacy of the hearing protectors in use unless changes to tools, equipment and schedules are made so that they are less noisy and worker exposure to noise is less than the 85 dBA.

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Remote key battery replacement of 2007 Honda Civic

It requires a small Philips driver to loose one screw.

The battery is CR1616 3V.

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