Variator Weights and CVT issues - Part II

This is an update of this post: 1986 Yamaha XC125 Riva - Variator Weights and CVT issues

So I took everything apart and found this: 

Notice the tear in the rubber: no good. Essentially, the primary sheave housing, which incorporates the weights I was hoping to replace, had burst at the seams. Taking it apart revealed that a few plastic sliders, which allow a plate to be pushed in and out by the weights inside the assembly, had burst into little pieces and torn the rubber seal. The seal is there because there is an unusually large amount of grease housed inside the sheave. Apparently, Yamaha is the only manufacturer that uses this type of 'wet' assembly, where all other manufacturers use a dry assembly.

Kahuna Powersports has recently decided to no longer be a Yamaha dealer, and so my neighbourhood parts supplier had suddenly become Snowcity Cycle Marine, which is much further away from me. Either way, I ordered my sliders from them, and the primary sheave cap was ordered from a kind gentleman (peteyb5) off of the Riva Riders forums. It was serendipitous, because we had been communicating regarding other parts, and he had listed off a few things that he had in stock, but I had no use for at the time. The light bulb went off in my head when I saw the torn sheave cap, and surely enough, he had mentioned that very part. He was kind of enough to sell and ship to me from the States at a considerable discount.

The grease that is packed into the sheave is something from Yamaha, known as Ultramatic grease. No one knows exactly what it is, but most people have good luck with other high-temp, waterproof greases. I opted for the Lucas X-tra Heavy Duty Grease, which met those requirements, for repacking.

I also received the Dayco 8231K belt, that I had measured out to be a particularly good fit my the Riva XC125 application.

I'm happy to say, that after receiving all the necessary parts, I've reassembled the scoot's variator with new weights, grease and cap, and then installed the new belt. The scooter is on its 350th kilometer right now with the new setup, and it's running great.

In all honesty, the top speed still isn't what it used to be, and I'll chock it up to engine wear at this point. When I have more leisure time on my hands (not to mention more disposable income), I'll keep the scoot alive by boring out the cylinder head and purchasing the OEM oversize piston and piston ring set. That'll liven everything up.

At this point, keeping the Riva alive has become a hobby on its own, and it's no longer about the necessity of transport. I want to keep her going, maybe to one day give it to my little sister.
Tuesday, July 16, 2013
Posted by Konstantine

crockTweet now also controls my 'Flower Pot Smoker' project.

A few posts ago, I described my attempt at building a PID controller for my Crock Pot to try my hand at Sous Vide cooking. It worked great, and in the process I made a PID controller that is an entirely separate unit and thus amenable to any later projects.

There's this excellent smoker on the market called the Big Green Egg, which is as expense as it is awesome. Its expense is enough for me to seek an alternative, which I found in Alton Brown's flower pot smoker, and some detailed instructions provided by another blogger. Two large 16" pots, a single burner and a day later I came up with this:

Single Salton portable burner, which I modified by
removing the hotplate and dremelling the outer perimeter
to fit the base of the pot.

The burner itself then fit nicely into the base of
the pot, which itself was seated into the burner's base.
A single bolt which held the burner in place was extended
to hold the whole thing together.

Here are the holes I measured out and drilled in the pot to
accommodate the burner's leads. The entire assembly is otherwise
in tact and plugs directly into my crockTweet PID box,
seen here on the right.

Here is the whole thing assembled. The temperature
probe is inserted at the top, and measures the dome temperature.
crockTweet PID regulates the whole setup to reach and
maintain my preset temperature for the duration of the
time I set it for.

Smoked sausages!

Whole chicken before.

Whole smoked chicken after.
Great success! The PID parameters needed to be tuned slightly to accommodate the new enclosure. Otherwise, everything was plug and play.
Friday, June 28, 2013
Posted by Konstantine

1986 Yamaha XC125 Riva - Variator Weights and CVT issues

So the little green scooter is starting to show its age. It's nearing 30 years old with ~35,000km on the road: a critical mileage where a lot of parts need to be attended to. I've noticed that although my acceleration has been steady, the top speed of my scoot has decreased drastically. In previous years, I was able to get up to 95kmph, but now I'm happy to see the speedometer creep past 79kmph.

A little research has shown that there are typically two culprits for this type of issue. Aside from regular engine wear, the scooter's continuously variable transmission has a few parts that require replacement to improve performance. A lot of how this nifty transmission system works can be found at this excellent forum post: "CVT Principles - How it works, how to improve it.

Essentially the belt and variator weights need to be replaced. The principles of how they operate can be seen here:

As the weights wear and are no longer their appropriate weight, they can't push the clutch housing to its highest position, therefore preventing the belt from reaching its highest gear and reaching its top speed. The belt itself is also worn enough that it can no longer achieve this.

Easy enough, replace the belt and the weights and we're all set, right? Except that the scooter is almost 30 years old. And as you can see on the Riva Riders Yahoo Group, there's a lot of discussion about the dwindling state of parts available for these great machines.

The weights in the XC125 from '86 to '01 measure 18x12mm and weigh 9.5grams. I found suitable aftermarket replacement at Chinese Motorcycle Parts Online (part RW147) where they carry 18x12mm 9gram weights. Slightly lighter weights will still sacrifice top speed for acceleration, but these will still substantially improve my top speed over the worn out weights I currently use. The weights are shipped from the UK, and I received them here in Canada within a week of ordering them. 

A little bit of quality control shows that the weights are manufactured quite well, and they should fit the bill nicely. We would expect 6 x 9gram weights to weigh in at 54 grams. I used a sensitive scale and indeed: six of them weighed in at 54.0670 grams. The height tended to be slightly larger than 12mm and the width slightly less than 18mm, but we're talking 10ths of a mm here: not an issue.

The belt that I need to replace is a Yamaha part number 50W-17641-00-00. The OEM belts are available, but retail for $150 here in Canada from Yamaha dealers. Too much for a simple v-belt. There is an aftermarket supply for these belts through the Gates Worldwide, a belt manufacturer. They run the Gates' Boost Belt Programme which lists part number 9802-21205 as the direct replacement for the Yamaha part number. It costs 20 Euro (~30CAD)! Gates hasn't been helpful when I called and emailed them numerous times to obtain more information and see if I can order it from them. I found a dealer in Madrid, Spain, who has been trying to sell me the belt, but requires me to wire him the money, something that costs as much as the shipping and part together. Other options are being pursued.

The other issue is that there are not standard belt measurements available for this part. Most of the measurements are hearsay and unconfirmed. The other issue is that aftermarket manufacturers who list sizes (length, width and angle of belt) tend to list these figures in a non-standardized way. It's not conducive to finding an appropriate replacement. The hearsay numbers for the Yamaha OEM belt floating around are that it is 940mmx19mmx9.5mm with a 28 degree V. Again, this is unconfirmed. Dayco in Australia produces belts that are of a similar size (part 8231K), but it is unknown if this actually fits, as it does not cross-reference with the Yamaha part number, but instead is listed for a SYM HD200. Dayco has been kind enough to offer sending me a sample so I may test it out. We'll see what happens.

Updates to come!
Friday, June 21, 2013
Posted by Konstantine

@crockTweet: Programmable Arduino-Powered PID Sous Vide Slow Cooker

I purchased a very simple slow cooker ($20 at duty free!) a few months ago, which has four settings: High, Low, Keep Warm, and Off.

Most dishes prepared in the slow cooker will cook from 4-8 hours, depending on the setting used. There are a few issues though:
  1. There is no true control of the cooking temperature. 
  2. There is no automated way to switch from one setting to another (e.g. 8-hours of cooking on 'High' followed by 3-hours of 'Keep Warm').
A simple timer attached to the cooker's power plug would allow me to control the total cooking time, but not switch to a new setting, nor would it allow me to precisely control the temperature.

Some more advanced models of slow cookers allow for automated switching of settings, but have no way of notifying me of these things. 

Enter Arduino: an electronics prototyping system that allows the user to interface with the real world through sensors and react to this information based on scenarios coded onto the board through a programming interface.

In the case of the slow cooker, I wanted to use the Arduino to allow me to:
  1. Detect and control the temperature inside the slow cooker based on preset values.
  2. Control the amount of time the slow cooker spends at a selected temperature.
  3. Allow for a multi-step cooking (e.g. 8-hours of cooking on 'High', 4-hours of 'Low', 2-hours of 'Keep Warm').
  4. Tweet the progress (e.g. When the a new process starts or finishes).
I made a quick video of my progress as of last week:

I just finished coding everything, and I theoretically have the ability to do everything I want, except for Tweeting (still waiting for the network interface to arrive in the mail). The nice thing is that this system will work with any slow cooker, as it required no modification of the slow-cooker itself. I will be controlling its on/off state through a solid-state relay controlled by the Arduino, thereby controlling its temperature.

I will be testing everything out tomorrow morning.

Here's my Arduino code:

There is still tuning of the PID parameters to do once I hook everything up, but once that's done, I will post more.

Currently the list of items required for the project (aside from the slow cooker):
  • Arduino UNO Board
  • LCD 20x2 Display
  • DS18B20 Temperature Sensor
  • 20K POT
  • SPST Buttons
  • Breadboard
  • Assorted Resistors
  • Assorted Wires
Stay tuned!

Stuff to read about:
Friday, January 25, 2013
Posted by Konstantine

Letter of Intent for Master of Science in Cell Biology

I thought I would do a favour for any prospective graduate students who are looking for a guiding hand in writing their letter of intent, also known as a statement of interest. This letter got me into the graduate program of my dreams at a top university and a lot of effort was put into crafting it.
This is not a generic letter, and likely not one that will be easily adapted to your own case. It is very specific to my own program and background and, in the end, yours should be too.
It is with great pleasure that I submit my application for a position as a master’s student with the Department of [personal detail] at the University of [personal detail]. Having completed my undergraduate degree in honours biological sciences at the University of [personal detail], I now seek to gain a more thorough understanding of the skills and knowledge necessary to be successful in a research-oriented environment. Through my continued work with Dr. [personal detail], I am convinced that his guidance and support will ensure that I achieve these pursuits.
Graduate school became an earnest consideration after upper-level undergraduate courses ignited my curiosity in the dynamic area of systems biology. The appeal was born out of the discipline’s emphasis on integration of different scientific fields, with the express goal of understanding biological systems as more than the sum of individual parts. My undergraduate education has exposed me to the reductionist and static approach of understanding biological elements and processes; I now wish to understand how these parts work in concert as elements of a greater system.
I am primarily interested in applying the methods and techniques of biophysics and genetics to elucidate the relationship between sensory behavioural phenotype and genotype. My previous volunteer experience with the maintenance of Caenorhabditis stocks has shown me first-hand that these deceptively simple organisms have complex behavioural characteristics. My current work as a research assistant at Dr. [personal detail]'s laboratory involves the analysis of these behaviours through novel methods devised in-house at the instrumentation, imaging and analysis level. I have combined two passions in one place in this environment: my love of the study of nature at the biological level, and the innate inclination I have toward the technical. This research aims, generally, to answer questions about what it is, genetically and neurobiologically, that makes animals move and behave the way they do. This research is engaging, challenging and fulfilling to a degree previously unknown to me. I feel there is a great wealth of knowledge to be obtained from this fusion of technology and biology, and wish to be a part of the research that centers about it under the supervision of Dr. [personal detail].
Apart from my experiences at the [personal detail] Lab, my recent role as a lab technician at the University of [personal detail]'s [personal detail] Lab has underscored the versatility of the skills I have acquired thus far, and my propensity for acquiring new ones. In the [personal detail] Lab, I was responsible for the continued organization, recovery and systematic freezing of a large backlog of nematode strains, and for the optimization and troubleshooting of procedures associated with automated robotic equipment. These skills earned me the reference to Dr. [personal detail], who has since hired me. Additionally, my experience as a research assistant at the [personal detail], which involved using degraded DNA to construct phylogenetic trees of a model organism, made clear that my patience, tenacity and initiative are an excellent fit in the lab environment. I have also conducted research completely of my own design, at the organism level, by studying the behavioural effects of varying auditory stimuli on the Passer domesticus species. The stimuli were studied as they related to the birds’ feeding habits, with the guidance and final commendation of the ornithology department head, Dr. [personal detail]. These experiences, coupled with the upper-level courses I have taken, ultimately convinced me of my desire to pursue graduate studies to fulfill my interests in conducting novel research.
Having now worked alongside graduate students in several laboratories, I am aware of the heavy workload and demanding schedule that graduate studies entail. As an undergraduate, I worked a job 25 hours a week while studying full time for my BSc degree, which has taught me the art of prioritizing my time; a skill that will no doubt help me face the rigours of graduate school. The reasoning abilities I have developed through my coursework—in particular the ability to think logically and critically fostered by my minor in philosophy—will also be an asset.
I am convinced that the University of [personal detail] is the most appropriate venue for my studies, and that I can rise to meet the challenges that this will involve. I appreciate your consideration of my application, and I look forward to hearing back from you.

Best regards,
Konstantine Palanski
Friday, June 24, 2011
Posted by Konstantine

Scooter Adventure — Part II


I'm alive! My GPS is to thank, along with my perseverance and notably hardened buttocks. To keep you guys from an onset of ennui, I'll limit this post to little detail.

The entire trip, as per GPS, took 780km to complete. Here is a quick break down of expenses and mileage:
  • Gas: $25.14
  • Food and beverages: $68.57
  • Entertainment: $24.87
  • Lodging: $101.92
  • Mileage: 3.03L per 100km
Roughly, this is the route I took:

View Larger Map

The path I took deviated substantially from my initial plans, mostly due to the fact that was I making such incredible time. Arrival and two hours worth of hiking at Rondeau Provincial Park spurred me to continue on my journey and find a better place to set up camp for the day. I was fortunate enough to end up in Long Point Provincial, which has to be among the top three parks I have visited in Ontario. Here's my beachfront camping site. I was in heaven.


An immense amount of pride went through me when I finally arrived in Toronto. The fact that the scooter performed without so much as a hiccup was the main source of this, since I rebuilt and repaired it myself from a non-running state a few years ago.

On a scooter, no less, I've discovered what the open road feels like.
Monday, July 12, 2010
Posted by Konstantine

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I was born in Poland, raised in Ukraine, identify myself as Russian and now reside in Canada. How's that for an identity crisis?

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