Favorite Shot - V special
The story of a restoration
So the story starts!
Chris Wilson a collector of classic racing motorcycles in the UK came to New Zealand with some of his collection to an event I help organise, MotoFest. We have had celebrity riders over the years from Graeme Crosby, Hugh Anderson, Aaron Slight, Randy Mamola, Steve Parrish, Simon Crafar, Kevin Magee and engineers such as Mike Sinclair Jeremy Burgess, Dick Smart, Bob Toomey to name a few...
So Chris is chatting about a KR3 that he has in his collection....I may have mentioned that I was involved with a few three cylinder projects including the earlier KR3 and the BSL500 in NZ. He mentioned that his KR3 had an "issue" ( I should have run away then!), he mentioned that he had taken it to Tech 3 in France to be "fixed". It returned and the exhaust valve system was not operating (Power Valve). They were unable to help and they had "fixed" the water leaks. He was unsure what to do next. (Again, should have seen the signs then!)
Well my comment was: "It has no chance of ever being worked on if it was not in my shed in New Zealand." If it was, I would probably graft another ECU onto it has the original ECU was an EFI from Italy. EFI would have no interest in assisting nowadays. I really never thought any more of it.
Next minute and thanks to our mate Graeme Crosby... a van turns up with a KR3 in it.. one stand and nothing else!
There you go... have at it!
From here the story begins... now I took lots of photos and videos over the last three years that has just culminated in us running the restored KR3 being ridden up the hill at the Festival of Speed at Goodwood 2022 with non other than the original rider Jeremy McWilliams but also Kenny Roberts who funded and ran the whole string of projects that included the last KR3! A bit surreal for a project from New Zealand!
A few things here:
a) Never underestimate the scale of a project!
b) Never underestimate the state of something old!
c) Caution: (It just needs some electrical work!).. means.. anything is possible.
d) You have to be passionate and slightly mad to take on these projects!
e) You need to love whatever you are working on and its pedigree and history.
Onwards....
PT back in the day - so I guess I am qualified to take this project on!
I seem to have been inside two strokes for a long time.. this was actually the first chassis to have an adjustable swing arm pivot a PT and Sinclair special
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Initial work on sorting out when it goes "Bang"
And so the saga starts!
So first things first...how do spin the engine over on the stand so I could work out the firing timing? Roll up.. grandad's scooter...classic starter that has performed admirably for the whole project!
Now...ECU
Neil Sands a contact of Chris Wilsons in the UK had given the project some thought and we went backwards and forwards (before I knew I was going to end up with the project) and had started grafting a Motec M400 and integrating into the existing wiring loom.
Assisted by a wiring diagram from the exact bike that I managed to obtain from one of my old colleagues.
Odd-fire settings in the Motec world... have to calculate the firing splits... based on the missing tooth trigger.. how many degrees away from the missing tooth on the rising side of the tooth / signal....
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Grandad's scooter... spin the engine...timing light...etc...not exactly factory stuff but needs must..back to basics..
Now Tom O'Kane one of the engineers at Team Roberts now Suzuki MotoGP.. and a Dr in Engineering with a thesis in motorcycle chassis design!.. yep started with us at Team Roberts!... Designed the firing order and balancing calcs for the triple.. there were a few designs but this was brilliant.. had a balance shaft (which I will show you later) but more big bang.. yet able to be balanced.. a very tricky problem that worked beautifully! Well done Tom! I had never seen the finished result but very impressive!
Certainly had my head spinning to get ensure it fired at the right time and based on the numbers below.
More electronics!
All very well to get it to fire at the right time...interesting that Motec have "offsets" and "warm up" timing modes etc.. designed for four strokes that influence the final timing point it actually selects.. had to nut out all the self learning features and turn them all off so I could get to basic firing first.
Exhaust valve servo, power jets, throttle position and gear position inputs:
Once we have a basic ignition map based on engine RPM and per cylinder firing... the engine will start.. supposedly!..
We got it to start after cleaning carbs etc.. no chokes by the way so all a bit lean to start... sounded flat and like the timing was not right... plenty of strobe light and degrees on the trigger plate calculations...
Neils hacks to make the Motec operate were "creative!" Programming the Manifold Pressure sensor input to replicate throttle position sensor.. so had to program the MAP map against RPM to set the timing for the correct RPM against throttle.... messy and hard to keep your head straight around what you are trying to achieve.
Quote from Neil: "I had to be a bit creative as the m400 wont drive the servo valve so I used the drive by wire function to do this. Throttle position is actually put in as the map sensor 0kpa is 0% throttle 100kpa is 100% throttle. I have had to limit some of the break point due to limitations in the software"
I got it all to work but was pretty ugly.. and it didn't drive the exhaust valve into the right positions smoothly well... not at all really..
Got it good enough where I thought we should run it somewhere...so I went up and down the road a few times with no fairing .. yikes.. well dodgy!
By this time I had Ashley, Veggie and Sam on board for the madness so they helped start it hold it... shake their head saying "ummm PT that doesn't sound right!" Great fun!
Ashley!
Sam and Veggie!
Well it ran kind of OK... but not much power a bit flat...and it wouldn't run more than a couple of laps without overheating..and boiling... I should have given up then!
Opening large can of worms comes to mind!
Back in the workshop
So not only was it overheating but it was filling up the crankcases with water!...remember it came to me for an electronics issue!
All of the water galleries had corroded and some nice frenchman had filled them with Devcon... a filler we all used in the day... but so much it blocked the galleries almost completely...
Complete engine strip down to the crankcases.. again should have known better.. I was going to get good at this!
The plot thickens!
Now with the engine in pieces I needed to review the whole project and take a close look at the state of the engine before I could revert back to electronics as this had more issues than an ex wife!
Made a proper engine stand to ensure I could work on this properly..always a good trick!
I noticed that the balancer shaft bearing had also cracked the outer shell.. probably due to incorrect installation as it has a retainer than can easily be positioned incorrectly.. luckily enough I was able to locate a bearing in NZ and was able to fit this onto the balancer shaft.
Had to make a few tools to get the special nuts and tricky crankcase bolts removed and reinserted. there was going to be more of this.
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So I decided to just use a similar material to fill where the crankcases were damaged and grind out the old filler to ensure we had reasonable water flow.. tricky as the cases are complex, made of magnesium and fragile.
Slow and time consuming but has to be done right.
I had zero spares.. no gaskets, o rings.. nothing so I had to be careful.
With the help of Ashley and the team we slowly reassembled the engine..
Devcon is fine but really doesn't last forever especially in water galleries but I wanted to have the engine in a position where it was usable and I could revert back to the electronics.
So I wanted to run the bike somewhere in a controlled manner so I heard about a guy in the Wairarapa who had new motorcycle dyno.. cracking guy Evolved Performance - Hadyn Kennedy..brand new Mainline Eddie Current dyno.
So of course no starter on the dyno so back to granddads scooter!
Wanted to just run it to see if it was not overheating and the engine was running OK. Nice easy runs and no interest in running it hard..
Fun day and all went well so thinking good enough to run it at a track again.
More ECU Fiddling and off to the track.
So I decided to upgrade the ECU to a Motec M800 as the M400 really did not have enough control and enough options around servo control for the Exhaust valve.
More assistance from Neil in the UK as you need to purchase the correct licences from Motec to upgrade and expose parts of the software.
Remembering I needed really good DC Servo control and digital solenoid control for the power jets as well as the throttle position , RPM and gear position mapping.
Oh and a quick shifter if possible. The M800 enable me to have all this control..now all I need to do was get my head around how to program this.
PID Control
Because I wanted the precise control of the exhaust valve as this is really the heart of the performance of a two stroke to give you controllable power basically these bikes are unrideable without precise control. The KR3 had a reputation as one of the nicest engines in the two stroke era so I wanted this control and options.
DC Servo control is all about PID.
From Motec. (They have loads of tutorials etc.. )
What is PID?
PID stands for Proportional, Integral, and Derivative and is a type of feedback control system. It compares a measured value (from a sensor, say) against a desired value (the setpoint or aim) and adjusts outputs to reduce the difference (error) between the two.
The controller (or ECU in our case) uses a constantly updating calculation to control a physical system. It looks at the current value of the error, the integral of the error over a recent time interval, and the current derivative of the error signal to determine not only how much of a correction to apply, but for how long.
Started testing this but had to start the bike each time which was a pain.. -> Grandads scooter and the lads!
So worked out I could map against another input for testing.. so used throttle position 0-5V signal to replicate the RPM... made for a lot easier testing. Hours of fiddling, more reading...understanding PID... really interesting subject btw and used in all control systems. Got it a stage where I had a few options to test.
Off to the track
I thought it was now good enough to ask Aaron Slight the ex World Superbike rider and the most experienced world class rider I know!.. an absolute privilege to have him agree to test the KR3. S
The number one thing was safety.. these bikes are old and fragile so needed to be super careful with preparation. New tyres, warmers etc
Off to Manfield again and this time with my old boss in tow!. Mike Sinclair another legend of our sport so really didn't want to **** this up!
Assemble the team again.. Ashley, Sam and Veggie and off we go.
Mick Ruane from Palmerston North arranged and paid for a garage for us to work in.. very generous!
The open day at the circuit were also generous and gave us time slots etc to run.
Ended up making a pretty major change to the mapping with the M800 at the end of the day (based on some more understanding of Motec systems) and made a significant step forward.. now running well and Aaron very impressed with the handling, nimble and powerful.. phew.. a big relief!
Data recording now working also although had to get my head around all that .. a bit of jetting...power jets I left on as quite concerned about nipping it up in the cool weather.
Successful day!
More track time
We were invited to run the KR3 at Taupo Motorsport park with the New Zealand round of the Superbike Championship. A nice place to give it a run with Aaron and ensure it survives before I return it to the UK.
I am concerned about the crankcase as they are still dribbling..and primarily into number two cylinder. (the one that points downhill!)
I have to leave the spark plug out as it leaks internally....bugger...
We had a fun day and the bike actually ran really well.. Aaron did about ten laps and was getting quicker and quicker...
All of the team couldn't come so it was Veggie and myself with Aaron.
Dyno Land
So along the way I decided to investigate getting a dyno for the workshop.
Years ago I used to spend many days/weeks on a dyno in California with Bud Aksland the engine tuner for Team Roberts.
Bud and Mike in Manteca Ca.. Buds eddie current dyno.. was actually a really good dyno...a lot of work on exhaust valve mapping and ignition mapping with pipes and cylinders (single cylinder slave engine)
Actually looked at an old water brake that was going to be donated by Dallas Rankine.. another road racing enthusiast but they really dont have the control I needed.. looked at all sorts of control systems but rejected the idea in the end..(smart move)
A mate sent me a link to a dyno for sale...never used in NZ.. in parts.. and hardly used in Australia.. Negotiated a deal .. probably paid a little too much for it but it had a very good retarder on it and setup for motorcycles... how hard can it be! Things I do!
Well of course it didn't work....actually.. at all... the load cell was damaged... bought one locally...changed all the fittings etc as the Mustang dyno is American of course!
Controller and power supply was OK.. once I get my head around it... Sam and I spent many days scratching our head..
Stole a PC from the office ... new software from Mustang.. (well not new but old and no info....could not get it to work.... until actually I found that I needed the correct PID values... (havent I been there before??
Dyno Power supply and data acquisition board - old but quite good actually.
The trusty "slave" motorbike while I learnt how to use the dyno.. and fix most of the bits that were either broken or missing!
Ohh.. and like most bike dynos.. no starter.. so I wanted to run the KR3 and other road race bikes.. so better fit a starter..
Actually did the first KR3 runs using Granddads scooter as a starter.. built a timber frame to put it on...
Went up market and the only Chev starter motor we could find was chrome!.. Fully bling!
A bit of wiring, battery and a foot switch... voila!
A few more slave bikes...to get the software a bit better.. and an Air Fuel Sensor interfaced into the software..... oh and an exhaust extractor.. thanks Ashley and Veggie!.. and Sam of course...
Calculations... head scratching... so we can calibrate the dyno readings...actually pretty cool setup..
Then back to the KR3!
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Goodwood
Goodwood Festival of Speed
Lots of other older Links to the side! ->> Such a privilege to be invited to attend. So many thanks to Chris and arranging for the D...
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Chris Wilson a collector of classic racing motorcycles in the UK came to New Zealand with some of his collection to an event I help organise... -
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I seem to have been inside two strokes for a long time.. this was actually the first chassis to have an adjustable swing arm pivot a PT and...