Carbs are in..

Just came back from Skiing and had a great time although really cold up to minus 25 degrees celsius, still the snow was excellent so had a good time. Thought I would try and get on this afternoon (Sunday). I had received some throttle cables for the 350, and I thought I would try and fit the carbs. Well I was still missing 1 cm on the cable length to allow the slides to open fully. I realised that the 45 degree bends actually added 1 cm of length to the outers which was shortening the usable internal cable length.

Replaced the 45 degree ends with the straight ones, and finally the cables fit and will fully open the throttle, but the throttle cable outers actually rub on the frame cross member, so I'll have to see if this affects their operation. The left hand carb rubed a bit on the clutch actuation arm, although a quick bend had it sorted.

So the carbs are now in! Just have to decide if I can bodge an air box or whether I run with nothing (probably the case).

Ignition curves and other updates

Well, life was simple when I didn't have to think about ignition timing! I now have to make the most of my programmable ignition which means I need to understand how it works (or at least copy someone elses who's works well!)

The obvious way to tune in any variable component would be to setup the bike on a dyno, like this you can keep everthing constant, and just change increments at time to see if you get more power, and larger power band etc. However in my area I just haven't managed to find a place knowledgeable in two strokes with a dyno, so this option for the moment is out. That leaves seat of the pants testing, which can be a little subjective to say the least.

Igntion Timing as I understand it!
Ignition timing is important, because the burning of the petrol is not instantaneous and takes a finite time in which to produce high pressure on the piston. This finite time needs to happen precisely at the right time to avoid damaging the piston with excessive pressure either whilst it is still going up or lack of power because the piston is already going down. Ignition timing is normally expressed as either millimetres before TDC (Top Dead Center) or degrees (of rotation of the crankshaft) BTDC. As piston speeds increase the spark needs to happen earlier in order that the burn has time to reach maximum pressure as the piston rises to TDC. Therefore variable ignition timing is key for maximum efficiency of the two stroke engine.

Simple ignition systems have two position for timing, one at slow revs e.g. 15 degrees BTDC and one at high revs e.g. 26 degrees BTDC. With my zeeltronic ignition I can define 10 different engine speeds and equate that to a specific timing. This should enable me to be able to get maximum efficiency at all (at least 10) engine speeds.

On a fourstroke engine, ignition advance can continue in a nearly linear way to provide more and more advance as the revs. get higher, on a two stroke engine that is not the case, as exhaust polluants (unburnt gases) and heat will interact and reduce power, and the accepted theory is for a two stroke timing to RETARD after maximum torque, so you end up with a curve that has slopes on both sides around a pivotal point of maximum torque - almost a bell curve.

Well of course not having a dyno, I do not know where my maximum torque is, and therefore I am going to have to adjust things very carefully. The thing I didn't mention is that IF you advance your timing too much you will initiate detonation and eat pistons - so the price for messing it up is high!

I have taken examples of all the ignition curves I can find and plotted them on a chart to see what my options are, but of course as I have learnt on many occassions it is virtually pointless to base my bike's setup using anyone else's as they are just ALL different.

Randy Norian from the Gamma mailing list has a suggested "seat of the pants" style setup procedure which I will try out:-
"when I went to the dyno, the process was very simple.
I ran it with a standard ignition curve.
then I advanced the whole curve by 4 degrees , everywhere.
Then retarded it by 2 degrees everywhere
then by a total of 4 degrees everywhere.
then compared the power curves, and you knew what worked, and where. I did all dyno runs at exactly the same engine temp and after the same warmup.

So, do that on the street. You will probably find that +4 makes not so much difference in the midrange but pulls real hard in upper mid to top range and probably you will have less over rev.

a few gears won't hurt it at +4. find out where your shift point is - it's probably a little earlier than with OEM timing.
Try stock timing again. you should feel the shift point is a little later, maybe 300- 500 rpm.
So now you know where it likes extra advance, and tapers back to the stock timing.
so make a curve that uses the +4 in there, and pulls back to stock at some point- has to be based on your butt dyno.

Fooling with more retard at the end of the rev range- and this is going to likely be AFTER your normal shift point - that will give you over rev so it doesn't fall so flat on its face after peak power, and on the track will let you get away with avoiding an upshift in places."

Zeeltronic for the RG

I am getting fedup with working on the RD350, just because each time I try to move forward, I need to buy some small part or other, and then I have to wait for it to arrive by the post, and it all seems to be taking too long. This weekends objective was to fit my programmable ignition and power valve to the 500 - hopefully this would be more straightforward, and indeed that's how it turned out.

The ignition unit comes with loads of options e.g. quickshifter, rev. counter, program switch - all these I am not going to use at least initially. When you look at the number of wires coming out of the ignition box, you need first to sort through and tape these back so it looks easier to understand. I had payed Borut the extra Euros to get the connectors already crimped on, so really most of the wiring was just plug and play, however there are a couple of things to do.

You need to connect the green/yellow wires from the ignition box to the powervalve box, these both came with female connectors, but in my case the two boxes are placed next to each other, so would be close enough to plug straight in, this meant removing one of the females and adding a male bullet connector which was supplied in the kit. For some reason, you need to run seperate wires to the coils (on the RG wiring, the same feed is used (blue/white wire). So I decided to use the standard blue/white wire for one coil, and run a new wire for other coil. Unfortunately I didn't have any "good" coloured wire, so I ran in a brown wire all the way from the coil servicing cylinders 2 & 4, the return wire from both coils (white) is common, so was used as was. From the Zeel box, the pink and orange wires provide the low tension feed for the coils, and white is the return. I needed to find 12V from somewhere to power both boxes, the PPV box gets it from the standard connector, whereas the ignition box needs an additional supply, for the moment, I have plugged it into an orange wire on the original loom, which I believe used to supply the rear brake switch, anyway testing the resistance it would seem it should get 12V when powered.

The RG runs a big capacitor (battery eliminator) instead of a battery, for the moment I am not sure if the kickstart will give enough oomph to power the ignition box in order to start the bike, so I will have to try it out, although in order to do that, I need to put some fuel in and to be honest I have just drained the carbs etc... for the winter, so testing will probably wait for the spring. If it doesn't work I will need to use the LiIon battery purchased to replace the one I lost on the 350 in my accident at Croix-en-Ternois.

I have positioned the two boxes towards the rear of the bike, and I have cut a small trap in the undertray so that I can attach the Zeeltronic handheld programmer without having to remove the fairing or seat unit. I will need to make a small cover so that all the crap from the track doesn't get into the connectors!

Pro Classic Calender

Pro Classic 2012:
- 21/22 April - Croix en Ternois
- 2/3 June - Nogaro
- 30 June 1er July - Croix en Ternois (week-end ProClassic)
- 21/22 July - Le Mans
- 4/5 August - Magny-Cours
- 1/2 September - Ledenon

Endurance :
- 5/6 May - Carole
- 30 June and 1st July - Croix en Ternois

Apparently the date at Carole (Paris) is doubtful, as they are in the process of renewing certain parts of the circuit to take into account new owners (the FFM have bought the circuit).

Custom cables for VM34

Well, I've joined the club of the custom cable makers - I can now solder nipple on the end of a cable and it holds! The problem is that I still haven't managed to get my new cables to open the throttles correctly, I can have a fully open throttle with a third open at "idle" or I can have the throttle closed on the idle screw but only seven eighths fully open!

The technique to making a nipple stick, is getting the cable totally grease free, and then feeding on the nipple, and then squashing the end of the cable with pliers, you then push up the nipple until it sits about 0.5 mms from the end, and then after dunking the whole thing in the flux, you heat, and add solder (plumbers stuff not electrical), after a couple of attempts, I got it just about right, but I have given up for the day as I am getting frustrated about getting the actual length right. I have a feeling that my original cable setup is not capable of pulling enough cable to lift the bigger slides, and that I will have to buy another throttle setup.

Anyway it's another skill learnt at least!

I bought the "nipples" on line in a place called: trialbits.co.uk

VMA Preliminary Calender

- 21/22 avril CROIX EN TERNOIS
- 2/3 juin NOGARO
- 1 juillet PAU
- 21/22 juillet LE MANS
- 4/5 août MAGNY-COURS
- 1/2 septembre LEDENON
- 15/16 septembre Haute Saintonge
- 20/21 octobre LE VIGEANT

Not ethis is the VMA calender (not ProClassic), so relevant only for the 350. We'll see after the ProClassic Calender announcement next week, how many of these I can do.

It's Christmas!

Hi All,
Just realised I hadn't posted for some while. The Yam is waiting for me to custom make some cables, I've bought the nipples the gas burner, the solder, it's just really waiting for me to get motivated again. I need to finish fitting the VM34 carbs to the Yam, and also finish the foot rest hanger that I am trying to make out of a plate of ali that was sitting around - not sure it's thick enough really to support my weight, suppose we'll see...

I have orderd a Zeeltronic ignition and power valve controller for the Suzuki, in the hope I can move the hole in my power band around by opening/closing the valves at different times, the programmable ignition should allow me to gain a few horsepower as well, again I will need to test early in the year, in order to get it right.

The snow has arrived, and with Xmas just around the corner, I have other stuff to do, so will start on the bikes again in the new year, still keeping up the Gym, so with a bit of luck, I will keep my weight down, and muscle my upper body - especially the shoulder.

All the best to your families, and have a great Christmas and a happy new year.