Hi All,
I was supposed to be at Le Mans this last weekend, however we got pushed out. I did try and get a place from the VMA (a different series), but I was too late, so we decided not to go. Next race will be at Ledenon (home circuit) on the 10th 11th September.
Whilst I was preparing the 350 for Le Mans, I thought I would investigate a rather oily mess in front of the cylinders, this turned out to be leaky power valves because the retaining clips were both broken. This is seemingly a re-occurring problem as it has happened before. It allows the valves to float back and forth, and leak mixture out between the pipes. I have found a guy that makes stainless reataining clips (RDLCCRAZY.co.uk) so they will be going in soon. While I was there I also noticed some play between the rotation of the two power valves, about 20 degress difference betwen the valves. This is more serious as it means that the driving power valve (the left one) would open 20 degrees sooner than the right hand side one. Doh... I thought it was a little down on power the last time out!
This turned out to be a broken bushing in the outside cover on the right side. I can only guess that at some point in time, due to the valve moving about, the bushing got stuck, and eventually broke into 3 pieces, it also wore the joining piece between the cylinders, again I assume because it must have been jamming. I have a new (second hand) cover on it's way, plus a new joining piece.
So the 350 will be better than new in a couple of weeks.
On the RG, I want to up the pilot jet size. A guy on the gamma list assures me that for a tuned engine bigger pilot jets make a big difference - we'll see. Plus I need to investigate the clutch noises.... I also want to attach up the carb trunks to the old air box again, I am not really satisfied with the carbs sucking their air from behind the radiator (hot air), and I think I may get cooler air from the original air box, without the filter of course! Again something to try.
I am planning to do a track day to test out both bikes in August (around the 14th).
Speak to you soon.
Tuesday, 26 July 2011
Tuesday, 5 July 2011
A photo from Magny-Cours plus oin-board video
The video below, was from a GSXR with on-board camera, you don't see me, but who cares anyway !
Wednesday, 22 June 2011
Monday, 20 June 2011
Magny Cours Race Report
Arrived at Magny Cours Friday morning, before the first free practise at 10:45. The weather was pretty dodgy with thick clouds seperated with sunny intervals, and a westerly wind blowing across the pits, so I only bought one practise session in the morning as the second practise for my category was at the end of the day.
The bike was still feeling fairly flat, with not much below 7.5K, although significant punch after. Magny Cours has 3 sets of chicanes which can be taken progressively faster as you get used to the speed of the circuit. The slowest chicane is at the "complex du Lycee" leading onto the start/finish straight and this area is often the place for last minute overtakes with interesting results as the kerbs are quite high at this area. I really like the "grande Courbe" followed by "Estoril" where, from the start finish straight you can take as much speed as you can handle into Grande Courbe and then flip over to your right hand to take "Estoril" as fast as your balls (and your rear tyre grip) will allow. I love that sensation of full out leaning whilst travelling at a fast pace. Just to add some spice there is a bump in the middle of "Estoril" which I use as a marker for full throttle, but it can de-stabalise the bike a little, which drifts the bike out towards the edge of the track - this happened to me a couple of times, but luckily the painted areas were quite grippy in the dry at least.
The bike ran well in the first session and my times started to come down to last years pace.
Cleaned off the bike during the afternoon, as there is a bit of petroil mix coming from some where which is liberally covering the engine - I am not sure if it is coming from the carb area or unburnt mixture from leaky exhaust manifolds. I also changed my rear sprocket to a 39 tooth (up from 38), as I was only really using 6th at the very end of the long straight.
As the weather stayed clement I bought a second session at the end of the day, which went pretty well again, and I finished the session by a plug chop cutting the ignition at the end of the last lap and rolling back into the pits - Libby pushed me downhill back to our installation. The plugs looked a bit light (difficult to tell with SP98) but hey, I thought it was worth jetting up a little, especially as the weather forecast for Saturday was cooler, I just managed to finish the left side carbs (going up to 240 rear and 230 front), and the heavens opened, and we had to get the bike under cover to finish the right hand side carbs.
We had dinner with the bikes sharing our space under the tent, and keeping our feet off the ground as the water poured through the car park.
Saturday morning we had timed practise, and we awoke to rain on the windows of our bedroom (the van windscreen!). Cold and wet - typical English conditions - all the French guys think I should go well in the wet, but I hate it, plus I don't have any wet tyres..... Anyway the weather cleared a little for our session, and with a strong wind the track was dry, I managed a 2:09 in timed practise which put me in the middle of the grid. The grid is full as Magny-Cours is a popular circuit, so there were over 50 bikes in practise with 44 taking place on the final grid. Jetting up had made a considerable difference to the bike, it was fuller as it came on pipe and it reved out cleaner, so that was a good move.
The rest of the day, alternated between rain and sun, with the track drying out occasionally. Sunday forecast was for cloud and sun but no rain!
Race 1
I got an OK start from the 7th line, but with a long straight before the first bend I still had the big four strokes coming past on all sides, after the first time around "Estoril" and then the long straight towards "Adelaide" spread out the pack and I found myself fighting with a Kawa ZXR750 and a GSXR, where they definately had me on the longer straights, but I could make up time with higher corner speeds and more bottle on the fast bends. Eventually the Kawa got the better of me, and he was off, and then I spent the final laps battling it out with No. 71, finally getting past him under braking at the "Chateau d'Eau", fully expecting him to come straight back past under acceleration, but he waited until the right hand, right angle bend at the "lycee" to try and out brake me, he came past really too late, and over shot his bend, and I tucked in inside and got back past him, and then the final chicane on the straight, with the flag 100 metres further up, I managed to stay in front! Good race. My best lap was a 2:08 on the second to last lap! The race was won by an 851 Ducati with a best time of 1:54 - phew....
Race 2
I got a really crap start, the bike bogged a little, and I got stuck behind a slower guy at "Estoril", I got past a load of guys at the next few bends, and basically at the end of the lap I was back behind No. 71again! Fortunately I was on a roll and managed to take him almost immediately, and make my way to the next group, I was really pulling out all the stops to reach the guy in front, and I managed to put in a best lap of 2:05.7, so I was pushing my limit, however despite him making a few errors I was never in a position to get past. I did however find some areas where I improved my speed a lot, and there are still some seconds to come off my time! I finished 23rd - a fair way down, but I had a good time!
Thanks to my pit crew (Libby) for her support during the weekend!
The bike was still feeling fairly flat, with not much below 7.5K, although significant punch after. Magny Cours has 3 sets of chicanes which can be taken progressively faster as you get used to the speed of the circuit. The slowest chicane is at the "complex du Lycee" leading onto the start/finish straight and this area is often the place for last minute overtakes with interesting results as the kerbs are quite high at this area. I really like the "grande Courbe" followed by "Estoril" where, from the start finish straight you can take as much speed as you can handle into Grande Courbe and then flip over to your right hand to take "Estoril" as fast as your balls (and your rear tyre grip) will allow. I love that sensation of full out leaning whilst travelling at a fast pace. Just to add some spice there is a bump in the middle of "Estoril" which I use as a marker for full throttle, but it can de-stabalise the bike a little, which drifts the bike out towards the edge of the track - this happened to me a couple of times, but luckily the painted areas were quite grippy in the dry at least.
The bike ran well in the first session and my times started to come down to last years pace.
Cleaned off the bike during the afternoon, as there is a bit of petroil mix coming from some where which is liberally covering the engine - I am not sure if it is coming from the carb area or unburnt mixture from leaky exhaust manifolds. I also changed my rear sprocket to a 39 tooth (up from 38), as I was only really using 6th at the very end of the long straight.
As the weather stayed clement I bought a second session at the end of the day, which went pretty well again, and I finished the session by a plug chop cutting the ignition at the end of the last lap and rolling back into the pits - Libby pushed me downhill back to our installation. The plugs looked a bit light (difficult to tell with SP98) but hey, I thought it was worth jetting up a little, especially as the weather forecast for Saturday was cooler, I just managed to finish the left side carbs (going up to 240 rear and 230 front), and the heavens opened, and we had to get the bike under cover to finish the right hand side carbs.
We had dinner with the bikes sharing our space under the tent, and keeping our feet off the ground as the water poured through the car park.
Saturday morning we had timed practise, and we awoke to rain on the windows of our bedroom (the van windscreen!). Cold and wet - typical English conditions - all the French guys think I should go well in the wet, but I hate it, plus I don't have any wet tyres..... Anyway the weather cleared a little for our session, and with a strong wind the track was dry, I managed a 2:09 in timed practise which put me in the middle of the grid. The grid is full as Magny-Cours is a popular circuit, so there were over 50 bikes in practise with 44 taking place on the final grid. Jetting up had made a considerable difference to the bike, it was fuller as it came on pipe and it reved out cleaner, so that was a good move.
The rest of the day, alternated between rain and sun, with the track drying out occasionally. Sunday forecast was for cloud and sun but no rain!
Race 1
I got an OK start from the 7th line, but with a long straight before the first bend I still had the big four strokes coming past on all sides, after the first time around "Estoril" and then the long straight towards "Adelaide" spread out the pack and I found myself fighting with a Kawa ZXR750 and a GSXR, where they definately had me on the longer straights, but I could make up time with higher corner speeds and more bottle on the fast bends. Eventually the Kawa got the better of me, and he was off, and then I spent the final laps battling it out with No. 71, finally getting past him under braking at the "Chateau d'Eau", fully expecting him to come straight back past under acceleration, but he waited until the right hand, right angle bend at the "lycee" to try and out brake me, he came past really too late, and over shot his bend, and I tucked in inside and got back past him, and then the final chicane on the straight, with the flag 100 metres further up, I managed to stay in front! Good race. My best lap was a 2:08 on the second to last lap! The race was won by an 851 Ducati with a best time of 1:54 - phew....
Race 2
I got a really crap start, the bike bogged a little, and I got stuck behind a slower guy at "Estoril", I got past a load of guys at the next few bends, and basically at the end of the lap I was back behind No. 71again! Fortunately I was on a roll and managed to take him almost immediately, and make my way to the next group, I was really pulling out all the stops to reach the guy in front, and I managed to put in a best lap of 2:05.7, so I was pushing my limit, however despite him making a few errors I was never in a position to get past. I did however find some areas where I improved my speed a lot, and there are still some seconds to come off my time! I finished 23rd - a fair way down, but I had a good time!
Thanks to my pit crew (Libby) for her support during the weekend!
Wednesday, 15 June 2011
Technical Update
Hi All,
A very quick update before the Magny Cours weekend. One of the listers on the RG 500 mailing list had a problem with his exhaust valves not opening correctly due to a missing gasket on the exhaust valve external cover, and I had omitted one of the gasket's on mine last time I took the cylinders off. Unfortunately you need to remove the cylinder or unbolt the engine mounts to take the forward exhaust valve cover (actually the bit under the cover) off. Instead of doing this, I just made up a gasket out of an old coffee box, and split it with scissors, you can actually loosen the cover, and then slide the gasket in position without doing all the rest....
We will see if it leaks!
I also changed the rear sprocket to a 39 to give me some more speed as Magny cours is much faster than Croix-en-Ternois. I also rebalanced my carbs as the cables seemed a little loose on number one cylinder. I will be travelling up on Thursday evening to participate in the Friday morning practise.
Bad news for Pau and Le Mans. I have had to cancel going to Pau on the July 9/10th weekend due to house moving, and unfortunately ProClassic have been kicked out of Le Mans on the 23/24 th July. I am trying to reserve a spot in the VMA races (at Le Mans) for the same weekend, otherwise no racing until September!!!
Speak after the weekend.
A very quick update before the Magny Cours weekend. One of the listers on the RG 500 mailing list had a problem with his exhaust valves not opening correctly due to a missing gasket on the exhaust valve external cover, and I had omitted one of the gasket's on mine last time I took the cylinders off. Unfortunately you need to remove the cylinder or unbolt the engine mounts to take the forward exhaust valve cover (actually the bit under the cover) off. Instead of doing this, I just made up a gasket out of an old coffee box, and split it with scissors, you can actually loosen the cover, and then slide the gasket in position without doing all the rest....
We will see if it leaks!
I also changed the rear sprocket to a 39 to give me some more speed as Magny cours is much faster than Croix-en-Ternois. I also rebalanced my carbs as the cables seemed a little loose on number one cylinder. I will be travelling up on Thursday evening to participate in the Friday morning practise.
Bad news for Pau and Le Mans. I have had to cancel going to Pau on the July 9/10th weekend due to house moving, and unfortunately ProClassic have been kicked out of Le Mans on the 23/24 th July. I am trying to reserve a spot in the VMA races (at Le Mans) for the same weekend, otherwise no racing until September!!!
Speak after the weekend.
Monday, 16 May 2011
Technical Update
This weekend I set about measuring as accurately as possible the squish clearance of my cylinders, and I learnt some stuff in the process.
I started out using 2mm diameter solder which I bent into "L" shapes with roughly the radius of a piston, I then inserted the solder into the combustion chamber via the spark plug hole, and trying to get the solder pointing along the gudgeon pin axis, and touching the cylinder wall, you turn the engine over and the piston squashes the solder. In principle you remove the solder and measure your squish clearance. You then do it again in the same cylinder but on the opposite side of the piston, and then you have two readings which you add together and take an average.
The problem of this approach is that you can not be sure that your solder is really at the edge of the piston, and therefore it is not as accurate as hoped (good for a quick check though!).
A more accurate method, is to remove the cylinder head, and then "stick" some solder along the axis of the gudgeon pin with some grease, ensuring that as you move the piston the solder is not moved by any ports, once you are convinced that the solder will not move, you position the pistons some where in the middle of their travel ie. not at TDC or BDC, then you replace the cylinder head, and torque it down, and then using the kick start you turn the engine until both pistons have come to TDC (one after the other) and squashed the solder, if you have put too much grease to hold the solder in place, the solder may stick to the cylinder head, so care should be taken to only do one revolution of the engine - no more as the solder will have moved, and the results will be spoilt. You then remove the cylinder head, and remove the solder, and measure the squish clearance. Repeat for the other cylinders!
This method proved far more accurate although the next challenge is where to measure the thickness of your solder! When the solder is pushed up against the cylinder wall, and then squashed, the very tip of the solder is not squashed, because it is in the clearance gap between the piston and cylinder wall, so you end up will a small ridge of solder at the very tip, which should you measure here, will give incorrect results. You need to measure just behind this ridge at the very smallest width - I have tried to represent this in the following diagram.
The problem of this approach is that you can not be sure that your solder is really at the edge of the piston, and therefore it is not as accurate as hoped (good for a quick check though!).
A more accurate method, is to remove the cylinder head, and then "stick" some solder along the axis of the gudgeon pin with some grease, ensuring that as you move the piston the solder is not moved by any ports, once you are convinced that the solder will not move, you position the pistons some where in the middle of their travel ie. not at TDC or BDC, then you replace the cylinder head, and torque it down, and then using the kick start you turn the engine until both pistons have come to TDC (one after the other) and squashed the solder, if you have put too much grease to hold the solder in place, the solder may stick to the cylinder head, so care should be taken to only do one revolution of the engine - no more as the solder will have moved, and the results will be spoilt. You then remove the cylinder head, and remove the solder, and measure the squish clearance. Repeat for the other cylinders!
This method proved far more accurate although the next challenge is where to measure the thickness of your solder! When the solder is pushed up against the cylinder wall, and then squashed, the very tip of the solder is not squashed, because it is in the clearance gap between the piston and cylinder wall, so you end up will a small ridge of solder at the very tip, which should you measure here, will give incorrect results. You need to measure just behind this ridge at the very smallest width - I have tried to represent this in the following diagram.
Of course the other problem is the width of your vernier caliper, which induces some error in the measurement although mine has a quite sharp edge which I used to insert just after the ridge of solder.
On a 125cc cylinder the squish clearance is given as an optimum of 0.8mm, mine were all measuring around 0.78 or 0.75 mms, which is just about within tolerance. So I will not be changing them, which is somewhat of a disappointment, as it means there is no additional power to be had there!
Monday, 9 May 2011
Circuit Elevation for Jetting
Le Mans 70m
C-en-T 122m
Magny Cours 222m
Nogaro 96m
Pau-Arnos 202m
Le Vigeant 160m
Carole 73m
Ledenon 175-201m
Dijon Prenois 483m
Pommiers 589m
Grand Vivier 784m
minus 305m should equal an increase in main jet of 5 points
minus 609m should equal an increase in main jet of 10 points (for Mikuni 042 jets)
And of course assuming constant temperature and humidity.
C-en-T 122m
Magny Cours 222m
Nogaro 96m
Pau-Arnos 202m
Le Vigeant 160m
Carole 73m
Ledenon 175-201m
Dijon Prenois 483m
Pommiers 589m
Grand Vivier 784m
minus 305m should equal an increase in main jet of 5 points
minus 609m should equal an increase in main jet of 10 points (for Mikuni 042 jets)
And of course assuming constant temperature and humidity.
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