Where we are up to with the development of the club racer in 2011.
The VTR foot pegs are now mounted ok, the only downside is they don't fold like the others did but as they are about $60 a side cheaper I think we can live with non folding foot pegs. These rear sets are now all but finished as is the exhaust system, just a few tweaks and some springs fitted to the pipes' slip joints and I will be done. I bought some exhaust springs from JBM Industries in the USA when I got my carburettor diaphragms this week. He sells them for ultralight aircraft.
Bruce Cannon, a new
Geelong member has donated a bunch of
parts. He tells me he has bought
everything on the list below which was
all the parts outstanding on our want
list. As we get into the build we
may need some more parts so keep an eye
on our want
set for 750cc big bore motor (Part #18-0752)
Bernice Jurgeit was so pleased she sold her bike on our website she has made a small donation for our club racer which I will pass on when Dave Rayner gets back. This donation has now been transferred to the club racer account on 23/2/2011.
Went into Geelong today and picked up the donated parts from Bruce Cannon listed above, Bruce reminded me that he is not a member yet but soon will be. Either way thanks Bruce your generous donation is very much appreciated as are all donations to the club racer project.
I have decided that the rear set foot peg brackets are too high and I have designed some others to replace them. To make this easier to do I went to Geelong to buy another band saw blade as the 12mm aluminium sheet I am using to make the brackets is too difficult to cut with the current blade and too damn fiddly to do with a jig saw. I measured the blade and went to a place that makes them to any length and gave them the dimensions and they said come back tomorrow and it will be ready. So yesterday I went in and picked up the new blade. When I came to fit it I discovered it was too short. So back I go to get it fixed and was told it may be ready today and they will call me if it is, needless to say I did not get called so it looks like I will now have to go back again today.
I only mention this to point out that even the simplest of jobs on the club racer can end up taking days instead of hours. After three days and driving 120Km and spending $30 on a band saw blade so far, I still have to make the brackets !!!
Finally after the band saw blade fiasco I cut out the newly designed foot peg mounts for the club racer.
As you can see there is now much more scope for adjustment to suit whoever rides it and once I had the proper tools for the job it only took a couple of hours to do. I only have to make the adjustment rods for the gear shifter and brake now so I can retrieve the ones belonging to the rear sets I bought on Ebay.
Went to Geelong today and bought the rod ends and left hand nuts for the adjustable connector rods for the rear sets. I'm still waiting for the left hand taps to arrive from China to complete the job.
Ivan Hoey sent me these pics of the new engine mounts he has made for the club racer, made from aluminium, they weigh 600 grams less than the stock items. All the bolts have been drilled for safety wiring and the front mount is designed to add strength to the frame with the addition of the tube that clamps between the frame rails much like the Percy Tait modifications done by the Yamaha factory to the post '74 XS frames.
Ivan also tells me that Kevin Boss has been busy removing brackets that are not needed from the racer frame including the rear foot peg mounts, the removal of these has shaved over a kilo from the weight of the frame. Hopefully someone will take some pics of Kev's work and send them to me so I can keep you all updated on the progress.
I received the left hand threaded taps in the post today so now I can complete the rear sets for the club racer.
Gear and brake connector rods are now done and the rear sets have been polished.
Well it's been a bit of an epic but I have finally finished the rear sets for the club racer with the help of Kevin Palmer and Robert Lange Engineering here in Geelong. I just weighed them on our kitchen scales and the total weight is 1.31 kilos for both sides. I didn't weigh the stock brake and gear levers and foot pegs and mounts but I suspect they will weigh a lot more.
The next job is to weld some loops onto the mufflers and pipes to hook the springs which hold the slip joints together. This is a very effective way to hold the muffler on. I will post some pics when it is done so you will see what I mean.
I got some 3mm filler rod from a mate and bent up the anchors for the springs and put them on using hose clamps to make sure they are both functional and good looking. When these are welded on (tomorrow) I will lose the hose clamps.
I would like to go ahead and have the pipes and mufflers HPC or Jet-Hot coated silver like I did on my tracker pipes, but at a couple of hundred dollars I can't afford it at the moment so they will have to wait, unless someone else wants to pay for it? Any takers?
I have arranged to go to Warrnambool in April, to pick up the the engine bits for the club racer.
I was just talking Steve Hobbs and when I mentioned I had finished the rear sets for the club racer, he told me he thought the stud spacing for the foot peg mounts on the early frames was different to the later frames. You guessed it, he was right, so now I will have to remake the rear set mounts because they are different. The early frames i.e. XS1,XS2 & TX have a wider spacing on the foot peg mounting studs of 83mm whereas the later frames have a spacing of 80mm. Oh well, live and learn.
Finished at last with the proper stud spacing for the early frame. Polished and ready to go. Oh by the way these are now made from 7075 T6 alloy and laser cut by Lange Engineering in Geelong, thanks Rob.
I went to Warrnambool at the weekend and picked up almost all of the club racer engine bits, when I say almost all I mean everything that would fit in the car. All the new bits and the engine crank cases etc. All I left behind at Laurie's place was some second hand front forks which were unserviceable and some crank pieces left over from a rephase. I also left behind some second hand pistons and various small items which I will get the next time I'm down that way. I have yet to get from Matt his donated DelOrto carburettors and a camshaft he was making for us as part of a later development of the motor.
Now that I have all the necessary bits I need to work out the balance factor for the new crankshaft I can go ahead and make some weights for the jig I made a while ago and do the static balancing prior to dynamically balancing the crank. Daryl Hutcheon has kindly offered to press and align the crankshaft for us prior to welding. I also spoke to Steve Bell while I was in Warrnambool, for those who don't know Steve his business, Jettco , builds race motors for mini sprint cars using 600cc Hondas etc.
Steve Bell's 840cc Rephased Tracker.
To make a long story short, Steve has offered to run in our race motor on his engine dyno and check it out under controlled conditions and make sure everything is ok before we go racing. He also mentioned they can do a cam swap while the engine is mounted on the dyno for comparison purposes and do a bunch of data on the motor to see if it is working correctly. Steve has a very nice XS650 tracker himself and is very keen to build another XS this time a café racer. I'm sure if we can fit into his busy schedule our race bike will benefit from his experience.
Went to Broadford Sunday and dropped off the exhaust system and rear sets for the club racer to Herb Conlon who was down for the Bonanza with Mark Peatman. Hopefully everything will fit as it should when offered up to the racer.
Next job will be to weigh pistons and con rods etc. to establish the 50% balance factor for the race motor. The head will have to wait for a while as there is a possibility that some of the work may be done by a company in Sydney, this is being investigated by Steve Hobbs on our behalf.
One problem encountered is the exhaust sits too low, this is easily rectified and Ivan is onto this. Unfortunately the system was set up on a later frame to the one used for the racer where the motor sits lower.
Glen Voice one of the original members of the club racer build team has decided to take the family back to England for what may be forever. Glen was instrumental in developing a planned approach to developing a head for the club racer and helped us with his expertise when we were flow testing several heads in an effort to determine what direction we would take. Thanks for that Glen we will miss your input.
Glen Voice seated on his 840cc Tracker
Sent off the valve spring retainers last week and received them back today CrN coated. Dave Taylor has offered to pay for this process to be done to the club racer set, thanks Dave. Job was done by Surface Technology Coatings in Thomastown. The reason this was done was because of a reported problem with premature wear on this type of retainer. Surface is now harder and slicker and should prevent the problem. Here is how they compare.
On the left are the
Titanium valve spring retainers that
have been Chromium Nitride Treated and
they weigh 40.1 grams.
Here is a stock XS650 retainer and if we multiply by 4 a set would weigh 21.0 X 4 = 84.0 grams.
The last piece of our
very trick, and so far, very secret
crankshaft is finally being machined by
Lange engineering in Geelong.
Steve Hobbs has also been busy designing and building a new seat for the XS650 café racer boys which mounts to the stock seat mounts and does not require the removal of the rear frame loop. He wants to donate one for the club racer when it's finished.
Thanks Steve it looks fantastic, even in this unfinished prototype stage.
The latest picture I have received from Kevin Boss's workshop of the club racer.
After receiving the reground crank pin back from Lange Engineering, a job that needed to be done to allow easier assembly of the crankshaft for balancing, I got busy and weighed all the bits necessary to determine the correct balance factor of 50% for the race crank.
First thing is weigh the piston and all its parts i.e. piston, pin, clips and rings. total weight 439.2 grams
The conrods need to theoretically halved to determine which part is rotating mass and which half is reciprocating mass. This is done by suspending the centre of the little end of the conrod on a string and weighing the big end on some scales, this is done with the centerline of the conrod horizontal. Then it is reversed with the big end is supended and the little end on the scales. If it is done correctly adding the two readings should equal the total weight of the conrod. In our case the following applies.
small end weight 102.6g + big end weight 193.5g = 296.1g
measured weight of the whole con rod = 295.3 ( therefore 296.1 - 295.3 = .8 gram )
My measurement end to end has an error of .8 gram, this is minimal (0.27%) and nothing to worry about.
Next is the big end bearing and spacing washers, 60.4g
The big end pin is not weighed as it is deemed to be part of the crankshaft as in one piece cranks.
The only other part to be weighed and considered in the equation is the jig or device used to attach weight to the crank pin for static and dynamic balancing, the weight of this device must be included in the calculated weight. The jig I used in the static balancing exercise weighed 87grams.
The formula for working out the balance factor of a crankshaft is :-
Md = MROT + MREC
Md = Mass dummy or the combined calculated mass including the jig for attachment to the big end pin when balancing.
MROT = The Rotational Mass or 100% of the big end half of the conrod + the big end bearing + the thrust washers.
MREC = The Reciprocating Mass or the balance factor 50% of the reciprocating mass which includes the piston + rings + piston pin + clips + the small end half of the conrod.
MC = The Counterweight mass = the amount of weight required to balance the assembly prior to applying the formula = 651g
So for one half of the crank :-
MROT = 100% of the rotating mass (big end of conrod (193.5g) + bearing and thrust washers (60.4g) OR 193.5g + 60.4g =253.9g
MREC= 50% of reciprocating mass (piston, rings, pin, clips (439.2g) + small end of conrod (102.6g) OR 439.2g + 102.6g X (50/100) = 270.9g (note: 50/100 represents the 50% which is the balance factor we want)
Md= 253.9g (MROT) + 270.9g (MREC) = 524.8g
Now that we have both the measured weight of the counterweight (MC = 651g) and the calculated weight we need (Md = 524.8g) then it's simply a matter of subtracting one from the other to find out how much we need to remove from the counterweights to achieve the balance factor we want. Therefore 651 - 524.8 = 126.2g then if we divide this number by two we will know how much to remove from each flywheel (126.2 / 2 = 63.1g) or from our metal removal chart a 19.5mm diameter hole opposite the crank pin will remove 60.3 grams. (the hole is specified in radius in the chart so convert 19.5mm diameter to 9.75mm radius and drill to full flywheel thickness of 27mm) All these figures are only approximate at this time and will need to be rechecked several times for accuracy.
These calculations form only half of the crank shaft as we are treating each half as a single cylinder engine and then combining the two halves as a rephased twin.
If there are any experts out there who can see a flaw in this method or calculation please let me know. firstname.lastname@example.org
N.B. If conrods are polished or pistons lightened or different components are used, then this procedure would have to be repeated.
The next question is, do we polish the conrods and have them shot peened now or not worry about the extra reliability this will possibly give us and put the motor together using stock (unmodified) components? It may also be possible to remove some weight from the pistons which is also advantageous to a race motor. My guess is most club members just want to see it finished and don't really care about making it the best it can be. If I'm wrong let me know but it must be done now if it is to be done at all.
What we have to do now is make up some bob weights equivalent to this weight (including the method of attachment) and make a jig to allow the lightly assembled crank to rotate freely to determine the heavy spot. If the crank is heavy opposite the crank pin it will need to be lightened, if however it is heaviest at the crank pin it will need extra weight added opposite the crank pin. Once balance is achieved statically then we do the same again in a dynamic balancing machine. When this is completed we can disassemble the crank and reassemble for the last time using the proper components and align it and weld it ready to use in the motor. This is a considerable amount of work and may take a while.