Discussion in 'The Lounge' started by Signal, Aug 26, 2018.
Those 'justers are pretty!
Thanks for the update.
The craftsmanship to make all of this is just amazing. Such talent! This is a very cool project!
Oh great..... just what I need..... another thread that I just 'hafta' follow...
Nice work Signal!! Are you gonna set the crank up for 90deg. firing?
That's the spirit.
Gary, Mailman and Jim , thanks for the kind words.
Jim the crank will standard two up two down, like a TZ700. I think a cross plane crank would be turbine smooth but the ignition would be another problem that would need to be sorted.
Trueing the crank will be an act in itself.
Stage two once the initial motor is running well is water cooling the top end , that might be the time to build another crank. However this depends on anticipated rule changes to our class.
Since lean angle isn't a problem.... you could hang something the size of a VW distributor off the end of the crank. Direct drive would give you 4 pops at 90deg's per rotation. Imagine that exhaust note. You'd think you'd died and gone to heavan...
That's gonna be true no matter the timing. I don't envy you that task...
I have been able to put some time into the 700 lately so a small update.
Decided to go straight to O rings to seal the heads and made a cutter to fit in the boring head. It works but chatters badly so will cut the grooves by hand, luckily there is only four to do.
Started sorting through the motor top end trying to match heads and work out what needs to be repaired. They are in a sorry state but are repairable. If worse comes to worse I don’t think it would be that hard to make a head.
Used a DTI and the mill DRO to measure the spark plug heights in the heads and how much to remove from the cylinders and it worked out really easy to do. Milled the spark plug holes of the heads in pairs to the same height also helicoiled a stripped spark plug hole.
Now that the heads are in pairs I used a burette to measure each heads volume to let us know what we are starting with. This will need to be adjusted. From what I understand you set the squish then machine the combustion bowl to get the CR you want.
By using the measuring set up in the lathe the head can be left chucked up and if further cuts are needed it’s already to go. I still need to make a bowl radius cutter but luckily won’t need it for some time.
Got some 38mm tubing bent at the local exhaust centre for the rear swing arm, normally exhaust tube benders make horrible distorted bends but these guys’ race cars and have a proper bender for doing the roll cages in their cars.
Also started making the swing arm pivot bolt and the pivot mounts. I will post some photos when it is tacked together. Once that’s done I can start on the outrigger rear shock mounts.
This outriigger bearing - how far out will it be? About 75 mm or 100mm away from the RH case?
It occurs to me you could utilise the existing unused LH hole and pass a tube down throught that, and the outrigger bearing, that would abut directly on to the end of the ouput shaft. The OP shaft itself can be extended by say, 25mm and have a parallel nose on it that will insert into a needle roller bearing in the end of the extended support shaft.
The support shaft itself needn't necessarily be free to turn, but I'd think it would be best if it does, because if there's the slightest binding of the needle roller, the whole thing can turn and you can keep going rather than fry the needle bearing. Even if the shaft does turn, it's securely held by two decently-sized bearings.
To replace the sprocket, you unbolt the LH bearing retainer, slide the whole shaft out and bingo, there's your sprocket.
Details like the securing of the sprocket, I leave to you.
Grimly, yes it will be something like you describe.
Not too concerned about it yet as we will have a much better idea of what offset is needed when the sprocket / rear wheel and motor are placed on the building table.
wow - ....just WOW!
Beautiful work Signal! Enjoying this very much!
G'day from across the dutch,
Mate you have all the great toys and also the ability to us them.
Chose, Bro !!!
Managed to deck the barrels and cut the O ring grooves then went on to start to centre and dowel the heads to the barrels.
Needed a smaller drill bit so didn’t get that far but I did devise a way to do it.
The funny the thing is the job I thought I would have the most trouble with (cutting the O ring groove) was easy once the tool was ground and set up, the job that I thought would be straight forward (dowelling the heads ) is taking some time to sort.
Then went on to work some more on the swing arm pivot, pivot bolt and bearing mounts and this turned into a giant cluster fuck.
I have a few days leave left so will be back at it tomorrow and will hopefully be able to correct my mistakes.
Been a while as we have been busy racing and repairing our running outfit as well as doing other stuff.
I have port matched the cases to the barrels sorry lost the photos of this. I have read there is little or no gain from doing this but as I could not find anyone who said it was bad I decided to do it. Also we had a bit of a BBQ in the shed.
First the weld faces on the cases were chamfered and cleaned.
The internal faces where the cases meet was bead blasted to give the surface some texture. This is an insurance as if we need to fill the cavity with some form of epoxy it will get a better hold onto the cases. We probably won’t need to do this but once they are together these areas are not accessible.
Then I took the cases to a local powder coater and asked him to put them in his degreaser tank overnight. He didn’t charge for this but I gave him a box of ice blocks (popsicles) for his trouble. It is summer here and pretty hot.
Rebolted the cases together and preheated to 130 degrees C in the old BBQ I have been keeping for just this job. The BBQ is clearly labelled not for inside use and don’t use all four burners with the lid down .Ha what do they know.
The welding was done using 4047 12% silicon filler rods. The welding went without drama and then the cases were put back in the BBQ and slowly the temperature was taken down to room temp over about 3 hours.
The ideal thing for this job would be a glass blowers lare I know some glass artists but I didn’t ask to use their gear as I know they wouldn’t be keen on it.
Also made some progress on the swing arm. It won’t be long and we will be able to start laying things out on the table.
Absolutely beautiful work!
I always did that to my RD's... mighta' just been wishful thinking, but it always seemed to help...
You guys come up with a plan to true the crank yet?
Jim, trueing the crank will boil down to perseverance.
I had a hell of a time trueing the crank in our XS outfit it was bent like a banana at the joining pin. I suspect it was bent before it was rebuilt.
I had no clue why this crank was being so stubborn until my mate put it in a set of cases and you could see the centre bearings lifting out of the cases.
I made a tool to straddle the cam drive sprocket to press the pin straight. After that was sorted it was straight forward.
I hope this crank is not as challenging as that, luckily my co-conspirator on this project is a bit of a whizz at trueing cranks.
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