Farm boy’s Rattle-can Racer

Compression sounds OK. why stop at C16 when there's X16 or Q16 to spend those hard earned dollars on. Two 5 gallon pails or buy a bike? What's wrong with those numbers?

http://www.dragzine.com/tech-stories/dyno-testing/the-big-fuel-test-part-4-race-fuels-fight-back/

Boost ports are always a good idea by why not add reeds. I have seen cylinder reeds and crankcase reeds on those motors - not in my shop though. Crankcase reeds plus another pair of transfer ports, additional exhaust boost ports and decent rear boost port would transform that motor. If you like the idea of boost ports check out a later model XR05 (TR500 Mk 3). They have some interesting porting ideas.

At that point you start looking at adapting a pair of RM250 top ends or Polaris/Arctic Cat top ends and ten minutes later you are looking at Rob Tuluie's Tularis and thinking you could copy that idea. Anything is possible - not always practical though.

If I were you though, I would spend my time and money on getting it running perfectly and set up the chassis so that it handles and brakes well. A bucket load of HP is nice, but a bike that takes minimal effort to hustle round the track is way faster and more fun. Lighten the bike and get the controls set up for your riding style and add good tires and then get suspension set up and see how much fun that is first.

As it is it should make enough power to have the chassis shaking in its boots.
 
teazer said:
Compression sounds OK. why stop at C16 when there's X16 or Q16 to spend those hard earned dollars on. Two 5 gallon pails or buy a bike? What's wrong with those numbers?

Boost ports are always a good idea by why not add reeds. I have seen cylinder reeds and crankcase reeds on those motors - not in my shop though. Crankcase reeds plus another pair of transfer ports, additional exhaust boost ports and decent rear boost port would transform that motor. If you like the idea of boost ports check out a later model XR05 (TR500 Mk 3). They have some interesting porting ideas.

At that point you start looking at adapting a pair of RM250 top ends or Polaris/Arctic Cat top ends and ten minutes later you are looking at Rob Tuluie's Tularis and thinking you could copy that idea. Anything is possible - not always practical though.

If I were you though, I would spend my time and money on getting it running perfectly and set up the chassis so that it handles and brakes well. A bucket load of HP is nice, but a bike that takes minimal effort to hustle round the track is way faster and more fun. Lighten the bike and get the controls set up for your riding style and add good tires and then get suspension set up and see how much fun that is first.

As it is it should make enough power to have the chassis shaking in its boots.


That’s what i was figuring haha,
I have seen the XR05 cylinders, would love a watercooled t500. Would probably sell a kidney for an SB1... or Just buy an RZ350 with a 521 kit and call it a day. Or drop a banshee engine in if destroying a t500 frame sounds like fun. I get your point, just thought it might be an interesting proof of concept, but after starring at piston and the cylinders, theres no way to do it without reeds, the hole in the piston would be right where the second ring is. Way to high and risky for little benefit.

Back on track we gooooo
 
When I started building an RD350 based drag race bike for my wife, I soon started looking at RD400 cranks and Banshee cranks and CPI top ends and so on, but she is happy racing my RZ at the strip and the idea was to give her something with similar power but a lower & longer chassis. There is no way she would want 150hp, 250 pound rocket ship.

For all out performance, a sled motor with sled clutch and no transmission would be fastest, but that's not really the point of old bikes. We want to get the most out of our old bikes. We really aren't looking to build a modern bike. Old bikes are expensive, but new bikes are way out there in a totally different zip code.
 
teazer said:
When I started building an RD350 based drag race bike for my wife, I soon started looking at RD400 cranks and Banshee cranks and CPI top ends and so on, but she is happy racing my RZ at the strip and the idea was to give her something with similar power but a lower & longer chassis. There is no way she would want 150hp, 250 pound rocket ship.

For all out performance, a sled motor with sled clutch and no transmission would be fastest, but that's not really the point of old bikes. We want to get the most out of our old bikes. We really aren't looking to build a modern bike. Old bikes are expensive, but new bikes are way out there in a totally different zip code.


Actually track bikes are quite affordable in quebec.
See the cost of registration for 1 year has been at about 1400$/year
It’s set to go up to 1700-1800$ by 2019.
Thus there is an abundance of gsxr’s, cbrxxxrr’s etc. On the market. You can get a running crotch rocket for under 1500$ all day.
Old bikes are getting ridiculous out here.
You can either buy at running riding modernish 650 or a 1970’s cb125 for almost the same price. Retarded.
Even hacked up shit people are looking to get top $ for.


I did debate using an old suzuki 440 LC sled engine to make a field bike once...
realized it was cheaper to just buy a clapped out dirt bike and pound that to pieces instead.

I still dream of a rotax 850 etec engine mated to a gsxr gearbox in a beautiful trellis frame...
one day when i win the lotto hahaha

Bimota SB1, because they are awesome
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Engine is out of frame and apart again, kickstart refused to return when cases were joined.

Something was rubbing/pushing on it and there was too much friction for the spring to return it. It would return if i pushed it back easy enough. It works fine with the cases separated.
 
After becoming very efficient at removing and applying crankcase sealant with surgical precision...

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All that because the bushings were dry when I installed it. It had been sitting in the same place in my shed for 3 years!

Let that be a lesson gentlemen, always lubricate the shaft before sticking it in the bushing.
 
POS (previous owner syndrome) strikes again.
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10 points to whom ever can tell me what is wrong with the above piston
 
Nice job of welding that piston up. I'm sure it would run - but for how long before the distortion and dissimilar metals would cause it to fail? It looks so new and shiny. Did it detonate instantly or what?
 
teazer said:
Nice job of welding that piston up. I'm sure it would run - but for how long before the distortion and dissimilar metals would cause it to fail? It looks so new and shiny. Did it detonate instantly or what?


Hopefully i don’t need to run it long enough to find out.

I’m sticking it back in for now, going to replace it with a set of wisecos.

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RHS looks a bit dirty, but i’d say no more than an hour on these things, and 0 time since it was welded.
 
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Engine all buttoned up again.
Stole an un welded piston from the second engine, luckily (not really) it was on 71mm bore also so i swapped rings from one to the other and stuck the unholed piston in.

I took the time to check the primary reduction before buttoning up.
Straight cut 55:24 = 2.2916
Stock gears 65:26 = 2.5

Benefit of this i guess is less torque on the tranny. It does mean it will spin faster all the time, potentially wearing bearings and gear faces faster... only about 9% difference though.
 
teazer said:
Hope you took care of that raised thread insert on the left cylinder.
Yep, pulled it out and re threaded the hole before dropping 2 inserts down the hole.

der_nanno said:
Faster spinning gears will also help to prevent pitting on the gears. It's normally not the worst idea.
I figured it would help the gears a bit as there would be 10% less pressure on the teeth. (In theory i guess) these t500 are renowned for pitted 4&5 gears, although the later gt models had a bit more oil in the box which helped a bit.


Put the engine in the frame today.
Forgot how heavy these damn things are when they’re fully assembled.

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switched out the shifter pedal for a slightly longer and angled one.
Sat on the seat for 20 minutes, definitely not a bike made for someone 6’1”.
It was manageable.

Made a cardboard template of the ignition backing plate. Going to try to make a replacement that will fit further back into the cases. I really hate the magneto hanging that far out there bouncing around.

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Just need to put a notch where the screw is at the top and put two holes for the screws at the 4 and 8 o’clock positions
I don’t see why the entire unit needs to be able to rotate, the rotor is fully adjustable and so are the pick up coils.
 
On a TZ, the rotor is keyed in place with a woodruff key. I think that with the two pickups centered and timed perfectly, if a rider wants to add a little timing or back it off a little, it's easier to move the whole backing plate.

That ignition is more or less exactly where it woud be on a TZ, but the TZ has a cover over it to protect it in case of a minor crash.

How well does a stock left cover fit? It can always be cut down or modified to give some protection.
 
The cover fits on just fine surprisingly, but i don’t want the taper to snap off the crank like it did on the other engine. It worries me because the 250 rotor is half the size of the 350 rotor.


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If the crank was correctly machined it should not be an issue. J/K TZ's revved to 12000 so it should be OK on a T500. That assumes there are no hard steps in the modified crank to act as stress raisers.

But you have the 350 ignition fitted. How is that working with a smaller crank end or was that on a different crank. That's what happens with too many options - things get confusing.
 
teazer said:
If the crank was correctly machined it should not be an issue. J/K TZ's revved to 12000 so it should be OK on a T500. That assumes there are no hard steps in the modified crank to act as stress raisers.

But you have the 350 ignition fitted. How is that working with a smaller crank end or was that on a different crank. That's what happens with too many options - things get confusing.


All crank ends have been machined down to fit the yamaha rotors except the twingle crank, which isn’t going to be used.

I have two extensions to position the rotors at the correct depth with respect to the stators.

I also have half a crank that has a new longer pin pressed in, but the machining is incomplete as it lacks the bolt hole.


Twingle crank vs the half crank
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Went ahead a slapped the ignition in there.
Cover fits on nicely, speed holes and all
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Hooked up and gave it a few hand cranks, big fat blue sparks on both sides

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I think i’m going stick a blob of some metal putty behind the lower positioning screw of the stator back plate though, just so it has something better to rest against. Might even be able to drill and tap it to get a second screw on there.
 
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