Triumph Rat Motorcycle Forums banner

1 - 20 of 65 Posts

·
Registered
Joined
·
244 Posts
Discussion Starter #1
i just blew up my 1965 650 triumph LSR machine, at 2 mph under the top speed record for the mile.

LSR is land speed racing. top speed only. nothing else matters. it was messy:



but the crank guy just called and said he has the box with my crank in it on the porch, so we'll see what we can make of the mess.

this machine holds the record for any production-framed triumph bonneville running on gasoline without aerodynamic aids, at 133 in the mile and 135 in mile point five.

we're going back at the end of august.

lol.
 

·
Registered
Joined
·
244 Posts
Discussion Starter #2
here's what an LSR triumph looks like:



LSR bikes are minimalist machines, nothing on them that you can take off. my entire electrical system is an 18-inch 16-gauge wire running from the magneto to the kill switch. no battery, no harness, no alternator, nada y pues nada . . . the ignition on this one is a vintage ARD magneto, fixed advance.

head is worked by rob hall, like all the rest if the fast british bikes in LSR. dual plugs because the compression is 11.75 to 1.

chassis is a 1965 production triumph T120, using 1990 suzuki katana front wheels for both front and rear. the forks are a mongrel of triumph parts from a bazillion years. everything else on the bike is hand-made.

clip-ons are italian tarozzi, as are the rear set footpegs. controls are stock triumph. newby belt drive, stock 4-speed gearbox.

tanks hold 5 litres of fuel, per the american rules. actually 5.100 litres.

tires are goodyear front runners. automobile drag tires for cars. they work well on LSR machines. same front and rear.

when it runs, it goes very fast, when it blows, it costs lots of money.
 

·
Registered
Joined
·
1,072 Posts
Hi Kevin,
Are you sure you can’t polish out those imperfections in the crankcases!

I was rooting for you to beat Mr Ritchie Rich on his bespoke framed bike, to have the outright record.

It could have been worse, you could have broke the drive chain, or the gearbox, locking up the back end at 130mph.

Luckily you are not hurt.

Please keep us posted on the rebuild progress.

Regards
Peg.
 

·
Registered
Joined
·
244 Posts
Discussion Starter #5
Hi Kevin,
Are you sure you can’t polish out those imperfections in the crankcases!

I was rooting for you to beat Mr Ritchie Rich on his bespoke framed bike, to have the outright record.

It could have been worse, you could have broke the drive chain, or the gearbox, locking up the back end at 130mph.

Luckily you are not hurt.

Please keep us posted on the rebuild progress.

Regards
Peg.
yo peg

even blown up, this bike is the fastest triumph bonneville that has ever been.

. . . in a factory bonneville frame . . .

. . . on petrol . . .

having said that, i was quite happy to have it blow without much fanfare. i had just run the lights at the mile at 131 mph when the motor slowed for an instant. i chopped the throttle and pulled the clutch, and it blew a second or so after. so i dead-sticked through the mile point five at 95 mph and thence to the firetruck to introduce myself.

a rod bolt had given up. i shift at between 7000 and 8000 on the 3-4 gear change, and perhaps that was too fast. but the bolts had abut 70 runs on them, so if i change every rebuild instead, i might get away with it in the future.

the chassis is fine, and the motor can rise again. we'll see how quick i can do it.

in the meantime, the daughters set a record in overhead cam 250cc production at 101 and 103 mph:

 

·
Registered
Joined
·
1,072 Posts
yo peg

even blown up, this bike is the fastest triumph bonneville that has ever been.

. . . in a factory bonneville frame . . .

. . . on petrol . . .

having said that, i was quite happy to have it blow without much fanfare. i had just run the lights at the mile at 131 mph when the motor slowed for an instant. i chopped the throttle and pulled the clutch, and it blew a second or so after. so i dead-sticked through the mile point five at 95 mph and thence to the firetruck to introduce myself.

a rod bolt had given up. i shift at between 7000 and 8000 on the 3-4 gear change, and perhaps that was too fast. but the bolts had abut 70 runs on them, so if i change every rebuild instead, i might get away with it in the future.

the chassis is fine, and the motor can rise again. we'll see how quick i can do it.

in the meantime, the daughters set a record in overhead cam 250cc production at 101 and 103 mph:

Congratulations to your daughter, young and very brave.
Regards
Peg.
 

·
Registered
Joined
·
7,235 Posts
I would imagine it gets pretty hairy at over 130 mph on an old engine. I can reach over 130 mph on my Rocket 111 and have trouble judging distance at over that. My brain is slower than the bike. Keep at it as it is quite an achievement. No one seems to do it in the UK now.. See a few in hillclimbs but nothing like 130 mph.
 

·
Registered
Joined
·
244 Posts
Discussion Starter #13 (Edited)
the crank guy says he might be able to grind to -0.020 and save the crank.

that would be vastly less complex than trying to take a stock crank, cut it to clear the cams, nitride it, and then think about re-balancing it.

easier than welding it up, too

time is ticking by tho
 

·
Registered
Joined
·
1,364 Posts
... I use oversize shells torqued in the rod and the machine shop cut the crank for proper clearance. 010 shells plus the required clearance, I like .0016.....Then they were nitrided... depending on the actual nitriding process, the crank journals may grow a few 10 thousands...With Trufftriding it might be a hair more than for ferritic nitrocarburizing...
 

·
Registered
Joined
·
244 Posts
Discussion Starter #15
shoot, i know nothing about metal treatment for a crank, tony.

it's like porting. if i were to invest twenty five years in it, maybe i would have an opinion worth listening to. but i don't have that time, so i ask questions and then just trust the people who do have twenty five years in the matter.

plus, i listen to you. you got me into this mess in the first place.

and don't go all sheepish on me either, because you know more about these machines than me and any two or three other people combined. i can't figure out how, because you always shoot from the hip. but you keep hitting the bulls eye anyway.
 

·
Registered
Joined
·
1,364 Posts
Well, I probably know less than many others but I have learned what you can get away with...My own opinion, as expressed on Brit Bike is that measuring bolt stretch may be no advantage to torquing a bolt using the proper lube ...and making sure all bolt seatinf surfaces are true to the bolt.
My bike ran 133.1 at Maine right off the trailer with no tuning at the track..It was never tuned at the track for setting any previous records.
The 135 you ran took a lot of extra work...Speed is expensive and time consuming...You are now the guy to beat...:wink2:
 

·
Registered
Joined
·
244 Posts
Discussion Starter #17
well, i can measure bolt length to within about 0.0003 using an ordinary micrometer. the recommended stretch when torquing is 0.005 to 0.0055 (yes), but the maximum permanent distortion is to be only 0.001. so what i'm interested in doing is measuring the stretch to keep track of it. i can measure to 0.0001-0.0002 using pointed micrometer tips, so i will do that. but i'll be throwing the bolts away after one torque no matter what.

so it's really academic.

anyway, the blowup was unfortunate, especially with the bike going 131 in its first pass of the event. but the one going back into the frame is essentially a duplicate-- same head, parts number pistons and cams, same valve timing, same tuning . . . so it should run well immediately.

the chassis ran well. all it needs is pipes tucked in closer to the downtube, and i'll build those over the winter and test them in july in maine.

then it's bonneville in august, unless i run out of money.
 

·
Registered
Joined
·
244 Posts
Discussion Starter #18 (Edited)
building.

got my replacement cams from megacycle today. the old ones are out for magnafluxing. i think they're okay, but i need a set of hot cams for a track bike i'm building and those will go in that one if they check out. no time to evaluate them for this next event. the pistons and the crank are not here yet. so i'm doing everything else.

the DPO of my spare motor had decided that the oil level in the 1970 primary was too high. so he drilled three holes lower than the stock ones. i plug these holes anyway, because i run a dry primary, but his holes were drilled oversize, so i had to tap them 5-56 and then JB-weld in little quarter-inch screws to plug em up. the stock holes above them were easy. i drill them out to 0.070 and then tap in ordinary patent plate rivets. there's no alternator, so i just have bolts plugging up the holes for the stator studs. the piece that holds the front of the primary chain tensioner i just saw off and tap back in as a plug:




behind the clutch, i leave the trapdoor off completely and notch the primary so i can fit a 21-tooth gearbox sprocket in. 20 is as big as you can get in there without grinding. i dremel a notch and then use a coarse half-inch square file to open the notches up until the sprocket goes all the way in. precision is not required:



put the head back together, too. miraculously, it suffered no damage in a blow up that broke the crankcases to pieces. i'm guessing that the left exhaust valve was closed when the piston smacked it, because although the pushrod is S-shaped, the valve stem slides up and down in the guide as if it is new:



i have to check clearance on the tappet guide blocks, tomorrow, i hope. the ears are shorter than stock to clear a higher cam, and even then i had to file them and shim the blocks up 20 or 30 thousandths with valve spring shims to let the cams turn underneath:



still hoping to get this together before the end of the month, but i'm at the mercy of suppliers. if i can't, i'm thinking i may take tony's 1997 buell up and run the **** out of it:



it shifts on the wrong side, but it will do the ton two-up in a heartbeat. if i take the silly flyscreen off i can run it in M/PG 1350/4, and the record is only 133.885 in the mile, and 135.668 in the mile-point-five.
 

·
Registered
Joined
·
1,364 Posts
Kevin, you may have to put on the stock transmission sprocket or the engine will bounce off the rpm limiter at 6700 rpm before it hit 130...I believe I included it...Need a 1-7/8 socket and an impact wrench, its left hand thread..
 

·
Registered
Joined
·
1,072 Posts
Hi Kevin,
I believe that you (and Truckedup) are ambassadors for our favourite M/C brand, and the forum for that matter.

The bolt failure looks massively difficult and expensive to manage.
I have some spare parts put aside, there is a small chance that I have something that you might need. If I can help, I would be more than happy to give these to you.
If you need extra funds, set up a crowdfunding or PM me an account number, If I can contribute in any way to get you back on the track in time, I will be most pleased to help.

Regards
Peg
 
1 - 20 of 65 Posts
Top