busted Crank!

Here is some pictures of Parr Larsons crankshaft. His suffered two different blows one was when his clutch basket blew up locking the drive line and engien up. the other was repeated low rpm running in fifth gear and hammering the turbo detonating it untill the second fracture took its toll.





He put a used crank in it and has been riding her for two years now. He also land speed races it on ice but then he is from a cold enviroment. And a Nutter to boot. You should see the pictures with studded tires on her for the ice front and back. Of course he found out it was easier to fix the bike then heal his bones

This makes me wonder if metal shavings on the crank angle sensor could cause detonation (this may cause blow back). The crank does have a lot of hardware hanging of it so it wants to keep spinning while other forces are trying to stop it.

Gothlander said:

This makes me wonder if metal shavings on the crank angle sensor could cause detonation (this may cause blow back). The crank does have a lot of hardware hanging of it so it wants to keep spinning while other forces are trying to stop it.

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You have apoint there Goth my only other thoughts are the bike is fairly new and he had problems from the get go. He also stated they did some re-maping. I can't help but hope they had a dyno while they were doing this. Something tells me the timing chain was off from the factory and they were messing around with the timing trying to get it to fire after the valves were closed hence the simulated detonation. I also wonder what would happen if the balancing shaft was not timed with the crankshaft. You opinion is valid but it would also point to crank/valve timing being off. Gus from Baxter's told me he has seen some Rockets withthe timing off from the factory while he was doing the update kits.

As for the motion well it could add a twisting motion if it were detonating or firing early which would act like detonation. So when onecylinder was trying to rotate the crank one way the other cylinder was firing opposite direction so to speak because of timing issues.

I am just guessing and of course the Dealer would not out the factory so I doubt we will ever know. As long as he ends up with a good viable engine all will be good. I would take a extra mileage warranty out on it though to cover other things that might have suffered from the shock if any. Mostly just so he will feel confident in the bike.

Very interesting set of posts Scott - as usual.

Rocketeer55, this is what would worry me on a re-build - the forces generated to bust that crank were pretty high, there is damage to a lot of components from top to bottom, some components might have stress damage that is not immediately evident but be re-used, this may have been caused or at least made worse by the very techs who are going to do the rebuild . For these reasons alone I would fight tooth and nail to get the motor replaced with a new one, even if it took longer.

If this happened to me and the engine wasn't replaced, all trust I had in the bike would be over and it would have to go anyway.

Battersea said:

Very interesting set of posts Scott - as usual.

Rocketeer55, this is what would worry be on a re-build - the forces generated to bust that crank were pretty high, there is damage to a lot of components from top to bottom, some components might have stress damage that is not immediately evident but be re-used, this may have been caused or at least made worse by the very techs who are going to do the rebuild . For these reasons alone I would fight tooth and nail to get the motor replaced with a new one, even if it took longer.

If this happened to me and the engine wasn't replaced, all trust I had in the bike would be over and it would have to go anyway.

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Battersea does have a valid point there. Especially if you will to wait for a complets engine. It would be easier for Triumph to diagnos the problem if they had the whole motor And ECU to see what they might have done to the mapping. SOunds like they had to have atleast had tune ecu or tune boy to make mapping changes. I do not believe the regular Triumph tool would do it.

Now on the other hand let me tell you these engien are tough they can handle thing like a internal clutch grenading at 80mph with a full lock up of the drive line and engine. Bending the inout transmition shaft which is what locked everything up. I can tell you its not a pretty sound or a fun ride.





Below is a couple pictures of the destructive force applied to the front blower cover in front of the clutch





My point here is these motors are tough both Les's and Parrs which snapped the crankshaft are running again with no issues on used crankshafts.

Mine is also but it did bend the tranny inout shaft a 1/4 inch which is why everything locked up at 80 mph. It was scary as anyone could imagine actually haveing to scan the side of the road to figure out where you could possible jump the complete ditch to end up in someones yard and punch out. Boy I had to toss my drawers when it was over. Anyway I tore out the engine flopped it over and changed the input shaft then put her back together and continued to be disrespectful to the engien by beating the snot out of it on a daily basis. As IMFASTTOO would say you can't keep racing it around and expect it to last. Well 10,000 miles later and no major problems. I di pop a head gasket bu tthats from bad gas during the winter mix change over. I will change it and get her ready for the LSR races this year. I intend on setting a record and then calling it quits before my luck runs out. The fact of the matter Desalvo set the FIM world record at 175 mph at the flats last year coodo's to him and Triumh. Me I refuse to go to the salt because I love my bike but on the asphault well thats a different thing. I know for fact I have done 179mph in fourth gear and let off her ZI also know I spun her to 207 in fifth with more left. So I want the 200 mph naked club and I am going for it. Of course it will go more and as long as I am there I will evaluate how I feel about the safety becasue there is not much room for mistakes.

Anyway back on topic which is the engien internals are strong If i were the techs I would definetly check the run out on the tranny shaft just to be sure it di not get bent. if it had the least bit of run out I would order another one they aint that expensive. Of course its his call with a lawyer I believe he could coax a new roadster out of them or at least a demo say like the one in MS. they with 228 miles on it they are selling as a demo. Hell If I had the cash I would have 3 Rockets by now just to stock up on beast to ride.

I still feel it is fixable and it is too bad Triumph does not say hey for all the trouble we will ship it to Carpenter Racing and have them ensure it is right. Then he could slip Bob the money for a stage 1 kit at the same time and Bob will make sure Eddie takes a close look at it. Anything Bob says is ok I trust myself.

I will answer all questions I can and try to answer a few that I have no experience in if I can reason it out. I would still like soem large pictures sent to me as the ones posted are hard to diffinetively see even with my Trifocals

I guess it's all about who does the rebuild. My mate's bike was rebuilt after a bust crank at around 20k an it's now on 72k. The motor runs good with no problems and after the rebuild his gearbox was better than mine.

kipper said:

I guess it's all about who does the rebuild.

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Got it in one, thats the most important issue here - not sure I could trust those guys.

Now if it was Carpenter or Warp :bch:

Still nothing new to report, I'm still in a holding pattern while the parts trickle in from triumph. I'm really starting to get the DT's. The weather is good and every weekend I see bikes on the road (of course).

did you mention the bike was started with no oil from the bearing surface evidence? or the oils pump chanin came off. Either way its notyour fault.
I would think they would give you a loaner to buzz around on.

I went to the dealership to check the status on my bike. They had a two page parts list, with all the parts in except the valves. I will be contacting Triumph this week to see about my Warranty Extension. With any luck this will be over and I'll be back on the road soon.

My wife and I were contemplating a long ride this spring. Any suggestions? (let's try to limit it to North America). I stupidly asked that question to some of my work Associates. Let's just say you can't actually ride to most of their Destinations for me.