dodged a bullet

[Fire-medic]

My recently-worked on bike began to run poorly, and I took it back to where the work was done. This was what he found.

This bike has not been drag-raced, it hasn't been run w/o oil. I have spent some $$ on it to get it working again after a long layoff.

The intake cam fractured cleanly across the oil galley under the #2 cam tower, towers numbered going from right to left. Thankfully, and probably the only "good thing" out of this, it happened when the valves were closed. There was no piston crown-valvetrain impact. A leakdown test shows the cylinder and valves are still good, so, it's replace the cam & cap, and I'll probably do the bolts too. The cap isn't badly-damaged, but it does have some deposit while strangely the bottom cam tower "saddle" integral with the head, doesn't.

This bike is beginning to try my patience. I've owned it for 20 years, I bought it from the dealer w/~1700 miles on it. Without a doubt, this is the worst vehicle I've ever owned for expensive damages to the powertrain. :damn angry:
I am gonna make a "thrash" to repair this tomorrow & then am going to leave for Daytona, with or without it. With it if I get it fixed, without it if I don't. :bang head::confused2:

Now I have an exciting new paperweight for my desk at work.

 

[[email protected]]

what would cause that to happen?

That sucks but could have been much worse!

 

[dannymax]

Wow! That's an unusual problem isn't it? :ummm:

Glad it didn't destroy yer motor! unk:

 

[95spfldmax]

:eat brains::snowAMN!.......

You got the spare parts all set? But talk about last minute before a big event......Good Luck, dude..............

 

[one2dmax]

I broke a rear intake cam in Daytona in 2002. Just figured it was down on power since it was actually still running.

Sean

 

[donnelly317]

Holy ****!!

 

[Traumahawk]

Damn!!!

 

[gamorg02]

jb weld?

 

[Fire-medic]

Sean, I'm sure you had some "hell-for-strong" build under you, w/stiff valve springs, high-lift cams, and more compression, probably displacement too, w/carbueration to-match. FYI, it was my rear intake cam, and it was still capable of running.

Mine is essentially stock internally, w/the exception of an undercut tranny, and the PCW full friction disc/heavy-duty diaphragm spring. It does have a DJ Stage 7 kit, & a UFO 4/1, but that's about it. My purpose of going w/a stock valvetrain, displacement, and carbs bodies was to minimize the chances of something radical such as this occurring. I guess it was just the piece's time to fail.

Yes, it could have put a lot of metal into the oil, and it could have thrashed-around inside the valve cover, doing damage. It could have failed with the valves on the lift, and the next sound could have been valve face vs. piston crown. For that I'm glad.

I am going to bed. Tomorrow is going to be a long day. I am gonna try to get this thing running to make the trip to Daytona, but I don't think I am going to make it there tomorrow, probably Fri. I'll let the brothers know how it goes. I have a good time at Daytona however I get there, and whatever gets me around.

I'd just like it to be on my 'Max.

 

[Miles Long]

Do you think this may be related to the lower end failure on the dyno run???!!

 

[bazwell]

Bad luck mate!

Broken cams usually keep it together for a while, so they keep turning and running when they break.
What you have described sounds like the cam caps have been mixed up (or the head is bent - same result). Cams usually run a fair bit of clearance, and most people don't get too much trouble from swapping cam caps around. But, each cam cap is individually matched to it's location on the head.
I honestly can't remember if they are numbered, but I would be surprised if they weren't.

If they are numbered, they may be around the wrong way, or the caps from the front head might be on the rear. Something like that.

There isn't any pics of the damage to the cam journals or the cam caps. Post those if you can. Both of them from that side of the timing gear at least.

Now... think about a cam in an engine. It is being pushed up by the valves.
So, in use, the cam is running on the caps, not the head.
If the caps are mixed up, they can be a bit out of line.
The wibbly wobbly effect of the cam flexing back and forth as it rotates causes it to snap. This is combined with the fact that one of the cam caps is damaged, and therefore creating drag.
So it's flexing, and being pulled by the gear, and being slowed by the damaged/misaligned cap.

Sorry about the bad news, but I think it's quite possibly the mechanics fault.


ps. Almost forgot.... the head being bent accomplishes the same thing, if the head was faced flat. You would have to check the head for straightness on the back. (Put a straight edge alomg the top of the head next to the cam cap dowels, with the cam and caps off.)

pps. The damage on the cam might be due to the fact that that cam cap is slightly lower on the cam.

ppps. I know how you feel.

 

[95spfldmax]

jb weld?

:rofl_200::rofl_200::rofl_200::rofl_200:...there's ALWAYS one in the croud.....

 

[ouchez]

Fire Medic, maybe time you bought a new machine.

Gen 2 purple I suggest.

O

 

[gamorg02]

:rofl_200::rofl_200::rofl_200::rofl_200:...there's ALWAYS one in the croud.....

haha i thought no one saw it!

 

[Fire-medic]

First the news:
"Fire-medic" rides again!!!

A 'this-morning thrash' results in a mighty-roar from a previously-wounded beast. It's fixed!

I have two spare engines for parts, which I made use-of.

"Bazwell" has no-faith in my mechanic/shop owner or my machinist. I do.

I had the valves done, the heads were surfaced 0.005" by a friend who was a machinist for Crane Cams before they moved to Daytona Beach. I knew Harvey Crane. This 'kid' and his father were both machinists for Harvey Crane. The 'kid' went on his own, and has been operating his own machine shop for 30+ years. He builds a lot of drag bikes. He builds a lot of street racers. How-fast do you want to go? Bring cash, as we know 'speed costs money.' No, 'Baz,' I don't think it was the machinist or the mechanic.

Yes the cam caps are numbered 1-4. No, they weren't mixed-up because I did the disassembly and I took the engine out of the bike. I replaced the caps correctly as they came-off and I removed the cams from the caps.

The machinist and the engine builder have worked together for many years and have had both national and world-record assemblies to their credit. They are both friends of mine.

Long story short, tyhe engine is back together and I intend to make an appearance at Boxenstopp's on Sat afternoon for the bar-b-q. I do not have a trailer queen. It's a bit rough-looking as I live close to the Atlantic Ocean. Salt water in the air, you know. Anyway, it's not the world's fastest, or a show-winner, but it has tried to die several times and I won't let it, so as I once posted before, I think it's earned the appropriate sobriquet, "Lazarus." Risen from the dead!unk:

See you in Daytona.

And, check out my new bike transport system. I fabbed that up this morning while my mechanic was working on the bike, after I showed-up early and stripped the needed parts off my spare engine, and then went to my other friend's garage where we welded up a platform using the receiver trailer hitch as a load-bearing component and a handicap ramp re-purposed as a platform extension for my truck bed, to place the load-bearing not on the tailgate (rated 200 lb.), but on the trailer hitch (rated 600 lb.). No-need for a trailer! I have a couple of arched ramps, one for the bike, one to walk beside the bike, into the truck bed.

Yes, I am "Daytona-bound!" See you there. :clapping:

 

[Redbone]

Excellant FM! Glad you got it turned quickly and properly, have fun at Bike week! I hope to join you fellas there in the next few years!

 

[Traumahawk]

Good news..and have fun.

 

[fltinstructor]

Dang!! I have never seen a cam break like that. Great it turned out okay for you. Have fun in Daytona!! unk:

 

[bazwell]

Good turn around time there FM! Glad you got it sorted so quick. I like your form!

Forgive the devils advocate post I made. I will always point to the worst possibility when giving advise without having facts. It's better that you look at these things than end up posting another sad story.
I have seen maybe 30 or 40 broken cams in my life, and all of them were caused by mixed up caps, bent heads, or as collateral damage in major blow-ups.

Have wicked fun in Daytona! :eusa_dance:


Edit - Your blokes sound experienced. What was their diagnosis? :ummm: