So have a riddle maybe y'all can help me figure out. Planned on dropping the bike off for a diagnostic check on Tuesday because a rattling noise that I couldn't pinpoint exactly where it was coming from. The Friday before, the clutch cable went out on me on my way to work. Made it home with just a few stalls in first, just gave it more throttle and was ok. Went ahead and dropped the bike off for them to check and ordered new cable. They called on Wed, "bike sounds good, can't hear any noises, running fine, nothing wrong with it". Cable came in on Friday, they installed, called "it's ready to go". Get there to pick up and it won't start. Now from running fine, to suddenly the timing chain jumped, exhaust valves were loose, compression test and leak test shows low compression, possibly piston rings or cylinder wall damage and I'm being told I need a new motor!! Can anyone explain how a bike that was having NO performance issues goes to needing a new motor when all they did was start it and listen to it to begin with??? And it still won't start!!

 

Id definitely be looking for a second opinion. The fact that it wont start now is odd.

If the rattling sound you heard was a really bad CCT , then it could let the timing chain jump.

But to go from "no noises , sounds good" to "your screwed" is a pretty big leap

I wouldn't authorize any work at that shop until you've had someone else look at it.
as for the valves and low compression?
Signs of a worn engine, not necessarily a dead one.
Its really hard to judge second hand.

Im still stuck on the "wont start" part of it. I guess if it was running for them , the chain jumped and something happened ? would they mention that or not. just seems off to me.

 

Yes, way off! From most of the stuff I've been reading, even if the chain jumped, it should still start and run, just won't run that well until it's be re-adjusted. Also, signs of low compression are bad performance, chugging along. If that's true, then my compression is good as I didn't have performance problems even with the clutch cable jacked up. I'm also curious as to what the actual reading was since the bike was cold. Would give a 10 - 15 psi lower reading with a cold motor, and since "it won't start"....🤔🤔🤔🤔🤔
But I could be 100% wrong on all of the above, so....🤷‍♀️🤷‍♀️

 

Well your definitely not off on the part about running with a jumped chain. Depending of course on how many teeth I guess.

We bought my son an R6 that seemed to run great while sitting in the guys garage, but after warmed up and under load it made a hell of a noise in the top end.
We tore it down and the chain had jumped 2 teeth.
We reset the timing and checked the valves and it ran like a top after that with no noises.

That was 2 teeth and it still ran "fine".

Does the bike even try to fire ? or does it just roll with no signs of life?

 

From what they told me it does try to turn over, but won't. When the cam chain jumps, doesn't it make a clank or some kind of noise? And would it jump when your turning it off or it's just sitting there?
I'm still trying to figure out how it went from running fine with no noises to the chain jumped?!?

 

No clunk. If the chain jumps, the valve timing goes off. That can reduce compression pressure and cause poor running.

 

Sounds like the buzzing was the cam chain tensioner lifter. Chain most likely skipped tooth eventually because of being loose. Your current shop sounds dumb AF as the kids say these days. Get a new shop. Doubtful there is any cylinder damage. Either take it apart to inspect, or re-time and attach the chain with a new cctl and see how it goes.

 

+1

Definitely where I would start.
I highly doubt you need a new engine.

and as mentioned above , valve timing can cause low compression.
since if valves arent closing / opening at the right time, the cylinder wont build compression with an open valve

 

Yea, I'm picking it up tomorrow so going to talk to the tech face to face to see what happened, and what all they actually did. Supposedly they put back on an adjusted the chain, and valve covers and the exhaust valves were loose so they tightened them. I'm told it still won't start. I have an extremely strong feeling that someone left the key on and the battery doesn't have enough juice to turn it over.
I know that's probably just me wishing it's something simple and a cheap fix!! Lol
I have this guy telling me the below. I checked his profile and the only bikes on there are cruisers. I really want to be a smart *** and go back n tell him when he starts working on sportbike then come and tell me about it!!

Quote
You said it was rattling. And yes once it jumped cam timing, it's screwed. I do this for a living. Doesn't matter if it's moving or not. Once it's jumped, it's done.
Unquote

 

WHAT?!!

This guys either incompetent or a crook.
Neither is a great option.

Like I mentioned earlier , I wouldn't say 100% whether someone was right or wrong about their diagnosis second hand.
I can however disagree with a blanket statement like that one. I know for a FACT ,
"Once its jumped, its done" is complete BS.