KDXRIDER.NET

Jaguar wrote:maybe you should clarify this statement then: "I did notice the engine was revving really fast as soon as I started riding"

When I gave it throttle, it revved up fast. I noticed it got on the pipe really quick. It didn't hang with a high idle, though, like I've seen air leaks do.

"Good job, guys. "

If you had loose nuts and no rservoir, it was doomed

Jason wrote:If you had loose nuts and no rservoir, it was doomed

Hmm. Do you think anything got damaged?

Seriously, though. Both of my bike came without a reservoir. I assumed they're supposed to be that way.

I suspect the loose nuts cause head gasket leaks?
"Good job, guys. "

The jetting was fine IMO/IME. This was a detonation problem due to low octane. 87 octane fuel does not work well in the hot temps/low humidity environment of the AZ dez. As detonation set in the bike would get hotter, causing loss of coolant, which would only exacerbate the problem. A coolant reservoir won't pull coolant back in while the engine is running so it was irrelevant to this meltdown.

Boy I sure learned a whole lot in the last few days!


"Good job, guys. "

guess it could have been either. And you didn't tell us you were running 87oct.

True. I researched it for awhile and from the information I saw it looked like 87 was fine. Lots of people saying they always run fresh hi octane. Lots of other people saying they run 87 without issue.
My gas was getting old too. Lazy lesson learning.

"Good job, guys. "

It looked to me by the color and the trash that coolant was getting into the combustion chamber

Jaguar wrote:It looked to me by the color and the trash that coolant was getting into the combustion chamber

That does make sense, with the ashy stuff on the spark plug and head.

So.....what does detonation sound like?

"Good job, guys. "

detonation put a hole in my Suzuki's piston although I hadn't noticed any. You have to know how to listen for it and even then if it's not happening rapid fire then you may not notice it.

Great. Still don't know what it sounds like. Hehe

"Good job, guys. "

look at that piston chart. it says one possible reason for a holed piston is water in fuel system.
So whether the water comes in with the gas from the carb or whether or not it squirts in (from a blown head gasket) when the piston is at the lower half of its stroke, the result is a holed piston. Why? the big temperature difference of big water droplets causes aluminum to chip off of a very hot piston.

Thanks. Couldn't access the image with enough detail to read anything.
Been reading up on identifying detonation. I definitely noticed a ringing. Thought it was normal, probably because this bike has been doing it for awhile.
What a gnarly result. Hope I learn enough about it that it's a one time event, and hopefully this thread will be useful to others out there.
Watched some rmatv videos on bottom end rebuilding today. With a engine splitter easy to rent and a crank puller being reasonable priced, I think I'll go for it. Crank rebuild by RB is a whopping 70$ shipped, IIRC. Have to purchase bearings still, but I'm getting myself psyched to do this (never split an engine before).

http://www.contactmagazine.com/Issue54/ ... asics.html

"Good job, guys. "

Detonation is a rattling kind of sound. It's much easier to hear while lugging the engine.

My DR does it when lugging under load. Sounds like marbles. Just never knew what it was. I didn't hear that sound with the kdx though.

"Good job, guys. "

Jason wrote:WOW.

Muriatic acid to remove any aluminum streaking

?

how do you apply the acid to do this?
T I A Mark

two-stroke-brit wrote:

Jason wrote:WOW.

Muriatic acid to remove any aluminum streaking

?

how do you apply the acid to do this?
T I A Mark

I thought he elaborated, but can't find the post. Something about wearing nitrile gloves, be in a well ventilated area, only apply MA to problem areas and don't spill/breathe/touch it. Wipe off with scotch Brite pad.
I haven't tried it. My build is on hold until I can get a crank or decide to scrap it all.

"Good job, guys. "

Update: I talked to Millenium Tech about the warranty on the cylinder and how to clean off the aluminum scuffs, and after telling him what happened he told me to send it in so they can figure out what went wrong and fix it if it's their doing.
So she may live again!
My rear shock is blown, but I've got a DR350 dirt shock in good shape I might just swap in, and I've got a dr350 front end with fully adjustable compression/rebound that will slide right into the triples.
If the engine works out, she'll live again!

"Good job, guys. "

I think the bike was never tuned in properly, and the lean condition was a factor from day 1. I remember you were afraid to ride the bike, because it was so fast. I think the loose bolts just happened over heat cycles. Antifreeze went away when the motor let go. How many plug chops since the rebuild?

Not enough. Your assessment is valid, although I never had a hanging idle to indicate lean conditions (which may or may not matter).
SS109 pointed out that another likely cause was that I was running 87 octane. I didn't know better.

I talked to Millenium Tech today, and they said it would be around $1500 for them to fully rebuild the motor. After a good laugh about that, we whittled it down to replating the cylinder so I could at least sell it off, ported and polished with the piston kit all ready to bolt on.
There's a crank on Ebay finally though, and I'm seriously considering getting that and a fresh head and reassembling it all myself.

"Good job, guys. "