KDXRIDER.NET

So earlier this year i was riding my kdx 200 out on the back roads and had been riding maybe 15 mins when the bike hit 6th gear it all of a sudden just would hardly pull its self anymore and died .I pulled over and went to kick it and it spun over easy like i had removed the plug so i knew i fried the rings and the worst part at that time was i was about 5 miles from home and pushed it the entire way!

I get home and decide to ride my 240BBK blaster and sure as **** it did locked up at WOT 6th gear both bikes blew up the same day!

So ive now rebuilt the blaster and had ken oconnor do the machine work which is awesome btw but now its the old kdx's turn.The piston i had in it was a 66.5mm wiseco pro lite and wiseco sleeve.I plan to go to 67mm since the piston basically looks like at 4 points evenly on the piston it seized up.Its odd its an X pattern but the bore for the most part looks good no serious gouging or anything so hopefully 67mm will be sufficient but the machine shop will determine that.


My actual question is has anyone had this kind of failure?I have taken this bike to the bad lands and rode it all over with no issues its basically stock except for the fmf desert pipe boysen reeds pro circuit silencer and the jetting.

I had done 3-4 plug chops and it was spot on maybe even a tad rich but not too bad i dont understand it i let it warm up and had been riding it 15 mins before the failure but why in a X pattern?It literally stuck at all four points of the "X" pattern but no where else.The plug looks new and didnt indicate a lean condition.im stumped but im ordering a wiseco kit as soon as i hear from the machine shop.

doesnt sound like anything ive ever heard of but if i had to guess at it i would blame the sleeve
i understand there are situations when a sleeve is the best option but our KDX is not one of them

if i were you i would seriously consider rebuilding the bike with a new (or gently used) cylinder with the origenal plating
or even a replated cylinder should stand up to the abuse much better then a sleeve


also, be sure you tear apart and clean the carb, maybe there is a blockade in there somewhere thats leaning out the fuel mixture.

what oil at what ratio are you using ?

A "4 corner seizure", which sounds like what you have there, is usually the result of piston overheating or heating up too quickly. This could be due to improper jetting or wringing it out too hard too quickly. Could also be improper piston to bore clearance to begin with, however that is unlikely if you had a good amount of time on the bike since the sleeve/piston.

I always get nervous when the weather changes.
Here in Lower Alabama it never really gets cold, coldest I've ridden in around here is maybe 35 F in the morning. In the summer it is 95+ all the time.
I don't change my jetting from summer to winter, I jet for summer. It is pretty lean in winter and I keep that in mind when riding in the "cold"

Have you been wringing it out in colder weather than usuall?

Have oil in your gas?

so BOTH of your engine seized up the same day??? Seems a bit odd and suspicious to me...
Like Fuzzy I have to ask: have oil in your gas???
what brand and what ratio?

Put straight gas in by accident, maybe... ? Would certainly cause that type of seizure.

that's just mean

I was thinking the same thing while reading the original post. I wonder if the lawn mower started smoking the same day too?

yes there was oil in the gas i have a specific gas can for just premix i checked that as well.

I run amsoil interceptor at 32:1.

Yea it was kinda chilly and i didnt wait but a few mins before i headed out on the acess road behind the house and if i remember correctly i was getting on it a bit both the kdx and blaster.

I have since then found out these things need to be fully warmed up prior to riding and now i fully warm them up before any riding.

Yea there was a decent amount of time on the sleeve and i hope its not the culprit.

Theres no real bad areas of the cylinder nothing that will hang a thumb nail even looks more like its been severely scuffed or even maybe melted some of the piston at those 4 corners will it most likely take to a 67mm overbore?

Also whats the limit on these particular motors for overboring before you have to resleeve or scrap it?

Also since im about to order a topend kit any objections to the WISECO top end kit?The gaskets of oem quality?

I know the vitos gaskets i originally got with their 240bbk were really generic almost like a treated paper of some sort.The guys at blaster forum advised highly against them so i didnt use them.They said the base gasket was the real pos of the kit.


so what do you guys recommend,favor,use and so on for pistons and top end kits?

This wiseco held up really good imo considering it didnt grenade on me.Suprising the cast vitos did the same as the forged wiseco just alot worse and it went from 72-72.5mm so i hope the kawi will to.And according to ken oconnor it looked as though i had sucked water up into the motor but i hadnt been in any water so idk???

Not sure what hte maximum overbore is. Most people re-plate, sleeving is not very common or desirable. Because of this it's not a huge subject of conversation. As long as the powervalves aren't in the way though, you should be able to go next over.

When it's chilly, not only do you need to warm up properly, but take into consideration that colder air is denser. With the air being more dense the engine will run leaner. Just something to think about. If you're going to be tearing around in cold weather, mught want to go up a size on your pilot and main.

The wiseco kit is great. Gaskets are fine quality, and the piston itself is fine as well.

With the air being more dense the engine will run leaner. Just something to think about. If you're going to be tearing around in cold weather, mught want to go up a size on your pilot and main.

Yep, that's why stock jetting is a rich blubbery mess in warmer weather/thinner air. So the bike will run without burning down when you hit a dense condition.

BUMMER DUDE!!!
REPLATING IS DEFINITELY THE WAY TO GO. WISECO PISTONS ARE GREAT, HOWEVER THEY'RE RINGS DO NOT DEAL WELL WITH DETONATION FROM FUEL STARVATION.(MORE PREDOMINATE WITH A CAST IRON SLEEVE) IF POSSIBLE, ALWAYS USE OE PARTS.
I'D RECCOMEND ERIC GORE RACING. YEARS OF EXPERIENCE, VERY COOL WEBSITE. AS FAR AS FIGURING OUT WHY THEY SIEZED HOW THEY DID? TALK TO YOUR MACHINIST!!!! IF THEY KNOW THEIR STUFF, NO ONE ELSE SHOULD BE ABLE TO POINT YOU IN A BETTER DIRECTION.

I DONT KNOW WHAT WE'RE YELLING ABOUT!!!!!

Indeed, please stop with the ALL CAPS posts. It's considered yelling on the interwebs, and not polite.

And hard to read.