bored to 240...

[KDX 17]

Hey everyone...

I took my 96 KDX200 to the shop to get a new piston and cylinder sleeve, and the guy "accidentally" bored it to 240...now I was wondering if I'll see any problems, or any of the maintenence on it will change...I know the guy said he'll take care of the jetting, because that will have to change (it'll need to be richer, right?) but other than that, I was just wondering if I'll encounter any problems with the oversized cylinder. And my other question...now that it's grown a little bit, what seperates the engine performance from the KXs? gearing? Or do alot of other factors play in? BTW, its got an FMF exhaust and boyesen reeds I believe...

I'm kinda new to dirtbiking...say a month, so excuse the ignorance...thanks, cliff.

 

[Racer#213]

i dont' know about the problems, but you'll prolly have to run race gas. did you have to pay for the boring or just hte new sleeve and piston?

 

[Racer#213]

oh and let us know how the 240 runs next time you take her out

 

[KelvinKDX]

Originally posted by KDX 17
Hey everyone...

I took my 96 KDX200 to the shop to get a new piston and cylinder sleeve, and the guy "accidentally" bored it to 240...

What piston diameter are you running??  ie.  what is the diameter of the bore?

 

[KDX 17]

well, we were originally supposed to get a new top end and stay 200 (198cc stock I think?), but the guy "accidentally" bored it, and he said he'll jet it for 93 octane. I'm not sure what size the piston is, but i'll find out tomorrow when I pick it up. We didn't have to pay for the overbore, but it kind of evened out b/c of what he charged for surfacing... I'm assuming it's a Wiseco piston and a L.A. sleeve, because that's what he mainly uses. From what I've heard, the guy does awesome work, so I guess I'll have to let you guys know how it runs after I take it out on saturday...thanks for the help

 

[Racer#213]

personally i would be really pissed if i sent it in for a new tope-end and it got over bored on accident, then something goes wrong bc of the overbore. but if it runs good, and i dint' hvae to pay extra for it i wouldnt' be to mad at all. but alond the way it'll caust you more, ie bigger piston coasts more, more frequent piston changes

 

[shr]

And they were smoking what?

You can't accentually bore a stock "LA Sleeve" to a 240 (not recommended) unless they ordered a 240 sleeve and 240 piston!

Your 200 would have used a KA-5252 sleeve with a ProX 431 or a Wiseco 711M0660 piston that is 66 mm.

A 240 sleeve would be KA-5252B and it would use a Wiseco W969PS piston that is 72 mm.

As you can see there is a 6 mm difference in bore sizes. The big bore kits do cost more.

Also the head needed to be modified for the larger bore (part of a big bore modification).

 

[dirt bike dave]

I had my old '84 bored to a 240 after I melted the stock piston by encasing the entire (air cooled) cylinder in mud at an enduro.  With the head mods, the 240  would run fine on pump fuel. 

In the old days, the LA sleeve kit was an old fashioned iron-liner.  This means no nikasil coating for the bore. 

FWIW, the 240 jetting was hardly changed at all from stock.  The bigger cylinder sucks in the fuel harder, so it gets more gas through the stock jets.  Your fuel mileage WILL go down.  A lot. 

On my old bike, it had great low end power with the big bore (as good or better than any 250 I've ever ridden), but peak power was probably no greater than stock and it would not rev out like a stocker.  IOTW, it is not going to run like a KX250 unless you port it to compliment the extra displacement.

I'd say try it and see if you like it.  But if you don't they should have some sort of plan to locate a stock cylinder for you. 

 

[Zerotact]

I think EG only goes up to 225 on the big bore kit for the 200. I am sure there is a reason for this..... Best of luck.....

 

[canyncarvr]

Yeah, there is a reason for it.

There's a problem with the KIPS otherwise. Also, the larger the bore, the more the ports 'change'...both in size, angle and the basic fizzicks of how they work.

re: shr and 'smokin''

Ha!

No kidding! That was no accident. Just stoopid. And saying he'll '..jet for 93..' is another indication of stoopid. You don't jet for an octane. The octane requirements are determined by the engine (compression, head geometry and such).

They'd be buying me a brandy new everything they messed up. They could sell the 240 to some other unsuspecting goober.

Hey...did I just call myself a goober?

 

[CaptainObvious]

Accidently went to 240! That's a line of crap!

I'd have them make it right. If you brought it in for a stock sleve, that's what you should get.

Is it possible that what you really got was a past mistake that the shop made (that they couldn't get the guy to buy)? Don't pay for their mistake. If this little "oppps" doesn't work correctly (see canyncarvr's post above) you'll hate the bike and in the end it will cost YOU a lot of money.

Dig in and get what you want.

 

[KelvinKDX]

KDX17 - Let us know what the vibrations are like with the 240cc.  I've seen several complain of excessive vibration when going to the LA Sleeve 240.  Could be just a bunch of whiners.

I do agree with the others - if a shop does not give you what you ask for then they should make it right if you are not happy.  You do have it in writing what you wanted with them originally - don't you!? :eek:

 

[skipro3]

Let me know if you need a stock cylinder and head. I have access to one with less than a couple of hours on them. Long story behind it but they are perfect.

 

[KDX 17]

Hey everyone,

Thaks for all the input/suggestions...I'll see how it runs saturday, and let all of you know.

There's a number at the top of the piston (Which is oopsing HUGE compared to the stocker) that's 71.95mm if i remember correctly. I'm assuming this is the diameter...BTW, sorry but the guy said he ordered the sleeve from LA, I assumed that was LA sleeve, but it could possibly be just the city.

Anyway, if this thing DOESN'T work, my last question is, what can I use to beat the guy with? Crank rod, T-handle, silencer....?

 

[KAY DEE EXER]

A fork leg would do a nice job...

 

[mudwalker]

Im running the 240 kit on a 96 200. It's bored once over due to improper installation of the rist pin clip (not me). I purchased the bike with the kit installed and it was ported. I was happy with the power and performance but I have often wondered how it compares to a stock cylinder with similar mods.

It would be my bet that there is only a small power increase with this kit but I could be wrong, happens to me from time to time. As far as raw power, 4th thru 6th gear wheelies, I'll need a bump or rock to "get it up" and thats with a 12/48 drive ratio. It's my understanding that this bike tuned peeeerfectly should be able to kick my ass (165lbs) off any time any where. I'm trying to understand jetting, really I am although my latest adjustments produced only cleaner running, not more power (42p, 158main, stock needle, clip up top). Bottom line, if it were me and my stock cylinder came back a LA 240, I'd be pissed. Nothing like a stock bore.

Regarding "There's a problem with the KIPS otherwise. Also, the larger the bore, the more the ports 'change'...both in size, angle and the basic fizzicks of how they work."

CC, tell me more (if any) as I believe I am having a problem with my PV. I suspect the problem is the centrifical actuator. In higher gears at lower rpms an almost grinding noise is occuring until the revs come up. This sound familiar to anyone? I'll be taking it apart to inspect, anything in particular or obvious items I should be looking for, nows your chance to share.

 

[canyncarvr]

I took a quick look on EG's site..didn't find what I was after. I recall the 225cc size for the 200 being chosen due to (for one thing) power valve issues. Obviously there is some point at which 'moh bigger' is not going to work. The 225 is a bore/replate, not a sleeve.

In any case, with any big-bore install, some attention to the power valve system is going to be required. Heck...if it worked fine to start with, you're not going to make the hole 6mm bigger with zero consequences!

Check your KIPS manually. If it's the valves making noise you should be able to get a clue as to what's up when you open 'em by hand (nut under slotted cover on LH side of cylinder).

I'd beat the guy with a lawsuit!

 

[KDX 17]

Hey again....

The bike isn't working. Not because of the new piston, because it's showing symptoms of why it wasn't running a month ago: tons of smoke out the back, the kickstarter is hard to move, and when it does, nothing...last time, we had a knowledgable guy to help, and he said the power valve was broken. We replaced that, and now it won't work still. I'm at the end of a long rope (which I could've used to tow the damn thing home last time it quit) here. The previous owner dumped lots of money into it...has an fmf exhaust, factory connection suspension, alot of aftermarket parts...he just took oops for care of it. I don't know what the hell is going on with it, so any help would be GREATLY appreciated...

 

[cr25096er]

could the right side crank seal be leaking tranny oil into the combustion chamber?

 

[skipro3]

Hi KDX17,
I am really sorry to hear of your delema.
I don't know about Florida, but in California we have a thing called the B.A.R. Bureau of Automotive Repair. They were effective for me when I had my last KDX, a 1984, in the shop for a main bearing change and they honed my cylinder. The manual states to not hone. They offered to replate and I said no. The B.A.R. was contacted and I had a new barrel and all the rest of the top end replaced for zero charge.
I think you need an advocate to assist you in getting this shop to correct their mistake. They may have caused lower end damage when they had the top end off from the sound of your kickstart problems as well.

 

[KDX 17]

Hey skipro,

Thanks for the advice, I'll look into it if I run into any trouble...I hope Florida has one. I'm sure they don't because you need barely any insurance to even drive here. Anyway, I don't think this was caused by the new top end, since it did it when it had the old stock cylinder and piston. That's the reason we had to tear the bike apart in the first place...we changed the rings on the piston, and the kawi dealer told us the rings they gave us would fit. However, they didn't, and after trying to MAKE them fit, my dad informed me we'd need a new cylinder : ) So here we are today, tearing the bike apart again and looking to see what happened.

CR,

I think it might be a possibility, but what would explain the kickstarter problem? We just put new gaskets on, so I'm not sure, but I'll check...

Thanks for all the advice so far everybody, I really appreciate it.

 

[Boot]

Hope you can find the source of the smoke and kickstarter wierdness. They might be two unrelated problems. I'd definitely suspect the crank seals if you're getting that much smoke, and make sure that some idiot hasn't dumped oil into the fuel tank or something.

On the subject of the 240 kit, my '91 has one. Previous posters suggest that you will get much worse economy and possibly vibration. I get fantastic economy with mine, better than the last stock 200 I rode alongside, and better than many four strokes. I do have a 28mm carbie, though, which probably helps. Vibration is a non-issue. My bike is extremely smooth.

Unless the shop has machined your head to match the big bore, you might get some pinging at low revs. Good fuel will help. I run Shell Optimax, and it only pings rarely. You might have to fiddle with the jetting to get it to idle right.

I've got more notes on my 240 kit page at:
www.copperleife.com/craig/bikes/kdx/240kit.htm

 

[canyncarvr]

I'm getting lost in the smoke here........

If you had a smoking problem, were crank seals considered at all? Empirically speaking was there any trans fluid 'loss'? A shop that had any reason to suspect crank seals would do a leak down test to determine for sure that the seals were ok.....or not.

re: 28mm carby
Yeah. That might have a teensy-weensy bit to do with it! ;)

re: make them fit (rings).
How do you go about that? Filing the ends? (that's a joke! You don't file the ends of two-smoker rings) Reaming the piston ring lands? Oops.

re: honing a plated cylinder.
It's done all the time. And not by mistake or error. If someone with the expertise and knowledge of EG can do it, it's certainly doable. Doesn't mean that attacking the cylinder with a rigid stone hone 'made for 4-stroke' bores will work. I'm assuming (that always works for me! ;) ) the honing process was done correctly.

re: 'hard to move and when it does, nothing'
? Meaning it's physically hard to move? ..or it's hard to engage the gear? 'Nothing' means no compression?

A broken KIPS isn't going to give you 'tons of smoke'

Do a leakdown test (or have someone do it that knows how. It's not real simple. Takes some gauges, adapters and stuff.) Take note that the piston at times blocks the intake port..it has to be positioned properly to pressurize the crank cavity.

But, yeah....seems there are a couple of things happening that aren't necessarily related.

 

[skipro3]

The shop manual I got from Kawasaki said to not hone the cylinder. (1984) I showed it to the mechanic and he called the local Kawasaki dealer who confirmed. This was back in 1987. I've sold off the bike many years ago so I don't have the manual anymore to prove or disprove. Maintenance practices may have changed since those days and a 1984 cylinder might safely be honed today. But if you say I'm wrong and full of it ala Jaybird, then I will just have to agree with you.

 

[KDX 17]

Everyone who replied,

Thanks for all the advice and help, but now I've got a huge problem. When we had the work done (by the most reputed shop in jacksonville), they forgot to machine the the dome where the spark is created, so the larger piston was BEATING on the the dome, since it (the flange that starts the curve towards the top where the spark plug is) wasn't made larger for the larger piston. The piston repeatedly beat itself off the top of the dome, smashing the electrode into the spark plug, loosening the connecting rod, breaking a pin valve (looks like a finger ring with pin like bearings on the sides) and sending the pieces through engine, leaving shavings everywhere, gouging the cylinder walls and the piston, and out the exhaust. God knows what happened in the crankcase, but we gave them the unsplit case, piston, and top end, along with all the pieces that came out of the pipe. My dad basically told them pay for it all, and they're going to redo everything. A trained motorcyle mechanic and machinist, dave, came over and told us exactly what happened. Even someone who has the slightest idea (if any) what they're doing when it comes to working on motorcycles can figure this out. It's not CSI. But anyway, we'll have the bike working this weekend (I'll do everything I can to have it working by friday blah blah blah please don't sue me) and I'll let you know how I fare.

thanks again,
cliff