E series engines

[Julien D]

Wonder if anyone wants to talk about the E series engine a bit. I hear several people who have ridden both E and H series bikes prefer the E series power delivery. Why exactly is this? We know the power valves are different, but are there porting differences? What differences ARE there really? Seems to me that the H series has a little more snap and is perhaps slightly less linear.

In light of my recent issues with E series power valves, and the fact that I have a spare cylinder laying in the garage, combined with spending some time reading here: http://www.craig.copperleife.com/bikes/kdx/index.htm leaves me wondering if an overbore on an would be a horrible idea. Workable with some head, porting, and carb work? For anyone who doesn't already know, you can't overbore an E series 200 engine and keep the KIPS valves. At least, my understanding is that you can't.

I think Craigs page there is the only documentation I have ever seen on a bored over E series engine. Anyone know of anything else??

If I decided to go for it, I always have my stock cylinder to go back to....

[Mr. Wibbens]

Carvr's bike always seemed to me to have a lot more snap, just from watching him. But then again, he's just a little Leprechaun and I've got at 100 lbs on him

He's always commented how much grunt my bike has

I've talked with a few oldskoolers around here, they say a 240 kit really wakes up an "E"

[Julien D]

Thx Wibbly. It is true the power valves get lost in the 240 kit, right? The 225 kit should also be considered. I presume that loses the valves as well. I would hope the displacement increase would be enough to offset the low end that would be sacrificed by losing the power valves.

[Mr. Wibbens]

AFAIK, you lose em

I'm not sure what effect the power valve has on the bottom end. By the looks of the one on mine that broke, it had been broke for a very long time

[Mr. Wibbens]

I have a friend that has an H that is now a 255

Sadly I did not get to ride it

[SS109]

...they say a 240 kit really wakes up an "E"

I didn't know you could get a 240 kit for the "E" series. Who offers them?

[Mr. Wibbens]

Pretty sure they sleeve it

[Julien D]

Yeah it's done with a sleeve from LA Sleeve. Not sure if the parts can even be procured any more, but I could give LA Sleeve a shout and find out. At this point I'm just tossing around ideas, not planning anything.

[fuzzy]

Yes, it's sleeved. Can bore/replace without going THAT big. IE a 225 I'm pretty sure is feasable on an E. Could do a 220 bore as well. Ports/head need massaged with bore change. Last thing I'd do is trade in my plated cyl for a 240cc sleeved jug. There are plenty of things you can do to increase grunt without the trade off of losing the KIPS. Woods pipe, increase header flex (Torque ring), DF reeds, RB carb, etc. Heck I've pondered an RB 33mm carb w/o touching the carb bore...For a 200 even.

[Julien D]

Fuzzy, the whole point of the exercise would be to lose the valves. My bike has plenty of grunt, and I quite like the power delivery as it stands. Not sure I'm keen on losing the power valves but I'm certainly keen on not having to replace the damn things any more. Darn E series bikes like to eat the valves frequently.

In short, I'm not looking at the overbore as a performance increase but more of a way to keep the low end power of the bike WITHOUT the darn valves.

[Indawoods]

If you want that... pull the KIPS gear on the right hand side. DONE.

[Julien D]

Yeah. I've ridden the bike without power valves, or with broken power valves at least. I much prefer the low end pull of the bike in stock form with the power valves intact. What I'm getting at here is the larger bore size should add some low end power to the bike, right? Enough to compensate for losing the valves? I dunno.


Why remove just teh RH side though? The LH valve seems to be the one that breaks more frequently. Keep in mind the difference in KIPS on the E series as opposed to the H. Removing the RH valve will still allow the LH and center valve to operate. I assume the LH valve will still shear off at some point in time whether the RH valve is in place or not. The center valve seems darn near indestructible.

Like I said, just tossing the big bore idea around. I did some interesting mods on the power valves when this last time so we'll see how long they hold up this go round. Last time I got 3 or 4 rides before LH and RH valves were sheared again. Of course it's a different jug this time that happened to have less play in the lower PV journals, and I fabricated a plate to take the place of the cheesy set screw that holds the PV rod in from the RH side. The whole setup seems more stable this build. Time will tell....

[Mr. Wibbens]

I heard it was the right side

My left valve was ok

[Julien D]

Yeah? That's interesting. Left valve was broken when I got the bike. Replaced it. Next time I was in there both valves were broken. Replaced. Next time I'm in there both valves are broken again. Replaced.

I kinda figured the left valve would be more suspect simply since it's furthest from the actuating shaft and play might be increased over there? Seems kinda a moot point in my case since they both seem to break pretty easy. My buddies 91 seems to only go through the left valves though. We haven't had to put a RH valve in his yet.

I did some see some aftermarket valves made from another material, looked NICE. dunno much about them though, foreign company and all that. Honestly I wouldn't feel the need for any sort of over bore if I can solve the issue of kips valves breaking. If they break again I'll be looking into some means of eliminating them and adding enough low end grunt to the engine that I can do without them.




http://www.carvalhoracing.com.br/loja/i ... a=0&id=263

[fuzzy]

Fuzzy, the whole point of the exercise would be to lose the valves

Gothca. I wonder what they do when they remove them? They must do something with some sort of epoxy/etc. It's one thing to disable them and leave them in, but to just remove the whole assembly? This would also leave you with the 'top end' exhaust port configuration. As you say, this exhaust port with the 240cc bore might be a good combo. I just wouldn't want a sleeve. If you don't care about top-end power you can always rig the kips shut?

Those aftermarket gears look sweet.

[Julien D]

Yeah. I didn't much like the way my bike ran when the sub valves were jammed shut. I get too much use out of the top end.

I'm hopefull that I can come to some agreement with my valves so they'll just stop breaking! lol


I agree completely on the sleeveing issue. I'd rather avoid the liner if possible. I Think I could do a 220 or 225 and have it plated.

[Julien D]

Dunno how much truth there is to it but I found an old thread a bit ago which indicates you can not do a 220/225 kit on the E series. Only option is to lose the power valves and run the sleeved 240 kit.

[fuzzy]

Well that would suck. I would be skeptical that the 240cc bore would provide enough low-end to lose the power valve (and have it be a net gain)

[Julien D]

You know, I spent a lot of time searching for threads on the 240 kits. It seems that one of the largest complaints especially on the E series engines was an erratic idle and some loss of power in the low end.

Looking at some information on KIPS design, it seems the CDI on KIPS equipped KDX's is designed around the power valve operation. IE different timing settings for under 6k vs over 6k rpm. Neat, huh?

So I think if you lose the KIPS, and don't switch out the CDI for a model that is not set up for KIPS (pre 86 KDX200 CDI perhaps?), you'd be missing out on a lot.

[fuzzy]

Agreed.