It looks like quite a number of people have put 440 kits in their 400EXs. I was considering this but was discouraged after talking to some shops about having it done. They were telling me that the sleeves have a tendency to shift and that there are problems with blown head gaskets. What's more is they said the performance to be gained is greatly overated.

I appreciate their honesty, but I'm still interested. It seems like a sleeve would be more of a concern in two strokes than four strokes where there aren't any ports in the sleeve.

Would anyone with 440 kit experience like to comment on these points? Any problems? How much of an improvement was there and do you feel it was worth it? Also, what make of piston and compression ratio did you use.

Thanks

 

I'd like to hear some input on this too...

 

Interesting feedback you've gotten from your local shop. Especially about the sleeve shifting -- Since most installations are done locally, I would have to wonder if maybe their installer has problems with these.

The mechanics involved with installing an oversized sleeve in the 400EX cylinder don't involve anything strange. In fact, it would be about the same thing as pressing out the old sleeve and putting in a new one -- only one other step is involved: that of boring the cylinder larger to accept the new sleeve. Done correctly (a simple procedure that most shops can do in-house), you would never have a problem. No one that I have spoken to has EVER had a sleeve drop in a 440 kit.

Correctly installed, the 440cc kit works. In the lower compression ratio (10.5:1), I have never heard of a blown headgasket, unless there were other problems (improperly torqued studs, bad surfacing on the head or cylinder, improper handling of the gasket, etc).

You can expect at least a 30% gain from the kit alone. Better than anything else you can buy for the 400EX for under $500!

As to reliability? Just like anything else, you get out of it what you put into it!

For riders who don't enjoy maintenance, I'd leave any bike stock. If you regularly maintain the quad, you can expect the 440cc kit to last as long as a stock piston would.

Oh, a question for you -- just to satisfy my curiosity -- What modifications DID your local shop suggest? Since they feel that a 40cc increase is greatly overrated, I wonder if they would sell an XR200 as a better bike than the XR250? Since that displacement thing is so highly overrated?? ;-)

 

Pam, thanks for your response! Those couple shops that I talked to really took the wind out of my sails. I am encouraged by what you've said. I had a feeling that those guys just didn't want to take on the job.

In answer to your question as to what they recommended I do, I think there were a few suggestions if I remember correctly. First, one guy said "those Japs really know what their doing and when you go in there and start messing with stuff, you're just asking for trouble." This guy then asked what kind of riding I do, I told him that it was mostly trail riding and that I wanted more bottom and mid. He said to try dropping a tooth on the front sprocket, which I did. I can't say that I really noticed much difference- a little quicker off the line but it's easy to hit the rev limiter if I don't shift quick enough.

Another guy told me that rather than going up on displacement I should run a higher compression piston in the stock bore. I went and got a 10:1 Wiseco -just finished putting that in last Saturday. This I can't say much about yet since I have only ridden it one time and that was on 6 inches of fresh snow out in our parking lot.

I have some other goodies for it too. I got a White Bro's/Web Cam 450/451 cam and set of hardwelded rocker arms. Haven't put these in yet.
I think it was Arlen at LRD that told me I should use a higher compression piston with that cam than the 10:1 that I had already bought. I think I'll run the 10:1 for a while and then get a higher compression piston.

Which brings up a question for you. I read one of your posts about pistons; it seems like you might prefer the JE piston over Wiseco? If I go with the 440 job do you think it would be better to go with a JE piston? What compression? I have been running 104 octane.

This is another matter; race gas, ignoramus that I am, I thought race gas meant more power and a hotter burning temp. I was concerned that since I had not rejetted after installing a E-series silencer and K&N that I had been running real hot. Well, when I took the old piston out I was surprised to see what I thought was a lot of carbon built up on it. The plug was a nice dusty brown. This is the first engine I have ever taken apart so I wasn't sure about the amount of carbon on the piston. It was about .03" thick and right in the middle there was a brassy/coppery sheen to it- I don't know what to make of that.

 

Ya know, why is it that I get booted offline just as I'm about to finish typing a post??? No, it never happens when I'm just wandering aimlessly in cyber-land -- It's gotta happen JUST as I get done writing some million-word essay on 400EX stuff! AARGH!

Anyway, back to the subject at hand!

Your question was:
<<I read one of your posts about pistons; it seems like you might prefer the JE piston over Wiseco? If I go with the 440 job do you think it would be better to go with a JE piston? What compression? I have been running 104 octane.>>

JE and Arias pistons are made from a little less flexible material. Meaning they have less of a tendency to wear and/or seize. This problem is exacerbated in larger engines -- the larger the piston, the more exaggerated the flex.

Don't get me wrong, I have had good luck with Wiseco pistons in smaller 2 strokes. I do run them in bikes when I know I'll be getting in and changing pistons frequently. They are cheaply priced and work well for race applications.

Would I run them in a big-bore four stroke? Not on a bet! How often do you really want to replace parts on that motor? A good quality forged JE or Arias piston will last as long as a stock piston -- meaning you should be able to go a LOOOOOONG time before rebuilding.

Compression -- well, since you're already running race gas, you can go with the 12:1 comp. piston. As long as you ALWAYS run race fuel. Keep in mind, if you ever run it on pump gas, it'll probably start spewing oil pretty quick.

If you ride right at sea level, you may have some problems starting the high comp. setup when it's cold. Once they're warmed up, we've never had a problem.

Next question:

<< This is another matter; race gas, ignoramus that I am, I thought race gas meant more power and a hotter burning temp. I was concerned that since I had not rejetted after installing a E-series silencer and K&N that I had been running real hot. >>

You're not an ignoramus! Race fuel is healthier in most engines than pump fuel. The reason is because it actually fires at a LOWER temp than pump fuel -- meaning it keeps the engine cooler.

<< Well, when I took the old piston out I was surprised to see what I thought was a lot of carbon built up on it. The plug was a nice dusty brown. This is the first engine I have ever taken apart so I wasn't sure about the amount of carbon on the piston. It was about .03" thick and right in the middle there was a brassy/coppery sheen to it- I don't know what to make of that. >>

Well, there's two ways to kill a piston. One is running a fuel which is too low octane for the compression. This causes predetonation (pinging) where the fuel actually ignites before the piston is at the top of the stroke. This causes a much larger explosion than the piston is ready to handle, and basically blows the ring lands (the piston sections between the rings) right off the piston.

Then there's overheating caused by a lean condition. Ya see, fuel is also an engine coolant. Too little fuel creates too much heat in the cylinder -- which then causes the piston to expand quickly and "become one" with the cylinder walls -- viola! -- we have seizure!

From the description of the piston, it sounds like the engine may have been running just about right. Maybe a TINY bit on the lean side of perfect, but okay. Now, turn the piston over. Is there any of that bronze coloring on the inside? If so, it's too lean, or overheating because of some other reason. Don't worry, I'm sure it's not, but it's a good thing to check.

The carbon buildup was probably due to unburnt race gas deposits -- since you're running more octane than the engine compression demands.

I'd say for a 10:1 or 10.5:1 compression setup, you'd be best to run 1/2 race fuel and 1/2 pump gas. This gives you the best of both worlds!

Hope this answered your questions!

 

Thanks again Pam! I really appreciate your advice. When I get my next piston I will definitely go with either a JE or Arias. Being new to the sport I had not heard of these brands. It seems like most parts distributors carry Wiseco but I haven't ever noticed JE or Arias pistons in their ads.

 

TRAILMIX
WHERE DID YOU GET YOUR HARD FACED ROCKER ARMS AND HOW MUCH DID YOU PAY FOR THEM? DID YOU GET YOUR STOCK ROCKERS REDONE OR DID YOU BUY A WHOLE NEW SET? THANKS IN ADVANCE

 

PAM
WHERE CAN YOU BUY HARD FACED ROCKER ARMS AND HOW MUCH ARE THEY? THANKS IN ADVANCE