Have you Decked the cylinder

[Matt Fisher]

Here's the stock cam oiling system. Look at the oil filter cover. There's a oil galley that travels up at about the 10 o'clock mark through the case cover. It goes to the base of the cylinder. You'll see an oil line cast into the side of the cylinder, the oil travels up from there to the cam. The sprocket side of the cam has a sealed bearing. The oil travels up the galley in the cylinder, fills the "pocket" created by the sealed bearing, and gets forced through the cam itself. It comes out of holes in the cam itself, and gravity feeds back down the cam chain area.

The FST cooler intercepts the oil before it gets to the cylinder. The side cover is tapped into the oil galley, and the line giong to the cylinder is plugged, forcing the oil to go into the cooler. After being cooled, it goes into the cam cover, where another hole has been tapped. Because the "pocket" fills up with oil just like the OEM system, the only difference is it's cooler oil.

Given the conversations I've had with Megacycle cams, Web cams, and after examining my cam, I really believe that cooling the oil before it hits the cam is a really good idea. I won't be using the FST cooler, as I have a much better one, but I'm in total support of the concept.

[MIKE400EX]

Figured it was time to get this thread up on the front lines again!

Some additions. I slapped on a FCR41 this weekend. Like Gabe(?) reported, incredible bottom end increase w/lightning quick response. I'm amazed at the difference over the stock carb (w/o a choke). Even with the GTT cam, the bottom end hit is way more than bone stock, very noticeable mid increase and top, well I didn't have a long enough area to really stretch it out - yet. It completes the whole 440 & cam combo. There's now more of a difference between my modded 400 and a stock one, than my wifes 250EX and a stock 400. Took the better part of a day to sort out the jetting, but it was well worth it. Dollar for dollar probably the best motor investment yet.

Mike thats a great sounding increase with the carb and I am glad someone here got their 440 running right.

I did not even start to think of the carb yet.

Did you notice any changes with starting??

[86atc250r]

Personally, mine starts easier with the FCR, even though it does not have a choke.

Sometimes when it's really cold, sub 20 deg, it will lean out pretty badly until you get a little heat built up, but if that's the case, you really shouldn't be putting the engine under load until it warms up anyhow.

That would also probably be easy to correct with cold weather jetting, but I don't really ride when it's that cold anyhow, so I don't generally bother.

As Mike said, the throttle response with the FCR is unreal - I've actually geared my quad up to tone down the response for cross country racing since it was causing steering problems coming out of corners & if you accidentially bump the throttle a little when going thru a rough section, you get a serious unexpected surge of power...

Expect some tuning time, but once you get it dialed in, it's a great carb.

[MIKE400EX]

Mine also starts up much easier than it ever has. The carb tunes, acts, and seems to be designed, similar to the Webers on my race car (at least something is familiar for once). Yes, Gabe, I know there's more fine tuning to go - but the results so far are MUCH better than expected.

[86atc250r]

Yep, I've still got some fine tuning to do on mine as well... But it runs well enough that it's not really a priority at this time. Just a couple little weird areas that could use a little time spent on them.

The FCR sounds like a great swap for the stocker hmmmm I guess there goes another $300.00-500.00, but I will not be getting into anything new untill I get this compression problem fixed.

I had talked to some local machine shops and even a shop that deals with bikes and quads and I looked like I was gonna be out another 100.00 for the valve job.

I have a friend that claims he has doen this many many times and from what it sounds like he is just doing a modified version of lapping the valves. I guess he is using lapping compound and basicaly just putting it between the valve and seat and then turning the valve by the stem with some sort of drill or whatever.
Does this sound like a good idea?? He claims it sets the valve and seat at the same time unless the valve is bent or bad and then would need a true valve job. HELP

I wan to get this right thew first time so I do not have to invest another 28.00 for the cometic 0.025 head gasket two more times if its wrong.

Thanks

Gabe did you ever get any testing done on the shocks or the measurements and numbers for the carrier info??

[86atc250r]

Still waiting on my PEP shocks.... I've got the dual row carrier info written down, I'll try to find it tonight, hope I haven't lost it.

Thats a reallllllllll longgggg wait, hope they perform as good as it is long to get them.

[Matt Fisher]

Did some measurements on Saturday. I show 38cc's for the head, and with a .020 base, .025 steel head, and the domed Ross piston, 39cc's. The good news is that that equates to a 11.28 compression ratio. The bad news is that without the head gasket, the squish is about .045, with it I end up with .070- yuck.

With the head gasket removed, I had a 35cc area, equating to a 12.57 CR. This tells me that the cylinder will need to be decked the same basic amount as a flat top Wiseco, but then I will need to remove material from the chamber by unshrouding the valves and/or shaving the piston top. Arrrugh. The good part of doing either of these is I'll get more power from the chamber work, and a lighter piston after it's machined.

I'm betting the JE pistons are a mirror image of the Ross ones, and they will have the same issue of squish vs. compression ratio. Has anyone checked the squish of a 416 piston, I'm very curious as to what they end up with.

The Ross piston delivers what was promised- a 11.2 CR. Too bad there's the squish issue.

440ex4me- you can go to Sears and get the valve lapping compound plus a tool for doing it by hand. The tool is a stick with a suction cup on the end. Pull off the springs, put some lapping compound on the seat, and use your hands to spin the valve back and forth. We used to do that in 4H with lawnmower engines. Cheap- but a 1 angle valve job sucks for performance. I'd do it but re-use the exisiting head gasket. If it fixes the problem, have a real valve job done, and then slap a new head gasket on there.

Good to hear about the FCR working so well- that's on the list...