Richer Jetting on the Inboard Carbs?

Gotta mention this as far as "over engineering". I've been riding Honda XRs off-road since I was a kid. And in all my years haven't seen anything more over-built than an XR. They are as bulletproof as you can get. The new CRF series is more advanced and powerful, but nothing close as far as toughness and durability . I currently ride a '99 XR400R, and it will outlive all of us.

I guess you missed it, I said of the day.
Steve

Didn't miss it, just agreeing.

A guy at dragbike.com has seen folks reduce the timing at #2 & #3 a couple of degrees to lower the temp.

VTEC wrote: A guy at dragbike.com has seen folks reduce the timing at #2 & #3 a couple of degrees to lower the temp.

Yes but you have to be careful there.... retarded ignition timing can actually over heat the engine dramatically!!

Have you checked your coils?
On my 78 the left coil handles 1 and 4 and the right handles 2 and 3
Maybe you have a weak coil
JD

He was talking about enriching 2 and 3 to make them run cooler. Kinda like micro managing to me. :lol: In the 40 years I'v had this machine, I've never had a problem with them. Even though I live in the desert. Still thinking about a cooler.
Steve

In his original post he said that the 2 and 3 plugs were cleaner, that sounds to me like his 1 and 4 coil may have a weaker spark :huh:

He was talking it being on a Dyno. Also O2 censors and such. Tweaking the carboration might make a few more ponies and enriching the two inner cylinders might make it run cooler, I fail to see the value in it. I too have access to a Dyno and smog equipment. Unfortunately my neighbor has a test only shop so it would have to be before or after hours. Californicate is very strict on this. It would be fun to find out though.
Steve

bluej58 wrote: Have you checked your coils?
On my 78 the left coil handles 1 and 4 and the right handles 2 and 3
Maybe you have a weak coil
JD

I'm using the Dyna 2000 ignition and it does fire the 2/3 coils separately from 1 and 4. There are two different pickup coils to fire each coil. That's how you can differentiate the timing between the two. I'll double check the coil output, but I'm pretty sure it's a fuel/heat issue. Bike runs great and 100hp at the rear wheel on the dyno.

swest wrote: He was talking about enriching 2 and 3 to make them run cooler. Kinda like micro managing to me. :lol: In the 40 years I'v had this machine, I've never had a problem with them. Even though I live in the desert. Still thinking about a cooler.
Steve

Hey Steve, Let me give you some more info on my oil cooler. It was a pain in the ass! Mine's a J engine so it's a bit different, but I've seen several kits for earlier models at japan.webike.net/ . I know it's a Japanese site, but it's no big deal for ordering and delivery, and they have a lot of stuff you won't find local. This is where I got my Keihin FCR carb set for the J engine which is no longer available in the U.S.

I originally bought the Earl's oil cooler kit for the J engine. But it just didn't fit.



It's a 13 row Earl's cooler which came with a universal aluminum bracket to bolt to the frame. Looked great when I bolted it on, but then I noticed that it's too low on the frame to clear the exhaust pipes with the fittings and the hoses coming out the bottom. And you can't move it up higher on the frame because it interferes with the wiring harness going to the headlight. So after speaking with the rep at Earl's, he was apologetic, and bought and shipped me the bracket from the Kipkawa kit. I had already customized the Earl's aluminum bracket top and bottom with the outside studs. So I incorporated it with the steel/black bracket which brought the cooler away from the frame, and cleared the pipes.



Now comes what they call the take-off. The adapter where oil pressure comes from the pump, unseats the pressure switch, then up to the head. In this case, through the lines/cooler then up to the head. I couldn't mount the take-off because it hit the cooling fins on the block. No big deal, I ground down the take-off to make it clear, got the whole thing together, and fired the engine. Now I had no oil light. Turns out the bore in the take-off was too deep for the pressure switch. The bottom of the switch's plunger never hit anything to complete contact to ground and turn on the light. Called Earl's again, and again they bought and shipped me the take-off from the Kipkawa kit.

Finally I had the cooler install complete. There are always issues with aftermarket stuff, but Earl's handled this as professionals, and went out of their way to do the right thing. Unlike a lot of companies I'm sure we've all dealt with.

I had one on in the wreck. I still have it but it looks like SHT. I had the fittings in the shop the Meth head burned down. Now and then I remember things I had in there I will have to buy now. Too bad he dropped dead from smoking Meth. His heart gave out. I was going to give him a 44 lead pill.
The reason I didn't put it back on even though it looked bad is, the oil would empty and I wouldn't have any oil at start up. I didn't think of flipping it up side down. I was planning on a check valve. That was in 87 before the internet and eBay.
Steve