JETTING and it's effect on 440 engine temp... HELP!

[Steven]

My TRX440EX has been getting hot!

I first noticed this when i started letting novice guests ride my bike. At first I couldn't understand it.

When I rode the bike, oil temperature stayed between 220 and 250 degrees. Everytime I let someone else ride it, oil temp would shoot to over 300 degrees????

After time, I discovered that when the bike was ridden for long periods (10-15 minutes) at 1/4 to 1/2 throttle with no W.O.T runs, it would get hot-fast, regardless of speed. Run the bike hard for a few moments and temperature would drop 50 degrees back to 250.

Only thing I can figure is that running hard moves more fuel into the engine, cooling it. What do you think?

I'm using Avgas 100LL.

Today I ran a 170 main, stock needle on 4th clip, and a 45 pilot (stock carb-no choke).

That 45 pilot is too rich I think. It won't ilde with the screw out 2.5 turns. With the scew out 1 turn, it idles slow. With the screw all the way in , it idles well. This means I have to drop to a 42 pilot, right?

Anyway back to the temperature thing. Might the engine run cooler at part throttle if I move to position #5 on the needle? Is this setting unheard of with the below set-up? Will it even run?

Help!

Thanks, Steve.

[Colby@C&DRacing]

Sounds like a tipical big bore kit to me. They need alot more air to keep them cool. Try the needle in the bottom clip, also if you do not have air scoops on that bike get some. You also need to be running a cooler plug.:)

[Waynes400ex]

Whats the number on the cooler plug? Who makes nice looking scoops and what else would help? I'am also doing a 440 and dont want it to get hot!!

[cals400ex]

ngk dpr9z is the colder plug. i know many people use to get the tinner scoops but i haven't heard of them lately. i am running a 45 pilot with 3 turns out on the fuel skrew. also, mine is a little rich with the needle in the 4th position, but it is too lean in the stock location.

[Waynes400ex]

ANy one know what to run with a 39 FCR on a 11 to 1 440 with K&N and Exhuast ?

[skemp]

Originally posted by Waynes400ex
ANy one know what to run with a 39 FCR on a 11 to 1 440 with K&N and Exhuast ?
Try a 168 or 170 main in the 440 with the OCEM-P needle on the 3rd position with a 52 or 55 pilot.

[Steven]

i do have the omf scoops and run the #9 plug

i will try lowering the clip another notch on the needle

now what about the pilot?

thanks, steve

[Steven]

guys i need help on the pilot jet. can anyone answer the question to the pilot jet symptom?

thanks, steve

[cals400ex]

i am running a 45 pilot with 3 turns out on my fuel skrew on my 406. i am also in the 4th position on the needle. is it still getting hot in the 4th position on the needle? my bike was doing the same exact thing as you. it would not get too hot idleing or while i was getting on it. however, if i gave it enough throttle to go, my headers would start glowing and the bike was getting hot. it was because i was running the clip on the needle in the 3rd position. putting my clip down to the 4th fixed my problem. actually, in the 4th position, it was a little rich but in the winter it should be perfect. i just ordered a shim from C&D so i could adjust the clip right between the 3rd and 4th position in the summer months. maybe you need to raise your idle up a bit if its not idling correct. i know after i put my cam and piston in my idle seemed to fluctuate some.

[Steven]

I think I've got it figured out.

The 42 pilot fixed the idle problem.

I lowered the needle to the 5th clip (richest) and it runs well!

I also went up to a 175 main.

I'll test it for temperature this weekend but as for function, it runs great with the new settings.

Steve