Running Very Hot

[pjv]

I have searched for this and dont see anything that covers my problem exactly.

89 fj12 with 32000, not very well looked after. I've had it a few weeks, trying to treat it right. I had the carbs cleaned and rejeted, swappped the crap K&N's for unipods.

The main issue now is that it's running very hot. Without leathers on, my legs get really hot and there is smoke from the crankcase breather filter (i'm trying to avoid an engine strip for that if poss).

I did a plug chop and the insulator part of the plug is bright white, that means hot right? (should be a nice tan color). So my two main potential culprits are advanced ignition timing and lean fuel mixture.

I know randy at RPM sells a beefed up oil cooler, which is now on my shopping list, but I would like to address the causes too. So I have a few q's
1) I dont see in the Haynes Manual anywhere that mentions how to check the ignition timing, am I missing something? Surely it's adjustable.
2) I'll look at the mixture settings, not too comfortable with that myself though, may take it back to the shop.
3) will the oil cooler upgrade really make much of a difference or am i just papering over the cracks with that?

Thanks again, love this board. Hopefully I'll add value at some stage.
Cheers,
Pat.

[andyb]

Sounds like a lean condition.  How trustworthy is the person who did the jetting?


Ignition timing isn't adjustable without some minor filing or grinding or such.  Metal has to move, anyhow.  Possibly the black box is bringing it in too early or something, but that'd be a new one to hear about.

More cooling is rarely a bad thing, but wouldn't fix the fundamental problem.

You will get a whiter plug than you'd expect with the proper jetting, but scary white isn't good.

[RichBaker]

Sounds lean, did they give you a list of what jets they put in her?

[Dan Filetti]

Eliminate the obvious intake leak symptom by spraying WD40 or starting fluid in and around the intake sleeve area while the bike is running.  If the RPM's increase, you have an intake leak.  It *could* be as simple as the boots not being seated properly.

Dan

[pjv]

Thanks gents, i was hoping it was lean as opposed to worn rings (causing the smoke from the crank breather) which i think is a possibility too (but wouldn't that cause smoke from the exhaust too??). And ok, timing eliminated as a cause for now, cool.

I used to have an FJ when i lived in europe and i dont remember it feeling this hot, even riding in spain.

I think the guys that did the carbs were good (do we mention specific shops here?), but i will def get them to give me a list of what they fitted and check charts etc, and maybe ask them to re adjust.

Dan, that's a good point, while i had the tank off today i pulled the K&N's off to put the unipods on, the outside k&N's came off with zero pressure (no need for unscrewing the clamps), but i wouldn't have thought a poorley fitted k&n would pass much more air than a well fitted one? Now that I have the unipods on i'll do a plug chop again, i wasnt expecting them to make much difference, maybe well fitted uni's will richen it back up?

Thanks guys, beers on me seriously.

[Dan Filetti]

i'll do a plug chop again, i wasn't expecting them to make much difference, maybe well fitted uni's will richen it back up?

There are others that know this stuff better than I, but it certainly seems to me that an intake leak from a poorly fitted air filter could indeed cause the bike to run lean.

If this turns out to be the case, do post it up. We have been amassing a list of why the K/N's are crap.  I know some folks like them but many seem to think they are worse than stock even.

Also, the boots between the carbs and the motor should be checked. If these are leaking/ cracked, not fitted properly, then certainly the bike would run rich, at least for those cylinders where there was a leak.  Did you check all 4 plugs?  Are they all the same?  Maybe a picture of the plug(s)?

Dan

[DreadRock]

Have the same problem with my KNs as the right out side filter is a pain to keep on . It seems to me that mine hits the top sub-frame bar right along the front bottom of the filter . Like to see how the UNI work out for you ! 

[pjv]

All four plugs were the same yes, very white insulator. I will take and post pics and feedback, will be away for a few days over the 4th so maybe alittle delay.

I had the same issue with the K&N's, they just dont fit, uni's are much nicer, cheaper, and someone mentioned that the inner two k&N's may not get so much air flow as the outside two? not sure if thats bs or not, but the uni's are pairs so i would assume much more even air distribution.

[racerrad8]

I presume you have changed the oil. If it is old, dirty or is contaminated with fuel, that will cause heating issues.

The K&N filter is a poor choice for the FJ, and the notion they breathe the inner carbs more than the outer ie something I have never heard, but that does not seem plausible.

Also, a loose air filter will not cause a lean condition. You need to find out what jets (all of them) and se if they set the needle height.

Once you have the jet info, I can point you in the right direction.

Randy - RPM

[SlowOldGuy]

Do you have adjustable needles?  If you changed to a low restriction air filter, then the stock needle position will be lean.  Shim the needles about 0.02 inches with small washers.

Smoke will escape from the crankcase breather.  It's HOT in there and there is as much air moving below the pistons as there is above them.  That's why the breather is plumbed into the airbox, to burn the oil smoke rather than allow it to vent directly to atmosphere.

DavidR.

[pjv]

ok, some updates. Really appreciate your help folks. Quick Recap - Engine running hot, white plugs, smoke from crank breather.

1) have road tested with the uni pod filters, they fit much better than the K&N's and actually stay on. Thanks RPM.


2) engine still runs hot (white plug pic)


3) the carbs were in bad shape, very dirty clogged jets etc, the dealer fitted a new dynojet stage 3 kit, with 118 main jets, the others are as per the kit chart (I wish I'd read Randy's "Kit" Rant before that). I called the tech and he suggested raising the jets one more slot (to the 3rd from the top), to richen the mixture (he also strongly suggested converting everything back to the standard air box and jetting for general street use, i agree, that will be longer term goal, just want to not have it melt down for now).


4) The type of riding i was doing to get this hot was nowhere near 3/4 or WOT, can't really do that in my suburb, so it was mostly slower speed 1/4 throttle type riding, so i dont think the white plugs are an accurate indication of the main jet settings but more the pilot air screw/jets? I think they need to be richened up. Probably that and one click on the needle. Or is that nonsense?


5) the smoke from the breather still bothers me, but i did a cheapo compression test and i got 170,160,160,160 psi on a cold engine (#1 had a little oil in it from a hot wet test the night before, (after i gave myself a heart attack and did the test without a WOT, i only got 100,100,100,100 psi at zero throttle on a hot engine and went to bed very depressed). So i think the rings / top end is good. The gauge climbed 30, 60, 90 150 psi kind of thing as i cranked the engine, hopefully that's ok. DavidR – thanks for the note re feeding the smoke back into the airbox, but some folks see this smoke as a need for a leakdown test, which would be tricky for me to get done.

6) engine oil was recently changed.

I think that's it. Thanks everyone.

[racerrad8]

Please take another picture of the plug and get the light source at the tip, the outer ring needs to be looked at as well.

If he put the clips at the top slot, that is the leanest setting. I am not sure about the DJ kit, but the stock needles that I supply with the adjustable slots start at the center slot. Meaning the center slot is stock and lowering the needle will enrich the circuit. If the DJ needles are the same you started off lean and still have not even gotten to the stock location.

Randy - RPM

[pjv]

Thanks Randy. will retake the plug pic.
Here are the needle options.

[Travis398]

lowering the needle will enrich the circuit.

I think that is a typo, or I haven't had enough beer yet 

[SlowOldGuy]

Check to make sure whoever installed the carb kit put the stock plastic spacer under the clip of the DJ needle.

If he didn't re-use the stock spacer, it will be extremely lean!

Pretty sure Randy meant to type "lowering the CLIP will enrich the circuit"

DavidR.