Hey guys,
My bike has the big bore kit, advanced ignition timer and it's tuned rich to keep it cooler. When my bike gets really hot and I take off from a stop it makes a loud clacking noise that follows the speed of the rpms and stops after about 3k rpm. In second gear if I accelerate super hard (only when hot) it does the same until about 6k rpm. Was curious if this is an overheating issue, common problem, or damaged something? I have done nothing to the bike recently, it's just been getting hotter outside.
Thanks for any info :)
Quote from: Targan on May 29, 2014, 01:25:04 AM
Hey guys,
My bike has the big bore kit, advanced ignition timer and it's tuned rich to keep it cooler. When my bike gets really hot and I take off from a stop it makes a loud clacking noise that follows the speed of the rpms and stops after about 3k rpm. In second gear if I accelerate super hard (only when hot) it does the same until about 6k rpm. Was curious if this is an overheating issue, common problem, or damaged something? I have done nothing to the bike recently, it's just been getting hotter outside.
Thanks for any info :)
"Clack" is not normally a word used to describe engine noises. It may well just be a difference in the local vernacular, but if it is a "clack" have you checked your chain and sprockets recently?
Noel
Plug check as well, preferably by using the killswitch and coasting with the engine not moving after it's done it for a spell.
Sounds like detonation to me (spark knock).
If it's hot and under load (with a lot of compression and advance) then you could be doing bad things to the motor!
Can you roll off the throttle (thus reducing the load) and make it stop?
That's my thought too. Plugs should show it clearly if it's that bad.
The other easy thing to try would be a tank of 100 octane (or higher, whatever's available... if you're rich and it's warm out, you should be okay even with an oxygenated fuel). It'll make the performance go a bit soggy, but should fix a preignition issue.
Quote from: andyb on May 29, 2014, 01:56:30 PM
That's my thought too. Plugs should show it clearly if it's that bad.
If it's detonation there will be flakes of aluminum on the plugs. The source of the aluminum would be the tops of the pistons spalling off. Not to mention what the explosive hammering is doing to the rod and main bearings.
Oh no! :sorry: This is what I feared. I am not the mechanically savvy type so forgive me for my errors. Hopefully I have not destroyed my engine (seems fine now). This has only happened a few times, but those few times it was doing it quite a bit. I'm going to bring it to my friend for a diagnostics check. If it were my chain and sprockets (which I do need to replace) why would only do it if it's hot? (curious)
What about your oil level? If it is too low the oil will surge under acceleration leaving the pump pick-up sucking air and run out of oil pressure which will make the motor sound "clacky" and return to normal when you stop accelerating. Oil thins as it gets hot and is more prone to sloshing around.
I can't see why being bored, running a few degrees advance and a bit rich would have any bearing it.
Start with the simple stuff, it won't take long to check and eliminate the chain and sprockets and oil level.
Noel
Quote from: ribbert on May 30, 2014, 05:36:24 AM
What about your oil level? If it is too low the oil will surge under acceleration leaving the pump pick-up sucking air and run out of oil pressure which will make the motor sound "clacky" and return to normal when you stop accelerating. Oil thins as it gets hot and is more prone to sloshing around.
I can't see why being bored, running a few degrees advance and a bit rich would have any bearing it.
Start with the simple stuff, it won't take long to check and eliminate the chain and sprockets and oil level.
Noel
OH MY GOD I have got to be the stupidest person here. I forgot I swapped oil coolers. I didn't install it tight enough so oil spurtted out everywhere and I forgot to fill it back up to recommended level when I fixed it. The oil light never came on so I never thought about it. Just checked and it was low. I'll have to see if my bike ever repeats this issue in the future! Chain is clean and tightened, but does have a tight spot. Will be replacing that soon. Scheduled to bring my bike in for a diagnostics next week too. It just hit it's 50,000th mile so it deserves some "spa time" haha.
Thanks for the help guys!
Update: Got my bike SUPER hot again, the noise still happens, but just barely and only when I'm pinning the throttle! So problem solved I guess lol. It doesn't do it anymore with normal riding. Also as far as highway miles go my bike stays nice and cool (relatively) and doesn't overheat even in 110+ degree weather all thanks to Randy's oil cooler! My bike was an absolute trooper on an 80 mile ride the other day. :yahoo:
Quote from: Targan on June 03, 2014, 08:23:52 PM
Update: Got my bike SUPER hot again, the noise still happens, but just barely and only when I'm pinning the throttle!
It is possible to get these engines so hot they will make strange noises that are unrelated to anything other than being too damn hot, what I would call SUPER hot. As far as your noise goes, there may be some residual damage from running it low on oil that becomes apparent when SUPER hot.
These engines are reasonably forgiving, just try not to let it get that hot. If you are stuck in barely moving traffic in 100 deg+ temps for long periods of time on a regular basis, find some other mode of transport.
Unlike a lot of older air cooled 4's, these things are not bullet proof when it comes to heat, you can seriously overheat them.
Noel
Quote from: Targan on May 29, 2014, 01:25:04 AM
Hey guys,
My bike has the big bore kit, advanced ignition timer and it's tuned rich to keep it cooler. When my bike gets really hot and I take off from a stop it makes a loud clacking noise that follows the speed of the rpms and stops after about 3k rpm. In second gear if I accelerate super hard (only when hot) it does the same until about 6k rpm. Was curious if this is an overheating issue, common problem, or damaged something? I have done nothing to the bike recently, it's just been getting hotter outside.
Thanks for any info :)
When you say "tuned rich" what exactly do you mean? What size are your pilot and main jets?
In the desert, with a high compression 1314 engine, it is entirely possible that you need 42.5 pilot jets...
I know this to be true, because I need them with my 1350 engine...I tried #40's but no go.....our toasty desert is unique.
Quote from: Pat Conlon on June 04, 2014, 12:11:12 PM
Quote from: Targan on May 29, 2014, 01:25:04 AM
Hey guys,
My bike has the big bore kit, advanced ignition timer and it's tuned rich to keep it cooler. When my bike gets really hot and I take off from a stop it makes a loud clacking noise that follows the speed of the rpms and stops after about 3k rpm. In second gear if I accelerate super hard (only when hot) it does the same until about 6k rpm. Was curious if this is an overheating issue, common problem, or damaged something? I have done nothing to the bike recently, it's just been getting hotter outside.
Thanks for any info :)
When you say "tuned rich" what exactly do you mean? What size are your pilot and main jets?
In the desert, with a high compression 1314 engine, it is entirely possible that you need 42.5 pilot jets...
I know this to be true, because I need them with my 1350 engine...I tried #40's but no go.....our toasty desert is unique.
Honestly I don't know the size, just that the previous owner had it done. It has an aftermarket fuel/air ratio gauge on the dash and it's 3/4's of the way to the top which is slighty rich.
Time for you to get dirty. Pull your carbs, take the jets out and tell us what your running.
No more guessing.
Quote from: Pat Conlon on June 04, 2014, 08:37:53 PM
Time for you to get dirty. Pull your carbs, take the jets out and tell us what your running.
No more guessing.
Pat, this development unfolded while you were at the rally, the source of the problem appears to have been found.
Quote from: Targan on May 30, 2014, 06:40:05 PM
Quote from: ribbert on May 30, 2014, 05:36:24 AM
What about your oil level? If it is too low the oil will surge under acceleration leaving the pump pick-up sucking air and run out of oil pressure which will make the motor sound "clacky" and return to normal when you stop accelerating. Oil thins as it gets hot and is more prone to sloshing around.
I can't see why being bored, running a few degrees advance and a bit rich would have any bearing it.
Start with the simple stuff, it won't take long to check and eliminate the chain and sprockets and oil level.
Noel
OH MY GOD I have got to be the stupidest person here. I forgot I swapped oil coolers. I didn't install it tight enough so oil spurtted out everywhere and I forgot to fill it back up to recommended level when I fixed it. The oil light never came on so I never thought about it. Just checked and it was low. I'll have to see if my bike ever repeats this issue in the future! Chain is clean and tightened, but does have a tight spot. Will be replacing that soon. Scheduled to bring my bike in for a diagnostics next week too. It just hit it's 50,000th mile so it deserves some "spa time" haha.
Thanks for the help guys!
Quote from: Targan on June 03, 2014, 08:23:52 PM
Update: Got my bike SUPER hot again, the noise still happens, but just barely and only when I'm pinning the throttle! So problem solved I guess lol. It doesn't do it anymore with normal riding.
Noel
Ok, gotcha...thx Noel..
Warning: This post is random because I don't want to start new threads and clog up the feed.
Another update: I would also like to point out that running lower on oil makes the engine hotter by far (probably common knowledge, just sharing from first-hand experience). I'm assuming it's because either 1: Low oil means less oil pressure to get oil through oil cooler, or 2: Less lubrication of engine causes more friction. Bike runs cooler now even though it's even hotter outside. Hitting 110 degrees and I sit in traffic, but no problems yet!
Also I seafoamed my bike (lazy/don't have tools/space to manually clean carbs) and just... wow. Whole new bike. It starts (stock horrible battery, slow as hell turn over cause of bigbore mind you) in 1 second every time and idles perfectly now. I never really believed in seafoam either until I tried it. I made the huge mistake of pouring it directly into the fuel line though, took me a day to get it running again lol. Trial and error.
After all my dumb trouble (half of it my fault) I have decided to permanently keep the bike, and learn to take care of it. Hopefully by fall it will be fully restored! What I need to do:
-Get undercut transmission and shift forks
-New fairings (this will be the hardest). Broken in a few places.
-CBR mirrors
-Integrated LED tail light from Randy
-New fork tubes (current ones have divets, running with zero oil)
-When fall hits tuning it for peak performance, won't have to worry about bike staying cool
-50/50 on new exhaust. Don't like the look of 4-1 or the sound of my long pipe.
-New brakes (everything from master cylinder to rotors). They're ok now, just mushy and I can tell they'll be done soon.
-Detail the bike
-Ride it until it dies because honestly I cannot find a better bike. I get all the power of a supersport with all the comfort of sport touring. And +1 for being the only guy to own one where I live (as far as I know). I love a bike with character!
Quote from: Targan on June 05, 2014, 08:55:31 PM
I'm assuming it's because either 1: Low oil means less oil pressure to get oil through oil cooler, or 2: Less lubrication of engine causes more friction.
or 3: the engine is oil cooled... having enough oil to keep the cooling system within its design parameters is going to be critical. Think about it... less oil = higher temperature oil due to having less oil to absorb the engine's heat. The higher temp actually works a bit better (dissipates more heat) in the oil cooler, but overall you get hotter oil since there is less of it. The engine is now trying to reject its heat into hotter oil, so it will need to be hotter by about the same amount as the oil temp has gone up.
Thought of another way, the oil is another heat sink like the fins on the cylinders. If your engine had no fins it would run MUCH hotter. Smaller heat sinks mean less heat dissipation and a hotter engine to dissipate the same heat (this part is determined by the fuel you're burning mainly... friction is insignificant compared to heat from combustion). The oil system is designed to lubricate of course, but it is also a complex heat sink and needs the oil volume to make the system work correctly.
Frank
Quote from: Flynt on June 05, 2014, 11:30:09 PM
Quote from: Targan on June 05, 2014, 08:55:31 PM
I'm assuming it's because either 1: Low oil means less oil pressure to get oil through oil cooler, or 2: Less lubrication of engine causes more friction.
or 3: the engine is oil cooled... having enough oil to keep the cooling system within its design parameters is going to be critical. Think about it... less oil = higher temperature oil due to having less oil to absorb the engine's heat. The higher temp actually works a bit better (dissipates more heat) in the oil cooler, but overall you get hotter oil since there is less of it. The engine is now trying to reject its heat into hotter oil, so it will need to be hotter by about the same amount as the oil temp has gone up.
Thought of another way, the oil is another heat sink like the fins on the cylinders. If your engine had no fins it would run MUCH hotter. Smaller heat sinks mean less heat dissipation and a hotter engine to dissipate the same heat (this part is determined by the fuel you're burning mainly... friction is insignificant compared to heat from combustion). The oil system is designed to lubricate of course, but it is also a complex heat sink and needs the oil volume to make the system work correctly.
Frank
Oh wow! That makes a lot of sense. Thanks for taking the time to explain it like that! I enjoyed the read. I thought it was just because not enough oil could get through the cooler.
Quote from: Flynt on June 05, 2014, 11:30:09 PM
Quote from: Targan on June 05, 2014, 08:55:31 PM
I'm assuming it's because either 1: Low oil means less oil pressure to get oil through oil cooler, or 2: Less lubrication of engine causes more friction.
or 3: the engine is oil cooled... having enough oil to keep the cooling system within its design parameters is going to be critical. Think about it... less oil = higher temperature oil due to having less oil to absorb the engine's heat. The higher temp actually works a bit better (dissipates more heat) in the oil cooler, but overall you get hotter oil since there is less of it. The engine is now trying to reject its heat into hotter oil, so it will need to be hotter by about the same amount as the oil temp has gone up.
Thought of another way, the oil is another heat sink like the fins on the cylinders. If your engine had no fins it would run MUCH hotter. Smaller heat sinks mean less heat dissipation and a hotter engine to dissipate the same heat (this part is determined by the fuel you're burning mainly... friction is insignificant compared to heat from combustion). The oil system is designed to lubricate of course, but it is also a complex heat sink and needs the oil volume to make the system work correctly.
Frank
Your engine turns over about one million times an hour at cruise. What makes this possible is the film of oil between the metal bits that keeps them apart, take the oil out and you would be lucky to get half way around the block before it blew up.
The clacking noise your motor makes through lack of oil is the internal bits making metal to metal contact, the oil film separating them has gone.
Oil on an air cooled bike has only a remote secondary effect on cooling. These bikes are primarily air cooled. Oil coolers are a relatively recent thing anyway, many here would have owned air cooled 4 strokes without oil coolers.
They are primarily air cooled with a radiator to keep the lubricant at a better temperature. The knock on effect does influence running temps but not a great deal. If I had to put a figure on it I would say 90% air / 10% oil.
"Oil cooling" is technically correct but mostly insignificant. Oil coolers on air cooled bikes are a relatively recent thing anyway.
Franks point about dissipating a given amount of heat into a smaller volume of oil is also technically correct but insignificant.
Quote from: Flynt on June 05, 2014, 11:30:09 PM
......friction is insignificant compared to heat from combustion).
Frank
That's also technically true, but close running metal parts and combustion are entirely different things. The principles Frank describes would apply perfectly to a water cooled engine where that is the primary source cooling.
Where is the oil present that takes away combustion heat?
Noel
Noel,
I encourage sharing some data here as you might have facts behind your assertions and maybe you can also answer the original question... is it #1 or #2 in your view?
From distant memory I believe the heat from the engine (all sources) is dissipated roughly like this for an oil/air cooled engine:
~50% goes out the exhaust (the heating of the fuel included here),
~25% goes out the fins and other surfaces,
~25% goes out the oil cooler
The FJ lump probably has a break down that's similar, but not exactly the same. Enough research would likely uncover a similar engine that has heat balance done to prove the percentages, but the oil is a very important part of the cooling equation and can become much more important when the fin temperature goes up...
Combustion heats the entire engine much more than friction. The pistons are heated directly and don't transfer much of their heat into the cyl wall (oil film insulates and slows the only significant transfer mechanism, conduction). Not sure how the FJ engine deals with cooling pistons, but it is usually either an oil spray directed at the bottom of the pistons or just a consequence of the oil being flung around by the moving internals. So nearly all of the combustion heat from the pistons goes into the oil, that's how.
Frank
PS - I'd bet there is some data out there in the Legends racing world to enlighten us all...?
Quote from: ribbert on June 06, 2014, 08:06:02 AM
Your engine turns over about one million times an hour at cruise.
5,000RPM (85mph cruise for me) X 60min/hr = 300,000 revolutions per hour... FJ redline is about half a million revolutions per hour. I'm a bit frustrated when people won't do the simple math (:mad:), but it also discredits your arguments.
Frank
Sorry Frank, I did do the simple maths, at 4000rpm and meant to say a
quarter of a million but I don't see it has any bearing on the point being made anyway.
The 90/10 figure I mentioned is entirely off the top of my head. I guess I view early motorbikes like the FJ as air cooled bikes with oil coolers added as opposed to engines designed around oil cooling. It wasn't long before that they didn't have oil coolers at all.
IMO "splash feed" is more about lubricating cylinder walls than drawing heat from the pistons.
Quote from: Flynt on June 06, 2014, 09:17:42 AM
I'm a bit frustrated when people won't do the simple math (:mad:), but it also discredits your argument.
Frank
I don't see the connection.
No matter, I shouldn't have bothered commenting on it anyway. It's one of those topics without a definitive answer and to no benefit.
Noel
No oil spray onto FJ pistons, so it's either fling cooling (never heard of that!) or heat transferred to the oil via contact (cylinder head perhaps?). Where else is there a surface heated by combustion and cooled via oil contact (OK, maybe some transfer via cooling fins).
Quote from: simi_ed on June 06, 2014, 10:18:14 AM
No oil spray onto FJ pistons
Sorry ed...
Incorrect, there is a oil spray hole located on the top side of the connecting rod to spray oil up onto the underside of the piston & cylinder wall.
We tried many years ago altering the hole size to increase the oil sprayed on the bottom of the piston, but with the weak oiling system of the FJ it lowers the main galley oil pressure too much, compared to any additional gain of cooling.
If we added an external oil cooler spray bar like my son's Miata has, that would help significantly.
Randy - RPM
OK, I'm starting to feel like Noel :dash2: I'm going back to my corner & observe for a while.
Oh my gosh you guys! (popcorn) You're so civil i love it.
I am by no means a mechanic and am relatively new to motorcycles, but talking from first hand experience i know:
1. Stock oil cooler in 90 degree weather=overheating (have done this a few times) in traffic, and running hot (but fine) on the highway
2. Randy's oil cooler in 100+ degree weather=haven't overheated yet (with proper oil level) in traffic, and runs perfectly normal on the highway.
3. Less oil in my bike=overheating faster
When I say "overheat" I mean too hot to start my bike if it shuts off, it struggles to turn over (I need a new, or need to clean, starter or a lithium battery).
I'm just saying maybe just maaaaaybe oil does keep the motor cool :rofl:
You could too replace the std plugs with 1 degree colder spark plugs. I use NGK DPR 9 EA9 (instead the 8 recommended) and it lower the temperature around 5ºC
And the Randy´s spin-on conversion get a welcome couple of degrees lower too due to the greater air flow and the extra-ammount of oil with the big filter
Quote from: racerrad8 on June 06, 2014, 10:41:20 AM
Quote from: simi_ed on June 06, 2014, 10:18:14 AM
No oil spray onto FJ pistons
Sorry ed...
Incorrect, there is a oil spray hole located on the top side of the connecting rod to spray oil up onto the underside of the piston & cylinder wall.
We tried many years ago altering the hole size to increase the oil sprayed on the bottom of the piston, but with the weak oiling system of the FJ it lowers the main galley oil pressure too much, compared to any additional gain of cooling.
If we added an external oil cooler spray bar like my son's Miata has, that would help significantly.
Randy - RPM
Details, Randy, please. It looks a great mod