Topic: oil cooler results on cb400f (466cc)

[jessezm]

Well, after one major fail involving poorly-routed oil lines melting and erupting oil all over me and the bike, I reattempted installing an old lockhart oil cooler on my CB400f (only this time, paying careful attention that the lines were not too near the exhaust).

I was a little skeptical about how much it would help, but figured it couldn't hurt at least, and with major work done to my bike, I could use all the extra cooling I can get.  In the interest of the "scientific" research and for my own edification, I did a pre- and post- test and thought I'd share  the results:

Bike details:
-466cc kit from Japan (Ebay)
-web Cam #2
-Stage 1 heads (JMR)
-Yosh-style exhaust
-bored carbs (Rick Denoon)
-HD springs, hardened alloy retainers, bronze valve guides)
-Pistons: ceramic coated domes, dry film lubrication on skirts
-K&N pod filters
-Dyna ignition and coils
-Lockhart oil cooler from the 70's
-Oil: Valvoline 4T Synthetic 20W-50
-Tires: BT45s
-Weight: 330 lbs

Conditions: 75 degrees and sunny (both days)

So yesterday, I went on a 20 mile ride on the highway before installing the oil cooler.  On the return 10 miles I kept the rev's high and ran at about 90mph the whole way.  Oil temp as I got off the highway was 260 F (per my dip-stick oil gauge).  Once back I changed the oil and installed the oil cooler and did a few other odds and ends, then watched Game of Thrones (Awesome!)

Today when the temperature outside got to 75 degrees again I went out on the EXACT same ride, and rode the exact same way on the return trip again (pushing 90mph for almost 10 miles and keeping revs high).  Temperature on my dipstick read 230 F.

So there you have it, folks.  I am satisfied that the oil cooler is both effective and has lowered the oil temperature 30 degrees F in the crankcase to an acceptable level.  I believe these are reproducible results that were measured in fairly well controlled conditions, so I hope this can be helpful to anyone in a similar situation contemplating adding an oil cooler (and with all those 466cc kits going into bikes these days I can imagine there are a few).

[Tim2005]

Very interesting, thanks for posting it. What kind of size is the cooler? The cooler on my 460 is quite small but thick, the only other 400f one that comes to mind is the one on the 09 bike, which is huge.

[kyre]

So basically get an oil cooler! I'm going to go that route but it's the last thing I purchase for my 466 as I still need a cam, head work, cylinder bore and carb bore... Man this thing is adding up but sounds like itll be worth it.

[jessezm]

Tim, the cooler is quite small really, especially compared to what the put on most bikes these days.  Here's a link to an identical one on ebay right now: http://www.ebay.com/itm/1970S-AMF-HARLEY-DAVIDSON-FLH-FX-XLCH-LOCKHART-OIL-COOLER-/200741563184?pt=Motorcycles_Parts_Accessories&hash=item2ebd212b30&vxp=mtr

It apparently does the trick, though.  Kyre, if you're going the same route with your engine work that I did, and it sounds like you are, then I'd recommend it.  At least if you like to stay up in the revs like i do... 

[grcamna2]

Jesse,
    Does the Lockhart oil cooler that you have make the engine take longer to warm up when cold...do you sit to warm it up a bit longer to get her up to operating temps when dead cold so the parts expand to uniform shape before you put the engine in gear and under load ?? I know some Vintage oil coolers had a built-in thermostat inside the cooler and just wondered if you're Lockhart came that way.I have an older motor w/ original bore pistons..and I can usually hear a bit of piston slap in mine until I warm it up for a few minutes w/o an oil cooler.

[jessezm]

Well so far I've only had it installed and started the bike on a warm day, and the bike hasn't taken any longer warming up.  Since I have the temperature gauge on my dip-stick I think it will be pretty easy to decide if I need to warm it up a little longer than normal, though.  I think the real difference the cooler makes is at the upper end of the heat range when I'm really moving--it is definitely not as efficient as some of the more modern coolers, but for my purposes, that is actually not a bad thing I don't think.

[kyre]

Where'd you get the dipstick temp gauge?

[Grey]

Well, after one major fail involving poorly-routed oil lines melting and erupting oil all over me and the bike, I reattempted installing an old lockhart oil cooler on my CB400f (only this time, paying careful attention that the lines were not too near the exhaust).

I was a little skeptical about how much it would help, but figured it couldn't hurt at least, and with major work done to my bike, I could use all the extra cooling I can get.  In the interest of the "scientific" research and for my own edification, I did a pre- and post- test and thought I'd share  the results:

Bike details:
-466cc kit from Japan (Ebay)
-web Cam #2
-Stage 1 heads (JMR)
-Yosh-style exhaust
-bored carbs (Rick Denoon)
-HD springs, hardened alloy retainers, bronze valve guides)
-Pistons: ceramic coated domes, dry film lubrication on skirts
-K&N pod filters
-Dyna ignition and coils
-Lockhart oil cooler from the 70's
-Oil: Valvoline 4T Synthetic 20W-50
-Tires: BT45s
-Weight: 330 lbs

I/we had an endurance bike with the same basic build as you. I noticed you had bored carbs. I'm sure that helped but they are still the smaller stock carbs. I had taken a set of 76 CB750 carbs and modified them for the 400. That really woke the bike up especially on the top end. It didn't give anything up on the bottom or mid range. They actually enhance those areas also. Just a piece of info I thought you might like for future mods.

[jessezm]

Where'd you get the dipstick temp gauge?

I got it on Ebay but just checked and the seller is no longer registered.  Not sure what gives...  I bet you could find one with the googles...

[jessezm]

I/we had an endurance bike with the same basic build as you. I noticed you had bored carbs. I'm sure that helped but they are still the smaller stock carbs. I had taken a set of 76 CB750 carbs and modified them for the 400. That really woke the bike up especially on the top end. It didn't give anything up on the bottom or mid range. They actually enhance those areas also. Just a piece of info I thought you might like for future mods.

Wow, I had no idea you could squeeze those in the 400!  Can you tell me what kind of mods you had to make, what your jetting looked like, and how difficult the modifications were?  Very interested to know more.

[Grey]

I/we had an endurance bike with the same basic build as you. I noticed you had bored carbs. I'm sure that helped but they are still the smaller stock carbs. I had taken a set of 76 CB750 carbs and modified them for the 400. That really woke the bike up especially on the top end. It didn't give anything up on the bottom or mid range. They actually enhance those areas also. Just a piece of info I thought you might like for future mods.

Wow, I had no idea you could squeeze those in the 400!  Can you tell me what kind of mods you had to make, what your jetting looked like, and how difficult the modifications were?  Very interested to know more.

The mods are not for the light hearted. I'm going off memory here so I don't really remember jet sizing or needle placement. I do remember that they have to be jetted big! I kind of remember like 5 sizes up from the stock size w/stock needles. Otherwise you will put a hole in a piston like I did. This was my first real carb mod in my beginning days. I may have info on what I did in some old racing files. If I can find them I'll let you know if I do.

I think the 750 carbs are 26mm and the 400 is 24mm. So I had to find manifolds 1st. I found a set of Mikuni manifolds from a snowmobile engine. They fit the 400 bolt pattern and the 26mm carb throats and were short. I then had to machine a sleeve for each inside to keep the port at 26mm from the carb thru to the head. Didn't look for a tubing size that would work like you might be able to find. The head port was opened up to 26mm and tapered to the valve. These manifolds came straight back off the head. That opened up the center distance of the carbs so I could get them to fit.

I then took a piece of about 3/16" aluminum plate and cut holes large enough to fit the carbs thru on center of each manifold/intake port so it was a straight thru to valve.  I then cut down all the fuel tubes between carbs and what ever else needed to make them work together. I used the 750 throttle cable bracket to operate them.

As you can see in the photos below I could not even fit K&N pods on because of there size. If you look close you can see the larger carb bodies. I could only get velocity stacks on. Notice how short the manifolds are also. That little bike pulled like a freight train with these. We would pull and pass any stock 750 of the day and some that were modified. It won the 1980 600 class at the 24hrs of Nelson Ledges road race.



Larger pics here.

http://s339.photobucket.com/albums/n464/geop69/MotorCycles/?action=view&current=scan0009.jpg

[jessezm]

Impressive!  You're right, those mods are not for the faint of heart!  Thanks for sharing

[Grey]

I was just looking at a set of CB550F carbs I'm working on and they are also 26mm and are tight together. They may work even better for fitment. Then all you would need is a set of manifolds. You may want to check that out.

[Killer Canary]

I don't see the cooler making any difference whatsoever to warm up time since at rest there's no air moving through it and there's no fan. I have a Derale on my 550 and was interested in an experiment like yours  to see what effect a cooler would have. Good job! What kind of adapter plate did you use?

[jessezm]

I just drilled some holes in the top mounting tab to correspond with a U-bolt that fit perfectly around the frame tube.  No adapter necessary.  But I think the 550's have dual frame tubes, don't they?  I'll try to post up a pic later on...

[jessezm]

Here's a few shots of the setup:

[Killer Canary]

The adapter plate between the crankcase and oil filter housing which the lines plumb into.

[jessezm]

Oh, duh!  Sorry, I didn't get a good photo of that (and anyways it's hard to see now with the frame and pipes in the way).  I salvaged the plate from another cb750 I bought a while ago and then sold to a friend who didn't use the cooler set up.  It's the standard adapter plate that came with a special bolt adapter, which holds the plate on and accepts the stock bolt.  I'll try to find a link to one.

[jessezm]

Not a great picture of it but here is one for sale on ebay as a kit.  That is the exact same adapter plate I'm using, but I don't know who makes it. 

http://www.ebay.com/itm/NOS-Honda-CB750-Remote-Oil-Cooler-With-Pump-Cover-Housing-/330709172745?pt=Motorcycles_Parts_Accessories&hash=item4cffcd8209&vxp=mtr

[Killer Canary]

!

[grcamna2]

Killer C,
     I like those Derale Oil Coolers..they are High Quality.

Jesse, That Custom Aluminum Fuel Tank is a Work of Art..it "makes" the whole bike  !

[jessezm]

Yeah I was just thinking of finally naming the project "the Silver Surfer!"  Kinda cheesy I know...   Sean at Roccity Cafe Racers did an amazing job.  This was a one-off tank and seat built to my specs.

[grcamna2]

Does that custom aluminum tank have more capacity than a stocker ?

[jessezm]

Oh I'm pretty sure it does.  It's holds about 5.5 gallons.  What is stock capacity?

[Killer Canary]

Stock for a 400 would 3.8 imp total.