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Name that oil cooler adapter! Please...

  • Thread starter Thread starter makenzie71
  • Start date Start date
M

makenzie71

Guest
Just curious if anyone happens to know what adapter this is and if it's just a simple bolt-on piece. I'd like to remove it and have it powdercoated, and replace the ghetto wanna-be stainless lines and cheap anodized ends with a real stainless setup.

gsoilcooler.JPG
 
Looks like a Lockhart adapter. Simple bolt on.
 
Interesting boots

Interesting boots

Hi Mr. makenzie71,

Are those your intake boots? Do they have vacuum ports for sync adjustment? How do the carbs connect? Please tell me about them.


Thank you for your indulgence,

BassCliff
 
They are going to be a direct replacement for the stock manifolds so no...no vacuum ports. The vac ports on the head itself are still accessible.

The carburetors will bolt up using petrol-proof silicon tubing and your typical hose clamps. I'll have pics up later of the port-matching and the 30mm CB750 carburetors bolted up.
 
Hi Mr. makenzie71,

The rookie that I am, I was unaware that the 8-valve motors had vacuum ports on the heads. I thought they were in the intake boots. What motor is that?


Thank you for your indulgence,

BassCliff
 
makenzie71 said:
They are going to be a direct replacement for the stock manifolds so no...no vacuum ports. The vac ports on the head itself are still accessible.

The carburetors will bolt up using petrol-proof silicon tubing and your typical hose clamps. I'll have pics up later of the port-matching and the 30mm CB750 carburetors bolted up.
Click to expand...

How could one get his hands on a set. What a much better design than the stock ones.
 
BassCliff said:
The rookie that I am, I was unaware that the 8-valve motors had vacuum ports on the heads. I thought they were in the intake boots. What motor is that?
Click to expand...

To my knowledge, it is a 1979 GS750E stock motor. I may be wrong as I'm not that knowledgeable of this variety of GS, either, but I see no evidence of tempering.

gs750intake1.JPG


NEO said:
How could one get his hands on a set. What a much better design than the stock ones.
Click to expand...

One could get a set by sending me $165 usd. I was intending to sell them for less but **** they took a LOT more time to cut down than what I had expected. Nearly four hours of labor.

Agemax said:
how will the longer inlet tracts affect performance?
Click to expand...


Intake runner lengths affect different engines in different ways. My EX500 gained nearly a hp with a 10mm increase in intake tract length, where as the old FZ600 I worked with lost about the same with a 10mm increase. I don't know how it'll effect the GS yet.

I can say that anyone running the stock carburetors, they'll see only about 15~20mm gained in length, but they'll also gain quite a bit more flow with proper port-matching. I don't think length is going to be an issue as the intake runners are very short with this particular bike. We'll see.

gs750intake2.JPG


gs750intake3.JPG
 
I'll add that I'm using 30mm carburetors, thus the larger bore and porting.

Stock is 26mm carburetors with 25+/-mm manifolds flowing into a 28mm head.

I'll post pics and a how-to for a proper intake port boring and polish with an assembled engine.
 
makenzie71 said:
I'll add that I'm using 30mm carburetors, thus the larger bore and porting.

Stock is 26mm carburetors with 25+/-mm manifolds flowing into a 28mm head.

I'll post pics and a how-to for a proper intake port boring and polish with an assembled engine.
Click to expand...
Those look pretty good man. One question from me: Whats sealing them to the head? Behing the metal flange on the stockers use a Viton oring. Is this what you intend to seal it with or you have something else in mind?
 
The o-rings are a poor design...they're effective and cheap but they are too easy to damage and can be hard to diagnose if they fail. So I've eliminated them with setup.

The new manifolds will use real gaskets.
 
makenzie71 said:
To my knowledge, it is a 1979 GS750E stock motor. I may be wrong as I'm not that knowledgeable of this variety of GS, either, but I see no evidence of tempering.

gs750intake1.JPG




One could get a set by sending me $165 usd. I was intending to sell them for less but **** they took a LOT more time to cut down than what I had expected. Nearly four hours of labor.




Intake runner lengths affect different engines in different ways. My EX500 gained nearly a hp with a 10mm increase in intake tract length, where as the old FZ600 I worked with lost about the same with a 10mm increase. I don't know how it'll effect the GS yet.

I can say that anyone running the stock carburetors, they'll see only about 15~20mm gained in length, but they'll also gain quite a bit more flow with proper port-matching. I don't think length is going to be an issue as the intake runners are very short with this particular bike. We'll see.

gs750intake2.JPG


gs750intake3.JPG
Click to expand...
just wondering as i have just got new nitrous adapters that fit between the head and the origonal inlet rubbers, and they are 10mm wide.
 
Ooh, this is fascinating, I've just done the reverse and built some adapters like yours for installing a set of 29mm Mikuni smoothbores on one of my CB750's! (1969-78 Honda SOHC CB750 carb size is 28mm)

The "smoothies" have apparently been re-racked into GS550 racks, (I'm waiting on RenoBruce to send me a GS1000 rack, but it's been awhile and he's not answering my messages, does anyone know if he's still around?) which make them almost a perfect fit on CB750 inlet rubbers, BUT, the Mikuni spigot ODs are too small for the CB750 inlet ID, so I came up with these:

Mikuniadapter2.jpg


Mikuniadapter3.jpg


Mikuniadapter4b.jpg


Mikuniadapter8.jpg
`

Now I could have made some "Spigot adapters" like Sudco made for the smoothies to allow them to be used in the later GS1000 "Big Port" head, but I needed vacuum ports as the CB750's have them on their carbs, so all in all I increased the length of the inlet tract by 35mm.

I'm not sure how that'll effect overall performance, but I'm told that it should increase my torque figure, and of course, torque equals accelleration, so so far, so good! Cheers, Terry.
 
Last edited:
agemax...terry...what you see with an increased intake tract length is the air the bike breaths in will be moving faster. Having a longer tract allows it more time to accelerate. This can be good...or bad. Faster air is warmer air, so you lose density. More momentum means more air is crammed into the combustion chamber, so you gain density. Runner length tuning gets complicated because the idea is to find the perfect balance between the two. On your average street bike it's nothing to worry about because you're not going to gain or lose anything you can actually feel, unless to go to extremes in length.
 
and that's odd because the Keihin smoothbore carbs I got off my '74 CB750 are 30mm bore.
 
Thanks for that Macca, I'm learning more and more every day. If your Keihin smoothbores are genuine Keihin CR's, they'll be 29mm or 31mm, they never made 30mm carbs. Cheers, Terry.
 
I'll get a good mic on them later and see exactly. 29mm would be slick...cleaner fit all around.
 
No worries mate, what's that silicon rubber tube you're gonna use to adapt them? I'd like to get some for another carb project. Cheers, Terry.
 
checked and it is certainly 30mm, but there's a polish inside. May have been bored out...but hard to see being bored just 1mm. Anyway...

Find a shop that deals in race cars or does custom forced induction setups. They always have silicone hose around. Typically, I can find enough in their scraps to do what I need...only costs a tip when you do it that way, too.

I have been trying to find a cheap source to get a large section of it, though.
 
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