Name that oil cooler adapter! Please...

[makenzie71]

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.

[Nessism]

Looks like a Lockhart adapter. Simple bolt on.

[makenzie71]

sweet...thanks

[BassCliff]

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

[makenzie71]

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.

[BassCliff]

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

[NEO]

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.

How could one get his hands on a set. What a much better design than the stock ones.

[Agemax]

how will the longer inlet tracts affect performance?

[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?

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.

How could one get his hands on a set. What a much better design than the stock ones.

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.

how will the longer inlet tracts affect performance?

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.

[makenzie71]

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.

[TheCafeKid]

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.

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?

[makenzie71]

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.

[Agemax]

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.





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.

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.

[terry]

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:







`

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.

[makenzie71]

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.