DOT heads - variation among models?

[Dezza]

Does the Ka.... sorry, nearly fucked up there, I mean 750 teapot DOT head have the same inlet port angles and therefore the same potential carb clearance problems as 750k/l heads?

[Captain Chaos]

20 minutes ago, Dezza said:

750k/l

750 J/K has dotheads

[Nik]

The DOT heads have higher inlet ports (appr. 15 mm). Chamber volume and valves are the same.  

Edited September 4, 2023 by Nik

[clivegto]

From what I have figured out the dot heads from the teapots and the J K are the same but the cams are different, not by much though. 

[Dezza]

Many thanks for the replies. Does anyone have any direct experience of the angle the carbs sit when mounted on the head re: teapot DOT v 750 slingshot DOT? It is common knowledge the slingshot DOT mounts the carbs at a slightly different angle to non-DOT oil cooled heads but I was wondering if it's the same with the teapot DOT.

[Nik]

I can't remember that the carbs are sigificantly more angled on a DOT head, only that the inlets are placed appr. 15 mm higher than other heads. 

I have a bunch, but I am not sure where (too many garages ... ). I'll see if I can find some and take some photos and measurements. 

Edited October 26, 2023 by Nik

[wraith]

I found when I first started building the gsx1157et (b12 motor) that the tank stat in the right place with the standard b12 head but when I fitted the gsxf dot head the carb top where just hitting the tank by APX 5-10mm ish (didn't Messer it) also I was using gsxr750 38mm carbs and rubbers, don't know if that makes a difference.

 

Ps, FBB maybe the man to ask as he's done one or two head jobs 

Edited December 14, 2020 by wraith
Add a bit

[Dezza]

49 minutes ago, wraith said:

I found when I first started building the gsx1157et (b12 motor) that the tank stat in the right place with the standard b12 head but when I fitted the gsxf dot head the carb top where just hitting the tank by APX 5-10mm ish (didn't Messer it) also I was using gsxr750 38mm carbs and rubbers, don't know if that makes a difference.

 

Ps, FBB maybe the man to ask as he's done one or two head jobs 

Yep, that was what I was thinking in regards to buying your teapot 750 DOT head or not. I will have a spare Blandit 12 engine to go in a slabby 750 frame as my next  project, (probably to be completed c2030...). I also have some BST 38s to go on it, which as you know are 'tall' compared with other carbs (including RSs) so getting all this in a 750 frame may be a bit of a push, although I will be modifying the stock slabby 750 tank I have regardless.

[clivegto]

GSXR 750 NWS frame, 1052 motor, flowed dot head 750k carb rubbers, RS38's with bell mouths. 

[clivegto]

Same motor as above but now in a 1100 slabby frame and mk2 b12 carbs fitted. 

[wraith]

I will get some pics later, as I've got a b12 head and this DOT head. I will put them together so we can all see what difference is 

[Dezza]

Looks like the 1100 slabby frame gives more clearance than 750 slabby frame. I am looking at cam cover to frame spar clearance here. The BST 38s are definitely taller than the 36s from a Blandit 12 so they wouldn't go on with those rubbers by the look of things. I have the rubbers from a 750L and they bring the carbs very close to the head so they may well just about squeeze in.

[Dezza]

2 minutes ago, wraith said:

I will get some pics later, as I've got a b12 head and this DOT head. I will put them together so we can all see what difference is 

Ace!

[wraith]

53 minutes ago, Dezza said:

Ace!

Hope this helps 

Not the best pictures, lh dot head rh b12 MK1 head.

 

[Dezza]

Formidable! The Creme de la Menthe of informative posts This is a 750 teapot DOT head but my guess is 750 j/k DOT heads are much of a muchness but a direct comparison would be mightily interesting Could you please add the pic to the sticky topic (sounds like a 70s chocolate bar) on carb compatability at the top of the oilcooled section. Otherwise after a while this pic will only be easily retrievable after a search.

Edited December 14, 2020 by Dezza

[clivegto]

Hear are some measurements I have taken. Measurements are from flat of head to top of inside inlet port. 

Edited December 14, 2020 by clivegto

[clivegto]

Magnesium 1052 cam cover should give you the most clearance. 

[clivegto]

I do have a gsxr 750k and gsx 750f heads that I know for definite that's what they are but they are on complete engine's. 

[Dezza]

That's great Clive! What are the exact landmarks used to take the measurements to and from? I assume head gasket mating surface to....??? I can then put these into a table and post onto the carb sticky thread.

[Duckndive]

3 hours ago, Dezza said:

Looks like the 1100 slabby frame gives more clearance than 750 slabby frame. I am looking at cam cover to frame spar clearance here. The BST 38s are definitely taller than the 36s from a Blandit 12 so they wouldn't go on with those rubbers by the look of things. I have the rubbers from a 750L and they bring the carbs very close to the head so they may well just about squeeze in.

Due to the 1100 engine being taller than a 750 engine ....

I was told the Slabby 750 frame being the lightest made it the ideal base for a 7/11 even though removing the cam cover is a challenge  

[clivegto]

22 minutes ago, Dezza said:

That's great Clive! What are the exact landmarks used to take the measurements to and from? I assume head gasket mating surface to....??? I can then put these into a table and post onto the carb sticky thread.

 

Measured from top of port to flat of head like this. 

[wraith]

@Dezza

Posted pictures in the carb thread bit 

[clivegto]

2 hours ago, Duckndive said:

 

I was told the Slabby 750 frame being the lightest made it the ideal base for a 7/11 even though removing the cam cover is a challenge  

 Yes it is in my opinion, cam cover does come of my 7/12 but not of my Harris 

[Dezza]

That aspect of the cam cover is not a problem to me; I have been a Harris Magnum 2 owner for 33 years and the engine has to come out to do the valve clearances.

I shall add some of these pics and info to the carb sticky thread along with a new table when I can be arsed. Thanks to all for the help

[clivegto]

18 minutes ago, Dezza said:

That aspect of the cam cover is not a problem to me; I have been a Harris Magnum 2 owner for 33 years and the engine has to come out to do the valve clearances.

 

Your Harris is air cooled so bigger engine.