Oiler Head differences?

[Metlhd]

After endless searches on multiple forums, I still find myself confused about some of the key difference.
What I'm fairly sure of:
1st gens are pretty much the same for 70mm long stroke.
2nd gen 88-89 DOT, 73mm bore, Larger valves yet smaller combustion chamber? What I am unsure of is if the DOT was used on other bikes such as TEAPOTS (notf'kingkatanas...R.T.F.R). IF so, How do I distinguish the origin of a head and or Cams?

90-92 is where I am not so clear other than it is again for a long stroke. Apparently the 90 does not use Shims which some claim is an advantage. Are there other differences in the 90, 91, 92 heads and how do I distinguish those?
Some claim (including Kelly Roberts) the 92 best suited for builds? What is different on the 92 from the 91?
Some claim the DOT is Head of choice while others say 90?

I understand some of this is subjective and it has ALL likely been hashed and re-hashed over the years. But as I mentioned, searched till I'm blue. Perhaps there is a definitive "Head Guide" I haven't found?

[banoffee]

Might be worth a read... http://oldskoolsuzuki.info/archives/404

[Metlhd]

1 hour ago, banoffee said:

Might be worth a read... http://oldskoolsuzuki.info/archives/404

Thanks, that is definitely a good read. One of my concerns is due to the age, a lot of these bikes are not stock (as in some of these swaps have been done). And used parts often have limited history. For example, I recently purchased a 92 motor complete. When I purchase it I asked the salvage place if they had any DOT heads. He brought one out with cams and all but it was tagged as a 91 GSXR750. Now obviously it's either tagged wrong or a swap/815 was done. But apparently the "DOT" heads were also used on KATANAS only with different cams?? I've also read 1100 cams can be used in some instances. So how are these parts distinguished, (heads/cams) between years and models? How does a guy know what he actually has? Are there markings on the castings or cams? 

[VJ]

DOT heads were fitted to GSX750F's and the 'dot' describes the identifier, just above the head gasket on the side is a cast circle in the fins about the size of a pound coin.

 

Cams wise theres a lot of numbers on them but the only way to be certain as to what cams are what is to measure them.

[Gixer1460]

46 minutes ago, VJ said:

DOT heads were fitted to GSX750F's and the 'dot' describes the identifier, just above the head gasket on the side is a cast circle in the fins about the size of a pound coin.

Cams wise theres a lot of numbers on them but the only way to be certain as to what cams are what is to measure them.

And the DOT heads never came with Shim adjusted valves so it couldn't have been a 91' 750!

The DOT heads are largely the same ie. same valves, only the cams varied

[wraith]

I've seen on this site (somewhere ) that the gsxr750 DOT head has a different port angel to the gsx750f DOT head, which makes a difference to the carb angle.

I don't know if this is true?

As I don't have the two types of heads to put side by side.

As to the cam numbers i believe some of the numbers stamped on the cams define which cams they are, (again there was a post about this about a year ago) but some say the gsxr750j/k cams are the best for top end others say any of the gsxr (oil cooled tapit type) work well ever the 750 or 1100, but if you want a more all round power cam look at the gsx1100f cams. You may need to change your cam sprockets to match you bottom end/cam chain 

May not be answering your question and may be giving you more questions, but I hope it helps some how 

[Oilyspanner]

Many bits have been mentioned already.

You didn't mention it, but this is just a 750 heads question ? The USA was the only country to get o/c GSXR750s in 1992, it was the same as the 1991 M anyway - they were both shim adjusted valve heads, nothing but colour schemes changed.

You can only fit long stroke 750 heads to long stroke bottom ends (okay with a huge amount of work anything is possible) - the 1990 R 750L was liked because it was easier/safer to fit lumpy, race cams to it compared with the shim heads and had the same sized valves. The shim heads did have slightly better inlet ports though, slightly raised floor and the divider were different.  You can get any head to work  much better with some flowing. It is possible to fit the valve train from 750L to replace the 750M (N)'s - the shim on top of valve retainer had the potential to lose a shim during valve float, more likely in a race motor.

The short stroke heads have larger valves than the long stroke 750's, same size as 1100's - head volume not smaller than other 750's, but smaller than 1100's, which is why they are often fitted to 1100/1200s (they give higher compression).

The short stroke 750 engines R and GSX-F models all have similar heads/valve sizes/volumes etc and have the 'dot' cast on them. These heads can be fitted to the 1100/1200 engines but not long stroke 750's, the casting is different, cam chain tunnel is different. Like Wraith  I've not looked at the R 750 J/K head compared with a GSX-F dot head, but some say the inlet port floor isn't as raised on the F ?... maybe someone who has checked can add to the thread. The cams are the big difference between the dot head R's and F's.

There are head casting details on the underside of the intake runners - eg  my 1100N has 41C amongst the markings, this tells you it's for a 41C model - GSXR1127  M/N. Unfortunately I don't know the 750 markings - anyone ?

[Metlhd]

Oilyspanner, thanks for all that. And yes this is for a 750 race motor I'm building. Do you have any idea how to confirm what Cams I have, as in markings? Considering the age of these, you never know what may have been swapped out?

[Gixer1460]

Not wanting to sound obvious but if its a 'race' motor throw 'race' cams at it - then it's not an issue? You are in Trumpland and have some of the best cam grinders available - use their expertise. And I think the CV's (if you are keeping them) will benefit from dual K&N's rather than singles........ just sayin'

[billd]

Great  thread!

[Metlhd]

On 12/14/2018 at 2:35 AM, Gixer1460 said:

Not wanting to sound obvious but if its a 'race' motor throw 'race' cams at it - then it's not an issue? You are in Trumpland and have some of the best cam grinders available - use their expertise. And I think the CV's (if you are keeping them) will benefit from dual K&N's rather than singles........ just sayin'

I heat ya about cams. I guess what I'm trying to figure out is:

A), The best head platform to start with (90,92,DOT?)

B) how to distinguish what pcs I'm currently dealing with (markings?)

As for carbs, I currently have OE BST (31?) on my 86 and a set of BST34's in a box. Starting to think neither will be sufficient seeing the 92 came with 38's in US trim and 40's in the UK. Looks like I can get NEW RS flatslides (38 or 40) with Velocity Stacks & filters for $800. That may be the rout I go considering the cost of a good Used CV and the inevitable rebuild but I figured that may be worthy of a separate topic.

 

[clivegto]

The id marks on the cams don't help as Mr suzuki had more than one cast & then ground to spec of model, but some have stamps on the end usauly stamped by tuners re-grinding. You need to measure them realy. Seem to remember @fatblokeonbanditDid a little study of his own on them. There is a link some where to the temporary site with a spec sheet for the cams.

[fatblokeonbandit]

 

 

if you put "gsxr1100 camshfts" in the search thingy, there is a thread about them

Edited December 16, 2018 by fatblokeonbandit

[Gixer1460]

The DOT head will only fit one model year of the 750's - sorry I can't recall which - DOH. Between the 90 and the 92, I'd pick the 90 - it may have a slightly inferior inlet port compared to the 92 but came with screw and locknut tappets and so a wider range of aftermarket cams. Unless the class or race series requires the use of 'stock' CV carbs - buy the RS38's or (my prefered carb) the Keihin FCR39's............unless you can afford TMR's. Knowing 'what' cams you 'have' is of interest only if selling them - knowing what you want aftermarket is more crucially important IMO.

[dupersunc]

This. ^^.

If you have a long stroke bottom end which the slabbie was originally, the short stroke dot head won't fit. Cam chain tunnel is different.

A 1990 head is a good start as is a set rs38 carbs. most Original carbs are worn out. After market cams and slotted pulleys to time them correctly.

A programmable ignition and a cylinder head cooler are worth when if you want to get the most out of it too.

[Metlhd]

2 hours ago, Gixer1460 said:

The DOT head will only fit one model year of the 750's - sorry I can't recall which - DOH

Wouldn't the DOT head fit 88 and 89? 

[Buzuki]

1 hour ago, Metlhd said:

Wouldn't the DOT head fit 88 and 89? 

DOT head originaly belong for 88/89 (J/K) R750 model  ,  88 cams have leter  B  stamped on the side .

[Metlhd]

5 minutes ago, dupersunc said:

This. ^^.

If you have a long stroke bottom end which the slabbie was originally, the short stroke dot head won't fit. Cam chain tunnel is different.

A 1990 head is a good start as is a set rs38 carbs. most Original carbs are worn out. After market cams and slotted pulleys to time them correctly.

A programmable ignition and a cylinder head cooler are worth when if you want to get the most out of it too.

Head cooler is certainly on the list. I've read about the 815 conversions using slingshot heads, jugs and spacer but wrist pin/piston conversion seems a bit more involved.