DOT head clarification

[flywalker]

So teapots also had DOT heads but with milder cams...

I have read two directly conflicting reports. One says that GSX750F heads are no better than a skimmed B12 head as it doesn't have the better porting. The other comment said that other than the milder cams the head was equal to the best of the best GSXR DOT heads, so S-1...?

Would appreciate a definite answer as I have found a low mileage(18,000) teapot head and want to use it IF it's all I am hoping it will be.

I put GSXR 1100 K cams in my Mk1 B12 and I am really missing the low end punch. Apparently upping the compression will go a long way towards recovering the grunt but I would rather throw on the best DOT head I can find if the porting is better on a particular head.

Cheers in advance!!

[oilyspanner]

A ported Bandit head (or 1100) will flow better than a dot head. The dot head has a slightly higher port entry compared with the later other OC heads which is a good thing and the inlet valves are almost the same size as the 1100's and B12 - the best thing is the raised compression (smaller combustion chamber for 750 engine). I thought about changing my 1100N head back along and found it flowed well anyway (M and N have best 1100 heads as std for flow), but porting would yield the best results by a distance - so I didn't swap it.
A big bore with a flowed B12 head and your 1100 cams would be best. The dot head a cheapish hike from bottom to lower top-end, higher compression doesn't have such a big effect around peak, but it would make your delivery much better.
I haven't seen the F and R dot heads compared for flow rates, it won't be night and day different though. Roger Upperton is considered the best OC head porter around, there are a few who still remember how to get the best from our heads. Keep us informed of your progress

[flywalker]

Thanks Oilyspanner!

I know the ultimate end game is a ported original head and big bore. Would LOVE to do that! Unfortunately it is far beyond my mechanical skill level to do anything beyond basic maintenance so I'm paying through the nose for shop time. I think fitting a DOT head may be as far as my wallet can extend.

I have received a subsantial boost from the cam swap but I am missing the low end stomp. If the DOT head will bring that back and be a relatively straightforward job for a pro then it's very attractive. However... as I mentioned if an F head is no better than skimming my own head then I might just re-install the original exhaust cam and be done with it.

I live in Japan so recruiting Mr. Upperton's skills might be very difficult unless I can find a B12 head in England dirt cheap that he can work his magic on.

[boilerdude]

dot heads are indians from india. feather heads are american injens.

[oilyspanner]

I had to think for a second and then had a chuckle !

[boilerdude]

no but seriously. So 89 gsxr 750 heads dont have quite as big valves and perhaps ports as b12?

but they do have "better" cams. and offer a bump up in compression...

So if you're doing a big bore kit on top of that. you should really just put the good gsxr cams in the b12 head and have some porting done

[katana]

If your 'doing a big bore' it'll probably put compression through the roof no matter what cams are in it!

[boilerdude]

So you would recommend just stock b12 cams to compliment a 1216 kit and not even the slingshot cams?

err... you probably mean BIG big bore kit. none of that little pissant 1216 shit.

[fatblokeonbandit]

Jun 11, 2015 11:26:26 GMT boilerdude said:

So you would recommend just stock b12 cams to compliment a 1216 kit and not even the slingshot cams?

err... you probably mean BIG big bore kit. none of that little pissant 1216 shit.

No, the DOT head will raise the comp to 13-1 If I remember correctly, ive got 2 1216, with flowed heads and one has gsxr 1100 cams and the other "new" reground road and track cams, the one in my bandit has 150 rwhp the other I don't know as its not been on the dyno yet..

[katana]

Jun 11, 2015 11:44:51 GMT fatblokeonbandit said:

Jun 11, 2015 11:26:26 GMT boilerdude said:

So you would recommend just stock b12 cams to compliment a 1216 kit and not even the slingshot cams?

err... you probably mean BIG big bore kit. none of that little pissant 1216 shit.

No, the DOT head will raise the comp to 13-1 If I remember correctly, ive got 2 1216, with flowed heads and one has gsxr 1100 cams and the other "new" reground road and track cams, the one in my bandit has 150 rwhp the other I don't know as its not been on the dyno yet..

Eggsackerly - on a std 1100, a DOT head will punch CR up to about 11.5 from memory so throw 12.5:1 pistons in the mix and sky's the limit!

[clivegto]

I have a slabby 1052 motor standard apart from it has a flowed dot head with 750k cams and it go's like shit of a stick.

Not so much bottom end but a revy monster at top end.