My next mod

[dan filipi]

I was talking on the phone with MSGT-R about cam profiles, lifts and whatnot which got me out to the garage after to compare the 1200 cam with the older cam.

Comparing the rockers and cam holders I then had an idea "how hard would it be to put this 1200 cam holder on an 1100 head?" (The 1200 has hydraulic lash adjusters.)

Well the answer to the little voice in my head was "not very easy man but the gains could be worth the effort".
No more lash adjustment and matched rockers to my already installed 1200 cams.

It looks like all the bolt holes line up, the 1200 cam holder sits right down onto an 1100 head with the cam in place. The most apparent challenge would be oil delivery. 1200 head has a flange arrangement on the head to deliver oil to the journals and adjusters. That little problem would have to be sorted out.

If I had a way to close off the cam holder flange I could easily tap in a couple fittings to distribute oil.

Hmmm.........

Why even consider this?

Well the intake and exhaust ports are considerably larger than the on the 1200 head.
It's all about performance gains.
And there has got to be a reason for 200+ psi on the right cylinders but only 160 on the left. May be due to the rockers.

 

[slabghost]

try this mod first.
https://ngwclub.com/forum/viewtopic.php?f=1&t=32916

 

[dan filipi]

Yeah I'll probably do that one but that's not really a mod, more like a maintenance thing.

 

[slabghost]

Yes it is more maintainance than mod. Still it may provide the same goal easier than the mod. If you want hydraulic lifters it may be much easier and cheaper to install 1200 heads complete.

 

[dan filipi]

I agree 1200 heads would be easier but that would choke the engine and make the whole mod a waste.

 

[joedrum]

not realy dan it improve low end flow ....im at the opinion that this could good for wings ....thees always the point of deminishing return on bigger ports ....the 1100s carbs have smaller venturi than ports and they seem to work beter than early carbs that are 32 venturi .....the 1200 heads maybe 30 all the way not nessarly bad....im diffinitly going to find out ...... :mrgreen:

 

[Tory]

I agree,Bigger isnt alsways better flow.When I was building the briggs engines to race,I would reduce the exhuast port to contour it for beter flow.It wil only move as much as the valve lets it,you just need to move it smoothly.

With that said would it be easier to start with the 1200 head,and play with the ports rather than adapt the 1100 head to hold the 1200 shaft?

 

[dan filipi]

The 1200 heads may be a straight bolt on, Joe could tell us if thats true.
The only question I had is if the 1100 carbs would line up to the intakes in both spread and width.

I may consider the 1200 head route if they line up but I still think the ports in the 1200 heads would reduce performance. I think more could be gained by porting the 1100 heads .

 

[joedrum]

yes they are a strait bolt up to the motor...they have an exhast heated carb ststem that would have to pluged and the 1100 carbs would have to moded to use on the 1200 heads.....the only thing sensible would be heads and carb rack switch dan ....i kinda like the heated carb rack ....and i diffinitly like the hydro lash adjusters on the 1200 head .....well see how it works with early cams installed.... :mrgreen: ...it would be hard to use 1100 carbs and all kinds of mismatch in port size it could be done and i seen it done but i havnt herd much praise about it tho..... :mrgreen:

 

[dan filipi]

Where is the problem with lineup to the 1100 carbs, width, spread?

 

[joedrum]

oay you force me tp look dan there would be no problem hooking up to the 1200 heads with the 1100 carbs and intake runners ...the only problem is th difference in size of intake runners and head port size whitch is a lot ....im guessing but the 1200 intake ports seem to be about 27-28 as compared to 32 on the 1100 intake runners .....the 1200 intake runners actualy taper from 30 to 27-28 im still guessing on the 27-28 figure....on the honda valkery 1500s with there 6 carbs feeding 250cc cylinders there carbs are 28 venturi size ...they run hard for anybody who hasnt rode one ....they get it right off the get go and keep it till the top ...idont think there mild cam bikes ....early oldwings stumble some in low rpm even with perfect carbs ...i think there lack of excellerator pump and to big venturi size carbs both contribute to this .....

i think the 1100 carbs would work well with 1200 heads ...but one might have to do somthing with the transition at the head maybe maybe not ....if it were me i wouldnt do anything at first and just see how it dose ....its not wise to fix problems you might not have ....you would have to block off the exhast ports to the carb rack ....im not sure what would be the best way to do that off the cuff but im sure it could be done rather easy maybe ...so thats the best info i can offer on just a looksie at things hope this helps dan.... :mrgreen:

 

[78AzWing]

Ok, now I am intrigued!

Would the 1200 heads fit a 1000?

 

[slabghost]

Ok, now I am intrigued!

Would the 1200 heads fit a 1000?

Fit? They should. Work (function?)? I don't know. The 1200 heads need oil to the lifters and has the exhaust ports to heat the intake manifold. Uncharted territory here as far as I know. Using 1200 heads on the 1000 with a 1200 carb rack might be a really nice combination but I think it will require a lot of thought and ingenuity to get it all fitted and functional.
All in all an interesting idea.

 

[dan filipi]

As far as fit goes I did trial fit an 1100 head to a 1200 I replaced head gaskets on, the fit is as if the heads are identical that far in.
The oil orifice looks the same as well.
I'm not sure if 1200 heads on a 1000 or 1100 would need 1200 belts, probably not because I think it's the block that's wider not the heads with relation to crank and cam centers.

The EGR port things on the 1200 head would allow exhaust gas and probably noise to come out but that would be a simple deal to close them off, epoxy comes to mind.

I wish someone would do it to satisfy my curiosity.

 

[78AzWing]

I wish some one with more money than I have would try it and report back.

I don't mind being the first, just don't have the ready cash to try it.

 

[MSGT-R]

* insert big sigh here*

Dan, if you're brave enough to let me grind those 1200 heads, bring me the heads and the 1100 gaskets for port matching.. Keep your fingers crossed that the castings are thick enough.

Knowing Honda, they are.

 

[dan filipi]

I would love to install 2 ported 1200 heads on this 1100 but I have only one and no money to throw at it right now.

 

[MSGT-R]

When you find a second head, let me know.. :ahem:

 

[dan filipi]

I may stud the block and make copper head gaskets.
As often as I swap heads around this will save time and money in the long run..

Any experience here making copper head gaskets?

 

[MSGT-R]

I've used them, but never made them.