Going from 701 to 760?

[WaveDemon]

Uh oh. Maybe I will be buying some tools and trying it myself.

Can't wait to see the pics. I would think 760 cylinders would need more than a single 44 though, right?

the low down on my motor:

760 cylinder bored to 86mm
61x case unported but opened up to accept the physically larger jugs
intake opened to 48mm (i've only ever had a 46 buckshot on it)
factory pipe head pipe opend up to 50mm
transfer and exhaust ported.
36 cc domes (only reads 150 psi on guage)


it has a hit that you could call upper low end. the hit is sudden and powerfull. it doesn't matter where your throttle is when you hit that RPM. it will take of like a raped ape.

I"ve got my hands on a SBN 46 and a 48mm plate. I plan on opening up the carb and slapping it on there.

 

[#ZERO]

Very nice looking job. :biggthumpup:

It's one of the cleanest looking port jobs that I have seen done by TLR.

http://www.tlrperformance.com/

 

[WaveDemon]

here are some fuzzy pics to look over...

I guess you can see the way the bottom of the transfers are worked with these. if you want better pics of the ports I'll take more. any other pics you want?

 

[DAG]

Paul told me a 760 can be prted to within 20% of a 61x big bore. He calls it a poor mans big bore.

I just bought one. The cylinders will go to Paul for porting and a lightened 61x flywheel/stator will be used. Paul said he runs 195 psi on pump gas (94 octane) for this set up.

have you rode it?

I got the same thing a few months back, but i havent had 30mins out on the lake... (school)

 

[MADMAT]

have you rode it?

I got the same thing a few months back, but i havent had 30mins out on the lake... (school)

No it will be at least 3 months I think.

 

[Matt_E]

Tim, get the exhaust port, looking from the top. Also, I'd be interested in getting the main transfer and secondary transfer together in one pic (to see how far apart they are or if they are stock size)

 

[WaveDemon]

i got my head out of my ass and took some better pics.

 

[Matt_E]

Thanks. What compression are you running?
(Or better, what size domes)

 

[WaveDemon]

i've got some calipers, do you want some measure downs from the top of the deck? suggestions for the widths. I guess I could do a rubbing and draw it up in cadd with dimentions.

at that point it's just begging to be plotted out on vinyl....

 

[WaveDemon]

Thanks. What compression are you running?
(Or better, what size domes)

post 20 in this thread. :biggthumpup:

36cc = 150 psi on this motor

 

[Matt_E]

Naw....I seriously doubt anyone touched to exhaust port roof. The tops and bottoms of the transfers look relatively unscathed, too.
It's a mild freestyle port. Ought to perform nicely.

 

[#ZERO]

i've got some calipers, do you want some measure downs from the top of the deck? suggestions for the widths. I guess I could do a rubbing and draw it up in cadd with dimentions.

at that point it's just begging to be plotted out on vinyl....

Tim, that cylinder looks good but the sleeves are super thin.

Are you going to hone it or have it re-sleeved?

 

[WaveDemon]

Naw....I seriously doubt anyone touched to exhaust port roof. The tops and bottoms of the transfers look relatively unscathed, too.
It's a mild freestyle port. Ought to perform nicely.

so you think they're just widend? the angled the bottom of the transfer runner and trimmed the bottom of the width of the cylinder on the intake side.

 

[WaveDemon]

Tim, that cylinder looks good but the sleeves are super thin.

Are you going to hone it or have it re-sleeved?

nope, it's an 86mm bore. it ran that way before, i'm going to run it that way again.

 

[Matt_E]

I meant that the exhaust is widened, not heightened. I doubt anyone would do that, especially on the T cylinder.
The transfer tunnel divider is a bit angled, correct. If you look at the pics #0 posted, you'll see that it's also angled there, but it's more recessed into the cylinder. Also, the sleeve is shortened right there (4 areas total)
Very similar to yours, but a bit more of each. I think the transfers on #0 are a bit wider than yours, but I wouldn't bet money on it without measuring.

Btw, each of the points I addressed can be taken care of by yourself purdy easily.

Oh, and the sleeves (intake side) are shortened to get a bit less obstruction in the intake runner of the cases.
However, that is there for a reason - it deflects air/fuel charge up the boost port as the piston goes up (reverse of transfer ports)
There's a trade off - you want boost charge, but unfortunately the sleeve obstructs the intake in the process.
Slightly shortening it, as in your cyl, is a good compromise.

 

[WaveDemon]

also, at the bottom of the boost port the back side is slightly buged out. all of the port runners have grinding marks the entire length of them so I guess they'be been opened up a little.

what do yo think about porting the x case? I'v been collecting pics of it and I think I'm close to trying it unless someone thinks it's a bad idea.


fyi. I got 180 psi on 31mm domes on this motor before. unfornatly I roasted some pistons on at WOT. this motor definatly hides compression. 31mm domes on a 760 = 230 psi

 

[Matt_E]

I have some ideas for the X-Cases. Most can be seen in that 61X case porting thread.
Except I came up with them before seeing the pictures...that was a nice surprise.
I'll make a thread about the process when the time comes.