61x cylinder decking/porting comments needed

[just joe]

I picked up a an ebay 61X that was supposed to be stock, but is not. looks like a light/mild port and significant decking. owner didn't know who did the work... he bought it that way :boggled:

I am hoping some of you can tell me something about it, or should I go to plan B (find another cylinder or use my 62T).

The cylinder:
81mm bore
base to deck: 119mm (should be 120mm's, correct?)
Exhaust port width: 53.4mm (66% of bore)
Top of exhaust port to top of cylinder: 37.5mm
exhaust port max height: 33.3mm
Top of transfer port to deck: 54mm

Transfer port roof angles at sleeve appear untouched. I think there is more to be had from this cylinder in terms of porting if the decking isn't a big deal. Is it?

fwiw/my set-up:
stock 62T cases
Blowsion head (35cc domes planned, but...?)
dual 38mm OEM carbs
Factory B pipe, ported manifold (62T), FX1 chamber (smaller than mod)
MSD Enhancer
61X flywheel/stator

Looking to Improve bottom end and mid range power, maintain/improve throttle response. All around freestyle/freeride performance on flat water.

Haven't checked squish yet with my head, but I am guessing I'll need custom cut domes.

Thanks in advance!

 

[Matt_E]

Exhaust ports are widened, perhaps raised - not sure, but it looks like they might have.
Transfers have been cleaned up. Nothing radical on the bottom, just a nice cleanup.
Looks like a good rec cylinder.

 

[robertg]

The exhaust port on a stock 61X cylinder is 40mm from the deck. It looks like it was raised 1.5mm if the cylinder was decked 1mm. I believe 62T is 37mm but I haven't measured one in a while.

 

[waxhead]

When i get home i will work out your figures
i can be a rough guide only but its better than nothing

 

[waxhead]

oh and cylinder is about 119. something
so i would say its not milled

at a glance at the pics it looks like a reasonable job

 

[SUPERTUNE]

4.685 is very close to stock deck ht. (within .005) just probably stock tolerance. Might suffer a bit of low end hit with exhaust port raised, Use a limited chamber to get some of the hit back...(Oh, maybe this is not a SJ, you have a FX1?) If you freestyle ride (don't treat it like a race boat/WFO you should be able to go down to a 34 cc dome, if you run a ADA head I cut out 33's to 34's for this kind of set-up. You will also gain more power for all around with my B' pipe mods and use a jetworks valve on the stinger.