- Location
- United States
How to tell if a 62t top end is over ported? just the exhaust ports look like they were ported.
Super Jet 62T over ported?
- Thread starter superjetchet21
- Start date
Nuklear6
I Dream 10' Surf!
Dont forget to measure the total cylinder height and post that as well. If its been ported theres a chance its been cut on either end as well.
- Location
- United States
Top of port to top of cylinder - Its between 1 and 7/16s and 1 and a half inches
Entire cylinder length - 5 inches and 9/16s
Entire cylinder length - 5 inches and 9/16s
Nuklear6
I Dream 10' Surf!
Sorry Chet you gotta get a more accurate measurement then that.. 1.5" would be ok 1.437 (7/16) would be a bit over ported.
Use some good dial calipers and measure in mm or thousandths of an inch.
Do you know who ported it? Looks like they slipped a few times. Additionally, the port width doesn't seem to go back very far into the exhaust port tunnel. I'd almost suspect a sport port.
Do you know who ported it? Looks like they slipped a few times. Additionally, the port width doesn't seem to go back very far into the exhaust port tunnel. I'd almost suspect a sport port.
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- Location
- United States
Yeah unfortunately I go to school away from my shop and thats all I had laying around to measure it with, so try measuring again with a caliper? Also whats the flaw of over porting? Will it be a big power loss?
'overporting' usually refers to exhaust ports raised high enough to lose bottom end power with normal compression. You can make up for it with big compression, total loss, or pump changes, or a combination of those things.
Used to be that people took full bred race motors but didn't want to pay for the race gas it took to run them. They changed out domes to lower compression, probably sold the total loss that was on it, maybe didn't buy the pump setup with the motor and bam! You got people bitching that their newly bought motor is gutless.
Used to be that people took full bred race motors but didn't want to pay for the race gas it took to run them. They changed out domes to lower compression, probably sold the total loss that was on it, maybe didn't buy the pump setup with the motor and bam! You got people bitching that their newly bought motor is gutless.
Nuklear6
I Dream 10' Surf!
When people use the term over ported they generally mean the port timing is too high. Which is good for top end run out but not at all good for off idle power. over ported can mean port width is too great as well. Engines that benefit from gear reduction can be ported much higher and make more power per displacement because it can use the transmission gears and gearing to always hit target rpm range.
- Location
- United States
Well this thing does have an ADA head with 33cc domes that doesnt get near the compression ada is saying it should, gets around 155 with fresh top end and I was using multiple gauges to test all same reading. Someone else says he has the same compression problem running the same set up. Just trying to get It fixed the right way why its all apart for a new top end. Id hate to spend the money to re-sleeve it if its not going to be that noticeable in power difference. Just kinda wanted to see what you guys thought
Keep in mind that the numbers ADA gives for their 701 domes are for a 61X cylinder with lower exhaust ports. So the same domes even on a stock 62T 701 cylinder will produce less compression. Now port that thing and it'll be even lower.
- Location
- United States
ah I did not know that, im almost thinking about putting a 61x jug on it?
- Location
- baldwin ny
fresh pistons on a not round cylinder do not make for "fresh top end" your bore looks like it has seen better days.
True. Someone on here once sold me a big bore cylinder, ported, with fresh bore and new pistons. I couldn't figure out why it was making low compression. I mean it was ported and all, but it was still super-low for no apparent reason.
Turns out, it had been bored to over 84.5mm and the new pistons it came with were 84.00mm. Awesome.
Turns out, it had been bored to over 84.5mm and the new pistons it came with were 84.00mm. Awesome.
- Location
- United States
very true, and I had it set up from a machine shop when I re did the top end last time they honed it and got pistons for it. I may know someone with a 61x jug and if its in decent shape and thats what ada goes by I may just go with that with fresh bore and pistons.
Nuklear6
I Dream 10' Surf!
I just looked at those pictures for the first time on my computer (was using my phone earlier). Wow is that exhaust port cut all wavey or what? I sure hope that was a sport port do it yourselfer and not a job someone paid for. And as said above that bore could be why your low on compression. I would move on from that cylinder. With that hack job it's not worth over boring.
- Location
- United States
Yeah I think I may just take this guy up on the 61x jug its at 81.50 and just bore it