Overboring block

O

OB_cbxchris

Registered
Can anyone tell me how much material is left in block after a 2mm over piston is installed. I`ve seen where Frank had problems with 4mm over. What was thickness on stock block before overbore. Debating whether to go with stock bore replacement pistons or 2mm over...do NOT want overheating or head gasket problems. Has anyone tried boring stock head gasket 2mm for overbore? I know very few have been down this road yet but all help is appreciated!!!
 
Dont go 4 if you want to use it on the street. I am surprised the head gasket even holds on the 1430. The sealing surface between the cylinders is pretty minimal(scarey!)
I would give it a little compression. The cc's are there. It was only last year when we would have all killed to have a 1300 cc motor. Pre Busa.
 
Cbx: I used a different type of gasket setup on my 1430. Not sure but that may have been my biggest problem. And if it was thats too damn bad because thats what held me up most of the summer last year.
Skip Dowling at Orient Express Built a 1430 and bored out a stock for his combonation. But I believe he's still in the R&D stages with his motor.

I think you can feel very safe to bore out a stock gasket 2mm. I know thats what I'm doing this time around.

Heating was a big problem with my 1430 but I don't see that happening on the 1360. Or at least anything you can't control.

Cbx, There is something I'd like to know.
There is alot of people speading Hp numbers around from Lee's Performance and Bob Carpenter, Has anyone SEEN one of these Busa motors in action? Or is it just hearsay that everyone is going on?

You know if somebody had a 205 to 212rwhp Busa, You'd be reading about it all over the web sites wouldn't you?

I talked to a guy in G-ville that was suppose have a 197rwhp 1360 Busa but when I saw his ET and MPH, I kinda felt like it was all B-S.

If there is 205's and 212's out there lets see it...

...Frank
 
Frank all I`ve seen is what people such as SBM and the like are claiming. I`ve got a set of stock bore J&E`s but have not installed yet....still may go with the 2mm over. Waiting on cams to return. I still want this to be a true street bike. I`ve always hoped for a 20-25 HP increase which hopefully would work out to 190 HP....just all hopes right now though. You are right about claims...they`re usually a lot of high priced smoke.
 
2mm over seems to be the perfect amount of an overbore. Call Lee at Lees Perf., he is currently doing a 2mm overbore and in the early stages is already at 205rwhp and is expecting more shortly!
 
There was a Bob Carpenter bike out at the salt lakes braking records a while back. It had over 200 hp. I think it was out there when Turbo Rick was out there.
 
Frank,
I want to say the MPH was 153-155. It was pretty dificult to launch with all the increased torque.Clutches get real grabby. It did nice 2nd and 3rd wheelies though. Best 60' were low 1.6"s
 
Only a fool would take a 200plus Hp Busa to a Dragstrip with a stock wheel base!

Turbo Tim, What was the MPH?

I rode Turbo1300's 205Hp down the return lane at Gainesville and when I hit 2nd gear at 3/4 thottle it stood straight up like a dirtbike.

Cbx: I think you can find 190hp with those stock bore JE'S.
Are you planning any Head work?
 
Frank, 1mm over on intake and exhaust...I think I could easily go another half mm on intake valves but since this is a street bike want to be on safe side. Will get a good port job on it ...head will be flowed. PM is now working on a valve spring kit for busa...they as of last week had no in stock off the shelf valve..all special order but they`re on the way. Another company has out in stock valves 1mm over that I am going to use.Got your note on chrome and you are right...some is on the way now....as of today as a matter of fact. I`ve met Terry once before at my friends shop..he was with Scott Barger from S&K...they were at Carolina Cycle...I get around don`t I! Later...
 
I will probably show my ignorance (I'm not a dragrace guy but the Busa's acceleration shows me they're not all bad), but for the nitrous and probably even turbo guys, wouldn't increasing stroke be a better answer?
By giving a boosted charge a longer lever to work through, and assuming that RPM is kept the same, (reliability goes out the window, but we are talking drag racing ) won't power gains be of higher quality?
Let me know what I'm missing in this line of reasoning.
 
TurboTim: Talking about the inside of the motor. No internal mod's.(stock) Yes, the cc's

Ask CbxChris, He was there when the pass was made.

Ask Brock Davidson, He knows of this also.

(Enough)

I ran a best mph of 145.5 (totally stock) 60 miles on motor.

Turbo1300: I'll e-mail you.
 
Turbo and frank...Lori at web said that stock springs could be used...thats what I was told BUT I`m not going to...PM is working on spring kit now...they have a head that someone sent them to do research on and they are working with web...I`m being patient and am going to wait on this to come out before final assembly...they also will have some valves soon.
 
Turbo 1300,
You have 205 according to the post above. What mph and times are you getting? If you were at Gainesville, what did it run?
 
Cbx, From what I'm told nobody is making valve springs at the moment.

I think yosh has springs but you still have to do some work with the retainers..
 
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