Topic: 130 mph club with a 1978 CB750K?

[Rick]

I've been a lurker and an avid reader of this forum and am beginning to get the "salt fever".  While undoubtably a noob question, and not wanting to sound naive and insult anybody here as proposing to achieve the impossible.....I was wondering if the following question was within reason: would I stand a chance at building my '78 CB750K to be capable of making the 130 mph club on the flats? Is it a good platform, or would I be better choosing another avenue?  I'm really attached to the old girl and think it would be great to achieve such a goal on a bike with such class.  I own a BMW K1300S but to be honest some of my most memorable and FUN rides have been on the CB!  If so, what type of modification and expense am I looking at?  I've red most, if not all, of the posts on salt and speed builds here, but most focus on a certain class for the racing and meeting the regs.  I don't have the spare change to be competitive in class racing, but thought I may have a chance at a street-legal bike in the 130mph club.  Any comments would be greatly appreciated.  Thanks in advance, Rick.   

[slikwilli420]

Seems more than realistic since the stock bike probably does 115-120 without much effort. It should be cake to hit 130. Much over that and power/weight come into play.

[Jerry Rxman Griffin aka MuthaF'er]

Depends on it's condition. How's it run now and what will it do? 

Stock - no. It'd need to be re-geared anyway and you'd need some more power to pull the gearing at the higher altitude. The 750's that were there last year were running 120 and 125. One that did 88 LOL. The 120 was from japan. Had some NICE carbs but not sure about anything beyond that. The 125 was 836 and no telling what else. I'm going to say you need the head ported by someone that knows what he's doing, bigger pistons and a good cam minimum. $2000 maybe. Bigger carbs MIGHT be necessary. $800.

How good a tuner are you?

[754]

130 at Bonneville is sort of like doing  138-140... At sea level on pavement..

[Rick]

I guess the fact that you only have one mile to break 130 is the big factor in my mind. I imagine withe time and distance I could build a 750 to break 130, but in a mile?  It seems a factor of 10% is off speed and traction is a realistic consideration according to a lot of posters on this forum.  The bike is in good shape 10k original miles, and I'm not a bad tuner.  Never did any head work myself though.

[andy750]

Well you are 87 miles or 1.5 hrs from Mike Rieck world class head tuner...PM MRieck or go see him in Ashland Ma and talk about mods that will get you into the 130 mph club. I want to see that!

good luck!
Andy

[NalleyRacing]

Research gearing as much as you can. I agree with proper pistons and head work will undoubtedly help. Pretty cool idea, lets see it happen! Lots of helpful dudes on here, ask as many questions as you can think of.

[scottly]

Instead of shooting for a record, why not find out just how fast you can go on your stock bike? Remember the flats are up there in elevation: for every 1000 feet you go up, you lose about 3% horsepower over what you would make at sea-level. 

[Jerry Rxman Griffin aka MuthaF'er]

On the short course you have 1 OR 2 miles to get up to speed before you are clocked during the middle mile.

[Greg H]

Instead of shooting for a record, why not find out just how fast you can go on your stock bike? Remember the flats are up there in elevation: for every 1000 feet you go up, you lose about 3% horsepower over what you would make at sea-level.

I agree , your always better starting out with a baseline figure ,than you can improve in a logical manner and measure your improvements . This project sounds familier to me , yeh I'll keep it simple and before you know it your working on building an all out race bike. Good luck . Greg "H"

[madmtnmotors]

Subscribed!

[POPS 911]

SAM GREEN ran 130mph at SGMP ON A DRAG STRIP running past the 1320' marker, in 2012

[Don R]

Maybe the Ohio mile would be a place to start. Closer and less altitude. One mile from a standing start.