Super hot 750 VS stock 1000 - Decisions, Decisions?

[Guest]

I was just talking to a local engine builder about some options for my 750. the guy is one of the Old school types and loves to make horsepower on old bikes, he comes highly recommended.

My 750 is getting tired and needs a top end refresh at a minimum. My thoughts have been towards picking up a used 1000cc engine and bolting that in to give me more power, ... odds are a used motor may need a refresh as well though.

He thinks that abandoning the 1000 idea and going high performance on the 750 would be a much better idea. His thoughts are:

install Wiseco 844 kit
Mill and port the head, grind valves
Degree the cams
install VM29 smoothbores
Dyno tune

Price wise I am looking at about 600-700 labour plus parts (I supply or he can order).

Any thoughts on going with the 1000 engine vs the above setup?

I am confused and cant figure out which way to go, looking for any and all input.

[Billy Ricks]

Depends on the character you're looking for. A built 750 will be rev happier than a basically stock 1000. In the end you'll probably have about the same hp either way with a stock 1000 being more reliable than a breathed on 750.

[TheRedlineMan]

If it's the L in your sig then I'd go the 1000 route. It'll give you more tractable power, more low down grunt than a worked 750. Then when you get around to doing up the 1000 the bike will really haul.

[nabrams]

I'm betting that if you look long enough on eBay that you can find a low-mileage 1000cc engine for a third of the cash that hopping up the 750 will cost you. AND you'll have a powerful engine that hasn't been tampered with.
Heck, I got an entire 1982 Honda CB750F bike with 9K miles for $300! All it needed was a carb cleanup and a new battery!!
The trick is to be patient and look every day. If you're willing to drive several hours (each way) to pick it up, then your options are greatly expanded.

[Dave8338]

I have to agree with the others, in that a highly built motor (in anything) is a great deal of fun however, the streetability of such a beast is always in question. Reliable/streetable power is best built using in this case CC's as opposed to compression, port-polish, cams, ect. My .02 cents.

[JHawkins]

Hmm, I am glad to see others are on my wavelength. While I think the 750 would be an awesome motor done up, especially knowing the reputation of the shop, I think the stock 1000 might be the best bet.

The trick will be finding a '79 or earlier motor. I have been watching ebay, but not seeing much of anything for a while. Anyone have any 1000's laying in the garage?

[chef1366]

Is the 1000 a direct swap?

[JHawkins]

as far as I can tell, the 79 750 and 79 1000 should be a direct swap. That's the theory anyway!

[TheRedlineMan]

any 2 valve GS1000 motor from 77-81 should fit. Not 100% sure on the engine mounting plates though.

[spyug]

Go with thw stock but bigger mill. You will spend heaps to get to the same level of performance or maybe a tad over. In addition, as the guys have said the hypo 750 will not be as streetable. Lumpy idle and an engine that only comes alive under revs is not going to be a lot of fun.

If your racing go as far as your wallet will allow. For the street keep it simple.

My 2 cents.

Cheers,
Spyug.

[t3rmin]

The shop obviously stands to make quite a profit with the souped-up 750 route, so I wouldn't exactly consider that objective advice...

[JHawkins]

The shop obviously stands to make quite a profit with the souped-up 750 route, so I wouldn't exactly consider that objective advice...

I definately considered this as well, however I think his suggestion is more towards his style of thinking. He loves making power out of the old stuff. He actually has a GS1000 motor sitting there in pieces that he could build for me, but he was really pumped up about doing up the 750. You really have to love the guys that love their work!

If I had an E model I might lean towards a hot motor, but with the L model I think the 1000 motor might be a little better suited.

[Jethro]

There is no replacement for displacement!

[brveagle]

anytime you "hop up" an engine, you decrease reliabilty

go with the 1000 swap

[chef1366]

Depends on who's doing the hopping. ;-)