83 vf750 needs crank

hey guys , i tore into my interceptor the other day to find that one of the rod bearings spun and took out the crank journal ,so then i tore into a parts bike i had and strangely enough the same rod bearing went in my parts bike. ive been looking on ebay for a new crank and its very hard to tell from the pics if they are worth using or not and alot of the ads say that they will fit a vf 700 and vf750 is this true ??and what year cranks would fit my 83??? i guess im really just looking for some pointers on buying a good used crank thanks

 

You want a 750 crank. The 700 crank has a shorter stroke to make it 700cc. The bore on both the 750 and 700 is the same.

Bore/stroke
VF750F: 70 x 48.6 mm (2.76 x 1.91 in)
VF700F: 70 x 45.4 mm (2.76 x 1.79 in)


Other wise both cranks should be the same.

 

:behindsofa:

You'd really rather sink more money into into that beast and wait for the next item to fail ?? Wouldn't it make more sense to buy a good, used bike ?? That bike likely needs new cams too. And other stuff, and where does it end ?

You're not married to that obsolete, troublesome pos, so why not split up now ??

She's unreliable, a nice-looking crack-ho who wants your money but gives a poor ride.

Forget about USED replacement cranks for used-up machinery. Move on, and find a bike that's ridable NOW.

 

Squirrel maybe you should have just said DOOM..... DOOM.... DOOM.... DOOM ....DOOM...




I think what squirrel is saying is not to waste your money... realistically you should find another bike to ride that isn't going to be a money pit unless you want to spend the money.... its your money good luck either way...

 

You read my mind.

 

:behindsofa: ( why i keep posting on these things all the time i still don't know, but not having cable tv might explain it. Let the young rider continue on his idealistic mission to rescue another VF from desuetude and neglect, usually with the hope of having a cheap ride.



If it's the kid's money and his learning experience i'll cease and desist from my wisecrack VF digs, and he could try re-constructing a good VF motor from bitsa this, partsa that, and whatever ebay special new parts he could find. Or pay a shop to do a full motor job. A fine long term project if you want to pursue it, MAYBE, but that bike isn't likely to be riding this season. Sometimes passion and idealism override practical or economic good sense, or any sense at all unless maybe your VF is the one bike you love best of all, for some reason.


Are there any good used cranks ?? Most cranks from that far back are going to show some wear. Get the micrometer busy, and don't think .001" out of spec makes no difference.

 

Hana I love this site. Hey man contact falicon cranks they'll be able to help you better with this problem.

 

i dont know if my engine has the after market oil tubes for the top end but i do know that the cams are in good shape, both tensioners seem to be working properly and cylinder walls and pistons have nothing wrong with them either so i figured it was worth throwing a crank and some new bearings into , are these that poor of an engine that they are not worth rebuilding??? i dont know much about them thats why i joined this site so i could ask people who know

 

Oh don't listen to squirrelman, he's a few nuts short for hibernation.

Those motors are tuff if you know what your doing. Proper maintenance and oil and you can beat the snot out of them. I do. With a Fox or good rear shock, 10w oil in the fork tubes and good tire they handle pretty damn good. I rode with a 5th & 6th gen in the Georgia mnts and there was no sucking of hind tits by any of us. The newer bikes have more top end though.

What squirrelman is saying is, your going to dump money in to it to get it back in no hind tit sucking shape. How much depends on how the bike is now. At least a grand most likely with you doing the work. Brakes, suspension, motor, chain-sprockets? What will it take?

You could for around $2500 to $4000 and get a newer 750 or may be 800. But they come with their own problems also. Plus I'm not so sure they are all that much better overall depending how you look at it. Though I must say I really like the 5th gens most of all. I'd like to find a super deal on a 99 or 00.

 

hahah yeah squirrelman kinda discouraged me from wanting to finish the project when i read the post ,but the rest of the bike is in good shape it was road legal last year and has good rubber it just may need fork seals but other then that its in good shape ,and i paid almost nothing for it and a parts bike so i figure if i gotta sink 500 bucks into the engine ill still have a pretty good bike for the price , i found a crank on ebay VF750 VF 750 MAGNA SABRE INTERCEPTOR CRANK CRANKSHAFT - eBay (item 300271768137 end time Mar-27-11 08:26:22 PDT)
i asked him last night to take some closer pics of the journals and he did from what i can see it looks to be in alright shape, i dont plan on building a race bike just something i can get a year or two out of i can get it shipped to my house for under 100 bucks so i think its worth a try
if anyone wants to take a look at the crank and tell me what they think that would be great ,then i can buy it slam it in and start putting the thing back together!

 

The Magna and Sabre cranks are different, unfortunately. You'll really want to find a VF750F crank if at all possible. If you don't mind the loss of displacement (you'd hardly notice it, actually) then a 700 crank could be used. You would need to get the matching rods and pistons as well.

 

Heres a different view I ran across of the discarded & abused machine in need of tlc in your possession. My only question is did it come with a good title so that you can title in your name, as its a street bike. In my mind its a classic. Make this one of your bikes. For the argument it may not run this year. Its a work in progress. If you also buy something thats running that you can get plenty of ride time, it takes all the stress out of it. I find breathing life into discarded cycles very rewarding. If you will notice, squirrel has many bikes, none new.As long as you have something to ride you have the best of both worlds.

VINTAGE: 1983 Honda VF 750F Interceptor
The real story of the landmark VF 750 F Interceptor was Honda’s departure from the air-cooled inline four...
Nolan Woodbury | One Man's Laverda - Vintage Motorcycles Online | Posted November 02, 2009 Charlotte, NC

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(Photo: vintagemotorcyclesonline.com)The High Performance, 748cc engine produces 86 chain driven horsepower for the 487lb Interceptor

Much has been written about the landmark VF 750 F Interceptor, most dealing with the Honda’s impressive production run, technical innovation and Superbike racing success. All noteworthy and all true, but the real story behind the Interceptor was Honda’s departure from the air-cooled inline four. Introduced fourteen years earlier, the venerable CB-series served as the foundation for what would eventually be one of the largest and most successful motor companies in the history of motorized transportation.

By the time Honda introduced the first V45 Interceptor in 1983, it had already gained a strong reputation for flexing its technological muscles. 1975's GL1000 rewrote the touring handbook with its long-lived, turbine-like flat four, and other deviations like the twin cylinder CX500 and CBX showed Honda wasn’t above digging into established motifs to make a point. Based purely on opinion, the public in general and Honda enthusiasts in particular seemed most comfortable with the company producing leading edge designs.

Based on the V45 Magna, the Interceptor’s 748 cc, liquid-cooled V4 measures only 14" across the crankcases and features a revised starter that kickes the engine’s rotation to match the direction with the wheels. Cutting edge for the era, the stout VeeFour featured DOHC with 4v per cylinder, four 30 mm Keihin CV type carbs and a compression ratio of 10.5:1. The transmission was beefed and revised into a standard five-cog box with the Magna/Sabre’s shaft drive and differential binned in favor of a conventional drive chain. Rated at just under 90-bhp, the 500-lb plus V45 Interceptor clocked an 11.9 second 1/4 quarter-mile and generated a top speed that approached an honest 140 mph.

Chassis specs featured a box-section steel perimeter frame, painted to look like aluminum; the same trick Honda used on the CB1100F’s swingarm. Ushering in the brief but unforgettable 16-inch front rim craze, the Interceptor didn’t suffer any with its adjustable Showa suspensions. Short and stubby, the Interceptor was among the best handling middleweights of the day and second to none for pure curb appeal with its blocky paddock styling, chin spoiler, dual radiators and brushed alloy aircraft spec dash.

Constantly revised through its long, impressive production run, the VF spawned the highly acclaimed VFR series; a model that claimed repeated ‘Bike of the Year’ awards and earned legions of devoted fans all over the world.
Nolan Woodbury

 

Spare parts

I have a spare 750 crank rods pistons, PM me if still interested.

 

so did you mean just if i got a crank from a 700 id need matching rods and pistons?
if i get a used 750f crank will my rods i have now match up with it ? or is it something they specifically fit from the factory ??
and one more thing the link i posted from ebay says that that crank would fit my 83 750f ,is that not true ???
and i appreciate all the help im sure i would have wasted tons of money on wrong parts already if it wasnt for this site haha

 

It's good to see a true enthusiast, Malaguci, but you omitted to mention the reality about VF motors, that many different pieces were poorly engineered and almost destroyed Honda's reputation for reliability. The development of the VFR from the VF series was Honda's necessary attempt to rehabilitate it's reputation, and the increased reliability, performance and loss of weight instantly rendered all VFs truly obsolete.

Out of a number of engine lines from a diverse range of manufacturers, the VF series still seems flawed in design and execution, notwithstanding the heroic efforts of a few to keep them ticking.

 

Anytime you change stroke on an existing engine, one or several other things must change also. Rod length, piston pin location or deck height. One of these will do it or any combination of. Yes that 700 crank will fit like the guy says (physically). But to make it work! You need some more of something else. See above.

 

Well, you can pull squirrel's tail but not very far! Thats a pretty strong real world case you have presented. I think a person could make a case that vincents are obsolete but highly desired & collectable.

apparently honda sees this model as special. If you visit honda collection hall Honda Worldwide | Honda Collection Hall click on collection search, 2 wheeled, on road sports, page 3, you will find a 1982 vf750f. I am sure you are aware of this site, but to anyone who isn't, its great motorcycle fun.

Theres got to be a lot of 83 vfr750f owners on this board. I would sure like to hear how they feel about this machine. This could be beneficial to coleross.

 

Just don't forget to pull a rod out of your parts bike if you just get the crank.

Unless that pulled rod has a good bearing and the journal is the same size, you will be buying a rod bearing too. You won't really know what the size was since it was spun.

Like others have said, it's up to you what you do with it.

 

i plan on getting a used crank and putting new mains and rod bearings in it , im aware that my rod is going to be miss shaped and ill need another one , but my parts bike i have has the same rod gone outa it , so are the rods interchangeable? cause id have to use one from another cylinder