700 cc conversion - SV650.org

20-08-06, 05:54 AM

Anyone out there carried out the 700cc conversions. Interested in doing this over the winter month. Would like in a few opinions before I spend the hard earned cash.

20-08-06, 08:35 AM

cheap'r to buy an sv1000?

20-08-06, 09:40 AM

And a lot less hassle,plus a better bike along with the insurance declaration being already listed. Most modified bikes that are up rated in cc and performance incur fairly steep loading so in the long run changing the bike is an easier option

northwind · 20-08-06, 08:48 PM

Cheaper to buy an SV1000? Nah. Wiseco piston set costs about £170 all in, rebore's not especially expensive (but be careful who you use, not everyone that'll do it for you really has the hardware) and the break and fit's feasible for a reasonably experienced DIY mechanic. Not easy, mind. Whether or not it makes any sense to do it, is a decision only you can make.

But, there's the potential for reduced engine life, and possible disasterous failure. Every power mod adds stress to the engine, simply because of the extra force. 677cc or 700cc boreouts also add more moving mass to the engine, which gives yet more stress. Also, you're thinning the cylinder liners, which has been known to cause warped liners under high-heat stresses.

Here's some numbers...

stock sv-319.2
stock busa-302.5
JE 3mm over,flat top-330.3
Wiseco stock bore, high comp-335.4

I can't remember how heavy the Wiseco 700cc is- it's lighter than the JE from memory.

I'll be honest, I'm biased against it... If you ride the midrange and take it easy, it'd give you a nice hefty mid boost, and staying away from the top end would reduce the strain- and how high the odds of a failure are from either the JE or Wiseco kits, is really impossible to say. But, I looked at it and decided I'd rather not risk the longevity of my engine. Your mileage may vary

I might put Busa pistons into mine and deck the heads, though, just for a laugh.

21-08-06, 08:12 AM

I have had a 700cc bore kit in my race injected SV since the start of the year. The motor has been as strong as ever contary to some peoples opinions on this - normally veined from conversations taken from US websites.

So far the bike is making 10bhp more all the way through than an untuned SV650 and has 8ft/lb of torque more too. Combined with a lightened and balanced crank and other mods the bike has so far been 100%, no oil useage even though it gets a damn good hard trashing everytime its used.

Recommended if you do go for the bore to get a slipper clutch fitted as this will reduce the stress on the engine under hard gear shifting - this is what causes most of the engine failures on the std bikes.

The bike pulls very hard in every gear and is a real hoot to ride.

If your down south way Bob Farnham is worth speaking to. Dont attempt the rebuild work yourself unless you really know what your doing. Time needs to be spent measuring clearances if you go for a small head skim at the same time (worth it if the motor is apart anyway) and there is no point going half hog with getting the bore done properly then half cocking the rebuild.

Some people also state the piston will slap after a while - not if the bore is done right

So far we have 3 bikes running in various states of tune with a big bore plus 3 bikes with std setup. So far its only the std setup bikes that have had probs...one engine failure!. Make of that what you will!.

Viney · 21-08-06, 08:14 AM

Ther you go straight fromt he Horses mouth...not that im calling you a horse i hope you understand.

I have though, seen 3 700 kits let go. But thats a another story altogether. Just choose your engine builder wisely

21-08-06, 08:32 AM

Quote:

Originally Posted by Viney

Ther you go straight fromt he Horses mouth...not that im calling you a horse i hope you understand.

I have though, seen 3 700 kits let go. But thats a another story altogether. Just choose your engine builder wisely

Dont worry...i shall steer clear of the horse jokes

To put things into perspective, i have seen a fair few std motors let go recently. Primary cause seems to be that the rod or crank snapped under hard downshifting or when the rider was constantly missing gears. This can happen to a Std or a 700cc motor or any motor.

If a 700cc motor is built and used properly then there is no reason for it to go pop. For road use where its less stressed it should be as reliable as a std motor.

FYI - the busa piston upgrade gives no gain

johnnyrod · 23-08-06, 10:23 AM

No slapping or oil loss? Good going, I've just come back from France where my mate's SV700 used over a litre of oil in about 1400 miles - on holiday!

23-08-06, 10:45 AM

oooh not good. Mine has done over 6 race meetings of four races a weekend and 9 full UK trackdays and one four day bash at Brno which included a race of 20 laps round a 3.5 mile very fast track - so far no oil useage and no slap!. Ticks over sweet as a nut.

23-08-06, 11:20 AM

Like the others have already said, it all depends on the quality of the engineering work being done and the quality of the build.

There's no reason why the engine shouldn't be able to take the stresses and strains of a big bore kit as the engine is so-said to have been design with a high factor of safety, aka over engineered, and will therefore be ok as long as its done properly.

JHS Racing in Bristol are probably ya best bet for parts/advice as they are SV specialists and have carried out many conversions, all reliably as far as I know.

20-08-06, 05:54 AM	#1
CHICKENSTRIPS Guest Posts: n/a	700 cc conversion Anyone out there carried out the 700cc conversions. Interested in doing this over the winter month. Would like in a few opinions before I spend the hard earned cash.

20-08-06, 08:48 PM	#4
northwind Moderator Mega Poster Join Date: Jan 2004 Location: In the garage where I belong Posts: 17,082	Cheaper to buy an SV1000? Nah. Wiseco piston set costs about £170 all in, rebore's not especially expensive (but be careful who you use, not everyone that'll do it for you really has the hardware) and the break and fit's feasible for a reasonably experienced DIY mechanic. Not easy, mind. Whether or not it makes any sense to do it, is a decision only you can make. But, there's the potential for reduced engine life, and possible disasterous failure. Every power mod adds stress to the engine, simply because of the extra force. 677cc or 700cc boreouts also add more moving mass to the engine, which gives yet more stress. Also, you're thinning the cylinder liners, which has been known to cause warped liners under high-heat stresses. Here's some numbers... stock sv-319.2 stock busa-302.5 JE 3mm over,flat top-330.3 Wiseco stock bore, high comp-335.4 I can't remember how heavy the Wiseco 700cc is- it's lighter than the JE from memory. I'll be honest, I'm biased against it... If you ride the midrange and take it easy, it'd give you a nice hefty mid boost, and staying away from the top end would reduce the strain- and how high the odds of a failure are from either the JE or Wiseco kits, is really impossible to say. But, I looked at it and decided I'd rather not risk the longevity of my engine. Your mileage may vary I might put Busa pistons into mine and deck the heads, though, just for a laugh. __________________ "We are the angry mob, we read the papers every day We like what we like, we hate what we hate But we're oh so easily swayed"

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20-08-06, 08:35 AM	#2
kwak zzr Guest Posts: n/a	cheap'r to buy an sv1000?

20-08-06, 09:40 AM	#3
Dicky Ticker Guest Posts: n/a	And a lot less hassle,plus a better bike along with the insurance declaration being already listed. Most modified bikes that are up rated in cc and performance incur fairly steep loading so in the long run changing the bike is an easier option

21-08-06, 08:12 AM	#5
SV650Racer Guest Posts: n/a	I have had a 700cc bore kit in my race injected SV since the start of the year. The motor has been as strong as ever contary to some peoples opinions on this - normally veined from conversations taken from US websites. So far the bike is making 10bhp more all the way through than an untuned SV650 and has 8ft/lb of torque more too. Combined with a lightened and balanced crank and other mods the bike has so far been 100%, no oil useage even though it gets a damn good hard trashing everytime its used. Recommended if you do go for the bore to get a slipper clutch fitted as this will reduce the stress on the engine under hard gear shifting - this is what causes most of the engine failures on the std bikes. The bike pulls very hard in every gear and is a real hoot to ride. If your down south way Bob Farnham is worth speaking to. Dont attempt the rebuild work yourself unless you really know what your doing. Time needs to be spent measuring clearances if you go for a small head skim at the same time (worth it if the motor is apart anyway) and there is no point going half hog with getting the bore done properly then half cocking the rebuild. Some people also state the piston will slap after a while - not if the bore is done right So far we have 3 bikes running in various states of tune with a big bore plus 3 bikes with std setup. So far its only the std setup bikes that have had probs...one engine failure!. Make of that what you will!.

21-08-06, 08:14 AM	#6
Viney Member Mega Poster Join Date: Jul 2003 Location: In the shadows to the left Posts: 7,700	Ther you go straight fromt he Horses mouth...not that im calling you a horse i hope you understand. I have though, seen 3 700 kits let go. But thats a another story altogether. Just choose your engine builder wisely

23-08-06, 10:23 AM	#8
johnnyrod Member Mega Poster Join Date: Jul 2003 Location: Doncaster, oop norf Posts: 2,122	No slapping or oil loss? Good going, I've just come back from France where my mate's SV700 used over a litre of oil in about 1400 miles - on holiday!

23-08-06, 10:45 AM	#9
SV650Racer Guest Posts: n/a	oooh not good. Mine has done over 6 race meetings of four races a weekend and 9 full UK trackdays and one four day bash at Brno which included a race of 20 laps round a 3.5 mile very fast track - so far no oil useage and no slap!. Ticks over sweet as a nut.

23-08-06, 11:20 AM	#10
Carrot Cruncher Guest Posts: n/a	Like the others have already said, it all depends on the quality of the engineering work being done and the quality of the build. There's no reason why the engine shouldn't be able to take the stresses and strains of a big bore kit as the engine is so-said to have been design with a high factor of safety, aka over engineered, and will therefore be ok as long as its done properly. JHS Racing in Bristol are probably ya best bet for parts/advice as they are SV specialists and have carried out many conversions, all reliably as far as I know.