Quote from: RoadstergalI'm terribly curious to meet you.  Thanks to the board, I have a mental image of you as a large, friendly dog.

Thank you. Very flattering. If you are ever on the east coast, I would respectfully entertain the opportunity.

I bought both sets of cams used. The older catalog had the price at $266 on your cams and $29 for the valve springs.

Necking the valves is not required. If you increase the carb size later, I would recommend it then. Doing this reduces the amount of area blocking the air flow in the ports, kind of like porting. I have always started doing them since I have a lathe. Generally, not enough material removed to cause breakage. I do not recall the amount I remove, I would have measure one.

This also reduces their weight and increases rpm before valve float. I had a gain of about 2400 rpm with necking and springs, mostly due to the springs.

Cleaning up the in/ex ports is a good idea. There are several casting lines that really need some work. I will polish the ex ports but leave the intake ports slightly rough.

When I plugged one of the holes in the slides, it eliminated the idle hang and reduced the hesitation (typical of CV carbs) when opening the throttle wide open too fast. Mechanical carbs will eliminate both of these problems.

No problem with asking questions. Better to ask how to do the work instead of how to fix it.

Just found a comparison pic of the valves......Click for Pic

Yes I did the ports myself. I used a Dremel. I just bought a small air grinder (about 3/4" in diameter) which should work even better. Clearance item at Home Depot for less than $30.

Turning the valves is no problem. Let me know when you want them done.

The first set of cams I got off the WERA board from a racer getting rid of his GS stuff. The other set was in a motor along with large lot of parts I bought.

There is another cam company but I do not recall their name. The price will probably be close to the same.

78.95mm is the correct size.

I paid $130 to have my cylinders bored. The higher cost is due to the amount of material that has to be removed, 5mm worth. Good thing it is only a twin.

It will be ok to run the modified valves without bigger carbs right?

And I could probably just clean up the ports myself then? No special know how required? Basically just clean up the seems?

No problem running necked valves with stock carbs, or even with stock pistons. With the 79's you will want as little of restriction in the ports as possible.

Interesting that I tried 150 mains and it ran too rich. I dropped to 147.5 and then to 145 which may have been just about right. Never tried 137.5 though, just did not get to it.

Cleaning up the casting seams is easy enough to do yourself. Just need a small grinding wheel on a dremel. Run a vacuum through the port as you grind. This will keep every thing clean. Increasing the ports is another subject which I cannot go into.

Also, look at where the carb boots attach to the head. There is usually a small lip where they do not line up properly. Grind so there is no lip.

QuoteInteresting that I tried 150 mains and it ran too rich. I dropped to 147.5 and then to 145 which may have been just about right. Never tried 137.5 though, just did not get to it.

This was on your GS555R project? I'm glad that I've at least got an idea of what sizes to try out.

I know that you never took your GS555R to a dino for official numbers, but do you have any idea of what kind of power it was putting out? Even just a rough estimate? I'm just curious of what I can expect with; 79mm pistons, .380 lift cams, necked valves, an exhaust, performance filters and a jet kit.

I was also thinking about sending my ignition rotor to Bob Broussard for the advancing mod. Will it be ok to run an advanced ignition plate with all of these other mods?

Yes on the 555.

Never dyno'd it but a rough hp guess would be in the mid 50's. A good gain of torque. Even in 6th gear at 10k rpms, it was still accellerating.  

Definity run an ignition advancer. I have used a V&H and a BobB advancer, they all work the same.

Can GSes modified in this manner run in classes for which SV650s are ineligible?  Pistons, bored cylinders, new cams, flat-slide carbs, etc. seem like an awful lot of money to spend for less than a 20hp gain, especially when the bike is so cheap to start with.  I can understand it if it lets you race in a class where other bikes that are faster from the factory can't compete, but otherwise I'd think just moving up to the next bike would be less frustrating.

The classes that they are eligible in will vary between orginizations.

Anybody can buy a faster bike. Why stop at the SV, why not just buy a 1000?

I find more enjoyment in building a bike beyond what they were designed. If I had another SV, I would be doing the same (again). I sold my race 02 SV for around $6000 a couple of years ago, and I never got into the motor.

The GS is a good platform to learn wrenching. Parts are cheap and if you are creative enough there are plenty of them. I have to live up to my nickname of Dgyver.

I bought my GS for $1500 and put less than $500 into it. There was not $4000 more enjoyment in the SV. The GS was able to out corner most every bike on the track, except for the 125/250 GP bikes. Sometimes I would have to slow down to keep from rear ending another bike. Yeah it was slower in the long straights, but any idiot can go fast in a straight line. At lil Tally, I was keeping up with most of the 600's. This was when the motor was still stock.

Last time at Jennings, everyone was cheering me on. Riding the underdog bike, I was able to catch a R6 in four laps and then pass him with 3 turns to go. There is a certain appeal to beat someone on a 14 year old $1000 bike.

Quote from: dgyvergood points

I guess the only caveat I could come up with to your argument is that the tool collection you'd need to be making a lot of the mods you've done probably costs more than the bike  Of course, it's a worthwhile investment, too.

Good tools and a sense of accomplishment have two things in common; they're unbreakable, and they last forever.

Expensive tools are not really required. The most expensive I used was a torque wrench and Dremel, both I already had. I did pay for the cylinder boring since I do not have the tools or the experience. I spent several hours talking motor building to the machinist who did the work. I gained more knowledge than I could have ever imagined, well worth the $130. I do have a lathe (it was my grandfather's) but it does not cost that much to have the valves necked, maybe $5-10 each.

But....there is a point of diminishing returns on building a motor.

Just to let you know....I necked a set of valves yesterday and I drop them down to 6mm, from 7mm. This is only in the area from the valve guide to valve taper, measured when the valve is closed. It takes about 1 hour to do them. Any shop can do them or I will gladly do them for you.

btw....if you change your mind about the pistons, I will gladly take them off your hands.

i do not reccomend 417 cams without converting to shim under bucket setup, i have personally DESTROYED two motors using shim over bucket and 417 cams at higher revs the high lift cams will tiddlywink shims out and cause catastrophic engine damage,goe w/ smaller lift and retain streetablity.

Do you have anymore info on obtaining the shim under buckets?

kiss wade buffington's (Buff---- long haired wasted hippy looking dude somewhere near the michelin trailer at a wera event) butt and he might tell you...give him beer and your chances go up
Buzz's psycle somewhere N of atlanta is/was his shop

if i remember he designed that cam profile back in the early 90's
i got my ass handed to me by one of his riders(100 # girl on a 65-70HP GS) jeanie Garcea??? i think

I was on her butt coming out of 9 at RRR and she looked over here shoulder....and rolled on the gass and she fricken went away :x

i used to call my dad after the race and say I got beat by the girl....again

dgyver, the shim under buket setup is kwaka kz650 buckets and shims,but you have to use blank stem valves and have the length and groove  measured and cut  my racebike now has this setup its not cheap but worth every penny,i now run 438 lift cams without any troubles,but did have to fly cut deeper valve reliefs in the pistons.the 438 cams are a better profile w/ smooth power throughout the rev band,the 417's were not smooth at all(very abrupt power surge on top very choppy throughout the rest of the rev band)