Did you keep your valves at stock settings? I'm racing a stock class for now so would maybe opening the intake valves from .002 to .003 or .003 to .004 be too hard on the engine? I'm just coming up with ideas to increase engine functionality without "breaking any rules" lol
If not your using a high lift megacycle cam, I doubt seriously you'd see any effect on tightening up the VL other than gulling the cam lobe from inefficient
oiling. I'd use the 256 cam or shell 1 cam if rules allow with the recommended L/S
Try to locate a XS1 head as they had better port casting and where very consistent port to port and had a flatter floor for increasing port velocity, secondly locate virago 750 valves and cut'em down to xs stock dimensions and radius the bottom of E/V. The head designs help with flow and the thicker margins reduce resistance.
 
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Would pay to find out just how stock it has to be, you should be allowed to bore out to maximum oversize on the bores, which would mean you could put the hoos 700cc kit in, also would recommend his ignition kit, stk465 it's an electrix world unit I use them and never had a problem, it means you can get rid of all of the electrics.
Carbs you should be able to run period slide carbs, and also as said in a previous post the shell #1 cam is about the cheapest cam going also from Hoos,
There can be a lot of taking the rules to the limits when it comes to classic classes.
 
The best thing I can say is to check out my blog page........ https://nrperformance.wordpress.com/portfolio/fzxs-650/

Checked it out,nice work. If you'll angle drop the front motor 6 to 10 degrees in that frame it'll feel more balanced than being top heavy, easier to flick
it left to right. Drop the side rails, mount an angle finder to the flattest part of the head,use a racket strap to support and lower to the desired angle. Lock it
then straddle it and flick it side to side and you'll immediately feel the difference in how it handles. You might have to drop the rear again to realign
D/S axis to pivot axis. You can always reconstruct the side rails if you like the look. Just making a suggestion, not trying to critique your visions or workmanship
 
I get what you're saying, Jack, with the forward angle change. Moving the C/G farther forward and down a tad. The problem is that to get the frame clearance to do that, I would have to also RAISE the engine. Kinda defeats the purpose.

Unless you are meaning eliminate the lower frame rails all together. In which case, I would have to pass. The XS650 engine design was never meant to be a structural, load bearing member of the frame.

Now back to our regularly scheduled thread..................
I under stand.You might wanna look at this.
http://www.xs650.com/threads/mule-frames.296/
 
Go-with pics.
cracked mount
crankcase_crack-jpeg.148644

Early
Resized_20170501_200644.jpeg

later
Resized_20170501_200857.jpeg

More of an engineering oopsie than a cradle or not issue but I understand the "not designed for load path" strength issue as being a real one.
Early frames are known to crack near the rear mounts area when pushed hard also...
 
On the other hand....... From a full cradle (stock) framed racer.
View attachment 148644
The cases can be problematic due to weak webbing when pushed beyond their limits not just from stress
but also pushing the Hp has it limits. The cases I have are "75" and have the reinforced webbing in the critical areas in those pictures. The XS engine has been mounted in a variety of stress loading frames
and I don't think in a street riding environment will put those case weak points in jeopardy.
gkqx4o0IIfSIdMQogbTLL5GeCbDdlKTkgXaxfekE0vudPWZStJMPn_eNtbIDa7zEEj_fphp7NdYHxdmxCRMYV44-UItFV4yYi1y6cGY19FNrTzlr7HFScpZU686w0kh1PAS15_UQTx13qdcbsjXkVEW8_drPjRUcXR3ChNVAlBzypgdmPX06AD_VWueejzRjEga2lLDTyNWQxoGzZTAAL7HhGTNVUoruM6EGux0WIKaLwX6-183dIE9UqxloVh-vs8IaV0vDl_Xl_agdJ2WZS1FMapMqP_XphHKvNByxSuZ-Rbgv5R1wjempTHcjqPNOq-f3mO9Xud7UsuZlSnnxdPSL3RXcwBl6xAnQ1XwutMn_Eu-ox5QPeaL1BPKPyYRSNOgj4bIn6a8THWhTAiEBFUxrGS3EPlUOTzFYkrwbGol3CebJheOLXmqFfZKjsmEmo8WMZ7GNmJ1VwnDCtvV3WG2bYGsoaoeow8rES3yuhCqhrkU7GfkQojDnH-0KDsbheI40PXhXBG5JMjIfLO3hybLJQsI4JaKAAX6VchJOgMUwEpzWv7XpOKpyZgG7chmaqGL8ccXmJJaOoTah8xEBsAnl2kBkYR8PjetgVMuqjhEQw5xUYrC9t1Cu-enVKduqKoZTBxuK9oOo_Hwf6-g7Bz6ARoj7gzLe7MpmNKbdZLYv9RN6W15bVUXHNhmkoo7ZmmymSNw47eeBLbZuReRT3TWqmtz2eZlcOU77VGT9w_KAheCo=w512-h355-no
 
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Would pay to find out just how stock it has to be, you should be allowed to bore out to maximum oversize on the bores, which would mean you could put the hoos 700cc kit in, also would recommend his ignition kit, stk465 it's an electrix world unit I use them and never had a problem, it means you can get rid of all of the electrics.
Carbs you should be able to run period slide carbs, and also as said in a previous post the shell #1 cam is about the cheapest cam going also from Hoos,
There can be a lot of taking the rules to the limits when it comes to classic classes.


My race class is nearly 100% stock, Other than removing all un needed lights, and kickstand mounts, and side panels if you choose to not use the stock panels then the only thing really after market allowed in my class is updated performance break shoes and pads, and air filters that meet standards for the class. The 700 or 880 cc bore out is allowed for racing, just a different class. I thought I would race a little bit to get used to it before I go fast lol
 
Just a little food for thought, Grimmith. You may want to also look at the WERA Vintage rule book. You may want to build a bike that will work for both.
I will definitely do that. My current plan was to, get this bike all ready for beginner racing as I read the rule book and build until it's complete with everything I need for however long that takes. Go to AHRMA racing school to pass test. Then race. After racing for a year or two, when I feel like I'm ready, I'll go up a few classes where the faster bikes are and what classes the the 880 to 890 cc engine bore out is allowed in. Go from there on parts, gear, etc.

Can you win money from these races?
 
I race this one in AHRMA Sportsman 750 class. There are classes you can race the 650 in. This has the 750 kit, 11:1 pistons, ported head with a Megacycle cam, racing exhaust, 36mm VM carbs, electronic ignition. She runs strong.

Good looking bike. Lot of work in those headers..............Can a rephased be raced under your class??
 
I race this one in AHRMA Sportsman 750 class. There are classes you can race the 650 in. This has the 750 kit, 11:1 pistons, ported head with a Megacycle cam, racing exhaust, 36mm VM carbs, electronic ignition. She runs strong.

That looks sharp! Any videos of you and your bike in action? Or even just a video of it running? :geek:
 
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