AUTOMAN
XS650 Addict
Not with the right cam.
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Another big bore question
- Thread starter Flash1977
- Start date
I'll probably have to go with the cam option that mikes xs offers. And I'm leaning towards the 9.0:1 kit
BTW. Found this on FB. Not sure what this cam is and whether the profile is conducive to detonation. It is asymmetric. A bit spendy but you can always make an offer. https://www.facebook.com/marketplace/item/581153374390687/?mibextid=wwXIfr
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AUTOMAN
XS650 Addict
I don't know, I'm gonna have to stick with the cam that is paired with the big bore kit to be safe.
Here is my opinion.
For ease of kick starting use the 9:1 big bore kit.
This is my opinion, other posters will no doubt differ.
If your stock cam is ok run that. A performance cam without port work will yield minimal benefit.
If not use a Shell number 1 cam, a Web 59A, or one of the milder Megacycle offerings.
You will need to upgrade your valve springs with these cam options.
I would not use Mikes XS performance cam or his valve springs.
You will also need to check piston to valve clearances when you assemble the motor, these motors are old and the head could have been machined. There is usually a lot of clearance but don't risk it if changing cams.
Best return on investment for extra performance.
1 Big bore
2 Port job
3 cam
For ease of kick starting use the 9:1 big bore kit.
This is my opinion, other posters will no doubt differ.
If your stock cam is ok run that. A performance cam without port work will yield minimal benefit.
If not use a Shell number 1 cam, a Web 59A, or one of the milder Megacycle offerings.
You will need to upgrade your valve springs with these cam options.
I would not use Mikes XS performance cam or his valve springs.
You will also need to check piston to valve clearances when you assemble the motor, these motors are old and the head could have been machined. There is usually a lot of clearance but don't risk it if changing cams.
Best return on investment for extra performance.
1 Big bore
2 Port job
3 cam
Thank you .I wish more people would give an explanation like this as to there opinion
Also being that my credit or purchasing options are what they are I will have to go with a mainstream company like mikes xs. In your opinion will I be ok purchasing the 9.0:1big bore kit threw them? And as far as a shell #1 cam where can I buy one that doesn't require PayPal. Is there one of the cam options that I can purchase threw a main stream aftermarket store? I would love to go with Gary hoes and rd but but I probably can afford that option and I can't use PayPal. So I may just install the kit like you said and keep my original cam .but I would like to put a cam in and see if I can find a local shop to port and polish if that's what's needed
I am absolutely no expert, but I would rather spend the money on proper machining of valve seats and valves, instead of "port & polish".
As a minimum, 3- angle valve seats (4, 5 or even a radius cut may give more), and some attention to the angles of the valves as well. This will help flow at low valve lift.
As a minimum, 3- angle valve seats (4, 5 or even a radius cut may give more), and some attention to the angles of the valves as well. This will help flow at low valve lift.
I also don't use PayPal and used Gary Hoos and RD. Go to the post office and buy money orders. It takes a little longer, but it works.
If you are buying a BBK you can save yourself about $100 by ordering it from Yamahaxs650.com instead of from Mike's. It is the same kit from a different supplier. Many here have bought these kits with no issues.
https://yamahaxs650.com/product-category/engine/page/6/
https://yamahaxs650.com/product-category/engine/page/6/
Appologies, looks like that vendor only takes Paypal and Venmo payments. Might be worth a shot to reach out and ask if they would do a CC or MO.
Was a few years ago, but I called YamahaXS650.com over a problem of some sort with my payment. Don't recall the details, but they were a great bunch to deal with. I'd lay odds that they would gladly help you with whatever payment method you use.
Call 'em.
mike in idaho
XS650 Addict
Here is a suggestion:
Why not develop the motor in stages.
Stage 1 Big bore.
Stage 2 Port job
Stage 3 Cam + springs (good springs are not cheap)
It is not a big job to pull a motor and install a cam.
Artic XS, from my experiments with porting a multi angle seat cut on the exhaust works well but on the inlet it killed flow. I have yet to repeat the test with 2 angle and 3 angle cuts.
Why not develop the motor in stages.
Stage 1 Big bore.
Stage 2 Port job
Stage 3 Cam + springs (good springs are not cheap)
It is not a big job to pull a motor and install a cam.
Artic XS, from my experiments with porting a multi angle seat cut on the exhaust works well but on the inlet it killed flow. I have yet to repeat the test with 2 angle and 3 angle cuts.
pull the top apart three times? My suggestion is either doing all three or just the big bore and be done with it.
ZRX100. I think in reality if Flash was to do the work in stages he would be so impressed of the result with just the big bore he would leave it at that.
What my point was is that its not an all or nothing situation.
What my point was is that its not an all or nothing situation.
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on a side note, the first time i fired up my 700cc build, there was no appreciable difference in performance vs stock. My intake and exhaust were all wrong. Opening both up really let the reworked head and cam demonstrate the motor's potential. I would add another $500-$1000 on top of stages 3 that you outlined to realize potential gains.
I went with the yamahxs650 big bore kit and am very happy with it. Lessened the vibes a significant deal and pulls REALLY well. It’s not going to win any speed awards, but for my little back road racer it does great. I had plans to do a cam, port work and new carbs, but honestly right now it runs so well for me with the tuned carbs that I’m leaving it alone. Whenever I need more work done that may change. Might I also suggest saving up a little money and upgrading your clutch as well?
very nice
