-
Enjoy XS650.com? Consider making a donation to help support the site.
XS650.com receives a small share of sales from some links on this page, but direct donations have a much greater impact on keeping this site going.
Want more horse power
- Thread starter Metal
- Start date
Hi Dan,
soft cams, drop the compression ratio a tad and strap a supercharger on it.
Or if you just want lotsa power for a short time, a Nitrous bottle.
Metal
XS650 Custom shop
So I’ve been messaging our friend Iron Heart Cycles and I be been talking with Rodger at Hoos Racing.
This is what I think is going on.
When I built the engine I started with a Xs1 that had already been fitted with a 750 kit.
I also wanted 5th overdrive so I took the gearbox and crank out of a 447 motor.
I sent the crank to Falicon Race cranks to have it progressively balanced to try and eliminate as much vibration as possible.
The Head was also heavily ported.
At 65mph I’m out of gears and any faster requires higher rpm. At about 70 Mph it starts to vibrate and and more speed really feels like I’m pushing the motor.
So I think that maybe the fly wheel is not welded and its out a tad. We also think the head is loosing me power by being over ported for my application. My other thought is when I got my 5th overdrive gear Mikes sent me one that needed Machine work to fit. I took it to my local machine shop and when I got it back I could feel a tiny bit of play when the gear was put on the shaft.
I have a 80’s complete motor spare. At this point do I rob from the old motor or the 80’s motor.
We do mostly hwy riding and it’s my goal to get the bike to sit on 80mph
This is what I think is going on.
When I built the engine I started with a Xs1 that had already been fitted with a 750 kit.
I also wanted 5th overdrive so I took the gearbox and crank out of a 447 motor.
I sent the crank to Falicon Race cranks to have it progressively balanced to try and eliminate as much vibration as possible.
The Head was also heavily ported.
At 65mph I’m out of gears and any faster requires higher rpm. At about 70 Mph it starts to vibrate and and more speed really feels like I’m pushing the motor.
So I think that maybe the fly wheel is not welded and its out a tad. We also think the head is loosing me power by being over ported for my application. My other thought is when I got my 5th overdrive gear Mikes sent me one that needed Machine work to fit. I took it to my local machine shop and when I got it back I could feel a tiny bit of play when the gear was put on the shaft.
I have a 80’s complete motor spare. At this point do I rob from the old motor or the 80’s motor.
We do mostly hwy riding and it’s my goal to get the bike to sit on 80mph
Unless you're clinically obese, a stock XS650 motor in a decent state of tune will "sit on 80 mph" all day with 17/32 gearing. Your motor is already geared too high without the overdrive 5th cog; it just won't pull at speed when you're running way below the rpm range where it makes power. Understand this: If a little bit does some good, it does not follow that a whole lot more will do a whole lot more good. Get some decent filters, 1.5" pipes at least 32" long as measured on the outside radius, install those on the stock motor with 17/32 gearing and no overdrive 5th gear, and find a trusting person to pay good money for your butched up 750 mill. Good luck.
Horsepower...…….Do the guys on the Honda Rebel forums have these discussions too?
Scott
Scott
Metal
XS650 Custom shop
Your not getting me. I have tones of power at high speed I just have a lot of vibration with my gear set up I can still overtake at 80 no problem. So thanks for the advice but it’s not focused on my issues.
Changing gearing changes the rpm you are cruising at. You either want to get above or below that rpm at cruise. At lower speeds you shift to stay below it, once in 5th you either have to go faster or change gearing to sit at a different rpm. No matter what you do there will be vibration.
Oh, I get you loud and clear, Metal. Like all of us, myself included, you want to have your cake and eat it too. You'll figure out your own compromises between style and performance. Best of luck to you.
Check out Jim Schmidt's on how he's reduced vibrations racing Nortons for decades. Might
give you some ideas.
A overly ported XS head can spell disaster . When you take into account
it's short stroke, lower port volumes is the key in producing a wider power band,etc, that's my
opinion anyway.
give you some ideas.
A overly ported XS head can spell disaster . When you take into account
it's short stroke, lower port volumes is the key in producing a wider power band,etc, that's my
opinion anyway.
And a well tested opinion it is, Jack! Will we see you at Townsend this year?
