650cc Ascot TT

thorshammer · Full Member Joined: Dec 12, 2008 Posts: 58

Hi loved my commando I could even see objects in the mirrors. Another fairly smooth brit was the 750 Royal Oilfeild Wink

not really my cup of tea but nice heavy flywheels. The idea of isolastic mounting for the 650 has some merit but maybe overrated. My personal choice for a smooth twin would be BMW but I haven't found the right one yet ( cheap ). So for a lot less money and hassle the xs 650s feel about the same as my old BSAs did, just take more work to make them handle as well. IMHO

xs1961 · Posted: March 27, 2009, 4:48 am Post subject: Re: 650cc Ascot TT

My smoothest twin ever was my 1971 Laverda SF750, superb bike, I reckon the main reason it was so vibe-free was the thickness of the frame tubing..Which inspired me to once fill the lower frame tubes of my XS with approx 6lb of lead shot (through a 1/4" drilled hole either side then plugged) - what a difference ! Soaked up the vibes and an added bonus was the handling due to the lowering of the center of gravity and the added un-sprung weight on the suspension ..
Going to try it again as soon as I can afford the lead !
EDIT - SPRUNG weight Embarassed

Barbara · Posted: March 27, 2009, 1:13 pm Post subject: Re: 650cc Ascot TT

xs1961--

No kidding--that worked? Where did you drill? (I retired from owning a printing plant, and we had a hot-lead/letterpress department....I have lead.) About 6 lbs--in each down-tube? Wow, if that really did the trick, I'm gonna do it.

xs1961 · Posted: March 27, 2009, 1:52 pm Post subject: Re: 650cc Ascot TT

Approx 6lb's in all - not each leg.. We drilled just below the headstock each side & also just behind the side panel below the seat.. Poured in small lead shot & some fibreglass resin to help stop the lead shifting! Not sure where I can get that much lead these days Confused

Buddy78SX650 · Posted: March 27, 2009, 4:04 pm Post subject: Re: 650cc Ascot TT

xs1961 wrote:

Not sure where I can get that much lead these days Confused

Old dead golf cart batteries have a ton of lead in them but watch out for the acid... and then you would also have to find a way to grind up the plates. Twisted Evil

jimmythetrucker · Full Member Joined: Mar 12, 2008 Posts: 1283

xs1961 -- you might have been able to stop the vibration by pouring in the resin only. It would be interesting to find out if that works just as well without the lead. Of course somebody has to risk a useful frame in order to find out. . . .

xs1961 · Posted: March 27, 2009, 5:20 pm Post subject: Re: 650cc Ascot TT

Im going to try that next week on a spare frame , got gallons of resin, cant harm the frame, helps seal it against water! Smile

xsjohn · Posted: March 27, 2009, 5:32 pm Post subject: Re: 650cc Ascot TT

And you guys pretty much laughted at me for lowering the compression a bit to reduce vibrations........ Laughing

Could weld a couple for feet of railroad rail across the frame below the engine....would work for foot peds that would vibrate less too... Laughing

All in fun guys.........

xsjohn

xs1961 · Posted: March 27, 2009, 7:34 pm Post subject: Re: 650cc Ascot TT

Not me John..Lower comp makes perfect sense..when I replaced my BSA A10RR (9.5:1)pistons for lowly 6:1 comp Ariel Huntmaster slugs the bike was transformed into the sweetest running Brit twin Ive ever !
as for the railway tracks , well, the theory's correct .Ive noticed that the XS's that Ive stripped down & de-lugged vibrate more than those with all the extra hinges/brackets/hangers etc. intact !

xsjohn · Posted: March 27, 2009, 7:41 pm Post subject: Re: 650cc Ascot TT

Think for the XS 6 would be weak......8 is ok though....150 psi to 130-135 psi......I want it to still blast down the express.....which it does........

Years ago I did change out my BSA Hornet from 10.5-1 to 9-1......still took me anywhere........

xsjohn

650skull · Support Staff Joined: Jul 19, 2007 Posts: 1186

Not me either John, I'm going to give it a go on one of my engines when i get some spare gaskets....... i have in mind one of mikes 5th gear and not changing the gearing so much................have to wait till i open up the motor though, wouldn't do that unless i had to...

nj1639 · Posted: March 27, 2009, 9:36 pm Post subject: Re: 650cc Ascot TT

Yep, got a spare head gasket just waiting for the next teardown, pickup coil top mount is slotted now.

Barbara · Posted: March 28, 2009, 12:21 am Post subject: Re: 650cc Ascot TT

'61,

If anyone in your area knows a hobby-printer, and they have a Linotype, you can get all the lead you can use. Actually, it's "type-metal", just a bit harder than lead, but still melts at about the same temperature. I used lots of it casting triangle weights for salt-water fishing. I've got probably 100 lbs still in the shed, from the Lino days.

Call a couple of printing plants, and ask for the names of hobby-printers. Hmmm---John's remark about the railroad iron gave me an idea---two metal tubes, one on each side-rail on the bottom of the frame, welded shut on one end. You could start with say four lbs of melted lead divided between the two, and add it until it felt right. If you got too much weight, just unbolt the metal tube, and hit the open end with a torch---out comes some of the lead as soon as it melts!

I guess my Nom de Guerre must be Rube Goldberg....... Laughing

thorshammer · Full Member Joined: Dec 12, 2008 Posts: 58

The weight in the frame is really sprung weight, adding weight in the lower tubes may make it feel different but the laws of physics still apply. More weight slower acceleration slower handling and braking that being said it probably would not make a noticeable difference on the street but on the track could be the difference between 1st or 2nd. Grinding off tabs and brackets will also alter the harmonics of the frame alowing more vibration to be felt. How about isolastic mounting of the footpegs and different grips or gloves with gell in the palms less weight equals better performance.

xs1961 · Posted: March 28, 2009, 5:50 am Post subject: Re: 650cc Ascot TT

Cheers Barbara, I know a bloke who knows a bloke.. Wink

Yep, youre right thorshammeer. I always get my sprung/unsprung confused..
Still, the frame did seem to absorb the vibes somehow..As for the difference of 6lb's or so I never noticed the difference performance-wise , there are so many weight variables from wearing a heavy leather jacket, a full tank of juice , a fat/slim rider or even one whos taken(or not) a recent dump! Smile

Tomterrific · Posted: March 28, 2009, 1:26 pm Post subject: Re: 650cc Ascot TT

I used a length of vinyl tubing that fit in my handlebars. I cut the tubing so it would not stick out and interfere with the throttle action. I filled the tubing with lead shot, #12 I think, and sealed the ends. Then I oiled the bars inside and forced the tubing into the bars. The weighted bars changed the resonance of the grips. I think if I do this again I'll seal up one bar end, fill the grip area with lead and the middle of the bar with sand. As I finish filling the last grip area I'll seal the bar. The sand will not add as much overall weight and save on expensive shot.

Tom Graham

jimmythetrucker · Full Member Joined: Mar 12, 2008 Posts: 1283

You guys live in a different world than I do. I rode my old '79 for nine years and loved every beat of its heart. There were things I didn't like about it: back then I only weighed 180 lbs, but I wished for more room on the saddle and deeper padding in the seat. On longer trips (10, 15, 20 days) I often wished for highway bars and forward controls. But the machine itself, the heft and the feel, the tone and general behavior of the thing, I never found fault with.

What Happened to 650rider.com?

Yamaha xs650