Top Speed?

[chris velo]

Your checks need to be done in order. Check and adjust valves, Compression check not forgetting to open the throttle full while testing. Adjust the points (Better still fit electronic ignition)Adjust ignition timing using a stroboscope for final adjustment. Always the final job is balance and adjust carbs to suit. Dyno on a rolling road is best,
As a guy that owns bikes from brit singles and twins to jap 2/3/4 cylinder bikes,
i have a sneaking suspicion low compression is a likely cause, My problem on my CB450 and my BMW R100 had a very tight valve.Low compression on that pot. dont get depressed you will get there.

 

[jay760]

Mines not stock but this is 1/8 and 1/4

 

[Raymond]

Uhm, this looks like an old thread being resurrected.

Chris, welcome to the madhouse. Why not tell us about yourself, what bikes you own, that sort of thing? Cheers, Raymond

Jay, that your speed at 1/4 mile, 108.88? Impressed.

 

[jay760]

Jay, that your speed at 1/4 mile, 108.88? Impressed.

Yes took me years to get there,
I prefer the 1/8th when you look at it it's doing 95mph on the 1/8th then only getting to 108 over double the distance, so just waiting for the end on the 1/4, especially as it's already in 4th by the end of the 1/8th so just one gear change and 13mph for double the distance.

 

[Kevin Werner]

Mines not stock but this is 1/8 and 1/4

11.80 quarter? Wow I guess it is not real close to stock...

 

[jetmechmarty]

11.80 quarter? Wow I guess it is not real close to stock...

It’s close to stock XS1100.

 

[jay760]

11.80 quarter? Wow I guess it is not real close to stock...

72 frame, worked 750 engine, where its twisting the frame its just cracked by the swing arm pivot

 

[40north]

What's the frontal area?

FA is whatever, but non faired scooter have totally bad drag coefficient, like maybe 2.0 or worse. Spokes, cables, all that stuff. If you really wanna know the numbers build wind tunnel and model scooter. FA can be estimated from a front view black and white pic, but it's drag wot gitchya.

I took the old gal to a ton and figured what the el did it with bare noggin... old saggy face became a sea of waves and it became very hard to see...thus in speed run recommend beanie and glasses, perhaps even the face thingie. Sandals are nice too.

They are a happy bike at 55...

Best!

 

[40north]

well, I looked, it's not 2.0, rather it closer to twice that of a modern sedan. Oldmanmemory was it was 2 x something...

see> https://simulation-blog.technia.com/simulation/how-to-calculate-drag-coefficient-for-motorcycle
BTW they discuss FA as well as drag.

evidently the beanie costs something too> https://www.researchgate.net/public...F_THE_DRAG_COEFFICIENT_OF_A_MOTORCYCLE_HELMET

https://badcurator.org/resources/Magazines/Cycle_Sep76/Motorcycle-Aerodynamics.pdf

The "cheatest" simple thing is to reduce FA mostly by rider position. inho some fairing and tucking in makes sense.

Best!