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Singles / Re: C15 ss Max speed
« on: 24 May, 2017, 18:34:53 »
I just sold my 250 Jap bike (Easily reached 85). It did not have the appeal and nostalgic feel for the old British bikes.
My C15 Now manages about 70 MPH, perhaps  a bit more.
I measured the head volume. - 35 cc. This works out at just over 8/1 compression ratio. The piston part number makes it 10/1 ?
I find the brakes are very effective.

Singles / Re: C15 ss Max speed
« on: 07 May, 2017, 11:59:31 »
I also have a Virago V  250 twin. This easily reaches 80 mph.
I have no liking for this 'cruiser' style bike, but it is one of the few bikes weighing about 300 lbs.
I have not the strength for anything heavier. Many of the 250 bikes are 350 lbs or more.
I will sell it soon.

Singles / Re: C15 ss Max speed
« on: 07 May, 2017, 11:53:01 »
Latest test this morning. Windy.
67 mph in one direction, 76 mph the other way.
Revs about 6600 with 2 teeth oversize sprocket.
I dont want to use the smaller sprocket. I prefer low revs on the engine.
This will greatly reduce stresses and (hopefully) stop it failing.

Singles / Re: C15 ss Max speed
« on: 25 April, 2017, 18:46:42 »
I bought a pressure gauge to check if my C/R was really 10/1.
After a number of kicks, the gauge reached 134 PSI.
So, with atmosphere at 15 PSI the ratio would be 8.93/1.
Atmosphere at 14.7 PSI ratio would be 9.12/1 ??
My bike accelerates well, pulls away lustily from 30 mph in (overgeared) top.
Now reaches 65 MPH, on satellite speedo, at 5500 Rpm, or 7750 rpm in third.

Singles / Re: B25 Difficult Starting
« on: 21 April, 2017, 18:51:13 »
I have just discovered a way of starting my C15 SS, from cold, First kick every time.
with the throttle stop set for a good idle when cold, I dont choke or tickle, or touch the throttle.
As it warms up, the stop has to be turn back lower for hot tickover.
To find the starting setting again, I have soldered a piece of piano wire into the throttle stop screw,
so that I can easily see or feel exactly where it is.

Singles / Re: C15 ss Max speed
« on: 21 April, 2017, 14:13:01 »
My standard 175 Bantam was faster. 65 mph normal, and with with the wind , 69.8 mph for 2 miles!
Only good news on the C15  is - one kick start every time, from dead cold, no choke, no tickle, no throttle.
Just with throttle stop set right.

Singles / Re: C15 ss Max speed
« on: 18 April, 2017, 13:32:52 »
I removed the 'Quietener' from the rear of the silencer,. I can now get up to 65 mph. (speedo reading over 70)
About the high gearing -
with 60 mph at 6600 rpm in third gear. this would work that at 80 mph the revs would be 7270, not quite high enough for max power??
but surely near enough to give better power than I am getting??

Singles / Re: C15 ss Max speed
« on: 17 April, 2017, 16:02:15 »
I found that the standard 1 1/16" new Amal carb on my bike, was feeding to 1" port in the head!
I was advised that any step in the inlet tract would affect the performance.
I filed out the head to match. I fitted the fibre heat insulating plate on to the head with the bolts. I was able to see
how the holes matched very easily.
The holes in the plate were larger than the bolts, so a step would certainly still be  possible.
I made alloy sleeves to glue into the plate, with exact fit on the bolts.
With the plate now unable to be out of line, I could cut the head to match the plate exactly.
With the cylinder head off, I mounted the carb and tightened the fixing bolts, aligning the carb to the plate.
With the head off, I could see through the intake clearly - not possible on the bike.
So, the inlet port was greatly improved. I changed the cams to the scrambles type. the piston is 10/1.
Running on a 18 tooth output sprocket, and using a satnav for checking, my top speed was now-
Top gear 60 mph, with difficulty, at 5200 rpm.
Third gear 60 mph more quickly, at 6600 rpm.
The engine did not seem to want to rev any higher. Very disappointing.
I cant think why this could be so?? All the parts seem to be in good order.

The Star and Garter / Re: Balancing on a bike
« on: 13 March, 2017, 07:03:30 »
I rode the virago yesterday, first for four months. (Knee replacement)
It was not as bad as I thought. Actually quite ok on the straight. I was worried that my destination had a pebbled car park.
CouldIi balance, and keep my bad leg up on the high set rear brake? Front brake no good on loose pebbles.
Actually, I managed ok, with a squerilly path out afterwards.
I want to move the foot rest back to a normal position, but it wont be easy.
I have looked for alternative bikes, which must be about 300 lbs weight, with good performance and lowish price. Fourstroke preferred.
The C15 would be ideal, if I could get it to perform as it should!

The Star and Garter / Re: Balancing on a bike
« on: 10 March, 2017, 18:51:46 »
On the question of front wheel trail, I wondered if cutting a V slot in the frame underside, then closing and welding up, to give a steeper fork angle and less trail, would  cure the problem?
The other characteristic of my Virago, is the way its track moves about on the road. It takes concentration to hold a line. My C15 holds well without effort.

The Star and Garter / Re: Balancing on a bike
« on: 07 March, 2017, 18:55:00 »
I guess upper body sideways movement would help.

The Star and Garter / Balancing on a bike
« on: 25 February, 2017, 08:14:24 »
My C15 ss balances well. I can turn round in my narrow yard, without putting a foot down. (old trials rider).
On my 250 Virago, (My first ride after have a new knee fitted) I was turning round in a side road when forks
reached full lock, and over I went. I was trapped under the bike with the engine revving in gear for a few seconds.
Question - when you reach full lock on a bike, is it still possible to retain your balance?? (remaining seated)

Singles / C15 ss Max speed
« on: 21 February, 2017, 07:55:10 »
Following my previous blog-
My 1964 C15 SS from America, with 10/1 piston, has a disappointing low top speed, 60-65 MPH.
I can find nothing wrong with it.
I wonder if the original road tests 'in the day' were done with the rider  lying flat on the tank, with
the normal handlebars, not clip-ons. How much difference would that make??
I have my bike with higher than normal gearing, which I prefer. This should give more relaxed cruising,
with higher speed available in third gear.
I cant go to a heavier bike. I have not the strength to lift it when it falls over.

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