Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Pages: 1 ... 6 7 [8] 9
Singles / Re: C15 Forks
« on: 02 July, 2017, 14:58:36 »
A quick fix so you can ride again. drain all the oil from the forks, carefully clean all traces from the outside.
Put the oil back after MOT.
(You dont get old but you get crafty)

Singles / Re: C15 ss Max speed
« on: 01 July, 2017, 14:06:52 »
This morning I changed my rocker box gasket. Bad leaks from top end.
I tested my top speed. Now 66 mph at only 5300 rpm, not the 8000 rpm
'red line' for this engine. Much more pleasant.

Singles / Re: C15 ss Max speed
« on: 24 June, 2017, 13:31:30 »
My C15 SS came with 15 tooth sprocket. As used on C15T
the standard for C12 SS, is 16 tooth.
For C15, 17 tooth.
I have now changed to 18 tooth.
I like it!
More relaxed at higher speeds. It still moves away from rest easily, and has lusty acceleration with a handful of throttle.
And that nice bang bang sound of a big single.

Singles / Re: C15 Max Speed
« on: 14 June, 2017, 07:27:22 »
I dont think that riders weight affects the top speed. It is only the acceleration which will be slightly less with heavier rider, although I doubt it would be noticeable without checking by stop watch.
What does affect top speed is air resistance. Crouching down will increase the top speed.
Of course gradient and wind speed/direction has a big effect.
My C15 ss now reaches 60 mph, then slowly creeps up to 70, no more.

The Star and Garter / useless brakes on classic bikes?
« on: 12 June, 2017, 11:51:32 »
It has been often stated that the old British bikes had 'useless' brakes.
I never found this when I rode many bikes in the 1960s.
My present C15 seems just fine.
The rear brake will easy lock the wheel. The front brake seems powerful, I am afraid to use full power
for fear of skidding. At low speed, it can lock the wheel.
Of course, my bike can only scrape up to 70 mph.
Comments, please

Singles / Re: C15 ss Max speed
« on: 29 May, 2017, 15:39:11 »
My figures were wrong. Tried again and got
6008 @ 70
6866 @ 80
So ,its about 1000 rpm too slow at 80 (if it could reach that.)

Singles / Re: C15 ss Max speed
« on: 29 May, 2017, 14:32:51 »
I have now reverted to the original absorption silencer.With a few short runs, I find that the top speed is 70 MPH, or a little more,
measured by satellite. Speedo reads 10 mph fast. (80 top speed!). Rpm reaches 5150 at 60.That should be 5956 rpm at 70.
, and 7940 at 80. isnt that about right??
I do not want go down on gearing. I dont like to run at high revs. At 50 mph, I would prefer to gear  UP! But that would mean using third for higher speed, No.
I really aught to increase engine size for result I want, but engines are expensive and one does not know if they will perform without renovation.

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.

Pages: 1 ... 6 7 [8] 9