175TS with 125S engine project

[George]

Today the sun is shining, went for local 15 mile ride. Good news is no sign of battery gassing off. New rectifier solved problem. Thanks for posts helping me out.
Only 25 miles since rebuilding engine so taking it steady. Bike rides steady at 40 MPH will increase speed when few more miles on clock. Checked speedo with GPS on phone, speedo is accurate and needle quite steady. Everything seems to be working as it should, impressed with brakes, clutch light, handling firm and feels safe.

Would like some opinions please. What are any benefits, if any, in fitting a 175TS engine to this 175TS bike. Looking at spec sheets 125S is 10HP 175TS is 11HP, not much difference. All suggestions welcome. I enjoyed my first proper ride and can see me keeping until I am to old to continue

[Duccout]

Well done George, sounds like you have done a good job. I'd guess that the bigger engine would give a noticeable increase in torque.


Colin

[DBDBrian]

Top result George, good everything is performing well. It's been a sunny day as well in Norfolk. You are making me quite envious, as I am still awaiting my registration number, I expect when it arrives (hopefully), the weather will turn.

[ranton_rambler]

It was sunny here too but I was working...
The little Ducati is shoved in the corner while I do some jobs on one of the Guzzis. Snow forecast this weekend so it will stay there.

[A.I.M]

A good result, George. If you are thinking about an engine upgrade it might be easier to find a 250 engine... but i'm not sure if one would be physically compatible with your frame?
Cheers,
Al

[George]

A good result, George. If you are thinking about an engine upgrade it might be easier to find a 250 engine... but i'm not sure if one would be physically compatible with your frame?
Cheers,
Al

According to parts catalogue same frame for 175ts 175t 175s and 200 version engines. This of course would add lots of extra cost, carb exhaust etc. I will continue with 125s engine see how I like it after running in.

[George]

Have put a few more miles on this week. Battery is gassing off on centre cell only, might have damaged battery with previous charging problems.
Battery is common 7ah 6 volt. Any recommendations for replacement battery appreciated.

Top gear engine not pulling well at 3/4 throttle and runs out of go above 45 / 50 MPH
Have been in conversation with Amal technical services, it would seem that Spanish 375/20 carb is different in as much as made shorter to give clearance at base and main jet is from 363 carburettor. Thought I would mention in case anyone else has this carb. My main jet is 85 recommended is 95 or 100. I am going to fit new main jet, needle jet and needle then set up carb. Main jet to small could be choking engine at wide throttle opening.

125 engine: primary gears ratio is 3 to 1. rear sprockets ratio 2.75 to 1. 16T front 44T rear
My set up : primary gears ratio is 3 to 1. Rear sprocket ratio 2.933 to 1. 15T front 44T rear
Not sure if 18" wheels instead of 17" wheels as on 125 will have any effect.
If I Change front chain sprocket to 16T should give bit more top speed. worth a try. Of course I am still running in engine patience required.

[veloduke]

Hi George

I use a MotoBatt MBT6N6 hidden inside a dummy case. It has worked fine for the last 2 1/2 years.

My 125 is a TS. I fitted a S piston after a rebore, but have retained the TS cam.
The original Spanish 18mm Amal 363 was well worn, so I fitted a Dell Orto PHBG18.

I can get to 50 on the flat (more downhill) on the 16/44 gearing, so a S cam with 20mm carb should go a bit better I would have thought.
I was running 15/44 for a while, but found that was too low geared. Having said that, 15/44 should make it easier to go flat out in top.
I am running 17" wheels though. 18" will make a difference I'm sure, but to what extent - some calculation and measurement is required.

I would double check cam and ignition timing and the auto advance for peace of mind, but the carb is most likely the issue.

Good luck

[George]

Thanks for your reply Max. I will sort carb first before changing sprocket. Will order motobatt battery. Pity they are not black.

[veloduke]

Yes, better black, but mine is hidden inside a dummy case so is not visible.

I also have one on my 250. It really showed up, so I just painted it satin black with Wilko paint, it's proved fairly durable so far.