Information Needed Ct 250 Sc Silk Road 1981

[ivorybull]

Hi

I've recently bought a CT 250 SC Silk Road which is almost identical to the CL 250 SC.

I have been told the engine is the same as the XL250 and CB 250 RS of the early 80's.

Can anyone confirm this and is it the same engine as the TL250?

As the CT250Sc is a rare bike in the UK parts are not listed as often as the supposed sister bikes so it would be good to know that I can get parts for the engine based on the other bikes.

Its in very good condition with 14k on the clock but the engine smokes which I have been told is likely to be the Valve stem seals or possible a broken ring.

Need to start getting some parts soon so any info welcome.

Thanks

Iain

Picture of similar bike attached

[janvixen]

Hi - sorry for the late reply, I've only just joined and I noticed your question..

The CL and CT250S are the last of the line with this motor and are rare - there are only about 30 of them left in the UK - I have a CL250S.

The CL had a twin saddle and was mostly sold in Europe. The CT had a single seat and was widely sold in Asia-Indonesia and Australia.

It was intended as a go-anywhere, do-anything wide-ranging farm bike, that bridges the gap between trials, road and mountain farming.

Honda's tough little 4-valve, 5-speed, single engines started with the SL (cam chain on the left, no engine balancer) and was redesigned by shifting the cam-chain to the right and fitting a pair of balancer shafts, driven by a chain on the left... That cut vibration so much that they could use a much lighter frame.

This engine was widely sold, and loved, as the XL250 and CB250RS - essentially the same engine with different gears and alternators.

Then, for the early 80's, Honda did an interesting re-design. Keeping all the same engine casings and main components, they dropped the rear balancer (which ran on the gearbox input shaft, and used just a single balancer shaft at the front of the motor, driven by gears.

This gave them a gap on the gearbox shaft, which they used to fit a 6th gear! Brilliant!

Two 6-speed motors were built - the CL250S and the XL250R, between 1981 and 1983 - being the same motor with different gear ratios.

The XL-R had a competition-spaced 6-speed box, the CL & CT had a wide 5-speed box with an extra ultra-low crawler 6th speed which is so low that you can't get into it without pulling a release lever built onto the outside of the clutch lever.

The electric start can be a bit sticky, but is a completely self-contained system which can be swapped straight onto a K/Start CB250RS or XL250 engine, swapping starter motor, alternator and cover and alternator flywheel. You can fit a kickstart to the CT/CL but it means splitting the crankcases...

So - most engine parts are the same as CB250RS, apart from the gearbox internals. If you have a serious blow-up, you can drop an XL250 or CB250RS engine straight in...

Some daft people even stick the 500 version of this engine into the CB250RS, which just makes it heaver, shakier, but not really much faster, and looses it's brilliant agility...

Incidentally, there was another version of the CL250S for Germany only, that had restrictors welded into the exhaust headers to cut maximum power by about 20% to meet the German 17PS regulations - otherwise identical. So German magazine tests only talk of how gutless it is - not surprising really....

I hope that some of this helps!

ps - change the oil very, very, very regularly - like every 1000 miles!

[Rubarb]

I recently bought what I thought to be a CL250S (I had one about 35+ years ago, until some scum stole it). Looking at the engine & frame numbers, it seems that it may be the very similar CT250s. Anyway, the balancer arrangement (as mentioned by Janvixen) differs in that the CB models have chain drive from the crankshaft to a front balancer shaft with 1 bobweight, and also to another bobweight which runs on the gearbox output shaft, but the CL/CT models have gear drive from the crankshaft to the front balancer shaft only, which has 2 bobweights on it. This leaves a space on the gearbox output shaft, onto which the super low gear is fitted. Also, the overall gearing is lower on the CL & CT models than what it is on the CB models, plus the CB has higher compression and a higher state of tune than the ÇL/CT, and a different carburettor. And the XL 250 engine is not quite the same, it has smaller, more restricted exhaust passageways, and is not machined on the right side of the cylinder head to take a tachometer drive gearbox. Hope this helps. M.S.

[Rubarb]

A further couple of points is that since I have got my CT (?) 250 running, it SEEMS that the super low gear is not as low as I remember it. I specifically tested my CL, and found it equated 7500 rpm to 10 mph  in super low. I'm now wondering if there is any actual ratio difference between the CL's and the CT's super low gearing. And also, the rear wheel HUB, with it's segmented ring cush drive, is the same as the hub on the CB250RSD, and is superior to the hub on the earlier CB250RSA, which only has 4 rubber bushed fins, and is prone to wear quckly.

[Amon]

I recently got stitched up by buying a ct250s, it started fine for a few days then the starter kept spinning off the flywheel which had worn away the teeth. Have looked for weeks to find a new rotor with no luck so not much else I can do but change the engine so I would like to ask which one should I  opt for the XL or the CB?

Many thanks 

[BobM58]

Hi, I am new to T.C, having just stumbled across the site whilst researching the CL250. I have a 1982, running, but not roadworthy. My only real problem is the exhaust system, which I want to (carefully!) remove and pattern (unless anyone knows of a new one?). Does anyone know if an XL can be modified to fit ?. All info gratefully received.