Ct70 with Nice 110 - considering installing a ct110 motor

RMHRC

RMHRC

Member
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Ok. Started taking off the old Keihin. Found my compressed air and contact cleaner and proceeded to work on opening fully blocked main jet. I’m talking no see through em blocked. Once unblocked I thought I’m pretty sure this little tractor would start.

https://photos.app.goo.gl/XBNeEgmpq12xUkCU9

after a few kicks got it fired right up. It runs great...bog when you whack the throttle but that happens with any non accelerator pump carb. If only keihin made a 20-24mm fcrmx. Bob is probably right in that my keihin is wrong sized but how’s that old song go - you gotta love the one you’re with.

What to do with my brand new carb..,

So apart from clean fuel and not 5 year old pump piss, is there a decent fuel system cleaner I could add to my massive fuel tank to thoroughly clean the carb as it runs?

Bob - what is the oil change procedure on these 110 nice motors ? How much do I tip in?
 
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dirtbkr188

dirtbkr188

Active Member
I haven't talked with him in a while, but, like I said above, if you PM him on here and he has his Notifications set to ON, he'll get an email letting him know that you PMed him.
 
theraymondguy

theraymondguy

Well-Known Member
In the USA only the 1984 and 1985 CB125S had the pumper carbs. The CG125 had them abroad, but I wouldn’t know which years.

Getting mine and having enough parts and knowledge to make it work on my build was a matter of luck, kindness and time.

There was a knock off of this carb on eBay.

The throttle cable came from the UK

The needle was from a CRF150F power up kit

I believe I landed on a 128 main and + 1 pilot.

As with all things, each component is part of a system. Sufficient engine, exhaust and ignition and carburetor. This carb worked very well on my 108, I’m sure your 110 would only be better with a modern ignition.
 
RMHRC

RMHRC

Member
Ok so update. It’s a beautiful pre spring day here in the socialist republic of Victoria Australia.
I went ahead and fitted the new Mikuni carb.

All I can say is why didn’t I fit this earlier. It starts perfect idles and revs perfectly. I didn’t do any filing or anything.

Very very happy to be end of the 24mm keihin.

Few questions

1. what do I do about the throttle cable ? It’s at full adjustment. I’m running a genuine ct70 throttle cable and the adjuster at the carb is fully at its limit.

2. what do I do about a proper nice fitting clutch cable?
 

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69ST

Well-Known Member
This is as expected. VM20 is so close to being the optimal size for this engine that attempting to max-out carb size (22mm...still slightly oversize) requires a disproportionate amount of resources. The only 22mm carb I'd recommend is the MJN22, unless port diameter, valve size & displacement are all increased. What you probably don't realize is that the VM20 is ~23% larger than what that engine wore from the factory. (24mm is a whopping 78% larger)

I would strongly suggest finding the rich limit of the main metering circuit, starting with a #150 main. The pilot (idle) circuit will either need a #20 with the airbleed somewhere around 1 turn out from seated or #22.5 with the airbleed screw closer to 3 turns out.


Changing inner cable stick-out length depends. Too little is easy...clip a coil or two from the outer sheathing. Too much is more involved. You can't really add outer sheathing; have to relocate one of the end ferrules, then clip the excess inner cable length. If you're going to attempt this DIY, mod the handlebar end...that way there's no risk of the carb end ferrule being inhaled and destroying the engine, should the solder job fail. provide overall cable length and the amount of inner cable stick-out needed and we might be able to figure out which reproduction cables would fit. A shop should be able to make them locally, or at least domestically.
 
RMHRC

RMHRC

Member
racerx said:
This is as expected. VM20 is so close to being the optimal size for this engine that attempting to max-out carb size (22mm...still slightly oversize) requires a disproportionate amount of resources. The only 22mm carb I'd recommend is the MJN22, unless port diameter, valve size & displacement are all increased. What you probably don't realize is that the VM20 is ~23% larger than what that engine wore from the factory. (24mm is a whopping 78% larger)

I would strongly suggest finding the rich limit of the main metering circuit, starting with a #150 main. The pilot (idle) circuit will either need a #20 with the airbleed somewhere around 1 turn out from seated or #22.5 with the airbleed screw closer to 3 turns out.


Changing inner cable stick-out length depends. Too little is easy...clip a coil or two from the outer sheathing. Too much is more involved. You can't really add outer sheathing; have to relocate one of the end ferrules, then clip the excess inner cable length. If you're going to attempt this DIY, mod the handlebar end...that way there's no risk of the carb end ferrule being inhaled and destroying the engine, should the solder job fail. provide overall cable length and the amount of inner cable stick-out needed and we might be able to figure out which reproduction cables would fit. A shop should be able to make them locally, or at least domestically.
Click to expand...
Thanks Bob

is there no off the shelf cable for this carb?

what did you do when you ran this carb?

anyone get Motion Pro to customise ?

also any tips on a clutch cable?
 
6

69ST

Well-Known Member
There is no such thing as an off-the-shelf cable for a custom application...by definition. Every cable I've ever used on a non-stock setup has either been a modded stock assembly, or custom-made.
 
RMHRC

RMHRC

Member
racerx said:
There is no such thing as an off-the-shelf cable for a custom application...by definition. Every cable I've ever used on a non-stock setup has either been a modded stock assembly, or custom-made.
Click to expand...


Hey bob what did you use for the clutch cable?

Did you simply use the 4 speed ct70 clutch cable? Are genuine ones still available or are they unavailable ?

I’ve ordered new fork seals to replace them once I pull the forks down. In your experience do the fork stanchions need to be rechromed ? Are there any tricks to pulling down the 72 model forks?

i know you’ve advised 15w oil which is what I’ll purchase for my 85kg weight

I still can’t believe how good the bike runs with that new carb - thanks so much Bob for the help 12000km away. The wonder of the internet and sharing ideas and advise really does make the world better
 
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69ST

Well-Known Member
I ran the stock lever and perch for several years, despite the fact that the R&L didn't match. Front disc brake required removal of the welded-on perch. Started out with a Jincheng clutch cable. I ended-up fabbing my own clutch cable, from scratch. Eventually, I replaced the clutch lever & perch assembly with OEM Honda Nice...along with the clutch cable. That cable is just long enough. I'd have simply fabbed another cable but, the Teflon-coated inner cable provides silky-smooth action. FYI, the OEM Nice clutch cable cannot be used with the CT70H lever & perch...in case you're wondering.

RMHRC said:
I’ve ordered new fork seals to replace them once I pull the forks down. In your experience do the fork stanchions need to be rechromed ? Are there any tricks to pulling down the 72 model forks?
Click to expand...

Rechroming the inner fork legs is a can of worms. Below the seal-swept area, OD is high-precision/tight tolerance. Plating thickness varies greatly. As long as a seal-swept area, and lower, is free of pitting, you're fine. Usually, the rust is surface rust and above the seal-swept area only. I polish the exposed portions of the inner fork legs, then clearcoat or/and grease them. Those can be fine-sanded/wire-brushed/Scotchbrited & painted. Anything that seals-out oxygen & moisture will keep the rust monkey at bay.

As for teardown, just remove the snaprings retaining the oil seals. Then wrap the leg with a rag and use the lower like a slide hammer to drive the seal out. Do not remove the screws inside the axle flanges or you'll create a leak that's fiendishly difficult to stop.
 
6

69ST

Well-Known Member
RMHRC said:
Many many thanks Bob

can I use a stock ct70 clutch cable ?
Click to expand...
That's kind of a loaded question. The answer is: "yes, but it depends". It is strong enough, overall length should be okay. Stock lever should accept the end fitting. It's going to come down to the bellcrank end fitting and, most of all, the cable bracket at the engine end. The stock setup has very little stick-out length. Cable mount is an integral part of the clutch cover and very close to the bellcrank. When you grab a handful of clutch lever, there's almost no exposed inner cable. That's very different from the stamped steel cable bracket you have on your Nice motor. I can all but guarantee that you'll need to cut a few coils from the outer cable sheathing to get the needed stick-out length.
 
RMHRC

RMHRC

Member
racerx said:
That's kind of a loaded question. The answer is: "yes, but it depends". It is strong enough, overall length should be okay. Stock lever should accept the end fitting. It's going to come down to the bellcrank end fitting and, most of all, the cable bracket at the engine end. The stock setup has very little stick-out length. Cable mount is an integral part of the clutch cover and very close to the bellcrank. When you grab a handful of clutch lever, there's almost no exposed inner cable. That's very different from the stamped steel cable bracket you have on your Nice motor. I can all but guarantee that you'll need to cut a few coils from the outer cable sheathing to get the needed stick-out length.
Click to expand...


Ultra thanks as usual Bob

here is a pic of the cable down near the motor
 

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