CB250 Carb HELP!!!

[maximuschatwin]

Hi guys and girls,

Come to a bit of a dilemma...

Found this part off my carb whilst doing a rewire on my custom cb250 nighthawk. Have no idea what it does.

Tested for resistance and can guess it has some sort of coil in there?

Don’t know how to add photo... it’s a threaded cylinder with two wires coming off, that screws into the carb?

Could be some sort of electromagnet.. can’t trace it back on wiring diagram as not there...

Any ideas much appreciated!!

[Tiggie]

Welcome to the forum

From your description it sounds like a thermoswitch. A heater for the carb to stop it icing up in bad weather.

Of course I may be wrong and someone more knowledgable will make me look stupid

[fastbob]

Whenever I'm in doubt as to what something does I always go to the CMSL parts diagrams . It's a carb heater . Part 14 . I'm sure the bike will function perfectly well without it . My ER5 heats the carbs by passing warm coolant through the carbs but I just looped the system . We don't live in Alaska .

[maximuschatwin]

Guys, honestly didn’t expect such a quick friendly response, thanks a lot you’ve really helped me out here.

You’re both right, turns out it’s a carb heater...

I’m guessing it needs Constant power supply as soon as ignition key is turned? Just checking to see how I can simplify wiring.

The bike actually ran without it but I just think if it’s already there, may as well make use of it!!! Or should I just ditch the thing?

Thanks, Max

[fastbob]

Guys, honestly didn’t expect such a quick friendly response, thanks a lot you’ve really helped me out here.

You’re both right, turns out it’s a carb heater...

I’m guessing it needs Constant power supply as soon as ignition key is turned? Just checking to see how I can simplify wiring.

The bike actually ran without it but I just think if it’s already there, may as well make use of it!!! Or should I just ditch the thing?

Thanks, Max

 

As I say , I've done thousands of miles on an ER5 with the carb heating circuit disconnected and never had an issue with icing .

[Snod Blatter]

I'm pretty sure my MC26 CB250 never had the heater, just a cap over where it should be. Ridden through all conditions that the UK could throw at it and never suffered carb icing, I never noticed the lack of heater in any way.

[linuxrob]

US spec bikes rarely have carb heater circuits, Bandits are notorious for carb icing in cold damp weather so the UK ones have them as standard, there will be a temp sensor somewhere to switch it on. As Bob says you may find it will run fine without one.

Lets have some pics of the progress

Rob

[fastbob]

US spec bikes rarely have carb heater circuits, Bandits are notorious for carb icing in cold damp weather so the UK ones have them as standard, there will be a temp sensor somewhere to switch it on. As Bob says you may find it will run fine without one.

Lets have some pics of the progress

Rob

 

I should have added that on the ER5 there is a wax based in-line thermostatically controlled valve that shuts off the flow of coolant as soon as it gets hot enough for the radiated heat from the engine to take over . There's even an in-line gauze filter on the return side of the carbs . It all seems a bit over the top to me . It's gone in the bin along with the Clean Air System .

[linuxrob]

True Bob, my mates GTR1000 has water heated carbs with a filter. As for thew "clean" air systems, the bin is the beat place for it.

[maximuschatwin]

I agree Bob, the ER5 definitely seems like it has an over complicated system that it doesn’t even need...

Sounds like I might just take the easy route and get rid of it - and if I don’t get any problems I’ll just keep it that way. And Rob, seems that if US spec bikes don’t usually come stock with them then I might be able to get away with it!

I’ve decided on machining a little threaded cap to replace it to clean up the look of the carb a bit. Will definitely be posting pictures of progress along the way

Max