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Hey guys,

I have a '73 CB200. I recently ran through the shop manual to get everything road ready, but the bike has very poor acceleration and the left exhaust pipe seems to never get warm. The right side on the other hand seems to always get piping hot even after only 3 minutes of riding. Any one else have any experience on this topic? I have the original airboxes on. Carbs have been cleaned and floats adjusted to spec. New gaskets for the carbs and stator cover. No drips/leaks. Air screws set to 1 1/4. When I adjust the jet screw on the left while it's idling it doesn't seem to do anything. Even if I have it twisted out several turns. The right on the other hand seems to make the RPMs jump by adjusting it just a fine bit. If I didn't know any better I would assume I'm running off of one carb. I'm confused. Thanks for any and all input. And I appreciate your patience if this is a stupid question. I truly am just learning how to be mechanically savvy.
 

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If one cylinder is producing no heat whatsoever, then there is no combustion taking place and you are effectively running a single-cylinder engine with further losses from the "boat-anchor" components that aren't doing anything, but still have to be spun. (AfaIK).

Whether it's due to the carb or something else, IDK. Is that cylinder's spark plug seeing any fuel?

Regards,
 

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Sensei
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Pilot jet or passage is blocked IF adjusting the mixture screw has no effect (OR the slide is set too high and beyond idle range, but unlikely in this scenario), or you have an air leak....OR, no spark IN the cylinder...(It HAS to be occurring somewhere because the other side won't fire if it isn't)
RE-clean the carb.....Check the manifold "boots" for cracking and sealing @ the gasket to head joint.....Check plug
 

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Did you find a solution to this? I have a 75 cb200 that is doing the same thing however, above 5,000rpm the cold cylender will kick in and both will run...
 

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With the engine running, pull the left spark plug wire loose and lift up about 1/4 inch and see if the spark will jump the gap.
 

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With the engine running, pull the left spark plug wire loose and lift up about 1/4 inch and see if the spark will jump the gap.
might want to insulate the "hand"....
 

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Did you find a solution to this? I have a 75 cb200 that is doing the same thing however, above 5,000rpm the cold cylender will kick in and both will run...
I had a similar problem with my bike. It had not been used for over 15 years and the previous owner started it without any maintenance. It was running really roughly so hubby started with sorting the carbs, cleaned, new gasket, needles, floats etc. Fuel tank was full of rust and the petcock needed new gaskets and filter. Then points, plugs, timing chain adjustment, tappets and timing. Checked there was no air leak in the carb insulators which can cause running/idling problems. We realised there was a difference in the exhaust heat and the timing was not staying set. Inspection of the engine was next after a compression check showed it was too low on the cool exhaust side. We found the cam shaft was badly worn together with the cam tensioner. One piston had been replaced but the rings had not been positioned properly and on the side of the cool exhaust one piston ring was broken. The oil filter was all gunged up and had some metal shavings in.

Engine has been rebored, machined, larger pistons, new camshaft, speedo and points casings, cam tensioner, cam chain, all new gaskets/bolts and is rebuilt just need to rebuild the rest of the bike to test it out!

I would advise not to run the bike until you have checked the oil is feeding to the cam shaft, it is a common problem. If the oil feed is ok check the compression on both sides. If both the oil feed and the compression are fine check the carb insulators are not cracked and are sealed to the head with no air leaks.

Hope this helps, let us know how you get on. :smile:
 

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I had this as well, after doing some, here:
1. plug: checked good
2. electricity: checked good

I realised the carb was the main problem, so main jet and pilot jet was clogged, so did some cleaning, and it works again
 
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