left side exhoust pipes cold

[adrianpl13]

hey newbie here

i got a one question  i just picked up a 1980 cb750c. first thing i did i cleaned the carbs the lefts side carb was full of gunk. i also had to replace the rotor becuse it woudnt charge the battery but now the left side pipes dont get hot at all. only the right side are hot. i no im getting gas into the cylinders and i have spark. is it possible thats happening because the carbs arent sync or do i have a bigger problem on my hand. also the  left side backfires at times thanks guys

[vern401]

Both left side are cold? Well lets find out what is going on.
1. Pull the plugs and look at the color of them. While out check all of them to make sure they are all firing.
2.If you done have one see if some one you know has a compression tester. Check the compression if the cylendars.
3.I dont like telling people to do this one but here goes. shut off your fuel valve and drain the carbs. then spray a LITTLE bit of starting fluid into the left carb. Try to start the bike. If it fires then goto the next carb and try it. If it fire up on both then you have a fuel delivery problem. Try cleaning the carbs again. use compressed air to blow through the passageways. Take your time at it since the passageways are quite small and easily plugged. Dont worry about the sync quite yet. you need all 4 firing before you do that part.

[Re-run]

Have you gotten a chance to check this out?

[adrianpl13]

thanks for the replay


i finally had a chance to take the bike to work to work on it. we were gonne do a compression tester but we didnt have the correct fitting. cyl 1 and 2 are misfiring at idle. tryed to run the bike on cyl 234 the bike would not start so this is not a spark issue. im getting fuel cuz you can smell it and it makes 60 miles to the tank. sprayed the rubber sleeves that go from the carburators to the engine with brake cleen to see if i have a air leak. sure enough the idle jumps up to 3000 and the pipes on the left side get hot. so my plan is to get 4 new sleeves and clamps and im also gonne take apart carb 1 and 2  mabye i missed a spot. anyone else had those rubber sleeves leaking?

[vern401]

As old as these bikes are this will be more common. Take your time with the carbs. I'd do all 4 if it was me.
Make sure all your floats are set right. The sync will come later and should not effect it right now anyway. You need all 4 firing to have a good sync. It is usualy one of the last things I do when rebuilding carbs. Most of the time if you dont mess with the setting screws you will not need to adjust them much. I'd get all four intake boots. If 2 are bad the others are not far behind.

[adrianpl13]

anyplace you recommend to get the intake boots i looked on ebay there pretty expensive $80 a set. when i cleaned the carbs the first time #1 was full of gunk ill probably run another tank with seafoam and wait to look at them untill i get the intake boots thanks

[vern401]

The forum has some sites listed.
But there are some tricks you can try also.
realy take your time with the cleaning. The ports in the carb body are small and over the years they build up gunk which is hard to get out. Pine-Sol seems to work well and will not eat your seals. Use compressed air to blow out the ports. brasso or CLR works on the brass parts.
On my cx500 Custom I did this to get me by for the summer with leaky intake boots.
Get a roll of electrical tape. I used thick black. Not duck tape
Start wrapping it around the boot whear the clamp goes. Make it tight " streatch the tape a little while putting it on " and over lap it a little about 1/4 to 1/2 overlap. No wrinkles or breaks. wrap it up and back so there is 2 layers on it. Stop whear the clamp goes. Why? the clamp will help hold the ends from unwrapping. do this for all intake boots. you want it tight enough so that the tape will not allow air to pass so the tape will streatch a little.

[adrianpl13]

i was also told i could use black silicone. i think ill silicone the whole outside and use the eletrical tape as well also i will get new worm clamps instead of the stock ones. hopefully ill get around soon to do it