The good and the bad (rear cylinders not firing)

[UK_in_NY]

Ok... so managed to put a little time into the old girl this morning. 

I adjusted the carbs (by ear/guess - sync tool being orderd soon) and it immediately was a lot happier. (starts quicker and idles, and now revs somewhat smoothly)

however.. quick check of the exhaust pipes shows it is only firing on the front two. Rears are ice cold. 

 

So I have two questions for you experts (remember this is an 83 - which I believe has a different ignition set up.

 

1. What is the logical order of things to check? I do have brand new spark plugs waiting to go in but don't want to foul them immediately if it is still running on two?

2. since i put my carbs back on after being rebuilt the choke cable now seems to be too loose when the choke is off - where is the adjustment to tighten it up?

 

Thanks!!!! 

[UK_in_NY]

haha! i got it! I bit of contacts cleaning, a little trim on the HT leads and new spark plugs and she fired right up on all 4!!!

I am gonna bet that is the first time those rear cylinders have fired in a while. A LOT of smoke but the motor sounds awesome!!!!! OK.. whats next.

[luvmy40]

Well, you beat me to it! I was going suggest Ohming out the coils and trimming the plug wires back.

Ya' got the go, now check the whoa! Make sure your brakes are up to snuff and the tread is good. Don't just look at tread depth, check the date code of the tires. I never run a motorcycle tire more that 4 years, the rubber compound starts breaking down and they can get real slick. Also, when looking at the brakes, inspect the lines and hoses for swelling and cracking. There may not be a leak, but the old rubber brake lines will start to swell up when applying the breaks and cause pressure loss, thus loss of braking capability.

 

 

[Marcarl]

You may have routed the choke line wrong, don't think there is an adjustment.

[UK_in_NY]

5 hours ago, luvmy40 said:

Well, you beat me to it! I was going suggest Ohming out the coils and trimming the plug wires back.

Ya' got the go, now check the whoa! Make sure your brakes are up to snuff and the tread is good. Don't just look at tread depth, check the date code of the tires. I never run a motorcycle tire more that 4 years, the rubber compound starts breaking down and they can get real slick. Also, when looking at the brakes, inspect the lines and hoses for swelling and cracking. There may not be a leak, but the old rubber brake lines will start to swell up when applying the breaks and cause pressure loss, thus loss of braking capability.

 

 

Thanks! - Unfortunately, while the tires are basically new.. they were new in about 2014. So they are OLD. They are also very cracked. So no road tests yet. 

And yes, next up is brakes. I have a front brake but it is marginal (although i am comparing to a GSXR race bike and my 2020 Katana - so that's a tough comparison. I suspect I've got some work to do there, especially in the back. I don't feel any rear brake at all at the moment. 

Forgot to mention, some of the exhaust smoke is me using some ethanol free 2 stroke gas to keep it well lubed. However, i am seeing a lot of smoke at the rear of the motor... so i think it needs a good clean up. (lots of oil from previous leaks)

have to say though... that motor does sound good.

[UK_in_NY]

4 hours ago, Marcarl said:

You may have routed the choke line wrong, don't think there is an adjustment.

Thanks Marcarl. Quite possible. Will take a look tomorrow. 

[luvmy40]

8 hours ago, UK_in_NY said:

Thanks! - Unfortunately, while the tires are basically new.. they were new in about 2014. So they are OLD. They are also very cracked. So no road tests yet. 

And yes, next up is brakes. I have a front brake but it is marginal (although i am comparing to a GSXR race bike and my 2020 Katana - so that's a tough comparison. I suspect I've got some work to do there, especially in the back. I don't feel any rear brake at all at the moment. 

Forgot to mention, some of the exhaust smoke is me using some ethanol free 2 stroke gas to keep it well lubed. However, i am seeing a lot of smoke at the rear of the motor... so i think it needs a good clean up. (lots of oil from previous leaks)

have to say though... that motor does sound good.

Take a look at the header gaskets on the heads. My 83 had leaks there and it smoked and caused decel popping until I fixt it.

[UK_in_NY]

58 minutes ago, luvmy40 said:

Take a look at the header gaskets on the heads. My 83 had leaks there and it smoked and caused decel popping until I fixt it.

OK, good to know. is that a horrid.job?

[Marcarl]

5 hours ago, UK_in_NY said:

OK, good to know. is that a horrid.job?

Usually not a big item unless the gaskets need to be replaced. With the right sized allan wrench, bcak off the nut and retighten, it may take a couple of trys, if that don't work then the exhaust pipes will have to be removed and new gaskets put in, that's more work.

[UK_in_NY]

6 hours ago, Marcarl said:

Usually not a big item unless the gaskets need to be replaced. With the right sized allan wrench, bcak off the nut and retighten, it may take a couple of trys, if that don't work then the exhaust pipes will have to be removed and new gaskets put in, that's more work.

Sound good! will give it a go! I also have a slightly leaky valve cover gasket - (I know, I know, chinese crap) I am going to try and reseat it but I suspect it won't work!) 

[UK_in_NY]

6 hours ago, Marcarl said:

Usually not a big item unless the gaskets need to be replaced. With the right sized allan wrench, bcak off the nut and retighten, it may take a couple of trys, if that don't work then the exhaust pipes will have to be removed and new gaskets put in, that's more work.

I think I need to go get the right sized allen socket. Any idea on size? I have the manual but it isn't the most helpful! - Assume it is the one referenced as the "sand plug?" - that needs loctite and 31lb ft torque?

[UK_in_NY]

18 minutes ago, UK_in_NY said:

I think I need to go get the right sized allen socket. Any idea on size? I have the manual but it isn't the most helpful! - Assume it is the one referenced as the "sand plug?" - that needs loctite and 31lb ft torque?

OK, think i got it. Thanks !

[Marcarl]

8 minutes ago, UK_in_NY said:

OK, think i got it. Thanks !

I'm confused.