DOHC working on pods, what to do after removing airbox?

[jacksondee]

Hey fellas

Just removed the carburetor for the first time ever in my life. That was fun, took a lot of elbow grease. It looks to be in good shape which is nice. The guy who sold it to me last summer said he had just cleaned the carbs, I guess he wasn't lying..

Anyways, what do I do here now? Where my index finger is, is that where I put one of those cute little crankcase breathers? The ones that look like tiny little oil filters?

Where my thumb is, what the hell do I do with that huge tube that seems so sink into the oil pan?

The old crankcase drain tube that ran out of the airbox- it ran into some other box mounted under the battery case, then from that to a plugged tube under the bike that I would drain from time to time. I'm assuming I just scrap that now?

thanks

 

[dirtdigger]

All of this is a closed emissions system to collect and burn blow-by. Both of them are breathers for the crankcase. The box under the battery catches the condensed oil vapors drawn out of the crankcase that aren't drawn back into the carbs and is a periodic maint. item to drain the tank. If you are not going to retain the stock airbox and crankcase emission setup then the tank is no longer needed.

 

[jacksondee]

All of this is a closed emissions system to collect and burn blow-by. Both of them are breathers for the crankcase. The box under the battery catches the condensed oil vapors drawn out of the crankcase that aren't drawn back into the carbs and is a periodic maint. item to drain the tank. If you are not going to retain the stock airbox and crankcase emission setup then the tank is no longer needed.

I do intend to get rid of the airbox and put in some pods. Do I get little crankcase breathers for both of those 'ports' then? Get a hose clamp to hold the one that goes into the thick hose coming out by dipstick, after I trim the hose to appropriate length? Am I missing a main keyword here that I can search for what other guys do when they get to this step?

 

[FTS902]

I too am curious about the large hoses. I purchased a bike with the pod mod already started. but the PO did nothing witht he hoses. they run together at a T joint with the perpendicular end open. what should i do to get rid of the hoses.

 

[jacksondee]

I too am curious about the large hoses. I purchased a bike with the pod mod already started. but the PO did nothing witht he hoses. they run together at a T joint with the perpendicular end open. what should i do to get rid of the hoses.

Here's what I ended up doing:



I got a crankcase filter for the smaller hose. That's a slick K&N and was 'only' like $14. Then I jammed some of that small hose into the end of the long hose, trimmed it to fit, and stuck it in the end of the box under the battery that it drains to normally.

 

[FTS902]

Does the crankcase even need the breather? Could I plug the two ports and call it good? I already have 4 pods on my bike, I dont think I need any more haha

 

[jacksondee]

Does the crankcase even need the breather? Could I plug the two ports and call it good? I already have 4 pods on my bike, I dont think I need any more haha
View attachment 3802

Someone else with a bit more technical knowledge could answer with a better explanation. But the reason I am leaving the one tube connected to the breather box under the battery, is because I've read if you just hook up a breather filter, it will eventually spit grease and grime all over your bike from through the breather filter. And the breather filter will have to be cleaned fairly regularly. I've also read the crankcase itself can develop condensation all over it, and the breathers help prevent that from happening.

My thought is the breather filter will let in the bit or airflow it needs, and keeping the one hose will give it a place to spit grease and not get it all over my bike.

Anyways, I really don't think you are supposed to plug them.

 

[FTS902]

Thanks

 

[losttravlyr]

just my .o2 cents worth here. you need the crank vent but you can leave it open to air without a filter on it. since you'll are rerouting hoses though and disconnecting the stock dump for them,,i would reroute them upwards toward the bottom of the seat or at very least away from the front or edges of the rear tire. rare that it happens but if it should decide to dump oil ,especially if you are rolling it's best for it not to be in front of where the rear wheel is fixing to roll.

 

[FTS902]

just my .o2 cents worth here. you need the crank vent but you can leave it open to air without a filter on it. since you'll are rerouting hoses though and disconnecting the stock dump for them,,i would reroute them upwards toward the bottom of the seat or at very least away from the front or edges of the rear tire. rare that it happens but if it should decide to dump oil ,especially if you are rolling it's best for it not to be in front of where the rear wheel is fixing to roll.

Good idea, I'll run my hoses straight up and ziptie them out of sight.

 

[Luis Etchenique]

could you explain how you removed airbox ?

Hey fellas

Just removed the carburetor for the first time ever in my life. That was fun, took a lot of elbow grease. It looks to be in good shape which is nice. The guy who sold it to me last summer said he had just cleaned the carbs, I guess he wasn't lying..

Anyways, what do I do here now? Where my index finger is, is that where I put one of those cute little crankcase breathers? The ones that look like tiny little oil filters?

Where my thumb is, what the hell do I do with that huge tube that seems so sink into the oil pan?

The old crankcase drain tube that ran out of the airbox- it ran into some other box mounted under the battery case, then from that to a plugged tube under the bike that I would drain from time to time. I'm assuming I just scrap that now?

thanks

View attachment 3547

could you explain/describe the steps to remove airbox ?
-- thank you !

 

[amc49]

http://www.cb750c.com/publicdocs/CB...ru83CB750ServiceManualChapter04FuelSystem.pdf

Page 4-3 shows top air cleaner housing bolt. 4-18 shows a clear pic of the air filter case assembly.

Loosen the 4 clamps at back of carbs and remove the top air cleaner bolt and spacer. A couple hoses remove. Past that how you do the work yourself, there is no more way to do it other than what you come up with yourself. Many yank the carbs to make it easier. Your choice.

 

[Luis Etchenique]

http://www.cb750c.com/publicdocs/CB...ru83CB750ServiceManualChapter04FuelSystem.pdf

Page 4-3 shows top air cleaner housing bolt. 4-18 shows a clear pic of the air filter case assembly.

Loosen the 4 clamps at back of carbs and remove the top air cleaner bolt and spacer. A couple hoses remove. Past that how you do the work yourself, there is no more way to do it other than what you come up with yourself. Many yank the carbs to make it easier. Your choice.

===============================

THANK YOU FOR THE LINK AND FOR YOUR HELP !
--Luis

 

[Wez_]

Can't believe we are approving pods on these bikes lol. At any rate, stock air box here. The stock rubber "T" that connects those two crankcase breather hoses was cracked in about 8 places. I applied epoxy to my original "T" fitting to fix all the cracks and hooked up those original hoses. Bike pulls hard to 10K RPMS without any hesitation. (about 5 miles of warm-up). When I had pods, the bike would max out around 8K RPMS. As far as what you do next. Get your hoses all buttoned up and the carbs synced. Take here out for a rip (I suggest 5 miles and red line the bike at least twice through all the gears) Bike should be warmed up and have a decent idle. You should be able to determine how she runs after being fully warmed up and the fuel all primed throughout the carbs. On cold mornings my bike will not redline properly until it's fully warmed up and ready to go. Last step should be getting any stumbles "Jetted" out by adjusting the jet sizes to fix any problems found after warm-up. Those 10K RPM redlines are important. This bike loves high RPMS and regular WOT.

 

[George Mooyman]

I'm pretty sure if you remove the airbox you have to change the jets as well.