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Discussion Starter #1 (Edited)
Hi all first post.

Just taken on a modified 2004 zr7. It’s been cafe racer’d by previous owner. Back end modified. The air filter box has been removed too and replaced with 4 x k&n filters. The previous owner has left the air temp sensor dangling between the air filters.

I’ve added a photo of the little dangler.

P/n 270101320

I’m interested to know exactly what this does. The internet says it adjust the air fuel mixture but as the bike is carbs, I don’t understand how it works. Can I lose it or should I securely mount it somewhere?
 

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I assume this is a UK bike.

If so, it's the "atmospheric temperature sensor" aka the switch used for the carb heaters. Here in Canada we don't have the heaters in the carbs (we do have the holes for the heaters) and we don't have this sensor switch. To my knowledge there is no electronic air fuel mixture unit - it's call adjustment needles in the carbs.

If the carbs still have the heaters installed (you can tell by wires running into the bottoms of them) you may want to leave it. I'm not sure how prone the carbs are over there to icing up. Perhaps someone who has carb heaters can chime in.

This would have been in the OEM airbox as per this photo from the service manual.

sensor.JPG
 

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Discussion Starter #3
Hi, thanks for your reply. This is indeed a UK bike. I was thinking I could mount the sensor on to a bit of metal and secure it between the filters but technically, it’s outside of the airbox and would therefore be recording cooler air temps than it’s tuned to do so...

Other option is to remove it and disconnect the carb heaters. I won’t be using this bike in the extreme cold...
 

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If you do remove all the stuff I think there is also another sensor that detects the heat of the carbs.

Best to check the service manual. If you don't have a copy, there are copies online you can download (or purchase a hardcopy from Kawasaki.)
 

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Discussion Starter #5
Thanks for the info. I have left it connected and hidden it for now. I won’t be riding in cold weather any time soon so I doubt it’ll be used.

I see there are a couple of vent pipes coming from the top of my carbs. I suspect they went to the air filter housing which is missing from my bike. These pipes currently vent to atmosphere and are hanging between the pod filters. Does anyone happen to know what I should do with these?
 

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Do not cap these. They did not go to into the air box, rather they are air vents for the carburetors. Shorten them if you want but they were that length to tuck in behind the side covers (which you no longer have) and keep them out the weather so they would not suck water in. Whatever you do try to keep them in an orientation that will not let water run into them. (perhaps you could make a simple upside down U bend vent hose?)

vent.JPG

Here's where they are on mine (hoses #2 & 4 - one on each side)

2.jpg 4.jpg
 

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Discussion Starter #7
Thanks for the diagrams. I’ve done exactly that, left them dangling downwards for now. I also have a larger hose from the breathers at the front of the engine. This is also hanging in the same area...
 

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If that large single hose runs up to a check valve and then splits to each valve cover it's part of the AIC system, and it all can be removed. There's a procedure here somewhere on what hoses to remove and the 3 things that need to be blocked off when you take it all out (you block the two hoses from the valve covers and the vacuum activation line form the carbs) - or one of us can walk you thru it.

That all being said since you don't have an air box what did they do with the crankcase breather line from the circle plate in the transmission under the carbs? Should look like this where the yellow arrow is (not the yellow dolly handle):

015.jpg

Normally there's a hose there that goes into the breather as well. My concerns would be if you block that off, as well as the AIC stuff from the camshaft covers, there's no way for the engine to "breathe" when the air expands/contracts as the engine heats and cools. I'm thinking if everything is plugged you'll end up blowing seals etc.
 

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here's what the EGR / AIC stuff looks like removed.

View attachment 120262

The long hose went to the air box, the two shorter ones to each side of the valve covers and the smaller diameter hose went to the carb.
That small line was the vacuum line that activated the metal vacuum switch in the middle at the top that let fumes from the engine top end get sucked back to the air box and reburned.
 

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Discussion Starter #10
Thanks for the info. I am planning on getting one of those small oil vent filters to pop on the crank case pipe that’s currently open to the elements. For now I’ve left the long vent pipe from the valve cover in place. I’ve not found a UK supplier for the blanking plates. I do have a sheet of metal in the garage so I could easily knock up a pair of plates to do the job. The hose is hidden though so it’s a job that can wait for now.

It’s not easy taking on a unfamiliar bike that’s been chopped around. It was so cheap though and I’m happy spannering so I’m not complaining.

I don’t have a user manual for the bike. What’s the PRI setting on the fuel tap?
 

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I don’t have a user manual for the bike. What’s the PRI setting on the fuel tap?
That's the "Prime" setting for allowing fuel to flow freely to the carbs with using the vacuum that the "Main" and "Reserve" settings do. Useful if you run the crabs dry and need to flush them with fuel.
 

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Discussion Starter #13
Crikey. That’s different. Lovely finish on the engine.

Been through some more of the bike this morning and found that the rear calliper is binding on the disc. It doesn’t look to be floating freely on its mount. I’ll be popping that off for a cleanup tomorrow.

Just ordered a small filter like the one on the engine in the previous post for my open pipe on the back of the engine.

Thanks for the welcome and help from everyone on this forum.
 

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Thanks for the info. I am planning on getting one of those small oil vent filters to pop on the crank case pipe that’s currently open to the elements. For now I’ve left the long vent pipe from the valve cover in place. I’ve not found a UK supplier for the blanking plates. I do have a sheet of metal in the garage so I could easily knock up a pair of plates to do the job. The hose is hidden though so it’s a job that can wait for now.

It’s not easy taking on a unfamiliar bike that’s been chopped around. It was so cheap though and I’m happy spannering so I’m not complaining.

I don’t have a user manual for the bike. What’s the PRI setting on the fuel tap?
As for the front block off plates you can also just take a piece of hose and connect the two outlets together and remove the vacuum operated valve and long hose. It's all tucked away under the tank and not really visible. I'd still make sure there was a vent from the crankshaft though.


* Bought a foot of 5/8" vacuum hose
* Bought a 3/16" vacuum cap
* Took the tank off
* Pulled the two vacuum lines off of the valve cover
* Pulled the small vacuum line off of the right side of the carbs that is attached to the EGR assembly
* Pulled the vent line out of the front of the airbox
* Took out the EGR assembly
* Cut a 7 1/2" section of the 5/8" vacuum hose and connected both nipples on the valve cover to each other with the hose

option1.jpg

* Put the 3/16" cap on the right side carb nipple (or whatever carb the hose that leads to the EGR valve is on)

option1a.jpg


You can also do block off plates or simply clean the spigots well and fill with silicone. (not my choice at all!)

silicone1.jpg silicone2.jpg

and finally you can just find a plug that fits over the spigots and cap them OR use a bit of the existing hose and fill it with silicone to make a plug. Just make sure it's all well cleaned of oil for the silicone won't stick well.

silicone3.jpg
 

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I followed this build on a UK based Facebook post, very similar to the bobber you have and this is what the engine breathers looked like:

View attachment 120264

They didn't do a bad job in the end, not my thing but good all the same, follow it here:

https://www.facebook.com/TheChopShop.Biggar/?__xts__

View attachment 120266
why have the filters on the air bleed covers, without the valve its always pulling air into the exhaust is it not?. not what you want. its better to blank them off.
 

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Discussion Starter #20
Out of interest, what would happen if the sensor was disconnected. Would it cause any harm if the bike wasn’t going to be run in colder weather.
 
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