Jet Sizes, Crankcase Breather

[maxim4rob]

Mike:

I will anxiously await your reply on the main and pilot jets. (By the way, where is the pilot jet located?) Another question I had is when you went to the four individual filters did you hook up the crankcase vent tube to something, or is it just stuffed up by the battery in back of the filters. I check your conversion pictures again and I can't tell. Would it be OK to cap the tube at the motor or what? Thanks again.

maxim4rob

[MartyA]

My crankcase vent runs along side the battery tube, just drop it down over the back of the middle gear. I don't think you want to plug it.

[sixtysix]

Here is the best way to take care of that cranckcase breather hose. Go to a Harley or custom shop and get a chrome breather (about $7-$8 at the bike shows also JC whitney etc sells them) then take a big hose clamp to mount it, and you have this stylish answer to your problem.



DO NOT BLOCK OFF THIS VENT TUBE!!!! IT HAS TO VENT TO RELEIVE CRANCASE PRESSURE!!!

BTW, I have the stock airbox, with a UNI filter, and got sick of cleaning oily crap from the vent hose off of it.

[MartyA]

purty, Mr. sixtysix!

Hows the weather up there? Frost here tonight....

[Mike Hart]

I found a ceramic-like fuel filter that fit inside the cc breather hose, routed it uphill and back.

Pilot jets are in the slightly shorter 'tower' next to the main jet 'tower'.

[skids]

I used a fuel filter also, but it was a larger automotive type. Be aware that if/when it gets clogged, it can case the button to pop out of the tensioner and can cause other oil leaks as well. Cherry Bomb seems to always out-breathe, so I just took the filter off and ran the hose to the rear. I just hope that it doesn't take a major dump on my rear tire as I am canyon carving. =8-o

Originally posted by Mike Hart
I found a ceramic-like fuel filter that fit inside the cc breather hose, routed it uphill and back.

Pilot jets are in the slightly shorter 'tower' next to the main jet 'tower'.

[sixtysix]

Originally posted by MartyA
purty, Mr. sixtysix!

Hows the weather up there? Frost here tonight....

They said frost but only got down to 44F, rode the XS today, got a few good twisties in, may be the last ride for it this year, fuel stabilizer is in. Winter is coming CRAP!!

[MartyA]

Yeah, krap, 34 here last night.

The only problem with "dumping" is if you put too much oil in. I know, don't ask, I had a brain cloud one day....

Funny this is a "thread size" thread and we are talking about breathers and weather, over on the "Bike Bandit" thread we are talking about threads. Life's funny....

To get this thread back, are jets jets? I came across lots of Yamaha wave runner sites, they have funny looking exhausts but are all selling Mikuni jets for $2.95. Are those jets the same Mikunis for our Mikunis?

[sixtysix]

They very well could be. I am not sure if Mikuni used the same type for those carbs or not. You would have to see one to be sure.

There are 5 types of main jets in Mikunis:

4/042
Large Hex type.
Fits VM, TM,
TMX.


M10/14
Small Hex type


N100.604
Large Round type.
Fits RS and HS.


N102.221
Small Round type.
Super BN


N208.099
Press in type.
OEM Yamaha
and Ducati


They also have 7 types of pilot jets.

[kenkrieger]

MR. Mikuni is everywhere it seems, at one point in resurrecting my 81 Special I was entertaining ideas of having him lynched. Or electrocuted. I have read that a few have used the newer Flat side carbs on these older bikes with much success. Witht the new ones there would be no more problems if they get broken posts and the like,,. They make the 34 mm variety which seems to be a match for the 1100, about 600 bucks but if you have bad carbs , it might be an alternative. Don't really want to lynch him anymore, maybe just a slug to the knee.
Jet Content, ahh I guess it was the Mikuni name that set me off, no jet content.

[Robert Haller]

Originally posted by sixtysix

...rode the XS today, may be the last ride for it this year, fuel stabilizer is in.

Aren't you going to the NC rally?

General Question: Is there a crankcase breather hose on a 79 Special? All I see on mine is a hole in the bottom of the airbox with some foam stuck in it.

[sixtysix]

Yep I am going to the NC rally but will be bringing my Bandit or Trophy. All XS's had the crankcase breather hose, there should be about a 1/2" ID hose just below the air box, connected to the engine.

[Robert Haller]

Originally posted by sixtysix
. All XS's had the crankcase breather hose, there should be about a 1/2" ID hose just below the air box, connected to the engine.

Where does it connect on the engine? Apparently mine has been disconnected, it that a good or bad thing?

[woodstoc]

Connects just below where the air box sits. Yours may be blocked off, but you need it to relieve crankcase pressure. The line on the 79 ran to the front (carb side) of the stock air box.

[Mike Hart]

The breather vent is directly behind and below the starter. You need to be sure your crankcase can vent pressure.

In this pic, it is the lowest hose, below and left of the fuel hose T, pointing away from the viewer, bending up and left...