Pilot screw adjustment/running lean

[georgiaboy]

I think i may have partial clogged pilot jets....On carbs 3 and 4 i can turn pms in all the way and engine rpm only decreases very little like from 1000rpm to around 900rpm..Now have the turned out 3 1/2 turns and bike is still running lean. Checked spark plugs--Lean--White tips...Did cold start check...#1 and #2 heats up fast. #3 and #4 only warm at first then eventually heats up...Have done seafoam treatment. Bike still runs lean.....Sounds like a slight misfire on right side .Bike has 23k miles and running Bub Mufflers...any suggestions appreciated....thanks

[gibvel]

When I had partially clogged pilots, on a couple cylinders, I put a double dose of BG 44K in the tank and ran it around at an idle or just off idle around the neighborhood. Then I let it sit overnight.

 

I knew they were partially clogged because when I went to the dealer to have them set they could get 2 of the cylinders to read correct (3.0) and the others would only adjust to about 1.5.

 

Also, when I did a cold start the bike wouldn't start without choke and when the choke was off it would surge. The speed would increase and decrease and increase and decrease.

 

After I did the treatment it started without choke and the surging was totally gone.

 

This was something that V7Goose told me to do and it worked. Now, depending on how clogged they are, this may or may not help. If they are totally plugged you'll probably have to tear the carbs down and clean them. If there is some fuel draw the 44K should do the trick.

 

Hope this helps.

[V7Goose]

That is excellent advice. If your jets are only partly clogged, a gas additive cleaner such as Seafoam or one of the harsher ones will almost always EVENTUALLY get it all cleaned out again. And your description does sound like partially plugged, so long as the RPM actually drops at least some when the pilot screws are fully closed.

 

But remember, any cleaner that is added to the fuel can ONLY work while the fuel is being pulled through the jets; that is why they can never work on totally plugged jets. The jets do not sit immersed in gas - they are positioned above the fuel level, and gas is only sucked up through them while the engine is turning over and creating intake port vacuum. So you must use the fuel cleaner in every tank of gas until it is fixed, and maybe at an extra strong concentration. You must ride the bike - letting it sit for extended periods does absolutely nothing other than make the problem worse as any remaining fuel clinging to the jets and carb passages evaporates and leaves new deposits.

 

Many bikes with partially (or even totally) clogged pilot jets are made to run fairly decently by just cranking up the idle adjustment so that the partially opened slides allow the main jets to compensate somewhat for the lack of fuel through the pilot jets at idle. A sure sign of this is when your intake vacuum reading is below 9" Hg at a measured 1000 RPM (going from memory there - you need to check the specs to be sure, but I THINK I remember that this engine should pull 10" at 1000 RPM). That is why it is important to have both a real tach AND a good vacuum gauge that actually shows the measured inches of mercury reading, not just a relative level to sync carbs together.

[vzuden]

V7Goose,

RE: "...important to have both a real tach ..." What do you recommend for a tach? Type? Brand?

[georgiaboy]

New to this forum but I knew I could get some "Good Advice"..Thank all of you for your input.....A+ Website

[Kirby]

Welcome Wayne(georgiaboy). I knew if you ever came on here you would find all the answers to your questions. Maybe that's an exaggeration???????!!# Anyway , you'll get some kind of answer. (hehehe) Welcome to the nuthouse! Looks like you've already saved enough for the $12.00 subscription. Again, WELCOME

[V7Goose]

V7Goose,

RE: "...important to have both a real tach ..." What do you recommend for a tach? Type? Brand?

I do not have any specific recommendations, other than to make sure you get one that works properly! I have discussed the technical details of our ignition system and what type of tach works in great detail in older threads (several years back). Here is a very brief recap:

 

We have a 4-cylinder engine, but our ignition is a bastardized mess - while we have four separate coils, each one has a waste spark, so it fires once every revolution, like a normal twin cylinder engine that uses a single coil. Sooo, if you want a tach that fires from a direct coil connection, it must either have a two-cylinder setting (if adjustable), or it must be specifically made for a two-cylinder engine with single coil (think stock Hardly Davidson ignition). If you have a tach that uses a pickup wire wrapped around the spark plug lead, you have exactly the same issue, since it will still sense one ignition pulse during each revolution (without a waste spark, a normal four stroke engine only fires a spark plug one time for each TWO revolutions, but our coils fire TWO times for each TWO revolutions). That means that a cheapo lawn-mower type tach that you might want to use in the shop for carb tuning will probably read the correct RPM on this engine (single-cylinder lawnmower engines are typically fired by a magneto that is triggered on every revolution).

 

I have a 40 year old RAC brand shop tach & dwell meter that actually has a 2-cyl setting, but I have no idea if you can ever find something like that now.

 

For permanent mounting, I prefer old-style analog tachs, but a digital works just fine too, so long as you have one that reads properly when getting one pulse for each revolution of the engine.

Edited June 8, 2016 by V7Goose

[BlueSky]

You may want to try the shotgun method of cleaning the jets.

[yamagrl]

V7Goose,

RE: "...important to have both a real tach ..." What do you recommend for a tach? Type? Brand?

 

 

I like this for tuning etc.

 

http://www.ebay.com/itm/Digital-Tachometer-meter-TACH-DWELL-Tester-Multimeter-Ship-from-USA-/271112134682?hash=item3f1f8ae01a&item=271112134682&vxp=mtr

You are only reading #2 cylinder (the grey wire from the tci on 1st Gens) The same position should work on 2nd gen. So you will set it to the 1cyl setting

 

http://i.ebayimg.com/images/a/T2eC16hHJIIE9qTYMbO1BQtSEPqySw~~/s-l400.jpg

Edited June 8, 2016 by yamagrl

[vzuden]

Thanks @yamagrl, that's what I was looking for. My 1960's vintage tach/dwell has finally died.

[ChrisFrench]

Here's what I found: A standalone tachometer and without electricity and with an accuracy of 10 revolutions / minute for 20 dollars.

Just wrap the wire on the plug wire of 4 laps

 

http://fr.aliexpress.com/item/Free-Shipping-Digital-Resettable-Inductive-Tacho-Hour-Meter-Tachometer-For-Motorcycle-Marine-Boat-ATV-Snowmobile-Generator/32231643007.html

 

 

[gibvel]

Very interesting ChrisFrench.

 

What setting do you use to make it work with our engines?

 

Wish I could find somewhere to get it from the US.

[ChrisFrench]

Hello,

Bought on aliexpress.com

Fits any type of engine, from 1 to 8 cyl. RPM automatically operates when the engine is running. No electrical connection.

 

http://www.aliexpress.com/item/Free-Shipping-Digital-Resettable-Inductive-Tacho-Hour-Meter-Tachometer-For-Motorcycle-Marine-Boat-ATV-Snowmobile-Generator/32231643007.html?spm=2114.30010308.0.311.iy2Wmh

[k9cottage]

i just got this on ebay in tassie should be here monday seems to have lots of settings for different sorts of motors http://www.ebay.com.au/itm/BLUE-hour-meter-tachometer-maintenance-timer-yz-yzf-wr-xt-125-250-450-Yamaha/152010357877?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20140106155344%26meid%3D31d40d6961f74c1dbdd7c7fc54e654af%26pid%3D100005%26rk%3D2%26rkt%3D3%26sd%3D161894488517