Author Topic: EFI cleaning and overhaul (Read 6530 times)

BRADEY · **on:** April 20, 2013, 06:54:37 am

Wondering if there is a tutorial or DIY video on
how to disassemble the fuel injector and Throttle body
for cleaning and overhaul. I could not find much on this
subject in the manual either ! Please ignore if this subject
has already been discussed. However please point me to
the correct link. Thanks

GSS · **Reply #1 on:** April 20, 2013, 04:10:35 pm

Some info to get you started.....there is a boatload over at the popular Indian site as well.
http://www.enfieldmotorcycles.com/forum/index.php?topic=14467.0

http://www.team-bhp.com/forum/motorbikes/

Vince · **Reply #2 on:** April 20, 2013, 04:48:31 pm

This is a non-issue unless you left it in a flooded ditch over the winter. Just run good quality gas and ride the bike regularly. I have never see an injector or throttle body on any bike that needed "maintenance". I have repaired/replaced a few that someone has "maintained". If you have some kind of problem it is probably electrical, not mechanical.

BRADEY · **Reply #3 on:** April 20, 2013, 07:10:02 pm

GSS, Vince thanks for your response.
The reason I am interested to do the maintenance
is because, my bike hesitates when I roll on the throttle
after a quick roll off, usually in traffic. Which makes me
believe that perhaps the spray of the injector is not a fine mist
as it should be, and may have become coarse. This is similar to
the AF mixture, rich...............sorry but I am not very good at injectors !!

Vince · **Reply #4 on:** April 20, 2013, 07:55:30 pm

Even with the wonders of fuel injection, you are dealing with a long stroke single. I can make any similar bike stall and stumble if I yank the twist grip. They rev too slowly for the amount of vacuum they generate, thus it will always run lean and stumble with a quick yank of the throttle. The cure is to roll on the throttle a little slower at low RPM.
There is one adjustment you can make to the system, but unless you are having other issues, I would try a slight change in throttle actuation. Try it and let me know. We can adjust for a richer mixture if this doesn't work, but that can lead to a plug fouling situation.

GSS · **Reply #5 on:** April 20, 2013, 10:17:44 pm

Techron fuel injector cleaner, followed by Seafoam in a tankful a of gas would be worth a try before you take things apart....I am assuming you already have the NGK spark plug? Is the idle set too low?

Arizoni · **Reply #6 on:** April 20, 2013, 10:46:28 pm

I would go the Techron route. It did wonders for my fuel injected BMW.

The actual fuel injector is not made to be disassembled.
If it is taken apart the super fine wiring in the coil that operates it would undoubtedly be damaged and the jets are too small for any mechanical way of cleaning them.

The Techron on the other hand will chemically dissolve any varnish or crud that has built up in the injector.

BRADEY · **Reply #7 on:** April 21, 2013, 04:12:42 pm

Even if the roll back on the throttle is very gradual and deliberate
the bike still hesitates a tad, which my carbureted bikes never do.
However It still gives me a very good mileage of 81 miles per US gallons
on highway, so I am not sure if the problem is with the injector or elsewhere !

High On Octane · **Reply #8 on:** April 22, 2013, 01:29:12 am

If you're getting 81mpg you have got to be running seriously lean. You should pull your spark plug and see if the electrode and ground strap are white in color.

Scottie

gashousegorilla · **Reply #9 on:** April 22, 2013, 02:08:48 am

Quote from: Scottie J on April 22, 2013, 01:29:12 am

If you're getting 81mpg you have got to be running seriously lean. You should pull your spark plug and see if the electrode and ground strap are white in color.

Scottie

+1

Although on my bike, we found on the Dyno . That the bike would go extremely rich when cracking open the throttle with the stock ECU.

BRADEY · **Reply #10 on:** April 22, 2013, 07:41:23 am

No the bike is not running lean.
The flame side of the plug (Bosch WR8DP)
is coffee brown and the opposite side a little off white.
There is very little sooting or carbon deposits, which makes
me believe the bike is not running lean. However it could well be
that momentarily the mixture becomes rich, which may make the
bike hesitate a bit, both in slow RPMs as well as mid range sometimes.
NGK BPR6ES is not available in my region in India........

Maybe somebody could help me source it, and I may pay by Western Union
or something like that ??

JVS · **Reply #11 on:** April 22, 2013, 08:49:07 am

Quote from: BRADEY on April 22, 2013, 07:41:23 am

No the bike is not running lean.
The flame side of the plug (Bosch WR8DP)
is coffee brown and the opposite side a little off white.
There is very little sooting or carbon deposits, which makes
me believe the bike is not running lean.

The bike does sound it is running lean. No carbon deposits/very little sooting is an indication of a lean mixture, not rich. Please purchase a NGK BPR6ES over E-Bay or the like. Any other plug besides the stock one in India will be an improvment. Try purchasing a 'Champion' branded plug for UCE engines at a local mechanic. They might be able to source it for you. Spark plug gap should be 0.7mm-0.8mm.

Some plug readings for reference -

http://www.gnttype.org/techarea/engine/plugs.html
http://www.motocrossgear.com/wp/wp-content/uploads/2011/12/plugdiag.jpg
http://www.angelfire.com/fl4/pontiacdude428/Readplugs.html
http://www.dansmc.com/spark_plugs/spark_plugs_catalog.html

High On Octane · **Reply #12 on:** April 22, 2013, 02:48:42 pm

Stills sounds a little on the lean side if the sides are whiteish. Have you tested or made any adjustments to your TPS? Maybe that could be causing the fluctuations between rich and lean.

Scottie

Vince · **Reply #13 on:** April 22, 2013, 03:49:03 pm

On the top left rear of the injector body there is a post. In the post is a recessed brass screw. Mark its position. Use a flat head screw driver and turn the screw 1/8 turn clockwise. This will change the starting point for the programming and will slightly richen up the mixture. This should help. If it doesn't you can go back to the position you marked.

Arizoni · **Reply #14 on:** April 22, 2013, 11:35:48 pm

BRADEY
If you can't find the NGK BPR6ES, look for a Autolite 63, NDE W16EXR, Champion RN9Y, MEIYA F6RTC, or a DENSO W20EPR-U.

BRADEY · **Reply #15 on:** April 23, 2013, 05:53:59 pm

Vince the only brass screw I could find was in "the well"
and I believe it sets the idle on the motor. $:-\$

Arizoni, I have found a NGK dealer in my Region and hope to meet him
tomorrow, is it ok if I pick BPR5ES instead of 6ES or their Iridium version ??

NGK India lists BPR5ES/CPR7EA-9 or CPR7EAGP-9 and CPR7EAIX-9 as the probable choices for the UCE 350 engines. The first being their conventional plugs, the second being their G Power plugs and the third being their Iridium series plugs.

Arizoni · **Reply #16 on:** April 23, 2013, 11:42:48 pm

IMO, these Royal Enfield engines are low tech designs including the UCE's.
They are designed to use the old fashioned, low cost spark plugs so spending 3 times the money for a Iridium plug makes no sense to me.

If the engine was a high reving short stroke engine that is expected to run 40,000 km between spark plug changes (like modern automobiles) it would be different.

As for the difference in heat ranges (the numbers you gave are not a 6), I can't say how well they will work.
I guess you can try them and then, after riding 300 km or so, check the color of the electrode insulator to see how its doing.

Vince · **Reply #17 on:** April 24, 2013, 01:55:12 am

That is the screw. Just mark it's position so you can return to it. Try 1/8 turn. I have not had to go further than that. It affects idle by affecting mixture. The last customer I had with a lean condition turned it counter clockwise. It helped throughout the RPM range. His plug looked better and he had better throttle response. It will either help or make it worse. If worse, go the other direction. You can always go back if you marked your starting point. Put a scrape mark on the inside of the well at the screw's slot.

BRADEY · **Reply #18 on:** April 24, 2013, 04:05:55 pm

thank you vince and arizoni. the current setting of this screw on my bike is just about high enough, such that the auto decompressor is not activated, even during the cold winters of North India. And I remember quite well that when the bike came from the factory it always did actuate the auto decomp

So what do you suggest should I turn is counter clockwise (to make it still richer) or clockwise (so that the auto decomp activates on cold starts). Remember the motor can return a mileage of upto 80mpg on freeways at speeds of 50 to 60 MPH....on the current settings. I'll try to post the pictures of the Plug for your reference.

BRADEY · **Reply #19 on:** April 24, 2013, 05:45:53 pm

Here are the pics. On the left/lower side is my C5 plug
and the other one is my Electra CI 350 plug (which is too rich)
From whatever little I know of plug reading the C5 plug cannot be termed as running lean. In fact it is the perfect tan colour
we would want it to be.

barenekd · **Reply #20 on:** April 24, 2013, 06:13:21 pm

The auto decomp has absolutely nothing to do with the EFI. It is a purely mechanical device mounted on the exhaust cam. Oil weight and temp could affect it. They definitely get a bit sticky on cold mornings.
Bare

Vince · **Reply #21 on:** April 24, 2013, 06:38:14 pm

Both are too rich. I've had success in running improvements by turning clockwise. Just mark the starting point so you can return to it, then try one way or the the other. If it's better, great!. If not, go the other way.
The auto decompress is completely separate. It has no mechanical or electrical connection to fuel/ignition or anything else.

BRADEY · **Reply #22 on:** April 24, 2013, 06:53:53 pm

Vince do you have an example of a spark plug
that you would think is running on optimum mixture
so that I may compare it with mine.

I believe that if you lower the idle RPMs below 900 by
adjusting this brass screw, the auto decomp comes into play.
However, if you raise the idle RPMs, it may not. I understand it is a mechanical device, but is it not governed by the engines RPMs at idle. Correct me if I am wrong please !

barenekd · **Reply #23 on:** April 24, 2013, 07:07:26 pm

It is only affected by RPM. I've forgoten the exact rpm,but it's supposed to be somewhere around 800 RPM when the auto decomp stops decomping. It is operated by a flyweight on the exhaust cam, but as I said, the flyweight can get a bit sticky on cool mornings.
Bare

Arizoni · **Reply #24 on:** April 24, 2013, 11:30:45 pm

Just for the record, the Service Manual says the large brass screw down in the well on the top of the throttle body is a air adjustment screw that controls the airflow at the idle.
It does not change the fuel mixture by itself but the change in the idle speed is noted by the ECU and it (the ECU) modifies the fuel rate to accommodate the new idle speed.

JVS · **Reply #25 on:** April 25, 2013, 01:45:24 am

The C5 plug does not appear to be too rich, the electrode is the tannish colour you speak of. And that air bypass screw does not have anything to do with how the mixture is set. If you've been making short trips on your RE without it getting properly warmed up, it can explain some of that sooting. Just try swapping the plug with what Arizoni has recommended, set the gap at 0.7mm and see how it goes

JVS · **Reply #26 on:** April 25, 2013, 02:15:06 am

BRADEY

Also, I just realised that you have the Classic 350, correct? 81mpg is very decent and comparable with other UCE 350s. Your bike is running fine! Keep riding!

BRADEY · **Reply #27 on:** April 25, 2013, 06:58:44 am

Hi JVS its a C500 and not 350.
I did some research on the NGK plug guide,
and find that their BPR6ES and BR6ES are essentially
the same plugs. The later is available in my city and
I am going to give it a try and report on my findings.

The "P" seems to be one slightly longer. I suppose it
could have better heat transfer properties !!

JVS · **Reply #28 on:** April 25, 2013, 07:19:12 am

No worries, and thanks for clearing that up. Let us see how your new spark plug goes. Hopefully, all will be well.

heloego · **Reply #29 on:** May 26, 2013, 01:06:07 am

I jumped on the forums today to ask about equivalents for the BPR6ES, since everyone here wants to sell me the iridium one. Good thing I checked this thread first!

Thanks for the post, arizoni!

BRADEY · **Reply #30 on:** May 26, 2013, 07:07:25 am

Would a BR6ES work as well..........I guess this one will be less projected
inside the combustion chamber ??

Arizoni · **Reply #31 on:** May 27, 2013, 01:25:47 am

Yes, the BR6ES does not have the projected tip that the BPR6ES has.

IMO the projected tip is better for high speed engines where placing the spark out in the middle of the combustion chamber can help to reduce misfiring.
With our rather old fashioned slow speed engines I'm not sure it makes any real difference but I haven't tried the non-projected plug in my bike.