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General Category => Yamaha FJ1100 / FJ1200 Running Problems => Topic started by: jono on July 04, 2021, 12:17:38 AM



Title: a couple of issues on first open road ride
Post by: jono on July 04, 2021, 12:17:38 AM
well Ive finally finished rebuilding my 3xw apart from painting it which i will do when i get it's certificate of fitness i took it for a ride today with the fairing and all plastics fitted properly and it goes pretty good ,there are two things that aren't right and any advice from you guys as always would be greatly appreciated ,
first problem is it starts good even though the choke cable is stuffed (ill be ordering 1 from RPM very soon) i have to hold the plunger out till its warm enough which isn't to bad but it spits back or makes a popping noise for the first couple of minutes off running and also when it is warm enough which isn't to long when I rev it quickly it dies back slightly then slowly comes back to normal rpm now i presume it is running lean Ive adjusted the screws out to there max and Ive modified the air box by cutting the box completely away on the air side of the filter which is a k&n filter so i obviously need too richen it up but how should i go about it ? just go bigger pilot jets? and then do i need bigger air jets to compensate for them ? and if i do raise the needles should i increase my main jets or is that not necessary ?
second problem is the needle on the speedo wobbles from 60 to 100 km and i cant tell how fast im going could this be caused by the drive unit ? i bought a used speedo from a wrecker that should be OK and a new cable from Rpm, today was the first time ive actually  ridden at open road speed and at low speed it seemed fine .this bike had 2 replacement speedos according to its history

jono


Title: Re: a couple of issues on first open road ride
Post by: T Legg on July 04, 2021, 02:02:46 AM
This thread shows a way to lubricate your speedometer http://www.fjowners.com/index.php?topic=19154.msg194494#msg194494 (http://www.fjowners.com/index.php?topic=19154.msg194494#msg194494)


Title: Re: a couple of issues on first open road ride
Post by: ribbert on July 04, 2021, 05:15:26 AM
This thread shows a way to lubricate your speedometer [url]http://www.fjowners.com/index.php?topic=19154.msg194494#msg194494[/url] ([url]http://www.fjowners.com/index.php?topic=19154.msg194494#msg194494[/url])


Travis, that's an excellent fix. Can't argue with 200k since!

Jonno, according to my mechanic, it's not a symptom of the speedo drive.

Red, HUD's (GPS speedo) that work in full sun are out there. I've had one for 10 years, it's my favourite mod. My speedo works fine but at speed (wind buffeting and possibly age), I find the FJ's speedo takes a second or so to focus on. Perhaps not a problem in most places but here, tolerances are absurdly low and I need to know exactly how fast I'm going.

(https://live.staticflickr.com/3927/15407517561_7c43d0d531_b.jpg)

There is no combination of sun, reflection or road colour that makes that difficult to read at a glance, I love it. The display projects a little higher than in the photo.


Title: Re: a couple of issues on first open road ride
Post by: red on July 04, 2021, 07:57:15 AM
the needle on the speedo wobbles from 60 to 100 km and i cant tell how fast im going could this be caused by the drive unit ? i bought a used speedo from a wrecker that should be OK and a new cable from Rpm, today was the first time ive actually  ridden at open road speed and at low speed it seemed fine .this bike had 2 replacement speedos according to its history
jono
Jono,

A jumpy speedo needle is almost always a non-lubricated drive cable.  It binds up inside and releases repeatedly, and that makes the needle jump.  You can disconnect the cable and slide out the  cable core (use rubber gloves, and avoid any dirt).  Use a premium dino or synthetic grease to do the job, not white grease, then re-insert the cable core and re-install.  Use Ty-Wraps as needed to get the cable housing straight (minimum possible bending) and keep it that way.  Sometimes a speedo cable is just shot, but new speedo cables are available for the FJ and inexpensive.

I do not regard guesswork on carbs, jets and needles to be wise in terms of performance or engine longevity. 
Even the altitude of your town becomes a factor.  I know it's the "customary" and old-school approach, but . . .
These days, a good shop with a dynamometer and exhaust gas analyzer would provide you with the best results.


Title: Re: a couple of issues on first open road ride
Post by: red on July 04, 2021, 09:09:50 AM
Red, HUD's (GPS speedo) that work in full sun are out there. I've had one for 10 years, it's my favourite mod. My speedo works fine
https://live.staticflickr.com/3927/15407517561_7c43d0d531_b.jpg
There is no combination of sun, reflection or road colour that makes that difficult to read at a glance, I love it. The display projects a little higher than in the photo.
Ribbert,

Do tell!  I found a cheapo on Amazon, which I use as a direct-readout dash instrument.  If you have a make and model of GPS that works as a HUD, post up a link for it, and maybe there is a similar unit from that maker, by now.

Thanks!    :yes:


Title: Re: a couple of issues on first open road ride
Post by: ribbert on July 05, 2021, 03:34:07 AM
If you have a make and model of GPS that works as a HUD, post up a link for it, and maybe there is a similar unit from that maker, by now.

Thanks!    :yes:

That was probably 10 years ago, I have no idea where it came from now. If I was in the market for another one, I would be taking pot luck on ebay...again.

What you have, a digital GPS speedo sitting on top of the instrument bezel does the same job (but without the novelty factor) and although a bit lower, it's still so much easier to read at a glance than the finely graduated analogue speedo and keeps the road ahead in your peripheral vision.

Noel


Title: Re: a couple of issues on first open road ride
Post by: jono on July 06, 2021, 01:58:20 AM
thanks for the input guys i'm going to lube the speedo and cable this weekend and reroute the cable, when i reassembled the bike the last time and refitted the front guard i used a cable guide i thought was for the speedo cable but looking at the way the cable tracks it looks like its distorting it slightly so fingers crossed the grease and a different position for the cable will fix the wobbly needle then all i have to do is figure out how to go about richening up the carbs properly

jono


Title: Re: a couple of issues on first open road ride
Post by: jono on July 11, 2021, 12:11:30 AM
speedo sorted thanks again , I lubed the new cable with grease and pumped bicycle chain lube in to the speedo drive and main housing
I also changed the routing of the cable and now its pretty steady .Now to richen the carbs do I need to increase the air jet size if I increase the pilots and mains ? it seems to come back to full power slowly if I rev the motor quickly could this be to lower fuel  level in the bowls ? I set them to the height in the manual when I fitted new o rings, needle valves and gaskets but maybe with the modified airbox and mufflers it's starving at high revs does this make sense ???

jono


Title: Re: a couple of issues on first open road ride
Post by: Pat Conlon on July 11, 2021, 07:42:14 AM
Now to richen the carbs do I need to increase the air jet size if I increase the pilots and mains ?
No, there is no need to change your 155 air jet.
it seems to come back to full power slowly if I rev the motor quickly, could this be to lower fuel level in the bowls ?
No, adjust the fuel idle mixture screws leaner (turn in)


I set them to the height in the manual when I fitted new o rings, needle valves and gaskets but maybe with the modified airbox and mufflers it's starving at high revs does this make sense ???

If you are worried about lean running, check your plugs. Check your float bowl fuel levels.
With bigger Pilot jets, shimmed needle jet and larger mains, you should be fine.
Did you replace those intake manifold o rings? That’s important. It is futile to fine tune your FJ with old dried leaky o rings….cheers.




Title: Re: a couple of issues on first open road ride
Post by: jono on July 11, 2021, 12:04:34 PM
yes Pat I fitted new inlet manifolds as the old ones were perished ,and new o rings i also replaced the airbox  carb rubbers with good used ones 'so as far as i can tell there are no airleaks, ive fitted an old 1tx airbox because the original one had bad rubbers but my donor 1tx rubbers were good but didn't fit the 3xw airbox because  there too short ive cut the open side of the new airbox completely away and am running a K&N filter which is completely open to the air side the good thing about this set up is it is easy to fit the box to the carbs because the 1tx box is smaller and sits closer to the carbs it did take a bit of plastic welding and fabricating but works well and is airtight 

jono


Title: Re: a couple of issues on first open road ride
Post by: Pat Conlon on July 11, 2021, 01:23:37 PM
Ok, good….it sounds like your air filter system is fine. That should not impact your carb fine tuning.

….but maybe with the modified airbox and mufflers it's starving at high revs does this make sense ???


Why do you think your engine is “starving at high revs” ?  Can you describe your symptoms?

Verify the fuel levels in your float bowls, adjust floats as necessary.
http://www.fjowners.com/index.php?topic=3592.0 (http://www.fjowners.com/index.php?topic=3592.0)

If you already have:
1) #40 or #42 Pilot jets
2) stock 155 air bleed jets
3) the main jet needles shimmed up 1/2 step***
4) At least #112.5 or 115 main jets
With these ^^^ you will have no problem with any air box modifications.

All you should need to do is to dial in your idle fuel mixture (via blip test) set your idle speed, and ride.

I’m not sure why you think you are lean on your top end (it’s not from your air box)

*** shimming the main jet needles are important. In your day to day street riding you are on your needles 80% of the time. http://rpmracingca.com/proddetail.asp?prod=Carb%3AMainNeedleShim&cat=39 (http://rpmracingca.com/proddetail.asp?prod=Carb%3AMainNeedleShim&cat=39)

(https://www.mikunioz.com/wp-content/uploads/2015/02/pilot_jet_intro.gif)


Title: Re: a couple of issues on first open road ride
Post by: jono on July 12, 2021, 01:02:47 AM
thanks for this information Pat i'll order the shim kit with the choke cable from RPM  very soon. and check the jet sizes again and increase maybe one size up on both mains and pilots the
reason i think it's leaning out is if I rev the motor to say 5000 - 6000 rpm when stationary a couple or three of times when I let go of the throttle it takes a couple of seconds to return to a good strong idle again I even noticed the same when riding quickly then coming to a sudden  stop  like its hasn't got enough fuel "if that make's sense"like its running out of fuel immediately  after high revs

jono


Title: Re: a couple of issues on first open road ride
Post by: jono on July 21, 2021, 01:40:05 AM
well Ive started to learn how to tune my FJ. Love working on this bike every thing seems to fit and work like it should ,"kind of !!!" I pulled the carbs and re jetted using Pats advice ,the carbs were set at 3rd slot of 5 on the needle, at first i lifted them to the 5th slot but when I assembled them the slide's all bound up so Ive settled for a 0.20mm shim and still at the 3rd slot.The main jets were 110 so Ive gone to 112.5  and the pilot jets were 42.5 so ive stayed with them and ive fitted new emulsion tubes  it's really bad weather at the moment so ive only ridden it a short distance in the rain it seems a bit smoother and feels more powerful but I wont really know till the weather improves. The speedo is pretty stable now so it should pass the warrant of fitness  now ,that GPS speedo looks like a good mod Noel I might look at one later on but there not acceptable here in NZ for a WOF so I think ill spend my money on a good radar detector first Ive only ridden it once since re jetting but it's showing 100kph at  under 4000rpm so I think it's going to cruise pretty quickly on the open road

once again thanks for your help guys

Jono