Hi all,
I've just got hold of an 1986 FJ1100. In the main it is a great bike, easy to ride, generally smooth and pretty agile for an old girl.
Ive been lurking for a while now and this seems to be a great site and I look forward to getting involved.
My problem is that as it gets hot, say after 30 - 40 mins of city traffic it begins to run really rough. To the point where it struggles to get of the mark and misses and carries on until it hits around 3K revs then it takes off.
Very frustrating and makes it difficult to ride.
The bike was rebuilt about 2000 klms ago and I bought it of the second owner after the rebuild. my guess is he couldn't fix the problem.
I have had a bit of look through here for some info but cant seem to find a similar issue?
any ideas?
Quote from: Rustyas on October 10, 2013, 04:34:19 AM
Hi all,
I've just got hold of an 1986 FJ1100.
My problem is that as it gets hot, say after 30 - 40 mins of city traffic it begins to run really rough. To the point where it struggles to get of the mark and misses and carries on until it hits around 3K revs then it takes off.
Very frustrating and makes it difficult to ride.
The bike was rebuilt about 2000 klms ago and I bought it of the second owner after the rebuild. my guess is he couldn't fix the problem.
I have had a bit of look through here for some info but cant seem to find a similar issue?
any ideas?
:hi: Welcome Rusty. If your in Brisbane it may not be the bike`s fault. Bloody hot here lately! What part of Australia you from?
They do get a bit hot in city traffic, but it`d be a good idea to take a peak under the tank to check the fuel line`s not too close to some hot componentry. Does it run perfect out on the country faster roads? Spark plugs look okay? Not that it helps ya heat prob but are you sure it`s an 86 model? - Love those ambulance colours! Got some pics? we love pics! :drinks:
Welcome Rusty, we can always use more Red & White 86's.
Quote from: Rustyas on October 10, 2013, 04:34:19 AMHi all,
I've just got hold of an 1986 FJ1100. In the main it is a great bike, easy to ride, generally smooth and pretty agile for an old girl.
My problem is that as it gets hot, say after 30 - 40 mins of city traffic it begins to run really rough. To the point where it struggles to get of the mark and misses and carries on until it hits around 3K revs then it takes off. Very frustrating and makes it difficult to ride. any ideas?
Rustyas,
It sounds like the gasoline is boiling (vapor lock), when the bike gets hot in traffic. You should be able to fix this problem with some insulation. You can make (or buy) a patch of heavy-duty foil-backed insulation material to fit under the entire gas tank, which will help to keep things cooler. You can also fold a strip of this insulation around the fuel lines, to keep gas cooler inside the fuel lines. Office staples will secure this folded insulation strip around the fuel lines, well enough. At some point, the fuel line has to dive through the large insulation sheet to get to the engine, but you just make a slit in the insulation, for that trick (no need to disconnect any fuel lines). I do not know what types of insulation materials may be available there, but others here can chime in, with that information.
Start up Google.com then Copy-and-Paste this entire line, as the inquiry:
insulation under tank site:http://www.fjowners.com/
You will see what others here have done with this idea.
Cheers,
Red
From my experience with gunked up carbs that Randy cleaned for me, I would suggest you pull them and clean your pilot jets.
Mine would do the same thing, run ok at first but as it warmed up more, the below 2000 range was rough, and it wouldn't idle well and eventually die if i didn't give it some throttle to keep it going.
It's not a bad job to pull them and clean the jets. Ask if you need help.
Also, Randy diagnosed that my cams were out of time, and if your engine has been rebuilt, they might not have gotten the cams quite in time, and that will do what you're saying too.
It's not hard to check their timing, and it's not too terrible of a job to get them back in time, just takes patience and a little trial and error.
It is possible that you have a coil that is going bad. I had this on my '85, where sitting at a light/ very slow traffic, the engine heat (without sufficient airflow) would begin to affect the coil and it would begin to 'cough'/ miss with greater and greater frequency, until it would stall. Keeping the RPM's up would prevent it.
Simply putting a timing light on it in the garage showed clearly the issue was a no spark from the coil to the spark-plug.
It's a fast/ easy test and will, at worst, eliminate this from your solution set.
Just a thought.
Dan
A timing light???? Awesome idea, Dan! I didn't even know they made timing lights anymore. :-)
Quote from: FJ_Hooligan on October 10, 2013, 10:10:50 AM
A timing light???? Awesome idea, Dan! I didn't even know they made timing lights anymore. :-)
Cheap one from Harbor Freight. I picked a real nice almost new Penske one at a yard sale for 1.00. Check out the used tool store in your area also. Lots of them floating around. About as useful with the new cars as a dwell meter... :lol: :lol: Nice to have for the old stuff.
George
Hi all
Thanks for all the replies and the welcome.
As to the bike, its located in Sydney, and from what I can glean from the replies it could be fuel/vapour/heat issues.
yesterday was bloody hot and by the time I got near home it was playing up temps were high 20s low 30s. This morning the temps were a lot lower and I made sure I kept good clear air flow to the bike and it seemed to have improved dramatically.
I'll see what I can do about insulating the fuel lines etc.
Ill keep you posted
Cheers
Rusty
Just a question. Do you have the factory insulation pad glued to the bottom of your tank ?
George
Quote from: movenon on October 10, 2013, 08:37:32 PM
Just a question. Do you have the factory insulation pad glued to the bottom of your tank ?
George
George,
from what I could see there was some there but looks as though most is missing. I'll look for something to replace it.
Im now starting to think the problem could be in the fuel line or the vacuum line from the petcock they are pretty old and may open up when hot.
Cheers
Rusty
Quote from: Rustyas on October 10, 2013, 10:18:35 PM
Quote from: movenon on October 10, 2013, 08:37:32 PM
Just a question. Do you have the factory insulation pad glued to the bottom of your tank ?
George
George,
from what I could see there was some there but looks as though most is missing. I'll look for something to replace it.
I'm now starting to think the problem could be in the fuel line or the vacuum line from the petcock they are pretty old and may open up when hot.
Cheers
Rusty
OK that's a good start. I would replace the heat shield. Try to get a FJ one if you can. If not perhaps a local wrecker has a bike with a shield you can adapt.
Anything rubber under the tank deserves a good look at. No shortage of heat in that area. I would try to protect the fuel line as much as possable.
George :drinks:
SORTED!!! :yahoo: (I Hope)
The small hose, I think it is a vacum hose, that runs from the petcock to the carby was split where it attached to the carby and was causing it to run very lean. Took me ages to find it :dash2: as it looked ok until I actually removed it.
There was enough play to allow me to trim the split end and re attach. :good2:
Even in todays heat, in traffic it ran much smoother, not good, but much better.
I am wondering if whilst running lean it may have stuffed the plugs? It still has a miss down low but seems to run ok at 3K revs or more.
Thanks for the help, much appreciated
RustyAs
Glad you are making progress and keeping us informed. There is a good lesson in your finding the crack in the vacuum line. There is a big difference between looking at something and doing a good inspection.
George :good2:
After fixing the hose from the pet cock to the carb the bike still runs rough when it gets hot. :diablo:
From what I an see from other posts and topics, it may be running very rich.
The plugs are all carboned up, all the same
The bike runs ok when cold, as it gets hotter it runs worse
All the hoses are now sorted.
My next plan is to strip down the carbs and check the jet sizes. Any suggestions on how far to go with the resizing? Not sure what's in there at the moment
Cheers
Quote from: Rustyas on October 25, 2013, 04:02:27 AM
After fixing the hose from the pet cock to the carb the bike still runs rough when it gets hot. :diablo:
From what I an see from other posts and topics, it may be running very rich.
The plugs are all carboned up, all the same
The bike runs ok when cold, as it gets hotter it runs worse
All the hoses are now sorted.
My next plan is to strip down the carbs and check the jet sizes. Any suggestions on how far to go with the resizing? Not sure what's in there at the moment
Cheers
Cleaning and rebuilding the carbs is always good and truthfully is probably what it needs. How does the the idle react when you adjust the idle air screws ? Did you do a blip test ? Have you synced the carbs ? If you clean or rebuild the carbs you will need to sync them to make it run smooth.
On the carbs I recommend to go into the "File" section and read through the carb information. There are some good "how to's" in there. While the carbs are pretty basic there is a lot of little details that can mess with you. Randy at RPM (racerrad8) can help you or suggest jets for you. Send him a PM or e mail from his web site. http://www.rpmracingca.com/products.asp?cat=24 (http://www.rpmracingca.com/products.asp?cat=24) .
Also lots of posts on carbs to read through. Try the Search function and scan those. Ask questions as you go. Pictures do help when trying to describe something. I never did pick up where you are located. Perhaps there is a FJ owner in the area that can also advise you.
George
Hey Rusty, I'm not an expert by far, but have just gone through a full rebuild of the carbs, became a character building exercise. George gives great advice, and there is heaps of info in the files on carbs. The "blip" test and the idle mixture is a good place to start. When I did mine and the beast actually ran, I had to do the synch before she actually ran "RIGHT" Kookaloo !!
Good luck, and you know where to find us.
Cheers, Dazza
Guys,
Just had a thought :unknown:
I haven't mention the fact that the bike uses oil in a big way, probably a litre of 15/50 per 1000klms.
Trouble is it doesn't blow smoke, any smoke at all.
I am assuming the rough running is due to it running very rich and I'm going to look at the jetting. The spark plugs are all covered in thick black carbon
BUT could the oil be burning and depositing on the plugs causing the thing run rough? :wacko3:
Should I pull it down and replace the rings?
Or should I just burn it???? :bomb:
Could certainly be the cause of the rough running due to the plugs being fouled - sounds to me like new rings at the very least are in order - that is a lot of oil being burned.
Harvy
Have you done a warm compression test to see what you got?
High mileage FJ's use oil....and they still run, seemingly forever. You could be loading up your plugs with oil from leaking piston rings....or you may just need to clean out your pilot jets, jet nozzles and idle circuit.
Which would *you* do first?
Do you know when the last Valve Adjustment was done on your FJ :mail1:? :scratch_one-s_head:
I agree with Pat.
Here was my experience with my '92 that had been sitting for 3 plus years:
Randy cleaned the carbs, I tried to clean the tank.
Ran ok when cold, but as it warmed up it ran poorly under 2500 rpms or so, and would not idle very long. Above 2500 it ran great.
Cleaned the pilot jets mulitple times because they were still getting plugged from residual crap in the tank.
Randy sent me new pilot jets the next size up.
Still did not want to idle very long and Randy diagnosed that the cams were out of time.
Put the cams back in time.
Runs like a champ... almost. Might need to play with the idle mix screws a little. It chugs sometimes at steady low rpms.
Hey all, sorry for the delay, but other than stuffing around :dash2: trying a few things :ireful:there was not much to report.........Until now.
It finally got the better of me, I decided to start at the beginning and work my way through.
My plan was to remove carbs look at the jets and sizes etc and also pull it down and replace the rings. Between myself and my brother in law we reckoned we could have it disassembled in two nights, purchase parts required and re assembled in two nights, allowing for delays we reckoned we could get it done over a period of one weekend, five week nights and then another weekend.
Bugger me if when I open the air box, I found the air filter laying in the bottom of it, not up in place where it should be. Closer inspection showed the rubbers between the carbs and the barrels were not on on the bottom and there was no seal at all
So where I thought the bike was running rich ( as the plugs were blackend and all carboned up ) it would appear it was running lean! :wacko3:
All of a sudden it made sense: motor running hot, idling at high revs, lack of power down low. missing and coughing at low revs..... had to be due to running lean
I fixed the air cleaner, "manufactured" a wedge to hold it in place ( clips were missing), spent hours trying to get the rubbers to seal
finally got it all together and it works!!! :yahoo:
Where as before it was 2/10 - 4/10 on a good day it is now 7-8/10. still has some minor down low issues, but for now good enough to enjoy the ride.
Thanks for all the help fella's. I"ll keep you posted
:yahoo: Gotta love it when it's the simpler things.. Good scootin' to ya!
In trouble shooting, "take nothing for granted" always start with the simple stuff first and put things into spec.. Glad it was a no expense fix. :good2:
George
So, where is all that oil going? :unknown:
Quote from: oldktmdude on December 16, 2013, 04:02:48 PM
So, where is all that oil going? :unknown:
Good question :scratch_one-s_head: I'm assuming that due to the motor running hot, recent rebuild etc it just was burning it at a higher than normal rate. I was adding about 1 Litre about three times a fortnight.
Since I "fixed" it seems to have slowed the usage dramatically. I can see by the sight glass that it is dropping but no where near as much as before. The bike does about 250-450 Klms per week, depending on work. so I figure if I need to top up once a month that would be OK
Sounds like a botched rebuild to me... I'm no expert, but I've had a rebuilt bike engine before done right. No oil burning issues. I've also worked with a guy who did his own rebuild, his first one--it wasn't a flawless job, and it burned oil.
Cross your fingers. Also, post some pictures of your plugs. Also, maybe some basic spray adhesive from a fabric store might help you get a really decent seal on your air filter, without being a permanent fixture.
How many miles on the bike since the rebuild?
Seems I have developed an oil leak :dash1: :dash2:
How do I post pics here? :unknown:
Quote from: Rustyas on December 19, 2013, 06:43:01 PM
Seems I have developed an oil leak :dash1: :dash2:
How do I post pics here? :unknown:
When you want to add a pic to a post, first the pic has to be hosted on the web somewhere (not just on your pc).
Then you use the image button:
(http://fjowners.com/gallery/6/22_19_12_13_7_03_08.png)
and post the link to the hosted image between the img and /img with the brackets around those 2 codes. The above was done like this:
[img]http://fjowners.com/gallery/6/22_19_12_13_7_03_08.png[/img]Harvy