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Author Topic: '86 1200 rode rough under 3K RPM, now won't start at all  (Read 451 times)
fj316
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« on: July 19, 2022, 08:51:48 AM »

I'm starting to hit the wall with my latest FJ dash1 so I'm turning to the experts for a little guidance. The bike was put away for storage way too late last year and ended up spending the winter outside anyway, lesson learned and free favours always end up costly. I'm currently thinking I need at least a carb overhaul but I want to be sure I get most if not all of the issues seeing as I need to order some parts from RPM. The PO has stripped the head of the carb screws so I need at least replacements and maybe a new set of intake manifolds since the old ones are cracked (no response/reaction however to leak tests with WD40 etc. sprayed while idling).

Storytime:
This spring the first ride was a bit ruff and gruff with a lack of power and kookaloo. I wrote it off as "crud" in the system and it held up for a decent while with fresh gas in the tank. But the problem resurfaced during the summer and manifested one day after filling up the tank and going for a highway run with relatively high speed cruising. It lost power and started "misfiring" and riding very rough especially in the 2.5 to 3k RPM range. This cleared up somewhat once you passed the low-end and touched the 4K+ RPM. A lot of searching both in this forum and on the net in general led me to believe that it was the pilot circuit that was at fault.

Before diving into the pilot circuit rabbit hole I've changed air filter to a K&N, tried a new battery and installed a fresh set of spark plugs. In addition to various carb/gas cleaner products added to the fuel. I eventually managed to tune it to just a mild roughness in the 2-3K range but any significant distance on a highway at speed just seemed to make things worse. On the last test run I did not turn back in time and had to park the bike overnight at work since it just died out on the way and the next day it refused to start again even with the battery changed to a new fresh one and pilot circuit adjustments reset.

I've tried to tune the pilot circuit with all kinds of combinations and also ended up having to shorten my fuel hose a smidgeon because it cracked from removing and refitting the tank so many times. In that regard I have also always made sure that the fuel line routing always was properly situated/routed as per this forums recommendations.

So thus far I am thinking removing the carbs for a cleaning/overhaul but I am unsure if I need to account for additional hard to source parts and also if there could be anything in the fuel delivery system from the tank that might add to my problems that needs to be addressed (petcock is safety wired and epoxied). I want to be sure that I have most of my ducks in a row before I start the disassembly since it's probably gonna take me a while without a garage to work out of  wacko3 Any tips hints and tricks are well appreciated!
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Pat Conlon
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« Reply #1 on: July 19, 2022, 11:00:59 AM »

Do not worry about the stripped JIS carb screws, they are soft as butter so this is common, besides you will be replacing them with new stainless steel Allen head cap screws from your $24 RPM kit: http://rpmracingca.com/proddetail.asp?prod=carbkit
Yes, plan on removing your carbs for a complete disassembly, cleaning and replacement of the O rings (included with the RPM kit)  instructions to follow are in the Carb Files.
When you have your pilot jets and needle jets out (aka: emulsion tubes, jet nozzles) they are brass so look for deep corrosion and replace if needed.
Do you have ethanol in your fuel in Norway? We have 10-15% over here in the states. If you do, *never* store your bike with fuel containing ethanol. https://samscycle.net/storage-warning-local-gas
Also, plan on an inspection and cleaning of your fuel tank. Hopefully rust is not an issue, but with ethanol in your fuel, rust may need to be addressed.

Don’t be discouraged, since the addition of ethanol in our fuel, we have become proficient at carb cleaning.
Think of it as a right of passage….like starting your FJ with the clutch slave not installed, kinda like that…

Your bike ran right at one time, it will again. We will help you….please ask questions.   Cheers…Pat




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1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don’t store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the ‘84-87 FJ’s:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3
Waiex191
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« Reply #2 on: July 19, 2022, 11:14:59 AM »

Here is my journey:
https://fjowners.com/index.php?topic=19343.0

I think no magic fluid in the tank will fix anything. The carbs are not hard to take apart and clean. I did grind special flat blade screwdrivers for the pilot jet and the air bleed.  Also, RPM's advice to use a spring loaded center punch to remove the float pivot is excellent. 
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Bryan
1989 FJ1200
1981 Suzuki GN400
Poplar Grove, IL
 
Millietant
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« Reply #3 on: July 19, 2022, 12:27:31 PM »

Pat is 100% correct, you will become proficient at carb cleaning, removal and installation now that we have 10% ethanol in our fuel - this isn’t a FJ thing, it affects basically all pre 1990’s carb’ed bikes.

The very first tip I would give you, when you try to remove/re-install the airbox, is to remove the top bolt on each side that holds the rear subframe in place, and loosen the bottom bolt on each side - this will give you clearance you need to easily remove/put back your airbox.

Other than that, it’s all standard carb maintenance fare, but getting the choke/pilot circuit clear of crud is the key to making your FJ run well at lower rpm’s good2
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Dean

'89 FJ 1200 3CV - owned from new.
'89 FJ 1200 3CV - no engine, tank, seat....parts bike for the future.
'88 FJ 1200 3CV - became a race bike, no longer with us.
'86 FJ 1200 1TX - sold to my boss to finance the '89 3CV I still own.
Millietant
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« Reply #4 on: July 19, 2022, 12:31:37 PM »

Also, if at all possible, get someone in the USA from here to receive and send on your parts from RPM (as a gift), it will save you a lot in taxes and admin fees.

My $24.99 carb screw and O ring kit ended up costing me $72 partly because these things. Lesson learned for me  good2
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Dean

'89 FJ 1200 3CV - owned from new.
'89 FJ 1200 3CV - no engine, tank, seat....parts bike for the future.
'88 FJ 1200 3CV - became a race bike, no longer with us.
'86 FJ 1200 1TX - sold to my boss to finance the '89 3CV I still own.
fj316
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« Reply #5 on: July 19, 2022, 12:40:42 PM »

Thanks for the guides and support pat, I'll try to get the carbs off the bike as soon as possible and make sure i follow the carb instructions. Unfortunately we also have ethanol fuel and the tank might be very lightly pitted but I'll do a closer inspection and see what needs to be done. Taking this rite of passage head on and being sure to ask on the way  good2

Will probably make a project thread on this since my older 85 1100 is due for retirement and this 1200 otherwise is in pretty decent shape. Thanks for the sharing of your project Waiex, beautifully detailed writeup! I'll take the pointers as needed and should anything be worse for wear.
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fj316
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« Reply #6 on: July 19, 2022, 01:00:10 PM »

Pat is 100% correct, you will become proficient at carb cleaning, removal and installation now that we have 10% ethanol in our fuel - this isn’t a FJ thing, it affects basically all pre 1990’s carb’ed bikes.

The very first tip I would give you, when you try to remove/re-install the airbox, is to remove the top bolt on each side that holds the rear subframe in place, and loosen the bottom bolt on each side - this will give you clearance you need to easily remove/put back your airbox.

Thanks I'll keep that in mind to get the airbox out easily


Also, if at all possible, get someone in the USA from here to receive and send on your parts from RPM (as a gift), it will save you a lot in taxes and admin fees.

My $24.99 carb screw and O ring kit ended up costing me $72 partly because these things. Lesson learned for me  good2

My trick for that is to make the order large enough to not make the shipping plus tax matter  biggrin I'll keep that one in mind too though for future purchases, but I feel the hassle factor both for me and the re-shipper is a tad too much for moderate purchases.
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Millietant
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« Reply #7 on: July 19, 2022, 02:28:42 PM »

Presumably your import duties and VAT are not as high as ours then ?

For us they’re almost an extra 25% on top of the price  good2
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Dean

'89 FJ 1200 3CV - owned from new.
'89 FJ 1200 3CV - no engine, tank, seat....parts bike for the future.
'88 FJ 1200 3CV - became a race bike, no longer with us.
'86 FJ 1200 1TX - sold to my boss to finance the '89 3CV I still own.
fj316
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« Reply #8 on: July 23, 2022, 09:31:30 AM »

The carbs are finally off the bike and I have managed to get a first look and done some initial testing by blowing into the fuel hose and gently closing the various floats. It holds pressure but one seems significantly more open than the other ones so there seems to be some clogging going on. And the rust caking indicates a look at the fuel tank and petcock is probably also in order. Looks better that one could suspect though apart from the rust-crud pebble that was in most of the bowls. So I probably need to take a closer look a the tank and make a project thread on this journey  yes



Presumably your import duties and VAT are not as high as ours then ?

For us they’re almost an extra 25% on top of the price  good2

Nah, we have the same import VAT so I'm really just keeping up a brave face  crazy

Now to complete the parts list and get an order off so I can hopefully have it back in shape in time for the work commute after the summer holiday  rofl2
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