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General Category => Yamaha FJ1100 / FJ1200 Running Problems => Topic started by: Stevelmk on September 10, 2019, 07:20:39 AM



Title: real rough running fj11 85 model us import
Post by: Stevelmk on September 10, 2019, 07:20:39 AM
Hey people
I am A REALLLY GREEN HOME MECHANIC  :Facepalm:


I have an 85 FJ1100
it has a 4into1 Remus system and
cheap pattern Chinese pods
new battery put in this week
serviced with new oil and filter when i bought it plugs that were in it looked okay so i did not change them
really thirsty bike and i wondered can i get advice tried to give as much detail as i can below cheers for the replies

got if a few months ago besides a few weeks driving its been sitting out back not driven

the bike was driving but not great really heavy fuel consumption for an fj i believe all motorway miles in top gear at cruising speed and the bike would be empty in 139 miles. i do not drive it on at all if i did drive on blow through half a tank in 60 miles give or take. Reason it off road now is i was driving and after about 20 miles it suddenly bogs down and no matter how much throttle you give it just died and i had to get it towed home.

I have  never attempted  carbs before took them off and ever screw top and bottom the threads are burnt i got into the carbs the floats are set to factory spec the main and pilot jets seem to be clean  all in good con there was a very small bit dirt in some of the main jets i blew through every hole with carb clean and a carb cleaning  brush as well as compressed air. The old pattern pods are toast so  i had to buy another set to keep me going till can buy rpm ones.  the one diaphragm that i could get access to had a clip on the needle that was 4 clips down i don't know does that make any sense to anybody there were no holes in the diaphragm when put it up to light all four vales open and close i bench synced the carbs just waiting on my pods to come to fire up and hope that it runs.

usually i take to a mechanic but cant afford one so all me this time just want it on the road and enjoying it


Title: Re: real rough running fj11 85 model us import
Post by: Pat Conlon on September 10, 2019, 09:05:51 AM
Welcome Steve, we have lots of info. for you to read down in our Carburetor Files section.
Best advice I can give you is to take your time and do it correctly. RPM also offers a carb cleaning service for you if you get stuck.
Spend $24 and get this kit: http://rpmracingca.com/proddetail.asp?prod=carbkit (http://rpmracingca.com/proddetail.asp?prod=carbkit)
Throw away all those old soft JIS screws and use these ss Allen’s.
Be sure to replace the float needle seat O rings.

Re: bog down and dying, I think you may have a fuel delivery problem.
1) Your vacuum petcock going bad: http://rpmracingca.com/proddetail.asp?prod=M%2FC%3A36Y-24500-01 (http://rpmracingca.com/proddetail.asp?prod=M%2FC%3A36Y-24500-01)
2) You have a fuel line incorrectly routed and it is getting pinched when hot.
http://www.fjowners.com/index.php?topic=18286.0 (http://www.fjowners.com/index.php?topic=18286.0)


Title: Re: real rough running fj11 85 model us import
Post by: Motofun on September 10, 2019, 11:00:54 AM
Also, perhaps, too much heat getting to the float bowls?  20 miles is enough for everything to get hot.  There should be a heat shield between the barbs and the engine.


Title: Re: real rough running fj11 85 model us import
Post by: Stevelmk on September 10, 2019, 01:08:39 PM
Moto fun will have a look at that tomo pissing rain here at mo. Hey thanks pat when I have the funds will definitely buy that kit nice upgrade the stock ones are like butter so soft


Title: Re: real rough running fj11 85 model us import
Post by: Tuned forks on September 10, 2019, 04:07:12 PM
Patrick, is it possible since he reported really poor fuel mileage, that the diaphragm in his fuel petcock is/was leaking and therefore sucking fuel directly into the engine?

Joe


Title: Re: real rough running fj11 85 model us import
Post by: Pat Conlon on September 10, 2019, 04:12:48 PM
Good deal Steve...that RPM kit has to be THE best deal in motorcycling.

Joe: Not sure what you mean about  “sucking fuel directly into the engine”. The only path for the fuel is through the carbs...even with a dodgy petcock...but Yes, a leaky petcock can cause all kinds of grief although Steve did not mention anything about pissing gas when the bike was parked.
I was also thinking about the poor fuel mileage. I’ll bet a jelly donut that the carbs are out of sync. so Steve, once you get your carbs sorted and bike running, check your carb synchronization.

I didn’t see anything you posted that mentions no heat shield....which is needed.

Also Steve, while your bike is down for carb repairs, check your valve clearances. Adjust the shims as needed.
It is always a good idea to check your valves before you sync. your carbs. I have found that correcting valve clearances can change the airflow into that cylinder. When that happens the air sync. thru the carb also changes, so do your valves first, then sync.

Cheers. Pat


Title: Re: real rough running fj11 85 model us import
Post by: RPM - Robert on September 10, 2019, 04:39:13 PM
Gearing will affect fuel mileage if its got big sprockets.

If the emulsion tubes and or main jet needles are worn out, it will also decrease the fuel mileage.

 Just a couple ideas on the fuel mileage issue.



Title: Re: real rough running fj11 85 model us import
Post by: ryanschoebel on September 10, 2019, 09:01:41 PM
Gearing will affect fuel mileage if its got big sprockets.

If the emulsion tubes and or main jet needles are worn out, it will also decrease the fuel mileage.

 Just a couple ideas on the fuel mileage issue.



Follow up question to the heat shield. I havent fitted the one I bought yet, and keep kicking myself for not finding the time to do it. Could this affect throttle response? My bike just doesnt seem to have the same snappy response once the engine is thoroughly heat soaked. Could this be the heat shield, or the fact that I havent sent the carbs in yet? Cause I keep meaning to do that too haha


Title: Re: real rough running fj11 85 model us import
Post by: Pat Conlon on September 10, 2019, 10:02:59 PM
Poor Throttle response from hot carbs? I don’t know Ryan. I’ll let others chime in..
 I do know you can boil the gas in the carbs from the engine heat. Summer heat, stop and go, slow traffic absolutely the worst case scenario.

In the olden days we had cars with carbs which suffered from what we called “vapor lock”, gas boiling off into vapor in the fuel line and carb bowls. Stalled many, made hot starts impossible.
We would heat insulate the fuel lines and put a phenolic spacer (special type of heat gasket) between the carb and intake manifold.

Engine heat and carbs do not play well together, they never have.


Title: Re: real rough running fj11 85 model us import
Post by: Stevelmk on September 11, 2019, 12:52:27 AM
Good deal Steve...that RPM kit has to be THE best deal in motorcycling.

Joe: Not sure what you mean about  “sucking fuel directly into the engine”. The only path for the fuel is through the carbs...even with a dodgy petcock...but Yes, a leaky petcock can cause all kinds of grief although Steve did not mention anything about pissing gas when the bike was parked.
I was also thinking about the poor fuel mileage. I’ll bet a jelly donut that the carbs are out of sync. so Steve, once you get your carbs sorted and bike running, check your carb synchronization.

I didn’t see anything you posted that mentions no heat shield....which is needed.

Also Steve, while your bike is down for carb repairs, check your valve clearances. Adjust the shims as needed.
It is always a good idea to check your valves before you sync. your carbs. I have found that correcting valve clearances can change the airflow into that cylinder. When that happens the air sync. thru the carb also changes, so do your valves first, then sync.

Cheers. Pat
 

No leaking petcock the fj no longer has a fuel tap that it came with from factory will take a pic Tomo it has fuel line coming from tank then a tap with an open close position. It could well be the fuel boiling. As when taking the tank off the length of fuel hose just lay on the carbs not really routed. Tbh I never really had to route a fuel pipe on a bike before. So never thought bout it. Valve clearance is next on list so hell if I can strip carbs I can try a valve clearance


Title: Re: real rough running fj11 85 model us import
Post by: Stevelmk on September 14, 2019, 12:54:53 PM
The beast lives put it all back together today after cleaning fired on 2nd crank nice strong idle at 1100 no backfires. Shot up the road like crap off a stick