Fired up the 4AY 1990 1200 a few nights ago to ride to a VJMC gathering at Harry's Cafe de Wheels in Newcastle. It hasn't been getting much use lately as I've been enjoying my 1100 since I got it registered.
It started easy enough in the usual manner. Full choke, hit starter and it runs. I went away to get my riding gear on while it warmed up but within, say, half a minute the revs went up to about 3000. The revs usually rise a little as it warms normally but this time it was quite sudden.
I knocked it back to half choke and all was ok, normal again. With my gear on I'm set to ride off and I normally shut the choke off completely and ride away. This time, as soon as I shut the choke off it stalled. Hmmm. Gave it a little choke and restarted, into gear and rode off down the street but all was not well. It was running rough as guts. Got to the main road at the end of our street and gave it some throttle and it accelerated really well but as soon as I backed off it went to running rough again. So I do a U turn and come back home and put it back in the garage. Swap to the 1100. All sweet.
So today I decide to have a look at it. I'm thinking there's some dirt got into the carbs but before I dive in I thought I should get some opinions and, possibly, eliminate any other problems.
Sorry this is a little long, are you still with me?
So today I decided to take notes on starting it up again. Here goes.
Ignition on, full choke, hit starter and it starts normally and is idling at 1500. After about half a minute it slowed to about 1200.
After about a minute I push the choke in slowly to about half way and the revs rise to 1800. I then pushed the choke in all the way and it stalled.
Restarted it with half choke and its idling on 1800. Push choke in to about one quater and idle dropped to 800 then within less than a minute it slows and stalls.
So, in short it wont start or idle without at least half choke. It also seems reluctant to restart unless I start pumping the throttle.
I then let it cool down and took the tank off with the idea of draining some fuel to look for any water contamination, there was none.
I also pulled the plugs. They were all barely finger tight which was a surprise as plugs usually need a little effort to 'crack' them free. The PO kept a log of its service and it showed these plugs have done almost 15000klm so time to replace. Took some pics of the plugs and they seem normal (considering the above). I replaced the plugs and nipped them up properly but it made no difference.
What's the consensus on plug type? My NGK book says DP8EA but it has DPR8EA in it. R=Delta ground electrode, is that significant.
Plugs are pictured 1-4 left to right.
Adding pics, again. oops, need to resize
Sounds like dirty pilot jets to me. :morning1:
George
How old was the fuel? Did you try fresh fuel?
I don't know about the fuel you get down there...Does it have ethanol in it? (hopefully not) If it does have ethanol in it, don't store your bike with ethanol laced fuel, especially if you have the luxury of choice to buy non ethanol fuel.
Sounds typical of choke circuit and idle circuit obstructions. Time for r/r and cleaning. Pay attention to the fuel pick up point for choke circuit located at the bottom of the carb bowls along with the Pilot jets and needle jets (aka emulsion tubes, jet nozzles, etc)
How old is the fuel filter on your '90?
Quote from: Pat Conlon on January 21, 2016, 08:23:49 PM
How old was the fuel? Did you try fresh fuel?
I don't know about the fuel you get down there...Does it have ethanol in it? (hopefully not) If it does have ethanol in it, don't store your bike with ethanol laced fuel, especially if you have the luxury of choice to buy non ethanol fuel.
Sounds typical of choke circuit and idle circuit obstructions. Time for r/r and cleaning. Pay attention to the fuel pick up point for choke circuit located at the bottom of the carb bowls along with the Pilot jets and needle jets (aka emulsion tubes, jet nozzles, etc)
How old is the fuel filter on your '90?
Thanks for the tips.
I never use ethanol fuel. I use ULP95. Recently I started my 76 CB750F1 for the first time in over a year. Didn't add any fresh fuel. It fired up first stab on the button and idled happily. Same fuel.
+1 pilot jets.
Diving in!
Now to get that airbox out.
Quote from: krusty on January 21, 2016, 07:02:06 PM
What's the consensus on plug type? My NGK book says DP8EA but it has DPR8EA in it. R=Delta ground electrode, is that significant.
Plugs are pictured 1-4 left to right.
NGK DP8EA9 is the correct plug the "R" is a resistance plug and makes no difference - either will do...... the 9 on the end is the heat range.
Cheers
Harvy
Yeah, I agree with Pete, pilot jets are clogged.
And, the "R" in the plug type stands for Resistor. Unless you have changed your ignition wires and caps, keep the R.
Your plugs look pretty carboned up, probably due to the choke being ON before you removed them.
Consider the value of your time vs the cost of UNI DualPod foam filters. They pay their way very quickly :-)
R = Resistor of course, thanks for pointing that out. Prefer to keep it stock. Looks like I don't have to remove the airbox to remove the carbs.
As I mentioned the plugs have done almost 15000klm which is their replacement interval according to my book. Haven't changed anything but this bike looks totally stock so I'll replace with same. I've only had this bike just under 12 months, it replaced another of same model and colour that was nicked.
Found this:
https://www.youtube.com/watch?v=CbWAAyz4mFc (https://www.youtube.com/watch?v=CbWAAyz4mFc)
SuperCheap carries DPR8EA-9 plugs. They'll probably have a 20% off sale for AusDay if you can wait.
There's a Supercheap 5 mins up the road. It'll prolly take that long for me to do the carbs. Thanks
Quote from: krusty on January 21, 2016, 10:13:38 PM
Found this:
https://www.youtube.com/watch?v=CbWAAyz4mFc (https://www.youtube.com/watch?v=CbWAAyz4mFc)
Interesting to note in the video that he removed the throttle cables from the grip instead of the carbs,( seems easier) but he didn't lower the subframe and seemed to struggle a bit to get the carbs out ( harder). Like to see him getting them back in.
Its good to see how other people tackle things and if it seems easier adopt that practice. As the saying goes, work smarter not harder.
Krusty,
I didn't notice any mention of draining your float bowls. I would.Also,before you go to all the bother of carb r&r, it's simple to remove the mixture screws, the springs washers and "O"rings (After you've made sure to clean off the carb tops) A good shot of compressed air down each hole is often effective in clearing out the pilot jets.In the hundred times I've done this it has never caused any damage to a carb diaphram. If you do remove the carbs, you do know that lowering the rear subframe makes the job easier, right?
Harvy
The heat range is the 8, after the D.The -9 refers to the gap or tip design. At least that's what NGK would have us believe.
Jeez Earl, you've read my mind. As a matter of fact I have pulled the mixture screws and was about to post the question "Is it ok to use compressed air?". You just answered it.
I followed the procedure in the video but couldn't get the rack out and didn't want to force it so I've just left it loose for the moment. Besides it was too bloody hot out in the garage and my back was starting to play up.
I forgot to mention that I haven't drained the carbs but I did run the engine with the tank off for a while. I've read about lowering the frame so I'll keep that in mind if I have problems. looking like its the 1100 for this Sundays' VJMC fish and chip ride to Patonga.
Just unbolt those 2 large side bolts on the rear sub frame, unbolt the bolt on top of the air box and rotate the rear sub frame down. Finish unbolting that air box and remove the box. Only takes a few min and makes it a lot easier to remove and install the carbs. Forcing them like in the video IMO increases the chances of damaging parts.
Note on your mixture screws be careful each screw has an spring, O ring and a washer. Easy to loose the very small washer and or the O ring.
George
Spray some carb cleaner in those holes and follow that up with compressed air
Quote from: Earl Svorks on January 22, 2016, 01:12:31 AM
Krusty,
I didn't notice any mention of draining your float bowls. I would.Also,before you go to all the bother of carb r&r, it's simple to remove the mixture screws, the springs washers and "O"rings (After you've made sure to clean off the carb tops) A good shot of compressed air down each hole is often effective in clearing out the pilot jets.In the hundred times I've done this it has never caused any damage to a carb diaphram. If you do remove the carbs, you do know that lowering the rear subframe makes the job easier, right?
Harvy
The heat range is the 8, after the D.The -9 refers to the gap or tip design. At least that's what NGK would have us believe.
Correct Simon.... my mistake:
http://www.ngk.com.au/spark-plugs/product-information/part-numbering-system (http://www.ngk.com.au/spark-plugs/product-information/part-numbering-system)
Cheers
Harvy
Quote from: movenon on January 22, 2016, 09:37:24 AM
Just unbolt those 2 large side bolts on the rear sub frame, unbolt the bolt on top of the air box and rotate the rear sub frame down. Finish unbolting that air box and remove the box. Only takes a few min and makes it a lot easier to remove and install the carbs. Forcing them like in the video IMO increases the chances of damaging parts.
Note on your mixture screws be careful each screw has an spring, O ring and a washer. Easy to loose the very small washer and or the O ring.
George
That's nicely explained, sounds much simply/easier.. I'll give that a go if the compressed air fix doesn't work.
Quote from: movenon on January 22, 2016, 09:37:24 AM
Just unbolt those 2 large side bolts on the rear sub frame, unbolt the bolt on top of the air box and rotate the rear sub frame down. Finish unbolting that air box and remove the box. Only takes a few min and makes it a lot easier to remove and install the carbs. Forcing them like in the video IMO increases the chances of damaging parts.
Note on your mixture screws be careful each screw has an spring, O ring and a washer. Easy to loose the very small washer and or the O ring.
George
Managed to extract all those little bits without losing any.
Went to Supercheap this morning for their 20 percent off sale which ends today. Bought 4 x DPR8EA-9 and 4 x D8EA for $3.99 each. The D8EAs are for my CB750.
I happened to notice the fuel filter attached to the bottom of the tank. Do they have an auto equivalent of do I need OEM?
Quote from: krusty on January 22, 2016, 05:49:46 PM
Went to Supercheap this morning for their 20 percent off sale which ends today. Bought 4 x DPR8EA-9 and 4 x D8EA for $3.99 each. The D8EAs are for my CB750.
I happened to notice the fuel filter attached to the bottom of the tank. Do they have an auto equivalent of do I need OEM?
On the fuel filter I would recommend the stock Yamaha filter. Been down that rabbit hole. In this instance because of it's location under the tank and on top of a hot engine I say don't risk using an adapted unit. There are the hose fittings and also some of the auto filters appear to use a pretty thin plastic shell that may not hold up well under heat. I am all for cutting costs but on this one I say use a stock Yamaha filter. Its not like anyone replaces it every year. I bet there are some many years old still working in the bikes. Some owners are not even aware there is a fuel filter there (only applies to the fuel pump models 88-93)
George
Krusty,
You may be wise to this already, another reader may not.
A good dab of your favorite grease will serve to hold all them little bits on the pointy screw when you put them back into the carbs. The grease will make installation easier. It will also help prevent seizure of the screws into the carbs. The little rubber bungs Yamaha installs at the factory often seem to go missing. If they are absent, without grease water will accumulate in the bore. I have had some real struggles with mixture screws that were seized in the carb. Ya' don't wanna' go there.
I believe an update is due.
I have removed the pilot screws. Blue-Tack worked well for that and some fine copper wire hooked out the spring, washer and O rings that didn't come out with the jet. Using a syringe I injected some Wynnes injector and carb cleaner in the pilot jet holes then left it for a while. Later on I used the compressed air as previously suggested. I'm not going to pull the carbs, just yet. I then put everything back together.
When this problem first raised its ugly head I had only ridden the bike a short distance so' today, with Australia Day holiday long weekend out of the way I decided to take it for a longer run, give it some berries, and with any luck possbly blow the problem away. Wishful thinking? Yep.
First off, when I went to start it fuel was running out onto the floor - I'd forgotten to do up the drain screws. I blame 'Old-Timers' for that. :dash2: Fixed it and then started it up. Fired and ran first go on half choke.
So off I go down the street headed for the Pacific Highway out of Swansea. After a couple of ks I could shut off the choke but had to keep the throttle on a bit to stop it stalling. Pulled over and adjusted the idle screw so that I could get close to an idle without it cutting out. Made it through Swansea and onto the highway proper, 100kph limit, and wound it out. It went like an FJ should. Accelerates as normal and no problem sitting on the speed limit. Ran it up and down through the gears and rpm range. Cruised into the little historic mining village of Catherine Hill Bay which is about 10ks from home. Then rode back to Swansea turned around and back to catho bay again. Back to Swansea.
https://www.google.com.au/maps/place/Swansea+NSW/@-33.0899591,151.6169469,14z/data= (https://www.google.com.au/maps/place/Swansea+NSW/@-33.0899591,151.6169469,14z/data=)!3m1!4b1!4m2!3m1!1s0x6b7323df69e4aaa7:0x5017d681632f4f0?hl=en
Swansea, at the entrance to Lake Macquarie, has an opening bridge across a channel from the lake that runs to the Pacific Ocean and the bridge was up, to let cruisers and yachts in and out. The bridge was up and there was about a 400 metre, double lane queue of traffic waiting. I was able to filter between the staitonery cages to the front without problem but while waiting for the bridge to close the engine was constantly threatening to stall.
A few minutes later I was home and the miracle I was hoping for had not happened. The bike won't idle. I checked the idle adjusting screw and found I had wound it all the way in. It's looking like these carbs are gonna have to come off.
All this time I've been wondering why this has occured so suddenly. Considering the fuel is filtered before it enters the carbs. I drained some from the tank and it looks clean, even when I ran it through a tissue filter into a jar (grabbing at straws). There's no water contamination evident.
Situation now is I'm giving the carb cleaner and compressed air one more go and if that's not enough there's nothing left but to go into the carbs.
BTW, the new plugs are in.
Another VJMC ride last |Sunday, 250klm of fun on the 1100.
Please forgive the dumb questions. Did you remove the pilot jets and then clean them or just wash fluid down the holes ? They need to be removed to get them clean. We are talking pin head diameters here in the pilot jets so it takes almost nothing to plug one or more up. You didn't mention anything about syncing the carbs or how you adjusted the fuel air screws.
George
Quote from: movenon on January 27, 2016, 02:05:01 AM
Please forgive the dumb questions. Did you remove the pilot jets and then clean them or just wash fluid down the holes ? They need to be removed to get them clean. We are talking pin head diameters here in the pilot jets so it takes almost nothing to plug one or more up. You didn't mention anything about syncing the carbs or how you adjusted the fuel air screws.
George
[/quote
Yes, jets removed and cleaned. PO log book showed synch not too long ago. Before removing the airscrews I wound them in and counted the turns making a note of each in pencil on top of the card vac covers.
My advice is to set all the fuel air screws to 2 1/2 turns out and then sync the carbs. If it improves then do some blip testing watching the tach. If you readjust the fuel air screws then re sync the carbs again. You will probably have to adjust the idle as you work through the adjustments. Final idle should be around 1100 RPM.
The PO's intentions were probably good but better to set the base line yourself. "trust no one, demand proof" :).
You can build a tool to sync the carbs cheaply if you don't have a commercial tool. IMO anyone that owns an FJ should have one.
George
All the PO's servicing and tuning has been done by Yamaha dealer.
Interesting to note that air screws were set between 3.75 and 4.25 turns. I have a set of Honda vac gauges which I've used on my Honda 4s. Before this problem started the bike was running fine and very smooth.
Quote from: krusty on January 27, 2016, 01:47:15 PM
All the PO's servicing and tuning has been done by Yamaha dealer.
Interesting to note that air screws were set between 3.75 and 4.25 turns. I have a set of Honda vac gauges which I've used on my Honda 4s. Before this problem started the bike was running fine and very smooth.
3.75 -4.25 is pretty rich. I would go down to 2 1/2 turns as a base line. Then sync the carbs. See if it improves things. Nothing like knowing for yourself.
George
Checking my manual it shows 1984-1990 2 turns.
1991 on 3 turns.
My bike is 10/90, 4AY (3XW) so which applies, 2 turns or 3.
That said, 2.5 turns would be a starting point.
IF it were as simple as 2 turns or 3 turns out, then for your bike it would be 3 turns.
HOWEVER, those are merely starting points. Yamaha set the mixture individually for each cylinder using an EGA.
If you or the PO has changed the relative positions, then you have to start somewhere and 2 or 2.5 or 3 is a starting point. You'll need to do a "blip test" to fine tune (assuming you don't have an EGA)
Also, unlike the Kehin carbs on the Honda, these are mixture screws not air bleed screws. They control how much additional mixture is allowed into the engine at idle. So, further opening allows extra air & fuel both into the engine.
Arnie
The bullet has been bit. I've had the carbs out, cleaned them, reinstalled and synched. A few points noted in the process.
First off, I used the above recommended method off removing the rear sub-frame bolts and tilting it back. I couldn't move it very far but enough to make the job much much easier.
With airbox removed I took out the airfilter. Hmmmm. PO has done regular oil & filter changes (according to his log book) but has neglected the AF. It's done 40000ks since it was last replaced (whoever last replaced it had written the klms on it with a marker), the foam was disintegrating and paper filthy. Also noticed the airbox had been out before because the crankcase breather was not attached (it still isn't).
With the carbs on the bench it wasn't long before I had all the boowls off. Except for brown sediment in the bottom of the bowls, they were very clean looking. Then I pulled the pilot jets and found the cause of the idling problem. Although not totally blocked there was enough crud to cause my problem. The pilot jets only have the one hole in them, unlike some that have extra holes in the sides. I soaked them overnight in solvent and then gave then gave them some time in an ultrasonic cleaner. I also removed the main jets and they were perfect. I also checked jet sizes and they were all stock.
Jets and cleaned up floatbowls were all reassembled and the carbs and airbox refitted. I happened to have a few spare airfilters left, from some that were given to me a few years ago, so one of them went in.
No problems putting everything back together and, on restarting the bike was it again idling properly BUT it now had an obvious rattle that indicated synching was needed. This was all a couple of days ago.
Today I resynched the carbs. It all went smoothly (under an hour all up) and now the rattle has gone and it idles just like it should.
Will give it a test ride in sometime this week and I'm confident all will be well.
Thanks to you guys for your info and advice with this job that I was a little apprehensive about tackling.
I now have the confidence to do the carbs on my 1100 that hadn't been touched since 1998.
Now you are on the right track :). Never trust what a PO has done. Don't think the "Yamaha" shop knows everything either. No substitute for knowing yourself :) Best you become the expert on your bike especially with the older bikes.
George
^^^ +1 to what George said.
My experience (years ago) with the service dept at a local (now out of business) Yamaha dealer proved that the kids know very little about the workings of our CV36 carbs..
Lesson learned, never again..... It was 17 years ago and thinking about it still pisses me off :ireful: Got to let it go....
Today I plunged into doing the carbs on my 1100. Happy to say all went well. Pretty much the same story as the 1200. Nothing untoward was found. The carbs were very clean considering this bike had stood for 15 years before I bought it last year. With everything buttoned back up I took it for a 20klm run and all is good, only needed slight adjustiong of the idle screw.
Something I just remembered, the mixture screws were wound out three turns but the book says 2 turns. I reinstalled them with 2 turns. I'll do a sych on it later as its running pretty smooth at the moment. Have been running Valvoline Injector and carb cleaner in it since I've been riding it.
Before and after pics of the bowls.