Poor low speed running

[cyclobutch]

Forgive me if we've gone through this before, but I'm still trying to tick things off, a bit at a time. We're talking an '89 1200.

It's not really run right at lower revs since I got it last Spring time. I think it's probably worse in lower ambient temperatures. When I first bought the bike, because it was had not been used much in some years I did check the fuelling system. Everything was clean as a whistle. I have also since run a few tanks of carb cleaner through it anyway.

Symptoms are uneven running at very low engine speeds - I'm having to use the clutch on real low speed corners (roundabouts out here in the UK for instance). Also an occasional hesitance - misses a beat - when picking up at low speed from a closed throttle. Runs fine at the mid/top end.

The bike is an original 1200 and running Screaming Eagle loud pipes and K&N air filter element, I think every thing else is as it left the factory. First step I guess is to go back in to the carb and check the jets -what should I probably be running as a main and idle here? Any other pointers? Thanks.

[mayor]

first thing you want to do is see if the "tamper resistant" plug from the air/fuel screw is still there (plug may already be removed), if it is then you should remove it (carefully drill a small pilot hole, thread in a sheet metal screw into the hole, then pull the screw with a pair of pliers).   Turn the adjustment screw in and count how many turns it takes to become lightly seated (this will give you a reference for when you turn back out). I think your bike should have a 45 pilot stock, but I'm not sure. The 45 pilot should be what you need.  You may want to pull the bowl to verify.  Turning the screw in leans out the idle AFR, turning out richens up the mixture. Set the idle afr screw to about 3 turns out, then let the bike warm up- the adjust the screw out until the engine starts to stumble at idle, then back in until it starts to stumble (counting turns in the process).  Now split the difference between the two and check for a smooth idle.  I generally don't like settings of more than 3 1/4 turns out from lightly seated, since the afr screw could fall out while riding if turned too far out.  If you find best idle is 3 1/2 turns or more, switch to next larger pilot.  I generally run my idle towards the richer side of the sweet spot. 

hope this helps,
mayor

[cyclobutch]

OK

Pulled the carb on Saturday and had a look around. The main jet is a 200 which seems a little large from what I've read around here, though it seems to run alright at higher speeds. I also found an adjustment screw in front of the float bowl (inlet side) which I'm presuming is the one you're talking about. Unfortunately I was in the process of removing this when I realised it was a sprung adjustment screw, so I now have no idea how many winds out it was set to. Clearly any protection cap has previously been removed from this. Questions:

- Does the pilot jet sit behind this?
- How on earth do I get to this screw to make adjustment when the carb is on the engine and everything is hot?

[PC_Hater]

I increased the pilot jet to 45 on my 1999 1200S.
My 2000 1200S runs well enough so I haven't bothered looking...

Main Jet sizes for the bikes vary by market.
For HDI - that's you and me the 1200 had a 200 Main Jet.
For the USA it was 170 or 185 or 195 - they have EPA and run lean, we have noise to worry about!

1- the pilot jet doesn't sit behind the protection cap. You have to remove the float bowl.

2- remove the air cleaner, take care! I think I did mine cold and just twiddled around multi times until I was happy.

[cyclobutch]

Looking again I see I might be able to get to that screw with the carb on the bike. It's a bit tight with the exhaust balance pipe running just beneath though - I might need the oven gloves for this.

I'm left unsure on the pilot jet. I had the float bowl off when I checked the main jet of course and didn't see any thing that fit the bill. Would I have to remove the float to see this?

[mayor]

I'm left unsure on the pilot jet. I had the float bowl off when I checked the main jet of course and didn't see any thing that fit the bill. Would I have to remove the float to see this?

here, see if this helps 

[xlfan]

''Symptoms are uneven running at very low engine speeds - I'm having to use the clutch on real low speed corners (roundabouts out here in the UK for instance). Also an occasional hesitance - misses a beat - when picking up at low speed from a closed throttle. Runs fine at the mid/top end.''

Given you have the stock -89 carb, you would have an accelerator pump. Do you know if it works?

BTW, when you state ''very low engine speeds'', do you mean below 1500-1600 rpm? Personally, I don't like to WOT below 2500 rpm. If pickin' up slowly, I don't like to be below 2000 rpm for 2nd gear and up.

xlfan

[mokeypoole]

Have you checked the intake seals?  Spray them with WD40 while the engine is idling,  If the idle changes the seals are bad and need to be replaced.  These seals get brittle and start leaking from either age or overheating.  I have replaced several sets on many different bikes for boh of those two reasons

[cyclobutch]

Thanks for the input folks. I'll take another peer this coming weekend if time permits. Cheers.

[cyclobutch]

OK - Armed with those pics, plus a manual I've picked up, I located and pulled the pilot jet. This is numbered as a 35. Looked there may have been some muck in that so I blew it through before replacing it. One anomaly that I seem to have is with the accelerator pump. With the carb off but undrained I tried the throttle but had no spray of gas. With the carb in my hand I do not seem to have that pump on it. From both the pics above and the manual it looks as though I should have that extra circular fitting at side of the float bowl. Mine does not have this. Other than that the carb does look the same. ? The bike is registered here as an '89, though where I'm seeing date stamped parts they're all marked up as '88. The carb does have HD logos cast in to it, rather than Keihen (sp?) or whatever.

Went for a test drive with around a zero ambient temp. I've got the mixture screw set at 3.5 turns out at the moment and it may be a little better than it was, though could still improve. Maybe a change to a 45 jet then. I cut down a screwdriver to make adjustments with the carb on, but that still doesn't look like a good place to work when the header pipes are hot.

[mayor]

the early CV's (-88) did not have the accerator pump (that circular area on the float bowl).  You probably have an early year '89, and they were probably using up old inventory.  The early non-acc pump CV's is where the famed sporty needle came from.   

35 pilot?  I didn't know they existed.     if it is a 35, try putting a 42 in and see what that does.  A 42 pilot shouldn't be too hard to find.  If you have any buddies who put jet kits in their bikes, they probably have one lying around.   

If your bike still has the stock crossover pipe, adjusting the afr screw can be kinda painful when hot.   


As mentioned earlier, you might also want to check to see if the intake seals are still ok. 

If it is the carb, you can always take the easy way out and try to find a newer style CV that has the pump.   

[PC_Hater]

Are you sure it started out as a 1200 and is not a converted 883?

The VIN number on your sportster starts with either
1HD1 = 1200cc
or
1HD4 = 883cc

then two letters to indicate the model
C? = MODEL

then a letter to tell you the displacement
M = 883
P = 1200

The part number for the 45 pilot jet is 27170-89, the 42 pilot jet is 27171-89.
There is a 40 pn 27821-92, the 35 is 27117-88.

Checking my notes to find this info my 1999 1200S had a 42 but I fitted a 45 pilot jet.

Buy the parts manual for your bike!

[cyclobutch]

Thanks folks.

VIN number runs 1HD1CAP... which I guess shows it as an original 1200 at least. I have comprehensive history on this one so that is as I expected.

I don't have any pals running HD, I'm a bit out on a limb with this one - so will order up a jet. Think I'll replace the diaphragm whilst I'm about it, I'd presume it's running the original. Also, on air leaks I'd expect misbehaviour in other areas if much was going on there, but we'll see.

Of manuals, all I have is a Haynes that I've picked up. Covers all Sportsters from 1970 until quite recently so you do have to pick the relevant bits out.

I've had enough trouble with this bike that it's on third strike now so I'm not going to want to spend much more money until I've had some miles out of it. I've got enough projects on the go as it is and this was never supposed to be one of them.

[PC_Hater]

Fitting a new diaphragm is an awkward job.
My 1200S was so badly tuned by the dealer I went to a man with a dyno who knew what he was doing.
He ended up having to call DynoJet UK for help.
Long story short - with the right bits everything worked.
My bike needed a DynoJet slide but you re-use the original diaphragm. Watching him remove it was so terrifying I went for a walk until he had finished.

The Haynes manual will cover most things for you. The parts manual has pictures and part numbers so you don't have to rely on the idiot down the end of the phone line or on the parts desk to know what they are doing. With a couple of honourable exceptions - they don't know what they are doing.

[cyclobutch]

Hmmmm - I'd kind of figured that the diaphragm would be a straight forward swap out, may have to rethink on that./ My concern here was that given it's age - I'm presuming that it is the original, I'd prefer to replace it in the garage now than have it strand me at the side of the road somewhere.

Meanwhile I took the bike out for a run last night. About 15 miles each way in freezing conditions (frosty). Managed to convince myself that whilst not perfect it was at least improved. Stopped about three miles short for gas on the way home. On restarting it was awful, needing some stick just to haul off the forecourt. Rs. I think pulling a bit of choke on cleaned it up a little.

Another bit of muck gone through and blocked the jet? I have previously checked the tank and tap and it was all pretty clean. I don't recall now but I'm thinking that there will be a gauze on the tap, is there anything to strain the bits out at the carb end?   

[PC_Hater]

Are you sure the carb isn't icing up?
Mine did that a few times in cold weather. I wondered what on earth was happening the first time.
It was as I left the motorway, by the time I was at the end of the slip road the bike was barely running. I had to pull in and wait until the bike would start - which was after the engine heat had melted the ice!

If you stretch the diaphragm a bit and hold it up to the light you can see if there are any pinholes. No pinholes, leave it alone.
Problems with the diapgragm should affect high speed running a lot more than low speed running. It did on my SAAB. Started and ticked over lovely but wouldn't rev enough to let you drive away. The holes in the diaphragm were not hard to see! That was 20 years old and done 140,000 miles when that happened.

[mokeypoole]

Did you check the intake seals where the intake manifold goes into the engine?  You can work on the carb all day long but if the seals are leaking, it is not going to get any better.  It will skip and pop at low speeds.  It may also idle real fast when you pull out the choke.

Its just 4 more bolts to remove the intake after you have the carb off.  Before you take it off, mark the manifold and flanges so you can get it back together in the same position.  If you have the o-ring type seals, coat the seals in vaseline before u put them on so that they don't get pinched during installation.

[cyclobutch]

Well it was OK rolling onto the forecourt, and idled OK until I turned it off. I did wonder vaguely about fuel vaporisation tucked in as it is to the middle of the V, but it was OK last Summer. Icing - from what I've seen I don't think so. But ...

Looking at the manifold it looks like a plastic/rubbery two into one arrangement - all one piece from what I can see. Rather disappointing - I'd hoped for a nice casting there (got too used to Italian machinery I guess). I've experience leaks before on other bikes and it just doesn't feel like that. But as you say; whilst I'm in there ... I shall be pulling it out again to stick a 45 in anyway.

Of the diaphragm the replacement was just for piece of mind - I'm sure that's not a problem right now. Just don't want it letting go next time I'm out in the middle of France somewhere. Sounds like I'd be best off just packing the spare and worrying about it as and when.

[mokeypoole]

Ok, you have the early evo type manifold and seals. 
I guess it looks like the one on this page

http://www.network54.com/Forum/47852/message/1277578661/evo++intake+manifold+for+sell

I am not familiar with those intakes but they were later upgraded to the intake on this web page.

http://i66.photobucket.com/albums/h257/Lumpy88/RoadKing%20top-end%20rebuild/IMG_9847.jpg

You can see how the seal is gone in the image.

You may still check with the WD40 method and if your system leaks, you may want to get a manifold like the newer one and upgrade your bike.

[andyxlh]

hello mate,
you really are having no luck with this bike! I must admit mine has caused a few problems over a few years, but never like this....
Just my couple of cents worth:
the 35 idle jet - never heard of it but would be way too small I would think - try a 42 or 45. If you have to buy one they are really cheap even OEM.
the intake - my '89 (october) has the later type of intake which is a metal casting with rubber seals. This works well and seals last 10+ years with me (2 sets from new). the rubber one in the referenced photo does look rubbish. I would have thought this would be a cheap part to find on ebay, try to get all 3 pieces (the metal castings which bolt to the head too).
the part numbers are:
27004-88A - manifold
27009-86A mounting flange front
27010 -86A mounting flange rear - as they are '86 parts you shouldn't need these as they should be the same as on your bike.
the main jet - I'm not an expert here, but 200 seems awful big for a 1100. However, as you have the older carb without the acc jet that might be correct.
I have not seen a diaphragm problem with this carby, may be others have. mine has not been replaced.
Once these get set up they run really well and tend to hold ther state of tune, as long as you haven't backed out the idle mixture screw too far!
cheers
Andy
Sydney

[cyclobutch]

Stuck the new 45 jet in on Saturday and got her out for a run late yesterday afternoon. Again in pretty cold ambient conditions. This bike does take a while to warm from cold compared with what I'm used to. Anyway, on first impressions all seems a whole lot better. As a start point I ran the slow run jet in from 3.5 turns out to 2.5 turns out at the same time. I suspect that will need a little more tweaking, I'll just need to pluck up my courage and get in amongst the exhaust balance pipe to work on that.

On a point of luck with this one - I also got my speedo back from a very expensive repair as the needle had fallen off so fitted that at the same time. Lasted just 15 miles before sticking at 60 per regardless of doing 90 (according to the bicycle speedo I still have clipped on) or zero. And even giving it a beating with a stick when I got home. Doh.

[andyxlh]

probably worth taking the speedo back to the repairer, getting the cash back and getting a secondhand one from eBay usa for less money!