Lumpy running XS1100 lump

[catdna]

Hi All

First time poster to this forum, but I've been reading it on and off for a while now.

I'm the proud owner of an XS1100 based trike :





The carb main jets have been 'upped' to 145 (because of the K&N style filters and the 4-1 exhaust), but it's still 'lumpy' at the bottom end - poor acceleration unless I crank it open a lot - it seems fine above 3-4000 revs though - just recently I've been getting the odd mis-fire (quite a loud one at times). I balanced the carbs recently and it didn't really make a difference to the 'lumpyness'.

The engine has done approx 20,000 miles before it was put in the trike - no idea of it's history / past abuse, but everything under the rocker cover looked nice and clean - no weird noises from the engine.

Plugs seem fine - not too dark or too light, but I have had a weird 'carb spillage' issue now and again if I leave the fuel switched on - doesn't happen all the time, but sometimes one of the bowls has been leaking.

I know it could be a multitude of things, but wondered if anyone has any other suggestions ?

So far I'm considering :

upping pilot jet by a size
checking needle height
checking float bowl height
checking timing (is this possible on an XS11 ?)

I'm not that good with maintenance - completely self taught (enough to be dangerous ;-)), but willing to give anything a try.

Cheers
Chris

[petejw]

Hi Chris,
Welcome to the board, nice trike.

Im assuming by the size of the main jets, you have an early model xs engine, check the engine number to confirm what model its from. The carbs differ between early and later models.

With your carb issues, the air filters, are they actually KnN or cheap egmo filters, the cheap filters have a rubber lip on the inside that restrict the rear ports of the carbs.

The fuel leak needs to be repaired, this is usually caused by fuel seeping past the needle and seat, this could cause the carb to run rich, backfiring under throttle.
Also check your float heights, float height affects acceleration to around 4000

Check your oil level, if fuel has leaked passed it can also enter ur engine, if theres a heap of fuel in the engine mixed with the oil the bike wont idle or idle ruff.

What size pilots are you running?

The 78 model can have the ignition timing adjusted cant remeber with regards to the 79 later models arent adjustable, not to hard 2 check, just remove the left side cover, the ignition is in there, look at the timing plate itll have 2 ellongated holes in it for adjustment.

hope this helps you out.

[DGXSER]

The fuel leaking is typically a sticking float needle valve inside the bowl. Typically pull the carbs and clean the fuel lines, Tees, bowls, everything in general by the time you get that far into them. Which may well cure your lumpyness, by cleaning up the pilot jet system.

As to timing, it all depends what year engine it is. What is the code on the engine, just above the oil fill on the flat area is the engine number. If it starts with 4RO it is an 81 engine and will have little to no timing adjustment. Otherwise, it can be adjusted.

[tarzan]

You can actually adjust all years timing,on later ones you just have to drill off the heads of the bolts securing the timing plate(very easy).Once the heads come off you can usually unsrew the threaded part by hand.I just replaced those screws with socket head cap screws.
Also I didnt notice anyone mention the floats can sometimes get caught on a bowl gasket and hang up,some guys have had to trim the gasket a little.Also you want your floats to be even,sometimes they can get twisted so the level measures good on one pontoon but is high or low on the other.
Another thought,if your motor is soggy on the bottom maybe your running a little rich?

[trbig]

It looks like it started out being an XJ tank, and barely able to see, but looks like an XJ head maybe? XS sidecover over the ignition though.

I never had any problems at idleto low rpm with the Emgo filters. It's on the top end it would die. It sounds like you have some needle valve and seat issues, as stated. Poor running sounds like dirty carbs.. leaking needle valves usually goes right along with that. Time to get acquainted with the carbs for a little cleaning session.. lol. It won't take long to pop them off with those pod filters.


Tod

[dbeardslee]

Welcome to the forum. Soft and boggy on the bottom is often a symptom of float height being too low (with carbs upside down). Just something else to think about. Way cool looking trike .

[catdna]

Thanks all - certainly a lot for me to go on there - I'll take the carbs off / strip them down one night this week as it's finally getting light in the evenings again

The tank is a modified harley sportster tank - there's nothing 'xs' about the trike really except for the engine / wiring loom - the rest is a frankensteins monster of parts / custom bits & bobs

- here's a shot of the tank before it was painted - *lots* of filler / welding on there :



Cheers

Chris

[catdna]

Hi All

A quick update - I took the spark plugs out of the trike and noticed all were running pretty rich apart from #3 which was 'perfect' (well, according to the haynes manual )

I took the float bowls off the carbs and they were full of nice orange gunk so spent a good hour or so cleaning them out - then used carb cleaner and discovered carb #3's pilot jet / circuit was completely blocked - a quick blast of compressed air and plenty of carb cleaner later and I had them all completely clean (and a nice spray of it in my face when I wasn't sure where the carb cleaner would come out )

Put them back on the trike and balanced the carbs, and .... WOW ! what a difference - the trike has never run so well, and having never ridden an XS11 before, I'm guessing they're one hell of a beast - the performance was great on the trike (but then it weighs about 470kg's - a bit more than a XS11 )

So - this brings me onto something else (of course ! )

I want to adjust the mixture screws to get them running 'just right' (if there's such a thing). I bought a colortune plug ages ago to setup my GS550 chop, but just never got around to using it - so the instructions have of course gone missing - looking around on the web, there's various places that sell them, but most of the links to the online instructions are missing

Can anyone point me at an idiots guide to setting up the colortune plug and how best to use it ? I'm pretty sure I know what I'm doing (getting the buncen burner blue) - but do how do I set it for idle *and* higher revs ?

Any advice greatly appreciated !

Cheers
Chris

[dbeardslee]

cat - With the bike warmed up, the way I do it is to first attach my synch gauges and make sure they're right. Then I start on number 1, put the colortune in and attach the plug extension wire thing and plug the cap on. Start her back up and adjust the mixture screw out till it gets yellow, and then back in to bunson blue. Then I go 1/2 turn in from there. Take the colortune out, resynch, and repeat the process on the other 3. I always put a fan blowing directly on the engine during the process, and I try not to leave the colortune in too long as some parts are plastic and can melt if they get too hot. I use a little tab of high-temp grease to hold the washer to the colortune while I'm screwing it in. I adjust the carbs at idle speed - 1000 rpm's on mine.

Here's a link to the Gunson site where you can download a manual - http://www.gunson.co.uk/item.aspx?cat=673&item=1822

[catdna]

Thanks for the reply - does that take care of the mixture at higher revs as well as at idle (the turning back in 1/2 a turn from idle) ?

Cheers
Chris

[bikerphil]

The higher rev mixture is controlled by the position of the needle clip, center position is the recommended setting. Remove the diaphram from the carb, take out the c-clip, remove the needle, and you will see the adjustment. If you have the early model carbs, this can be adjusted, late model carbs, needle is fixed in one position.

[dbeardslee]

Cat - I turn them in 1/2 turn from bunson blue at idle to lean it out a little. The one problem with a colortune is that you see the color that the colortune provides - not your regular plugs. Might have to play around with it a little for your setup. With iridium plugs, hot coils, 4/1, pods, and the jets I'm running, 1/2 turn in gets me nice brown plug insulators across the board. YMMV