recent purchase '82 RJ SECA idling high rpm when warm

Hi anyone.
I have just joined XJBIKES
Recently purchased XJ650 RJ SECA. Had to go back under warranty cos running @ 3000+ idling when warmed up. They had it for one week, and had carbs off and balanced carbs etc. over two labour days etc.
Warranty now run out, and still idles at 1500+/- when warmed up.
Is this too high still? Sounds it, uneconomical on fuel, and wont come down any, even when reduce the idling screw right down....Manual says warm idling should be 950+/- 100rpm(?) *CORRECTION. Will come down a tad, if put into gear and slowly engage clutch, but this just creates premature clutch wear surely?
Saw an article that said check rubber boots between carbs and ports for cracks, clean and silicone seal, and after inspection, done the outside boots for this (but not yet looked under tank for numbers 2 and 3)
Vendor says that they have greatly improved it, but it is an old bike and I must accept that it won't run like a new one......?!
Anyone got any other ideas.....ie heard about valve clearances, shims or something, and air filter, whatever....
Regs
Pl

 

check valve clearances -> sync carbs

 

There is a LONG list of reasons why the Bike might be behaving like that.
Long.
All ... Fine-tuning related.

When I'm introduced to an Engine that does not respond to efforts made to have it run better, ... before getting heavily involved, ... I need to know what is the present condition of the Engine.

I'd conduct a Compression Test and see where things are at.

 

Welcome to the site! You need to give more information in your signature line (what year bike, mileage, any modifications etc.) and turn on your location feature (in case someone is near and can help you).

What your vendor (seller?) told you is a lie. Just because a bike is not new does not mean it can't run right, or be tuned, or be as good as it was the day it rolled out of the factory. They said that to you because they are clueless (99% of their experience is with <15yr old bikes) and they don't want to mess with it anymore. And if your fuel economy is bad then they did not greatly improve it.

As for your issue. There can be multiple causes, but as you will learn there is one sure fix. To make sure all needed maintenance has been done and done correctly. Bottom line you need proper valve clearances, proper carb operation: 1)clean 2)floats set 3)synched 4)mixture right, good plugs, no air leaks anywhere. If you follow the advice you'll get in here you will get it fixed. Use the search tool and look up threads on the above topics.

I am no expert on carbs (becoming one though) but sounds like your getting too much fuel. Either from your pilot mixture setting or enrichment circuit (wrongly called choke). One thing you can check easily is to see if your enrichment plungers are being released all the way when you close it off with the lever. There is one for each carb and a little fork lifts them when you engage the choke. They should drop free (2mm or so) and not be touched by the fork when it is off. Rick is our resident carb guru so heed his advice. Does it run right otherwise? No backfiring, lugging, smoke, etc.?

 

Thank you all, for your contributions!
In answer to MercuryMan, in particualr, as I am new, I am finding it rather confusing to navigate and check all the necessary buttons etc. I. will take your advice (signature line info, and turning on location feature) I'll get there!
My bike is an XJ650 RJ SECA, 1982, 29,000 MILEAGE, IMPORTED TO UK FROM USA, no engine modifications, that I know of. It has been resprayed in 1990's, to a red, (Cardinal?, as per the Canadian?) from the original silver and blue spec USA. Frame and engine no. 5V2-003440, which pertains to USA RJ SECA 1982. NOT Maxim.
The bike otherwise, I am very happy with. It starts first time, runs smooth, and acceleration etc. is fine. (this suggests that compression is ok, but I bet someone would suggest otherwise(?)!
Only other irritating thing (apart from the idling!) is hard to select gears, when engine is cold, (I know its a shaftie, and I've already got an XV535, which selects gears much better when cold!), and selection is slightly better when warm.
I will be able to carry out some of the tests myself, but I haven't got a garage, I am not a mechanic with access to the tools that are needed to do carb checks, valve clearances etc, and winter is coming on, as you over the pond, have already had experience of(!!!)
Thank you so much, and keep suggestions coming........
Appreciated.
Dale Grantham
Radford
Nottingham
UK

 

It wasn't a "suggestion." What's just been explained to you is the solitary raw truth of the matter.

-Old XJs can be made to run like new, or better; a whole lot of us have done it successfully.

-Certain things HAVE TO BE attended to, and regularly, or you can damage the motor.

-Valve clearances: The initial check and adjustment was to have been done at 3000 miles; it is also due every 5000 miles thereafter. The valve train on these motors doesn't loosen; the valve clearances get tighter until bad things happen if not set right.

-Carbs: Cleanliness and proper float valve operation are critical to how the bike performs as well as fuel economy. Float levels are important, and only have a 3mm adjustment tolerance. A proper running vacuum sync when all of the above have been attended to will be necessary; however it cannot be performed accurately if the valves are not in spec FIRST.

From the factory service manual:



Your "vendor" likely had no idea or didn't want to get involved in TRULY bringing the bike into spec; he just wanted to get it running well enough for you to go away until the warranty expired.

In order to get a 4-cylinder, 4-carb motor to behave 100% properly, it has to be rather finely tuned. Such fine tuning is impossible if the engine itself isn't operating to spec. There is no "quick fix" for this, sorry.

 

Thank you bigfitz52!
I have a collection of old test certificates as history only, but no mention of any service(s) etc. been done, which may have given evidence of last valve clearance checks etc....
Had been (8) previous owners, any one of which MIGHT have done this at any given time, but I have to go by current symptoms, to assume haven't been done for a long time and DO need to be done, which you have pointed out to me, before undertaking any carb tests etc.
which would have a big chance of solving the problem...........
I have always looked after the bikes I have had in the past, and done necessary checks, and any repairs needed etc. at the regular intervals.
The same is not of all individual bike owners, and I have to assume these checks have not been done for quite a while, and that's why this problem persists.
Thank you
D. Grantham

 

****************LATEST UPDATE****************************

:? Finally got round to doing valve clearances. I have taken two days or more and have really enjoyed it.
They obviously had not been checked for quite a while because 7 out of the 8 valves needed adjusting. (no 1 exhaust ok)
All that needed to be adjusted were too tight, apart from no. 1 intake, which was too big (probably accounts for the slightly sooty plug?)

PLEASE ADVISE ME I HAVE GOT CLEARANCES RIGHT FOR USA MODEL RJ650 SECA 1981/2 (NON-YICS) not Maxim

These are what I have set them to having been told from site, (but Haynes says different).........

INTAKE: 0.11 - 0.15
EXHAUST: 0.16 - 0.20

Haynes says both INTAKE AND EXHAUST should be
0.16 - 0.20 for RJ650????

Bit worried now......
Someone please put my mind at ease, or I have wasted two days setting to wrong clearances........!!!!!!!!!!

 

Haynes is indeed wrong on this one, if you followed what we have on this site, you should have done it correctly.

I was worried at first about this as well, but there are a couple of errors in the Haynes that this site has set correct--what finally convinced me I could really trust people here over the manual was reading about how Haynes had switched the jet screw numbers around, and how that had screwed a member up who had done everything on the system to get it running right, until they found out the manual was wrong here. Switched them as per the forum, and voila, worked perfect.

So you did it right. Go ahead and scratch it out in your manual and correct it.

 

As above, the Haynes is wrong so you got it right. If your bike still has the original decals in the sidecovers, the correct clearances are listed there as well I do believe.

So it took since last November until now before you finally checked your clearances? How many miles went by in the interim?

I'm concerned about intake #1. How "big" was that clearance?

 

I've just spent 1 hour typing a long, detailed reply, (including anecdote about oil squirting in my eye, after reinstalling shim! Ha Ha!) and lost it when reviewing, so this will be briefer...!!!!!
In reply to bigFitz, only a couple of hundred or so - no difference to symptoms.....been using my Virago 535...
Flushed engine and changed oil and filter....
Results now valve clearances checked, shims measured and recorded, and shims swapped about to accomodate etc..........need two new shims..sent to California for them
Must have been a long time since these were adjusted....7 out of the 8 needed changing..........
The two spare shims I have now are, 2.85, and 2.70

AS IT IS NOW....

INTAKE: (0.11-0.15)
NO 1: clearance: 0.11-12, installed 2.75
NO 2: clearance: 0.15, installed 2.75 (CLOSE?)
NO 3: clearance: 0.14-15, installed 2.80 (CLOSE?)
NO 4: clearance: 0.06-10 (out of spec) was 2.70 installed, sent for 2.65

EXHAUST:
NO 1: clearance: 0.18, installed 2.65
NO 2: clearance: 0.14-15 (out of spec) was 2.65 installed, sent for 2.60
NO 3: clearance: 0.16-17, installed 2.65
NO 4: clearance: 0.18-19, installed 2.70 (CLOSE?)

As for the intakes where I have accentuated ''CLOSE'', surely they are at their best gap, because it has been brought to my attention that adjustments need to be made when the gap gets too narrow, at the lower end of the specified range, and that's why problems start to occur...??
Exhaust NO' s ''CLOSE''? or OK?...any suggestions.

Is what I have done correct...and is my engine potentially on the way to recovering from this irritating overcomsumption, and high idling, in operating temperature....?

By the way, is it that the shims don't wear(?), but the cam bucket/or follower whatever, that wears, and that's why shims themselves need to be changed to reinstate the correct clearances.......bought a micrometer anyway!!!
Let me know...........

Thanks for all your support....

 

PS.
The No 1 valve intake gap WAS 2.0 (should have been 0.11-15)
Put a 2.75 shim in instead of 2.70, and now gap is 0.11-12
Regards

 

I'll make this real easy on you.

Especially if you're using metric feelers.

In spec is in spec. An intake valve at .15mm is in spec. Leave it. An exhaust valve at .19 is in spec. Leave it.

Out of spec is out of spec. Those you fixed.

Don't worry about close. I've got an intake valve on one of the 550s that's been sitting at .11 for the last two clearance checks, defiantly remaining IN spec.

For the first half of the life of the motor or so, or until they've been adjusted a few times and have "settled down" the valves "pound" themselves deeper into their seats, causing the clearances to tighten up. This is why the initial clearance check at 3K miles was so important, yet oft-neglected.

You need to do this again in 5000 miles, and every 5000 thereafter. Eventually you will find that only one or two need adjusting, eventually none or some may even loosen slightly. But they do need to be monitored as recommended, especially during the pounding-in process, for the motor to end up being solid for the long run.

 

Thanks Fitz
Will update when complete, and tested for consumption/idling again. Later............

 

*****************LATEST***********************
:?
Shims just arrived, and installed.....checked all clearances again........problem!!

No. 1 Exhaust clearance: a tight 0.155 (so 1.50-154)??
No. 3 Exhaust clearance: 1.50-1.54 (1.55 wont clear!)??

Both seem to be too tight for correct spec.

I may have measured wrong in the first instance because, I had recorded 0.18 (NO. 1) and 0.16-7 (No. 3), initially, and checked them again (!!)

Do the clearances change for exhausts, when installing new shims in other intakes and/or exhausts? (only changed shim in intake 4, and exhaust 2)

Obviously, should be 1.60 - 2.0 for the exhausts?

I think I have to acquire two new shims for the two exhausts.

Please advise.........

Regs. :?

 

Update from Sat. June 02............

Didnt get reply from my Sat presentation, so updating again today....
XJ650 RJ SECA - VALVE CLEARANCE UPDATE...... :? :x

Exhaust no 1 @154 (a very tight 155) - out of spec (currently installed 2.65)
Exhaust no 3 @150-154 - out of spec (currently installed 2.65)

I have only got feeler guages with increments of 0.05 (mm) lowest, and then go up in grades of 0.10, 0.15, 0.20 etc.
This limits me in exact accuracy of clearances, but it is obvious these exhaust measurements are too tight and out of spec..... :x :?

Need two 2.60 shims, and sent for in UK, 'cos site in California where I got other two from last week, has only got one 2.60 left.........

This might interest one or two of you......
Been looking for used vacuum guage set....

Was talking to chap on Wollaton Park, in Nottm. today, at the Autokarna, who seemed to know a lot about the XJ series, and I told him I was just doing my valve clearances, cos I had issues with poor consumption, and high idling (1500-2000rpm) at machine operating temperature (with the headlamp turned OFF - have installed switch to drive in daylight without light on - drops to @1500 with light ON) etc, and he suggested that it was most likely the carb synchronisation./float levels....but when I mentioned the XJowners site, and their 'experts' recommendations that yes, it could well be that, but first to ascertain this theory, the valve clearances must be checked and put in spec. beforehand, he hastily agreed with me.....valve clearances - and if still got symptoms - THEN carb fuel levels and synchronisation!
He went on to mention the problems with the carbs on the XJ series because of the Japanese needing to adhere to the emissions levels brought in, in the US, and this had implications with the choke /air jet(ok-fuel enrichment system!) screws and the air filters, or something(?)...how when synchronising, and/or changing to cone filters, you have to change the main air jets (bigger, or smaller (?).....also said these Mikuni carbs with the diaphragm at the top (under the four-screw plate) are prone to diaphragm rubbers withering or something which also creates problems with performance......and butterfly throttle valves, instead of sliding ones, aren't so efficient , be careful of rubber washers may be worn when reinstalling after cleaning - got them right way round? etc. etc. ...and on, and on! (anyone got anything to add to all this....)??? :?

Anyway, you may or may not be aware in US that it is Diamond Jubilee weekend for HM Queen Elizabeth II, in UK (and Commonwealth, for that matter), and so there is a Bank Holiday Monday AND Tuesday.
I, for myself am not that interested, apart from the annoying fact that it means I will have to wait an extra two days for my shims to arrive!!!

If anyone has anything to offer, as to my current valve clearance situation, or anything else as regards what my chance encounter with guy on Wollaton Park, and his views on XJs carbs etc, be glad to here from you....

Regs.
Dale

 

Dale,

Shims can be purchased from www.wemoto.com on the south coast, possibly a bit late for you.

however you may want to check out theit online store for other common parts. delivery and speed will be a definite improvement.

 

Thanks Redbeard!
Thats exactly where I have ordered them from yesterday ( had WEMOTO saved for a long time on favourites list)
It's cost me £20 tho' for two shims and postage, whereas, when I got two from USA last week, it only worked out at £14! (as I say in previous message, he has only got one 260 left, so I plumbed for WEMOTO, obviously quicker (I hope!)
Thanks for reply!
Regards
Dale

 

****************UPDATE*********************

Received last two shims needed today and installed (2 x 2.60 - both on exhausts 1. & 3. respectively)
Wouldnt start at first, and flattened battery, but hooked up to charger for a while, and heated up my spark plugs, and blew hot air down plug-holes - first time.

Got it to idling temperature, and still hanging at 1400, -if I bring down idling screw lower it just zeros and eventually cuts out.

So, still got the problem, even with valve clearances bang-on!

Went round my local bike shop, and I told him about it. (pretty sure from all the diaglogue we've had on the site, its either vacuum leakage, somewhere, or float height wrong on one on the carbs?, or sticking piston valve, or, or...or...!!!???)
One thing I do know, its definitely not the valve clearances....!!!

He suggested, being 30-year old, it could be a withered carb diaphragm(?), or vacuum pipe, from petcock to carbs, check air filter...etc

I have sprayed carb cleaner round the boots, and manifolds and it doesnt get higher (the revs), but if I spray underneath the boots, it climbs slightly then.....he suggested that, is probably because they are cooling temporarily...with the spray........?

I told him about the much talked-about throttle shaft seal leaks, on this site, and he said he has never had to replace them on a carburettor...? (unless the throttle shaft seal is the 'diaphragm')

Where are the thottle shafts, and how do I replace the 'o' rings in them , or 'seals' whatever..... cant see them in Haynes' diagram listed....

Realise Ive got to pull the carbs, and do a complete clean, overhaul, float levels, synch, buy some vacuum guages, more expense....
:?
Is the diaphragm, the throttle seal?
Regs.
Dale

 

http://www.xj4ever.com/hitachi%20thrott ... 0seals.pdf