XJ RJ SECA 650 1982 - exhaust collector?

Trying to start bike yesterday, turning over, and over, - then bang! Big backfire. Done this a few times last couple of weeks.
Bike started eventually, but sounds like a Land Rover, without baffles!
Can run it, but lost @10-20% exhaust compression. Had a look between top of silencer, and frame bottom at the exhaust collector top surfaces, and two BIG holes blown in it.
I know the silencer system has been changed once in this bike, but the collector must be 32 years old as the bike.
It has corroded thin, and then couldn't take the pressure of the backfire and blown the holes in it.
Looked on ebay, and chacal for possible replacement, but chacal discontinued (?), and can't fine one on ebay.
Anyone got a link to a shop that might have aftermarket, used, old new stock etc (USA or UK), so I can try to resolve this issue.
Regs.

 

We should have a good used one, but it won't be cheap to ship across the pond........

 

all the ones i've seen (2) were bad on the top and were easily patched by a incompetent welder (me) with a O/A torch. A real welder could fix it right up

 

You have to keep in mind that the collector box for the 650rj is unique to that bike......makes the availability level plummet----

 

The XJ650 "Seca" was sold in Europe for many years. It was only a one-year bike here.

There is a European-based company (UK?) called JAMA that makes aftermarket OE style exhaust systems. They are sold here under the name Laser and appear to be more available over there than here.

They list a system for the "4K0" XJ650 (Seca) that is similar to that on the Maxim I, no collector but just a crossover. It does have stock-style mufflers, see: http://www.laser-exhausts.com/wp-content/uploads/npipdf/YAM_057_0650_XJ_03_953013_XJ650.pdf

 

http://m.ebay.de/itm/271606915053

 

Well I've got a good used collector box on it's way from Len at Chacal, so I thought I'd drop the exhaust system ready. NOT so easy. Got #1, and #4 exhaust head nuts off (two included the stud also), but the other four nuts (of #2 and #3) are so corroded and thinned and softened (and one is SPLIT) that a spanner just turns on them.
Pics to follow, but has anyone any idea of how to remove them (I haven't got a lift). I have got a dremel, with applications (can't get big drill in). Does the dremel usually include an application that will 'cut' through steel, like a ?????? (forgot the name!), and even if I can cut the nuts off, I have still got to remove the studs, and replace them haven't I?
Any ideas welcome
Regards.

 

Your Dremel may have come with a cutoff wheel (what is includd varies depending on which kit you buy), if not they aren't too spend (get the fiberglass ones, tehy last longer). BE very careful using any rotay tool to cut the exhaust nuts off. I prefer to use a nut-splitter (stop laughing; it's a real tool), since there is less chance of one damaging the studs. Once you have the nuts off you can clean the threads of the studs with a wire wheel, wire brush, or a thread file (I prefer the thread file; it's more precise). The studs should not need to be replaced unless they are so badly corroded that the threads won't clean up.

 

The original header flange nuts also have an internal 8mm hex that nobody ever notices.

 

Yes Fitz, I was aware of them, but they're corroded out also. Regs.

 

Got six of the eight nuts/studs off, but one Ive had to grind down to surface of retainer (will have to drill and retap, then use stainless bolt) The other, on exhaust 2, got stud and nut together out of one, and the nut off the other, but retainer just won't budge on one side! Tried prising it off with rasp file, and snapped file! It seems as though its 'fused' to the stud, or the inner gasket(?) See pics.
Anybody had this problem before, and got any ideas please?

 

More than likely was tightened down unevenly and is just tightly jammed. You'll have to work at it to get it even again, then it'll slide off.

 

Well, worked on it, and worked on it, and still won't budge. Had an idea that putting the nut back on and tightening up, then retracting again might bring the stud out with the nut as well.......NO!.......just sheared off the nut from the stud level with the retainer surface! *a'%!issed off! Got two need drilling out now, and haven't got a drill bit that will touch these studs. Are the studs tempered steel, and need a diamond tip drill or something that is harder?

 

STOP. No drilling. "Level with the retainer surface." As in, the collar? Remove the exhaust system and the broken off studs will be sticking out there with enough showing to latch onto with a pair of vice-grips and turn them out.

If you broke them off even with the surface of the head, then that's a different matter. But keep something in mind: they're not in there that tight. They are not "rusted in" the head is aluminum.

They can be drilled with a small reverse drill bit, dissolved chemically, or you can pull the head and take it to a machine shop and have them burnt out with an EDM.

If you have to resort to drilling, like I said get a small REVERSE bit. Gently heat the area; just the drilling will probably run the nub out. If not, then use a screw-type extractor, not a (brittle) "E-Z out."

 

Thanks Fitz, for your input!

Yes, obviously once the exhaust system is removed, any studs are exposed, but it's the actual collars that have to come off before I can remove the pipes. And yes, the two offending studs are broken off level with the collars, (they're referred to as 'retainers' in Haynes) not the head.

The actual retainer (collar) on #2 exhaust port (inside-most stud), is the one that won't budge from the inside stud (the outside flange stud is removed), no matter what leverage I put on it, I could see the actual 'trapped' inside-most stud itself moving from side-to-side as I levered behind the retainer/collar (gave me the assumption that stud is somehow 'fused' inside the retainer/collar socket)? Perhaps it is trapped on a thread, or something. I have now sheared the nut off this stud off level with the retainer/collar head socket, and it obviously will still not lever off.

I haven't got a lift, and this area as you well know, if very hard to access and manoeuvre/leverage, get implements in etc, with the pipes, and the frame tube in the way? (even so, I still managed to get enough leverage, to snap a big long file in two!)

The same situation is with #3 exhaust port retainer/collar, right-hand stud. (innermost), where I actually ground the nut half-off, and then it still would not move with a smaller socket size hammered on, before rounding off the rest of it, so I ground it down level to the retainer plate, ready to drill out. ( I can clearly see the outline of the diameter of the stud surface)

I understand that once the retainers (collars!) are off these two ports, that I may be able to get a grip with what we call 'Mole' grips, to remove the remainder of the studs and then just replace them. (and if not, follow your instructions to remove them).

Then obviously, I can remove the rest of the system, and replace my collector box! (currently at customs in UK - wait for the big Import Tax bill!!)

I have mentioned this to a neighbour friend, who is a former mechanic, and he said it may take some heat with a blow torch to 'defuse', and release the retainer/collar from the #2port stud (also with a bit of leverage/banging with softer implement). If I go ahead and try this, he has reminded me to be aware of the aluminium parts, and go easy? - would this work in your opinion?

I've even thought of running the engine up to operating temperature, but perhaps this would not generate the required heat to break the seizure/seal? - and make a lot of noise for my neighbours - lol!

I think the #3 port, right-hand stud might need the same heat treatment to remove the retainer/collar, and if not drill that out also?

Off to the shop now, to purchase a blow-torch - try that first!

Regs.

 

That's quite an investment, Jama / Laser, 4 into 2 $622.00

 

I haven't invested in brand new Jama system (no collector box). I've bought very good used collector box only, from Len at Chacal.

 

Go ahead and warm it up and give it a good banging on (use a block of wood between the collar and the hammer). If it won't budge then it's time to cut the collar off. Preventing damage to the head is more important than saving any part of an exhaust. Replacement headers (used) are easy to find, and usually fairly inexpensive.

 

Thanks k-moe. Acquired a blow-lamp yesterday. Going to attempt today. - will post results later!

 

Well, the heat from the blow lamp, and then banging it did nothing. Banged it with something else, and it released it, but broke off part of corner (half circum of stud space) from collar. (the corroded steel had formed a tight set with the inside of the alloy!) Should still tighten down. Drilled it out to 4.5mm circumference, 20mm stud depth in head, ready for retapping, to take a stainless bolt @ 6mm? Not sure if stud is 5mm or 6mm, can't tell from measuring with rule across the top.

The other one, (collar) came off with some persuasion after cutting it down closer to collar, but I've made the error of not drilling perfectly central into the head for I couldn't see properly, and my pilot drill hole is now off centre at @ almost 4 0' clock! (if I cut a slot in the collar, then it will compensate for my error, and should still tighten down with large washer under stainless bolt. What a peanut I am!

The system itself came apart quite easily, (the inner downpipes of #s 2 and 3, are covered in nut brittle! - terrible, but sound, I think) Will have to get straps for the connection points ( between box and silencers, and downpipes and box), gonna use jubilee for now, til I can acquire something more appropriate.
Replacement box not arrived yet (see pics of the one I took off - bad or what!?)

 

Wow, that collector has surely seen better days........!!

 

Well, I received the replacement collector box and installed it - working fine itself. BUT - in my attempt to retap a thread to accept a bolt, or stud in #2 exhaust port (left side), the tap tool snapped off inside the 5mm pilot hole I had drilled, and with just the one side of retainer plate tightened up, there is obviously a gap (even though tried to fill it with 'gun gum'), and when engine is running it is making a frustrating blowing sound. It is definitely coming from there 'cos there are whisps of smoke, hardly noticeable but obvious on close inspection.
I can run the machine, but this needs to be addressed.
What is the best approach to get that stuck tap tool out of the hole I drilled. It has broken off to a point just beneath the surface of the hole. Broke two smaller drill bits, and made a bit of a pig's ear of it by trying to get at it sideways to centre.
Anyone got any ideas please!?
Regs.

 

Other than "don't run the motor with an exhaust leak at the head or you can bend a valve" I can't offer one.

 

I think I've thought of a way to rectify this. Use small dremmel-type (3-4mm) flat grinder head, to file the 'pointed' end off the broken off tool bit down to a flat as possible surface, inside the bore hole. Then, I've bought a 3mm left-hand thread drill bit, (the surface of the bit is 6mm diameter) and carefully (after adding some heat Fitz?!) and slowly drill centrally through (I think I got in about 10-12mm before the bit sheared off), and the part may then come out. If this is successful, I will do as I did with the other bore-hole on #3 exhaust port hole, and start the first 3-5mm with tap, and then put the hardened steel bolt in and this 'cuts' it's own thread 'cos the steel is harder than the aluminium?
If this doesn't work, for the time being, I am just going to try and seal the leak prematurely by packing the gap created between the collar bottom and the head on one side, (when the other side is bolted down) with gun gum, or silencer paste, and possibly double up on that side with a copper gasket, cut in two?!
Just one question Fitz - "don't run the motor with an exhaust leak at the head or you can bend a valve"
How does a bit of (probably more like 20-25% of one exhaust port) an exhaust leak at the head, possibly cause a valve to bend? I'm intrigued - is it heat, or what?
Regs.

 

Rectified the problem with the stuck tap tool inside exhaust port stud-hole. Bought carbide rotary file burrs, and dug it all out, then redrilled the 5mm socket, and retapped the thread to 6mm. Being held with stainless bolt now, and the leak has been eradicated.
BUT - Now got another problem.....
Set it up to do carb synch, and was adjusting the dials etc. when it just cut out, and strong smell of petrol. Looked on floor underneath, and fuel spilling out of the air box collector drain pipe. Bike would not start.
Looked in collector box and very wet with fuel.
Stuck float bowl again??
Took dials synching tool off, and set it up with tank back on after 'tapping' each carb to perhaps free the stuck bowl/slider whatever. Put on petcock to 'prime', tried to restart - no luck - just leaking from the airbox drain tube again.
Any ideas anyone PLEASE.......?
Much obliged!
Dale Grantham

 

Obviously a stuck float........
be careful with that--- I had a bike do that one time, and when I turned it off, it gave a little tiny back- pop, but it was enough to ignite the fuel in the airbox, on the overflow, and the bit that collected in the collector. I threw a five gallon bucket full of water on the bike and put the fire out quick, no damage but plenty scary.

Dave f

 

Seems you have gone full circle here. The original collector box was blown open with a backfire, most likely from the defective carburetors spilling gas in all the wrong places. If you have not serviced the carbs, you need to get them rebuilt with new rubber parts, particularly the float valves.

Some useful links to get the carbs back to like new condition:

http://www.xj4ever.com/hitachi%20throttle%20shaft%20seals.pdf
http://www.xjbikes.com/forums/index.php?threads/how-to-clean-the-enrichment-circuit-well.8918/
http://www.xjbikes.com/forums/index.php?threads/in-the-church-of-clean.14692/
http://www.xjbikes.com/forums/index.php?threads/how-to-bench-synch-your-carbs.6366/
http://www.xj4ever.com/setting%20fuel%20levels.pdf

 

Just did the test for petrol in the engine, and yes took filler cap off and could smell gas. Got to change the oil and filter. Took carbs off wet-checked float levels and #s 4 and 1 too high - way too high! - overflowing.
Re wetset the floats, and all in spec again now. Not had chance to put carbs back on to test now cos dark here and not got a garage.
Hope it is not as extreme as Rooster suggests!!? - the float valves look ok, and the levels look fine now.
Proof will be when I put the carbs back on the machine, and run again? It was starting and running fine (ie no backfires when I had installed collector box) til I attempted to do vac synch this morning - for some reason that might have caused this problem. (think I may have put the enrichment circuit - choke? on, and it was obviously temporary fuel supply, as in 'PRI')
That may have caused it perhaps.?
Thanks for all your replies and advice - will keep you posted, when reinstalled carbs and tested.
Regs.

 

ps - if it is as Rooster suggests, I've got a replacement bank of carbs in nice condition which I acquired earlier this year, and I can rebuild an nice new set

 

That collector wasn't blown apart by that backfire..... That collector was rotted beyond belief a long time prior---- just look at all that fiberglass "patch"

 

Thank you Hogfiddles, the collector was paper-thin, when I removed and inspected it. (I had already myself done the 'patch' with gun-gum two weeks previous, by reaching in between the tiny gap between the top of collector and bottom of engine with a flat knife?) The thing is with these boxes, they are situated in a place which you can't easily monitor, and maintain through observation and act a bit like a 'flat roof', where rain/moisture collects over the years (may even freeze on top if stored outside etc.), and so can't clear and dry easily. My box was obviously original from production of the bike, and was 32 years old.
I also took the precaution of coating the box in heat resistant paint (twice), top and bottom, and especially at the joints between downpipes and silencer, which I noticed were affected badly. Hopefully, this will slow-down the deterioration, and add a bit more life to this box.

 

Hogfiddles, first I wanted to air out that I totally appreciate your contribution to this site. You so often reply expeditiously with relevant knowledgeable information.

However, I don't really understand the relevance to the OP's overflowing carburetors in your last post.

I understand the collector was severely compromised to begin with, and that a backfire would not damage a structurally sound collector. Do you not think the backfire is a result of overflowing carbs? If the carbs have not been serviced with new components, wouldn't you recommend that they should be...at the very least the float valves? Isn't gas in the oil one of the quickest ways to ruin a nice XJ motor by thinning out the oil and compromising its lubrication characteristics?

I do understand the caution on the fire, which was great advice, but where should Paul go with those carbs? Seems he is planning to wet set them again and press on.

 

Uh.... He stated that he had fuel running all over the floor from the airbox----

I had that happen on a bike, too, and so I gave a brief description of what happened......

Very relevant, so be careful.

Dave

 

The fuel could have trickled from above the relevant carb(s) mouth(s), along the air boot(s), and a little entered the airbox, or trickled down the outside of it and exited via the drain tube (or along the outside of it?) In the failing light it looked like it was coming out of a drain tube.

I have taken in the cautionary note of hogfiddles, and after wet-setting the floats again, and testing, there are no leaks, and the bowls are filling up within specs.
I must confess, that when I last had this issue, (a few months ago?), after wet-setting the floats, I forgot to bench-sync the carbs before reinstalling them.

AND, I have had one backfire, now I remember, AFTER I installed the new collector box?! (the box I hasten to add, survived this time!!!!)

Perhaps this is relevant, because when I took the carbs off this time to reset, the butterflies in the set mode were all pretty well closed (almost impossible starting point?!) and this could explain being hard to start (and a backfire?!) until I applied the fuel enrichment circuit (choke), and opened up the throttle slightly.

I have just bench-set the carbs again, using the thickness of a paperclip wire, and have drained the old, fuel-contaminated oil from engine, and flushed it out with white spirit.
Waiting for new 10/40 oil, and also new oil filter, and when I have replenished these, I shall reinstall the carbs and try again
.
I do hope a backfire cannot result in the extremity of damaging throttle shaft seals, so deep inside the mechanics of the carb, and this float problem is the only result, because re-wetsetting the floats resolved the issue last time.

I shall also reinstall cycle innertube seals on the exhaust manifolds rubbers, as since they came off last time, it takes it time to come down to correct rpms (1050-1100) when stationary at operating temperature, and throttle off. (hairline cracks creating slight vacuum leaks when warmed up, and under pressure?)

Please feel free to add anything else and feedback on my thoughts on this issue.....
Regs. all....