XJ RJ SECA 650 1982 - exhaust collector?

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....