exhaust port repair (updated)

OK, here is the latest saga into the poor workmanship of the expensive restored bike I bought and have not ridden. I finally put the head back on and went to put the exhaust back on. I noticed that he, the previous idiot owner, had the thinner 750 exhaust nuts that are longer than the beefier 850 nuts. So I ordered the 850 nuts because tightening the 750 nuts resulted in the fins bending and or snapping off. I finally got the 850 nuts and went to put them on...........low and behold the 850 nuts do not seat all the way into the head far enough for the exhaust header to be tightened!!!! Sooo I look at the exhaust ports and see an obvious difference to my other 850 head. At some point there were inserts put into the exhaust ports probably fixing stripped threads. The inserts were obviously put into both ports, but were not ground down and faced off and appear built up about a 1/4". So the anger is flowing and trying to think sensibly is lost right now. Question: Can I use a grinder to face off the threads if I plug the exhaust ports or do I have to remove the head again and try and find someone competent to mill down accurately and face off the openings?

Old faithful



new messed up head

Re: exhaust to head issues and question

Britbike,
FIrst off, I understand how frustrating these things can be (I am still trying to make my 850 fire on both cylinders...it has comp, good spark, timing all good) so the best thing I can do when I feel the urge to throw things is go inside and pop a top on a cold Guinesss and contemplate my next move.

Your problem is EASY fix. I bought aftermarker exhausts from Commando Specialties. They are for a 750 obviously without the balance pipe. The 850 definately has shorter exhaust nuts because when I put the pipes on and tightened the nuts, I could move the pipes about 1/4" out of the head. Not good.
SO, I had two options.
1. Use 2 exhaust crush washers in each port to take up the space due to using 850 exhaust nuts (the 750 pipes have a raised portion where they go into the head that eliminates the use of the small spacers used on the 850...you CAN NOT use the spacers on the 750 pipes as they will not work.)

2. Use the spacers but put them BEFORE the pipe. Some sticky high temp RTV to hold them in place...should work.

I chose option 2 as I did not have another set of crush washers. As long as you can keep the spacers in place inside the head (sticky RTV) while you tighten the exhaust nuts (850) then you are good to go.

Mine are nice and tight now and do not leak at all (at least on the ONLY side that is firing!).

Just a suggestion....use is for what it's worth....GOOD LUCK and dont ever give up!!!!

Re: exhaust to head issues and question

Hi ludwig, Thanks, I was afraid that would be the sensible answer. I had the same repair done to my original 850, but cannot remember who did the inserts. Travnorton, I don't know what spacers you are talking about. I thought there were only crush washers inserted into the head before the headers? I didn't have spacers on the other 850. I really don't know if two crush washers would A) be enough to take up the slack and B) if it would be stable enough to keep the exhaust seated. The repair on my head sticks out literally a 1/4" to far and having that removed may do the job. If there isn't a way to do this without ludwig's solution, does anyone know who can do the job right?

Re: exhaust to head issues and question

Britbike -

The 850 exhaust nuts are shorter, to accomodate the collet system that has to be used with the balance pipe. When I changed my 850 over to 750 headers, I had the same issue at first. Phil at Fair Spares told me to double up with the crush washers or go on the hunt for 750 nuts with longer threads.

Check e-bay for the Commando Specialties 750 exhaust nuts. I think they're Andover, but don't quote me... They do have the three 'fat' lugs to use the spanner on. Use the right wrench, then lean on 'em good and hard while the engine is hot and running.

Best of luck,
T.C.

Re: exhaust to head issues and question

The 750 and 850 exhaust pipes do not fit to the head the same.

The 750 pipes use the longer collar on the pipe with the crush washer. The 850's use a shorter collar with a split collet and seal which can only be used with the 850 balance pipe exhaust, to get around the obstruction problem the balance pipe causes. Mismatching the 750 pipes with 850 collars will produce exactly what you've found, there's nothing wrong.

If you fit 750 pipes to an 850 you need to use the longer 750 collar (unless you've got some sort of hybrid pipe).

As to bending the lugs on a 750 collar, I've never heard of this with the standard steel collars even using a 2ft extension on the lockring tool.

Finally, whether to machine off your excess insert from the head it would depend on how deep the thread is. If, after it's machined off you're left with the standard amount of thread in the head then I'd have it machined off. If you're going to be left with less then normal thread then it's either use as is or have the whole insert machined out and get the job done properly.

Re: exhaust to head issues and question

If you're investing in new hardware maybe it's worth considering the bronze nuts sold in the UK by Norvil - they're 750 style length-wise, and expand at a similar rate to the alloy head, so less prone to working loose.

Not sure who stocks them in the US, but others closer to home should be able to advise.

Re: exhaust to head issues and question

B+Bogus said:

If you're investing in new hardware maybe it's worth considering the bronze nuts sold in the UK by Norvil - they're 750 style length-wise, and expand at a similar rate to the alloy head, so less prone to working loose.

Not sure who stocks them in the US, but others closer to home should be able to advise.

Click to expand...

I think someone said British Cycle or Walridge.

Re: exhaust to head issues and question

Britbike, just out of curiosity: what material is the insert?
Mine are steel, not welded but fixated at the "bottom" with 2 little machine screws (internal hex).
Still can come loose though...

Re: exhaust to head issues and question

slimslowslider said:

Britbike, just out of curiosity: what material is the insert?
Mine are steel, not welded but fixated at the "bottom" with 2 little machine screws (internal hex).
Still can come loose though...

Click to expand...

They look steel.. My other inserts were aluminum and were welded in from the front. the excess was ground off and filed flat you can't even tell it was repaired. These look steel and it worries me how they could possibly be attached. I do not see any set screws and given the sloppiness of the job I think it should be redone. On another note, I also think I can have two spacers machined 3/8 thick same od and id of the nut. This spacer could be put on the header before the exhaust nut and that would take up the slack.The problem all lye's in the excess build up around the port itself. So agreeably the best solution or the right way to fix it is to have these insert removed and new ones put in properly. So I can have spacers made for a few bucks and get it done somewhat quickly or I can dismantle again and send of for a few hundred bucks and hopefully get it done right. On the chance that I want to have it redone, Does anyone know a good man for the job?

Re: exhaust to head issues and question

I use 750 "unbalanced" (suits my temperament....) pipes and 750 nuts (antiseize on the threads), with Suzuki GS1000 crush washers, on my 850.

Torque to 60 lbs-ft and retorque after the first few heat cycles, with bike running, and ideally, a helper revving it (thank you Ludwig!).

Never have a problem with exhaust nuts loosening.

FWIW/YMMV.

Re: exhaust to head issues and question

On non-balance pipe applications my understanding is that a crush washer is fitted, then the pipe and the deeper exhaust nut is run up the pipe, screwed into the head and you are good to go.

For those people that are switching from balance pipe to non-balance pipe headers and don't want to spend the $48 (-+) on new exhaust nuts, can't they just reuse/purchase new 850 collets and be good to go?

In the case of the original post it would save BritBike the cost and agravation of removing the head and the expense of re-threading???

RS

Re: exhaust to head issues and question

It was weird I had the longer 750 looking nuts on it, but the norton nut wrench did not fit around them like it should, so upon tightening, the fins would bend and snap off. Looking at the other 850 I do have the thicker 850 nuts on it and I do not recall doing anything, but tightening them after a few heat cycles. Maybe I did put in an extra washer. Regardless the 1/4" the ports are build up are going to be a problem no matter what nuts I have. The 750 nuts that were on it didn't tighten all the way either so new nuts are just going to allow torquing not seating. So I figure unless I am able to get spacers made I will have to send the head out for repair. I will probably call Ella Monday and ask if I can exchange these for good 750 nuts. In the mean time I am waiting to see if a local machinist can turn some spacers for me. There are options, just been frustrating to have to keep dumping money into an already expensive bike that was restored. Certainly does reinforce the idea that you really can't trust to many people out there to do work right and 95% of the time anyone can do their own work given the time and resources. As much as I've grown to loathe wrenching and being the poor mechanic I am, I still feel most times paying someone to F*** my stuff up is senseless when I could possibly do it myself for free.

Re: exhaust to head issues and question

Britbike220:

Owning a Norton is all about doing your own work; it makes the smile you crack in your helmet that much broader... there are mechanics (technicians) and then there are "specialists" that understand British bikes, who know that most parts need to be fit, not just installed. There are a number of vendors that you can ship your Norton to along witha check for over 20 grand, nearer 30, who will deliver to you an amazing piece of work, but in any case you will still need to maintain it as if it were an original, if you want it to last.

I am suggesting that you can use your 850 exhaust nuts, with OE collets and be done with it, short of someone with more knowledge saying anything to the contrary??

RS

Re: exhaust to head issues and question

Bill, on mine the shorter 850 nuts didn't go in far enough to push the end of the pipe "home", so it could rattle and leak. Possibly you could stack multiple crush washers or the like to take up some of the room, but I didn't even try.

The 750 nuts don't screw all the way in on mine, a few threads remain exposed but not enough to be "unsightly," and they work well.

Are you open for business in Hudson yet? I'd love to see the shop one of these days.

Regards - B

Re: exhaust to head issues and question

There is one guaranteed fix for the problem that nobody has mentioned. Send the head to Leo Goff at Memphis Motorwerks. This and the solution to all things Norton are his speciality.

Re: exhaust to head issues and question

RoadScholar said:

Owning a Norton is all about doing your own work; it makes the smile you crack in your helmet that much broader...
RS

Click to expand...

Totally agree. These are the times I do wish I had at least a table top lathe. I probably could have made a fix myself this afternoon. I couldn't imagine, even if I had the money sending something off to have someone else make a bike for me. it is way to easy to throw money at old bikes having someone else fix them and zero satisfaction knowing you didn't do the work. This one just happened to be at the wrong place at the wrong time and made me buy it.

Re: exhaust to head issues and question

Brian: I' m open for business, call the web number for a beer.

T7275tr: Give Leo my regards, and thank him for the great job he did on my RH4 MkIII head!---no more advertising :roll:

BritBike: Good luck.

RS

Re: exhaust to head issues and question

Fred at old britt's suggested I try the split collets from the MIII exhaust with my 850 nuts and possibly doubling a crush washer. I am going that route as it is the cheapest at this point. I will probably have it redone at a future daye unless this doesn't work.

Re: exhaust to head issues and question

split collets were worthless, too small for the headers and the diameter wasn't the right size. So figuring I was going to have to remove the head again and send it out for a proper repair I tried grinding the excess off the exhaust port. I sealed the port and ground off enough to match the other head. Problem is I couldn't get it even so the threads are messed up at the start of the port. Is there a way to clean the threads up so I can get the nut to thread in the way it is suppose to or am I done? I tried for about 10 minutes to get the nut to line up right, but no matter what I tried it will not screw into the port. It looks like the first thread is messed up and I tried filing it but no good. Is there a way to fix the starter thread or am I done?

Re: exhaust to head issues and question

Make a scraper for the exhaust thread.

Get a 16d nail. Bend the last 1/2" 90 degrees. Grind a flat on the pointed end of the nail that is perpendicular to the thread when you grab the long part of the nail with vice grip. Scrape the aluminum out of the exhaust threads.

You might have better control when you cut down the thread insert if you use a wood rasp for the final cuts. The aluminum will clog the rasp. Clean it with a wire brush. A file for steel will give a finer finish, but it will clog up very quickly.

Greg