Time to rebuild my old GPz

[Garry.L]

Nice finish on the Block.

[GPZ592]

There's not too much progress since my last update as I've been limited in garage time, due to having to get the roof replaced. After 20 odd years, it finally had too many patches and was starting to leak too much in this recent heavy rain, so I had to cover the bike and tools until the old cement board roof had been replaced with a nice new metal one

Anyway, I tried to keep moving along with little jobs I could fit in, one of which was the oil cooler. As standard the GPz had small 3 row cooler fitted as standard. But I wanted to get a bit more oil cooling area, as I have fitted a big bore kit and the barrel liners are a bit thin ! I did look at aftermarket coolers, but they were quite a bit deeper than the standard item and would require a bespoke mounting bracket fabricating. After mocking it up in cardboard and taping it to the frame I found it would likely cause issues with the fork legs hitting the cooler/bracket near full lock. So after some investigation, I found that certain models of the later GPz had a 5 row oil cooler as standard. I reasoned the extra 2 rows would give me extra cooling area and being a standard part, should also easier to mount. I sourced a good used one, including pipes, from Germany and found the upper mounts were identical and by making up a small bracket I could use the existing lower frame mounts to the new cooler lower mounts. The cooler only required cleaning & touching up the paint, but I resprayed the black pipes to freshen them up.

I'll fit it to the bike once I have the engine finished up, which should be the next job, now I have a dry garage

New cooler top, standard below

Refurbished cooler/pipes & shrouds with additional mounting bracket

[r3sc]

That looks good! Should be a useful modification!

[Ultim8pc]

Looking good. Keep up the good work

[GPZ592]

So, after my last update I thought it would be a fairly straightforward job to mount the oil cooler & pipes - but no ! When I tried to line up the pipes to the cooler, they wouldn't sit right at all. After a bit of head scratching, I worked out that the oil cooler was sat too low and by moving the oil cooler to use the original lower mounting points, the pipes lined up ok (remember, I'm using a larger cooler from the later 550 and had originally re-used the upper mounting points). So, I made up some small brackets to bridge the gap between the original upper mountings and where the oil cooler now sat (only about 25mm) and everything went together OK. great, simple fix and on to the next job I thought - but no. When I turned the bars I found the lower yoke now fouled on the upper edge of the cooler before full lock - arrrgh

The lock stops on the lower yoke use a solid peg protruding from the lower frame as the stop. Looking at it, I reasoned I could make up a collar to slip over the peg and reduce the amount of lock to stop hitting the cooler. So, using some ally tube with the correct i/d, I made up a collar and tapped in a couple of M4 button head bolts to help secure it. I also used JB Weld to hold it in place as a belt & braces approach. I'm happy with the result, it's worked out well and I don't really lose that much lock and it doesn't foul the cooler any more

I did also get the cooler pipes ceramic coated as the paint I applied marked really badly during the trial & error of fitting. Whilst the ceramic coat looks good, I was disappointed to find out it also marked during fitting - especially on the upper nuts where the spanner left scratches even though I was as careful as i could be. Perhaps ceramic coating is not as tough as I had believed ???

Anyway, looking forward to making more progress, but without the little diversions

Oil cooler in place

Cooler in place.jpg (104.66 KiB) Viewed 81468 times

Lockstop peg

Peg.jpg (91.51 KiB) Viewed 81468 times

Collar ready to fit

Collar.jpg (20.4 KiB) Viewed 81468 times

and in place

Collar in Place.jpg (116.06 KiB) Viewed 81468 times

New full lock

New full lock.jpg (109.82 KiB) Viewed 81468 times

[GPZ592]

Last weekend was a good weekend in the garage and some major progress has been made on the 550 There was, of course, the obligatory last minute issue to overcome but even that had a positive outcome !

The plan was to get the engine completely oil tight and all the ancillary components & covers fitted, which would be a major milestone in the rebuild. During last week, I spent an evening in the garage getting everything ready in preparation for the weekend. However, when giving a last minute checkover of the alternator rotor, I found 2 sections of the magnets had cracks and one had a small piece missing I went on the internet thinking I might find a better secondhand replacement but actually found a brand new NOS one for £60 No thinking needed there and 3 days later it was in my garage !

Old Rotor

Old Rotor.jpg (41.4 KiB) Viewed 81362 times

New Rotor

New Rotor.jpg (56.91 KiB) Viewed 81362 times

With the rotor issue resolved it was time to crack on and work through fitting all the bits & pieces ! The cam cover went on first (after copiously oiling the cams & valve buckets), followed by the NOS alternator cover and ignition cover with their badges. Next on was the clutch cable, which also retracts the side stand if you leave it down, followed by the clutch cover, the starter cover and suddenly there were no more bits in my box. It all sounds simple put like that, but there was much fitting/removing/fettling to get everything to sit "right", especially the clutch cable & cover, but it was all worth it !

I'm know I'm biased, but I love the all black finish of the GPz

[r3sc]

It does look really well and the finish is superb! Top job!

[chrisNI]

Looks really good

[Skid Mark]

That is looking sweet!

[GPZ592]

Just a brief update on the 550, but it's not all good :-(

After the last update, I filled the engine with oil and spun it over on the starter to prime the pump and try to circulate a bit of oil around the system. All good, until the next morning when I found a small patch of oil under the bike. After a bit of investigation, I could see it was leaking past the seal on the gear change shaft, which is located in a cover that also goes over the gearbox output shaft and the clutch pushrod. So I had to drain the oil, remove the gearbox sprocket and remove the cover to see what had happened. Inspecting the seal showed the lower lip had twisted and the inner spring had come off. Annoying as I replaced all the seals in that cover and taped over the splines off the shaft to protect it whilst fitting. but it must have caught somehow. Anyway a new seal and reassembling everything provided a oil tight seal, thankfully

More serious happened a few days later when the GPz unfortunately fell over I'm actually too embarrassed to admit to what happened on here - no-one to blame but myself and my own stupidity Thankfully, it seems the garage gods were with me as the handlebar fell against a cabinet and the frame got wedged on the dehumidifier thus preventing the bike going completely on its side. The only damage I found was the rear indicator bent up at 90 degrees after hitting some storage boxes and some small chips in the paint on the lower c/cases, but it's out of view when the bikes upright ! The indicator bracket can be straightened and re-painted, the bracket on the frame will also need straightening, but it's a bit inaccessible, so will take a bit of thinking about.

As everything comes in threes, the last problem was I found a broken & missing bracket on the frame. It's for one of the dual horns to mount on and it obviously broke years ago, but I just didn't see it was missing before getting the frame powder coated right back at the start of the project. Now looking at it, I have 3 options -

1. Run with just a single horn
2. Fabricate a bracket and find a good TIG welder to weld it back on the frame. I say TIG as I think it would cause less damage to the powder coat than MIG ?
3. See if I can find an alternate way to mount the second horn. There are a couple of spare brackets I might be able to use but the bracket would be fairly long and convoluted

I'll have a think about which will be the best, but the perfectionist in me wants to re-instate the original bracket - we shall see.

This is the exisiting bracket on the R/H frame downtube

This is whats left of the L/H bracket - only a small piece still attached to the downtube

The two brackets in the middle between the frame tubes are used in the USA for "Reserve lighting device" - i.e daytime running lights. I thought I might be able to fabricate a bracket to attach on these and then bend it to position where the original should be. The only problem is I think it will be quite convoluted and therefore prone to fracture. You can see whats left of the original bracket in the bottom of the picture on the frame tube.

[moizeau]

That is a shame, I did the same with Batfink, fiddling with the carb piping, didn't remove the tank, just wedged it....undented tank fell off and now has a dent.
Regarding the missing bracket, could you make up a bracket and if you've got any engineering places near you see if they've got a single sided spot welder or mig a puddle weld. The puddle weld method is used to repair poor spot welds in production. Remember to disconnect all electrickery.

[GPZ592]

I've put the horn bracket issue to one side for the moment as I may have a solution that doesn't involve welding, but thanks to Moizeau for the suggestion on using a single side spot welder or puddle weld - I'll keep that in reserve

First item on the agenda was to straighten out the indicator bracket after last weeks mishap. The actual indicator bracket was fairly easy to straighten up in the vice and a quick repaint had it looking good. The mounting plate on the frame needed a bit more thinking about. In the end, I fabricated a plate that I bolted onto spare holes in the frame and used a bolt to pull the bracket straight. it worked great and didn't even crack the powder coat

Straighten bracket.jpg (55.54 KiB) Viewed 81107 times

Good as new !

Indicator.jpg (64.22 KiB) Viewed 81107 times

Next up, I rebuilt the carbs with all new "O" rings and gaskets. All the other original parts were re-used as still serviceable. I bench tested them with a dummy tank and It took a couple of attempts to get the float heights right, but eventually they stopped overflowing The head to carb rubbers needed blending in to match to the carb bores as the rubbers are 30mm i/d and the carbs 32mm. Once matched up, the rubbers were attached to the head and the carbs slotted in. It took a few attempts to find the best route for the throttle cables, but I got there eventually.

Freshly rebuilt

Carbs rebuilt.jpg (131.21 KiB) Viewed 81107 times

and fitted

Carbs installed.jpg (116.75 KiB) Viewed 81107 times

Then it was time to fit the exhaust. This is a genuine Harris system I fitted back in the late 80s. I documented the repair & coating a while ago, but now was the time to see if it was worth it. Even though I had numbered the downpipes, I still managed to get no 1 & 2 mixed up ! With that little mishap sorted, the end can went on and it was then I remembered just how close the end can bracket was to the swingarm. Not wanting to tempt fate, the end can came off and the bracket was relieved to give more clearance. A quick touch up with cylinder black (you cant see where I've relieved the bracket as its on the inside) and back onto the bike. Bolt up the header clamps to find header pipes 1 & 2 are touching. off with the can again - more fiddling & fettling, but eventually I got it to sit right, although there's still minimal clearance where 1 & 2 cross over. I think I also remember this from back in the day, but I may just be imagining it

Headers on

Headers on.jpg (89.44 KiB) Viewed 81107 times

add the end can

End can.png (408.27 KiB) Viewed 81107 times

with just enough clearance !

Exhaust Clearance.jpg (64.54 KiB) Viewed 81107 times

and you have a Harris pipe - lovely

Harris Pipe.png (476.18 KiB) Viewed 81107 times

Almost a runner

Almost a runner.jpg (126.64 KiB) Viewed 81107 times

Next time I post an update, it might just be a runner

Mark.

[Bill P]

Beautiful , Top job your doing

[GPZ592]

Well, the 550 isn't a runner yet - there's some electrics to sort out and I'm waiting on some help for that, but there's still jobs to be done :-)

First up was a slight issue with the oil cooler pipes, when I noticed one of them was touching the no3 header pipe :-( A lot of head scratching followed trying to work out why and I thought I'd have to drop the exhaust off (again) and put a slight bend in the oil pipe to clear it. But first I thought I would try loosening off the oil cooler bolts to see if I could get enough movement to get clearance. Once I tried that, it became apparent the top holes in the 2 small brackets I made up to bridge the top cooler mounting points, were slightly out of line - only a couple of mm, but enough to put the oil line slightly off line. Elongating the holes slightly brought it all back into line and problem solved :-) I will look at making those brackets again at some point in the future, but for now they'll do !

I was having a coffee and a chat with a mate whilst showing him progress on the GPz. As he's an aircraft engineer, I was picking his brain on the best way to replace the missing bracket - possibly welding as I'd already discussed or some other way of getting the horn mounted on that side of the frame. After looking at the problem he suggested making up a single bracket the spanned the width of the frame - use the good mounting point on one end and make up a tie bracket from the spare lug I'd already identified to support the other end - genius So that's what I've done - I've fabricated a bracket for the horns and a tie bracket, using the redundant mounting point on the frame for the USA spec "Reserve lighting device".

So this is the original bracket on the good mounting point

Original Horn Bracket.jpg (67.75 KiB) Viewed 81045 times

Here is the new bracket in place - the slot & holes are there for airflow as I was worried about obstructing air over the head as the new bracket sits right in front of the cam cover

New Bracket.jpg (82.46 KiB) Viewed 81045 times

It's supported on the other end by this bracket & spacer on the unused frame lug

Horn Bracket Stay.jpg (76.07 KiB) Viewed 81045 times

It'll all be sprayed gloss black before final fitting and I doubt you would spot it if you didn't know it was there. Sometimes it takes a fresh look by someone else to come up with the best solution

Mark.

[GPZ592]

A little progress on the GPz but, as always, there's a step backwards as well

The horn bracket has been sprayed, installed and is looking good !

Horns.jpg (110.12 KiB) Viewed 80278 times

The electrics have been completed thanks to the ubiquitous Ferret, but not without a couple of issues (not his, I might add !) After all the work was complete, I turned the switch and............. nothing. This was traced to a faulty main fuse, so I used another new one and the same thing happened, so I tried another and guess what - another faulty fuse Out of a pack of 6 new fuses, the first 3 were duff The rest went in the bin and Ferret fitted one from his stock and we had life !

Fuses.jpg (28.37 KiB) Viewed 80278 times

The fuel level indicator was not displaying correctly. A quick check pointed to the sender unit, so I stripped it and found corrosion inside. After a clean up and re-assembling all was good.

Fuel sender.jpg (52.31 KiB) Viewed 80278 times

I haven't seen this light up for a good many years !

Clocks.jpg (107.47 KiB) Viewed 80278 times

The next day, I went into the garage thinking I was getting close to the GPz bursting into life again, but a simple check suddenly had me on the back foot. I went to put the steering lock on and found it wouldn't engage. Strange, I know it worked earlier in the rebuild as I tested it. The came the inevitable light bulb moment. You remember the issue I had with the forks hitting the oil cooler and how I made up a sleeve to restrict the lock - well as I couldn't now get full lock , the steering lock wouldn't engage - Genius, NOT How could I miss something so obvious...................................

So, I've had to remove the lock stop and the oil cooler has had to move back to it's original position, which now means the oil lines are too long, etc ,etc. So I'm back to square one with the larger oil cooler. So I now have to modify or replace the lines. I've asked the question in the "help" pages as to whether this is possible so we'll have to wait and see what happens there.

Mark.