900 Monster - Putting it back together.

Well I've started putting my Monster back together after taking it to bits to investigate low oil pressure, burning oil and bits of metal on the mesh strainer. I haven't taken any pics of the dis-assembly process but I've tried to take a few as I'm putting it all together again.

I'm not suggesting that anyone uses any of the methods or procedures that I've used, there may or may not be better ways to do this, if in doubt don't do it and use a local dealer or specialist instead. Incidentally I'm always open to advice and suggestions.

It was easy enough to take apart, the only tool I bought was one for the cam pulley peg nut and a local garage used a big puller to get the primary drive gear off the crank, other than that I made up pullers using lengths of studding and various spacers and sockets to get bearings out and of course a bit of heat from the heat gun. I was tempted to try and get hold of this, the latest special piece of equipment but the price put me off a bit




Many of the allen head bolts appeared to be made of cheese, the internal hex form had corroded away on quite a few meaning I had to drill them out, especially on the front of the engine, the bolt heads had also corroded into their recesses on some, so they also got the drill treatment, funny thing was that once the bolt heads were drilled out, the threaded portion of the bolt came out easily so that saved some grief.

I was merrily removing bearings from the left hand crankcase when I found a good size piece of gear selector return spring hiding in a recess behind one of the gearbox bearings, that of course may go some way towards explaining the bits of metal on the mesh filter.

Well last Friday a big box of replacement parts arrived and I got started. I'd previously stripped what was left of the paint off the engine and cleaned it up in my parts washer. A few years ago I used to use Nitromors and found it well capable of stripping anything you wanted, the new stuff however is worse that useless so I used gasket remover and found it did the trick and after a fair few hours of wire brushing and scraping the cases were back to the metal. The missus had gone away to her brothers for the weekend so after the parts washer bath the bits were brought into the kitchen for a good dunk in hot soapy water followed by a good blast of compressed air to get rid of all the bits that may be hanging around. Then it was time to bung some paint on, I used Simoniz silver engine enamel pn the cases and Cal Gard Gun Coat on the cam end covers and rocker covers, then cooked the bits in the oven in the kitchen for the required amount of time. I have to say that there was a fair old pong so be warned as you don't want 'er indoors playing holy hell.


When everything had cooled down I started putting the new bearings back in place, here's the cam end caps with their bearings, these have a seal on one side only, little bit of heat required here to get 'em to ease in.



Then the cam bearings went in, I'm using a big hardened bolt and a socket with the old bearing pressing against the new one to get them in, don't forget the spacer that goes between the two bearings.



Then the rocker gear went back into place, me being a cheapskate, instead of forking out for the proper tool or an imitation I used a common or garden tie wrap to hold the spring on the closers when I took them out, I did them up nice and tight and after spending 10 minutes or more doing the first one I was able to do the others quite easily.



Then it was the turn of the cam shaft oil seal to go in, I just used a good fitting socket to tap it home.




Although I'm using all new bearings and seals I found that the valves were well within spec so they're going back in, the valve seats and faces showed absolutely no signs of any wear, pitting or corrosion. After holding each one lightly so as not to mark the stems in the three jaw chuck I gave 'em a bit of a spin using a Scotchbrite pad to get them all nice an shiny again, there was quite a bit of carbon on each of the exhaust valves but it all came off eventually.



I've put all but one of the crankcase bearings back in and that's only 'cos I forgot to order it. They all went in quite easily with a little bit of heat from the heat gun and using either a socket to bear on the outer race while tapping with a hammer or in the case of the main bearings I used the old outer races. Where I could, I used a draw-bolt and spacers to get them nice and snug




Well that's the story so far, I'll try and update this when I can but no promises as to when, hope it's of some use.

 

The stuff I'm using is called "Simoniz Engine Enamel", I do remember Sperex from the good old days but wasn't aware of the comnnection. The cases were very badly stained and pock-marked from corrosion so they had to be painted and even if this stuff doesn't last as long as I would like, it has to be better that the factory paint. I think I did enough preperation, plenty stripper, a good going over with a wire brush in the drill chuck and a scraper, then a good scrub in the parts washer followed by a nice hot bath with lots of detergent. After spraying I then baked everything for the recommended amount of time at the recommended temperature so it's now just a case of suck it and see.

For the headers on my Guzzis I've always just used BBQ paint and had reasonable results, I haven't decided what to do with the ones on the Monster as although they are looking a bit scruffy they are very sound so I might just clean them up rather than try and coat them.

 

Looking good. Did you bake it after spraying it on?

 

Well, I did a little bit more over the weekend. This is the piece of gear mechanism return spring that I found lodged up behind one of the gearbox bearings. Luckily it hadn't travelled far otherwise there might have been quite a bit of damage caused.
I fitted new oil gallery plugs, putting loctite on the threads then new big end shells and new bolts on the con-rods.


New output seal gently tapped home using an old gearbox bearing race.


Got the crank in and using the method in the Haynes manual I got 0.10 pre-load on the main bearings, I've read that anywhere between 0.05 and 0.15 is acceptable so I'm happy with that. Gearbox shafts and bits and bobs were bunged in and the whole lot boxed up.

This morning I got the Le-Mans out and had a ride down to Tan Hill, the highest pub in England, in North Yorkshire, bit nippy on the way down but the sun got out and by the time I got home at 3pm it was nice and warm again so back into my man cave to put more bits together.

Primary gear and oil pump went on first,


then it all came to a halt as I've lost the new oil seal that goes on the primary cover, I know I bought one as I've got the invoice but can I hell find it so it'll have to wait till later in the week. I'll pick one up at a bearing suppliers when I get time, so that's all for now.

 

Couple more jobs done on Monday and tonight, took the Le-Mans for a blast on Tuesday night so did nowt to the Ducati. I find early evening on weekdays is the ideal time to go out for a ride, it's light until late and there's very little traffic on the roads, especially in rural Northumberland which is where I like to go.

Put the gear selector mechanism in, there's a line on the claw which has to lie halfway between the pins of the selector, easy enough to line this one up by eye.




Then the primary cover went on followed by the clutch. Note the home made clutch holder, two clutch plates, one steel and one friction, tightly rivetted together then bolted to a bit of scrap aluminium which in turn is bolted firmly to the engine case. As long as there is no slack and the whole lot is done up nice and tight, it's a doddle to get the clutch nut off and on.



The more observant amongst you may notice the two missing pegs on the clutch hub, that's 'cos I broke one of them off a while ago while attempting to change the clutch basket and before I'd come up with the idea of two plates to hold everything still. I reckoned I might as well make things more or less equal so I snapped the opposite one off too. It's made no difference to the ability of the clutch to transmit power and if anything it's made it a wee bit lighter. It'll stay that way untill I get a replacement.

Cylinder studs went in too, just used two nuts locked together to wind them in. The swinging arm bearings and seals are in, I used a long draw-bolt with a couple of sockets to pull them in. To make sure that they all went in nice and square and to avoid using too much force I turned a drift out of scrap aluminium which was just a nits knacker under the diameter of the recess in the crankcase where they fit. This ensured that there was no chance of them going in at an angle.

I was going to crack on with the alternator side but I've lost, in the midst of my garage, the woodruff key for the cam pulley drive shaft so everything comes to a stop again 'till I get a new 'un. I'm going to call in at M and S in Newcastle tomorrow on the off chance that they have one in stock.

So that's all I've got to report for now, at least it's starting to look like an engine again.

 

Bit more done today. Heads and barrels went on with no drama, plenty oil squirted down the bores before slipping the barrels on, all new gaskets and o rings, I even remembered the little oil gallery jet thingies that go between barrel and head. You can see the head nut wrench that I use, it was made by a fitter at a place I used to work at, not pretty but it does the job.



Put the frame on the engine next, then put the carbs on, I also fitted the throttle cables at this point as they are a right royal pain in the jacksie to get in when all the other gubbins are attached. Then the swinging arm went on, shocker and rear wheel.



The swinging arm pivot pin is knackered so I'll be putting a new one in when it arrives but in the meantime I'm using the old one so that I can at least move the bike around when I get the front end on.



You can quite clearly see the wear marks from the roller bearings, they are only on one side of the pin and on one end, same end as the final drive. These cost about £70 a pop. Cam belts are on and tomorrow I'll put in the tensioners and stick the covers on.

 

Well, it's almost all back together, the only things left to do are to tidy up the wiring and try to get it all back in it's original location and to give the bits that I haven't touched a bit of a clean up. I'm also waiting for the new swinging arm pivot pin to turn up but the old one will do until then.

This hasn't been any sort of a restoration, just a freshen up of the engine and a new coating on the frame. All bearings, gaskets and seals have been replaced, I didn't touch the guides or small ends as I couldn't detect any play. Looking back it's been relatively easy, I had visions of shafts and shims bouncing all over the garage after spiltting the cases but with a bit of care and a bit research care of the net, there has been no drama. Only tool I bought was for the cam pulley nuts but even then the Haynes manual shows how to make one, all other tasks were performed using whatever was at hand, clutch holding tool was two old plates rivetted together for instance and I'm lucky in that I have a lathe for turning up the odd drift or mandrel.

When it came to the head nuts I was able to ask a truck fitter to weld up a u-shaped spanner for me but if you use one of those flat jobbies that are on ebay I found a neat little zip file to enable you to calculate the correct amount on torque to apply when using an extension, it's at:-

http://www.belknaptools.com/media/rte/product-images/ExtensionCalculator.zip

Just to repeat, I'm not suggesting that anyone uses any of the methods or procedures that I've used, if you're not sure, take it to a specialist.

So here's a few pics, still a little bit of tidying to do but it started straight up and sounds nice and quiet, just got to dig those old Termis out of my shed and away we go.

 

Thanks for the replies. The frame is a light satin grey, I think the pics make the powder-coating look a bit lighter than it actually is.