Hello folks  :)
I know it's not the right board, but let me first introduce myself. My name is Hristo Nikolov, I'm from Bulgaria and I am also Monster addicted. I have my M600 Dark since 2008 and with small cosmetic modifications it was my ride until the spring of 2013. In one of those cold days I decided to repaint it's frame and engine covers because they have paint damage caused of the well-known (but still new for me) battery leak. It wasn't so bad but it was a good reason to start this rebuild. The topics in Accessories and mods, Tech and Tutorials really gave me the need confidence, some technical information and mainly thrilling to start working on my bike rebuild.
Before the beginning of this topic here I made a lot of work on the bike, because nobody wants to read one wear old story which is not finished yet. I cut a lot of it's parts, throw away most of the plastics, fabricate a few custom parts, almost full repaint and some upgrades from the bigger monsters. But the bike is still unfinished and I need some help and advices for the final building and making it alive again.
It's budget, more old school style like in the 60’s with no fancy Rizoma and so on accessories and expensive stuff for a few reasons. But mainly because that's the way I see the motorcycle building culture and my personal bike philosophy is that the less is more.
Enough empty words. It's time to see the end of the previous life of the little monster.



It’s nothing special. Black M600 with dual headlights, belly pan, Leo Vince high mount cans, tail chop and repainted swingarm and foot peg consoles.

Let the fun begin:



A few hours after and there is what I call a naked bike:



It was time for a little “asslift”, because when I bought the bike it was freaking low. It was equipped with rear shock from a newer monster which is more of an inch shorter and I was forced to lengthen the suspension linkage to adjust the height and clearance. But this approach didn’t work at all, because the linkage was smashing itself into the frame in the moments when there was maximum compression of the shock.

This picture was made before the lengthening of the suspension linkage:



The decision was to lengthen the linkage from the upper side where it connects to the rocker arm to avoid the interference between the frame and itselph. Meantime I bought the proper rear shock for my model, but I didn’t give up from the linkage modifications. I bought the new (old) rear shock with rocker arm and suspension linkage, so I had a spare one to start modificating.

After some scanning, measuring and CAD drawing I had the parts laser cuted with new bushings:





But 2mm seemed to be thinner to my expectations and I made new ones with thickness of 3mm.



After welding:







And the final result with the standard shock and the new linkage on the bike:













Kinda sexy isn't it 
Now it’s time for more disassembling 

Let's proceed with taking off the wheels, front suspension and separating the frame and the engine.



The front end needs fresh oil and I changed the fork seals and dust seals too. Also I decided to paint the down part of the fork legs in black plus powder coating the steering head in black, like the 695 Monsters are painted.

The wheels are in good shape. Only the back tire was for replacement. I put Pilot Road 3 on the back.



The engine is in good shape, but the generator and clutch covers plus the valve and belt covers will be painted in ……black of course. I will change all the bolts with stainless steel ones plus all needed gaskets and o-rings. I was forced to buy a whole upper set of gaskets and o-rings but now I have almost all I need. The next thing on the engine is a little performance modification, but that's another part of the build where I'll need your help fellas.


Let's have a look at the frame. The only thing before powder coating was to get rid of the unneeded ears for mounting of the side body panels and the carburetor air vents and to sand down the weldings. As I sad I'll try to get rid of most of the plastic parts except the fenders, the belly pan and headlight fairing.



Also I decided to put two end caps in the holes where the frame was chopped. I made a mistake with the outside diameter of the caps, because they had to be the same diameter as the frame pipes, but they seem to look good.



Now the frame, the handlebars and the other parts are ready to become to the “dark side”







Sorry but at this moment you have to imagine how the repainted parts look, because I don’t have pictures of them, but there will be a lot of pictures I promise. 

Looks like fun!        

Good work.
Looking forward to seeing pics when its finished.

Nice!! 

Looking forward to seeing more pics.

Hi fellas !!!
First I want to thank you for the support and interest about my build.
Time to proceed with the next part.

To get rid of the plastic body panels was the easiest part of the job, but now I have two more things to do before I can review more of the gorgeous trellis frame.
First one is to hide the electric loom which goes on the right side of the frame. And the other thing is to replace the oil breather tank, located on the left side.
Yes it’s the ugliest bit of plastic on the bike, but I decided to fabricate new one and keep the crankcase breather system, instead of installing a little filter on the crankcase breather valve.
I believe that this system helps to reducing the pressure in the crankcase and to gain a little bit of horse-power from the baby monster’s engine, or just not impeding it to produce a horse-power 
So I had to find something which can be easily converted into oil breather tank. It has to be light metal, so why not use one of my cast aluminum boxes that I used for DIY guitar pedals. I had one (Hammond 1590B) with the following dimensions: 4.25 x 2.22 x 1.22 inches and it was looking perfect for the job.

Now I only had to fabricate two connection pipes and two mounting ears and to weld all the parts together.
I’m not a welder, but I know the right guys to get the job done.






And here it is mounted on the freshly powder coated frame:





On the last picture you can see how close it is located to the rocker arm, but I hope there will be no interference between them. Otherwise it will be too pity for all the work on that particular part 



I have the engine cases and other engine parts repainted and all the gaskets and o-rings, so the next one is the engine assembly. Stay tuned, because I’m starting with the questions soon 

Hi, it’s me again 

When I started the rebuild it was only caused by cosmetic reasons after the battery acid mess. But soon after the start of the project I decided to make some little engine improvements.
The first was to put oil cooler, because I like to ride it a lot and on comparatively long distances in a hot weather, but this upgrade will be theme of another post.
The second was to improve the power and to provide better throttle response.
I can't ask much from this engine, with only 53HP, except a little more power gain and smoother throttle response. The fuel economy is important for me too.

About the modifications that I'll try to make:
1. Leo Vince SBK slip-ons.
I don’t like high mounted cans, so I will bring them to my welder to make standard mid pipes from my high mount mid pipes. And then the cans and the pipes must be polished. This will be one of the last things on the bike, because I have to assemble it first before manufacturing the new mid pipes.

2. K&N air filter + open air box lid.
I bought K&N air filter and maintenance kit for it. And had to buy spare air box to replace my eaten by an acid air box. It came with the lid on it, so I have one spare to modify, but I’m not sure how much to open it.

3. Carburetor mods and adjustment
This is my biggest concern in this build, because it affects the total engine and bike performance.

4. Polished intake manifolds
They are extremely long ad I’m not sure about the benefits of polishing (grinding) in them, but I’ll do my best with my dremel and some sand papers 

5. Short velocity stacks
What about to shorten them

6. Iridium spark-plugs
I have a pair of NGK’s but I’ll put them after carb adjustments. 


I'm not sure about what will be the result of these small and simple mods, but i want to try!

It seemed to be hard to find DJ or FP jet kit on a reasonable price, because of the shipping costs from USA to Bulgaria. I can’t find jet kits in the British e-bay too. So I’m thinking of buying only pilot and main jets with new o-rings and to keep the stock springs and needles.

Already cleaned and disassembled the float bowls of carbs. Set the float height to 15mm.
My jetting is stock (132.5 main and 40 pilot). I found e-bay shop that sells original Mikuni jets, and it may be a better decision to buy 135 and 137.5 main jets plus 42.5 pilot jet and
o-rings for the mains from there.
But before making the order I like to hear your advices, about what jet sizes are reasonable to use combined with the other intake/exhaust modifications that I intend to do and my engine improvement aims.
Thanks in advance fellas 

#4) do not polish inside the intake manifolds. The bit of turbulence created by the "natural" finish is preferable. I believe a while back I was gonna do this and before taking my dremmel out Brad Black piped up and said don't do it and why.

Quote from: memper on February 20, 2014, 04:56:31 PM
#4) do not polish inside the intake manifolds. The bit of turbulence created by the "natural" finish is preferable. I believe a while back I was gonna do this and before taking my dremmel out Brad Black piped up and said don't do it and why.

I think "polish" is the key word here, you do not want a mirror finish. However I have, over the years, "cleaned up" plenty of intake manifolds and intake and exhaust ports. None of these ended up polished but casting marks were removed as well as matching the manifold and head openings. This is common practice and does not negatively affect turbulence and can bring improvements to flow rate

Thanks for the advices about the intake manifolds 
I’ll leave’em unpolished for now. I have a lot of more significant things to do on the bike, but your help is highly esteemed!

These are some of the repainted parts:



I checked valve clearances and they are all in spec. Then I attempted to put all the covers in their places. Starting with the starter and valve covers using new gaskets, but I forgot to buy some of the needed stainless steel bolts for the other covers 
After I have the other bolts I’ll proceed with the assembly.
Monster 620 manual from 2006 is recommending to use Shell Retinax HDX2 grease on the engine bolts. What about using high temp anti seize on engine cover bolts

I have new gasket for the clutch cover, but I’ll use some proper silicone sealer for the generator cover.

Next one â€" the rear hugger. It was ugly, scratched and even not for my monster (different profile where it sits on the swing arm) So time for cutting:



And with the new paint:





Now the profile is matching my chopped front fender 

And if you are wondering what happened with the original rear hugger:



It became to serve as fairing over the dual headlight.
I needed 4 years to find out this brilliant idea of the previous owner of the bike 

Nice work!

Clean up the intake manifolds if they are rough and leave a "machined" finish similar to the textured crosshatch finish on cylinder bores. I have seen both casting dags and mirror finish in M900 manifolds!

I found some benefit from shorter velocity stacks on the long manifold 900 or in combination with extensive airbox mods, by offsetting the too long intake tract for the 900. I believe it also helps utilize the volume of the airbox. However, it may be that the smaller the capacity the less helpful it is. Brad Black tried it on a 750 and it helped only a very little, so if the pattern continues I wouldn't bother doing it on a 600.

Hopefully some members with 600 experience will be able to give you some carb settings for the 600 with open airbox. I open the airbox completely, but some only open the rear part to keep water out. Others make Swiss cheese holes!

looking good!   

Looks great. What did you use to cut the rear hugger and how did you paint it to get such a nice finish?

Keep up the good work! (from another M600 owner)

...And keep us updated on your progress.

Many thanks to all, especially to you, Tony!!! 
In this moment I can only regret not having M900, because of your experience with the bigger carbureted 900cc engines and the wish to help.
I’m still in need of help with the jetting of my carbs, but this can wait for now.

@D3vi@nt, the cutting was made with small coping saw. And after that some final filing and sandpaper work for nice and symmetric curves. About the painting I’m using a professional painter’s services. The paint is made by “Mobihel”, with catalog number M-40600. On it there is matte clear coat and under it there is primer for plastics. I’m not familiar with painting, and I can only enjoy the good paintwork 

To put some update on the project I’ll show you the work on the headlight holder.
I cut the aluminum headlight bracket holders and then they were rewelded again about an inch lower.



Definitely don’t like how the horn is placed on the frame, and it can stand in the way of the oil cooler that I intend to install, so I decided to hide it behind the dual headlights. This was made by welding extra piece of aluminum to the headlight holder. After powder coating of the headlights and their holder it looks better but no pics for now