My M750 Rebuild

That is looking very neat.
You mean these things: http://www.ebay.co.uk/itm/like/27138...s=true&ff13=80
with this? http://www.ebay.co.uk/itm/AUTO-Stain...3D331634280627

Darren + DrD

Thanks fellas, that'll do nicely

Cheers

[Mr Gazza]

Going back to your question about the shock hitting the swinging arm.
If the engine is supported in the picture, and the shock is at full extention, then surely it can't hit the arm if it clears now....It will move away under compression..?

I reckon it got a knock during assembly?

Powder coating is looking very effective...Came within a gnats of doing my frame like that, but wasn't brave enough.
Did you see the mirror chrome coating that they do with colours dropped in?....You could get carried away...

Promise me you will be using a gel battery, like a Motobatt. Powder coating is chemical resistant and easy to keep clean. but I couldn't bear the thought of battery acid spilling on your frame.

[Darren69]

How weird was that? Dr D & I posted almost identical item links. Great minds. Yes, please use a AGM type battery, I think battery acid will damage almost anything to some degree. Motobatt seem a popular choice and mines been good so far. AGM type usually need a trickle/maintenance charger to keep in good shape.

[Flip]

I use the Tyagi Racing stuff from eBay on my little racer which seems pretty good quality but take care on the Monster as some of the fuel lines are pre-formed and so would probably kink normal lines.

Also because it is braided you would have to take care that it didn't rub against that lovely frame or the underside of the tank because it would be like a file against it.



The eBay quick release unions work well too but because my racer has old style taps I don't need them on that but I use them on a couple of other things

[Darren69]

Originally Posted by Flip

I use the Tyagi Racing stuff from eBay on my little racer which seems pretty good quality but take care on the Monster as some of the fuel lines are pre-formed and so would probably kink normal lines.

Also because it is braided you would have to take care that it didn't rub against that lovely frame or the underside of the tank because it would be like a file against it.



The eBay quick release unions work well too but because my racer has old style taps I don't need them on that but I use them on a couple of other things

Yes, good point about the paint, you could probably put some heatshrink over those parts that are likely to touch anything.

You've a Motobatt battery in there too I see!

[Dirty]

http://www.ebay.co.uk/itm/Sytec-Brai...item3cce6a2a9d

Originally Posted by Mr Gazza

1. Going back to your question about the shock hitting the swinging arm.
If the engine is supported in the picture, and the shock is at full extention, then surely it can't hit the arm if it clears now....It will move away under compression..?

I reckon it got a knock during assembly?

2. Powder coating is looking very effective...Came within a gnats of doing my frame like that, but wasn't brave enough.
Did you see the mirror chrome coating that they do with colours dropped in?....You could get carried away...

3. Promise me you will be using a gel battery, like a Motobatt. Powder coating is chemical resistant and easy to keep clean. but I couldn't bear the thought of battery acid spilling on your frame.

Yo Mr G

1. I couldn't understand it. Everything was the same as before (when the shock didn't touch the cross member) except for the addition of the Luigi Moto bits, and the shoulder of the shock was deffo touching the square section cross member on the swinging arm.

I thought i might have put the shock in the wrong way round (180 degrees off) but it was even worse the other way.

As a draftsman I was going to draw a swept path diagram to try and understand what was going on (but have been so busy in work blah blah blah blah) Think about it, wheel gets pushed up as suspension compresses, then that movement gets passed, via the swinging arm and suspension hoop, to the rocker arm which has an unequal pivot point at the top of the system - which then compresses the shock onto the bottom shock mounting of the very same swinging arm that moved up in the first place when the suspension started being compressed!! it's feck ing mind bending for me!!

Anyhow, the bottom line is that when the suspension compresses it appears to slightly change the angle of the shock (leans more forward), and the extra height of the Luigi Moto risers exaggerated the effect to the point that the increased angle caused the "shoulder" at the bottom of the shock to come into contact with the square section cross member of the swinging arm.

Proof of pudding - shock no longer snags swinging arm without risers.

From reading posts here I know that these risers are popular and used by loads of people and I haven't read a single post where anyone else has come across this problem so I am beginning to think the problem is more likely to be something I have done wrong rather than anything wrong with the risers - or an outside chance that i've got some kind of mongrel bike (see frame spacers post above)

2. Aerocoat are brill, I was almost entranced by the chrome effect powder coat with multicolour metallic glitter flakes and opalescent lacquer over, but I'm not quite gay enough, and I don't live in Brighton.
Was originally going to do the swinging arm in black powder coat, but am now glad I went for the full bling effect.

3. Gel battery will be used although I might use an old Fazer 1000 battery I have lying around here to get it started (and probably burn out after 4 charges in 24 hours!) for the first time in 6 years!


Albie

Earth lead now connected properly (honest) pic to prove to follow.


Recently saw a thread where the guy had blanked off the oil cooler bypass feed to the carbs - can anyone point me to that please?


Thanks to all for your help

Thanks Dirty - they look good for visible connections

[Mr Gazza]

1. Yes the dynamics of the rear suspension can be a bit mind bending, espesially when you are trying to get your head round the effects of changes to it.

I very slightly increased my ride hieght by winding the rose joints out a bit. I was very puzzled as to why that caused an increase in sag and a subsequent need to increase the pre-load....and then a couple of clicks of rebound too.

A swept path diagram would be beyond me, but I have considered a little balsawood model to study the dynamics...A simpler model could be made from stiff card and those paper fastener rivets with the two pointed legs that we used to use in primary school..

I doubt that your bike is a mongrel, but it might be posible that you have a different rocker?
I know there are different types, but whether they vary in geometry I couldn't say. There is one (Rare) design that is adjustable, from an 888 or 851 I believe.
If you have one of those you could be in the money..

2. How gay would I have to be?

3.

Yo Mr. G

Having a duvet day tomoz, so if I get a chance I will do some measuring and do a rough swept path diag for us.

But then again I might just drink, drink, f*****g drink all day!

[utopia]

I have risers fitted on my yr2000 750 and no fouling issues ..though the shock is a Nitron so its not precisely the std set-up.
I think your analysis that you may either have something mis-assembled, or an odd mix of mongrel parts, sounds like a sensible one.

I'm not certain, but I think the linkage geometry works out that the shock gets compressed 'from both ends' as the load is applied.
I have a notion that one day I might get round to plotting out the movement of the suspension linkage through its full range of movement, but ....
I did try once but came unstuck as its difficult to accurately measure all the relevant dimensions on the bike.
I now have an alternative plan which involves making a measuring device to replace the shock (basically two tubes, one inside the other, with a mounting at each end and a scale marked on the inner tube).
The plan is to fit that, then move the suspension in increments, noting the shock deflection at each point.

I'm not too surprised by your unexpected findings that more preload was necessary after fitting the risers, Gazza.
Not that I would necessarily expect that precise result but the relationships within the geometry are unlikely to be as simple as you might think at first sight.

I guess that really, I should have done my geometry investigations BEFORE fitting the Nitron but as you say, lots of folk have fitted them without problems ...and sometimes life's too short.

Originally Posted by Mr Gazza

I very slightly increased my ride height by winding the rose joints out a bit. I was very puzzled as to why that caused an increase in sag and a subsequent need to increase the pre-load....and then a couple of clicks of rebound too.

I'm always amazed how such small changes can have such a huge effect on the way a motorcycle rides/handles.

10 years ago I bought a 1997 FireBlade, which was a revelation (to me) in the way it handled.

Being a dumb*ss, i thought I could tailor it to my riding style (slow and wobbly) and that's exactly what I managed to do, it was unrideable, except in a slow and wobbly fashion, cos i had put two more clicks of this, and half a turn of that, and completely f**ked it up!!

I may be dumb, but I am a fast learner - if it ain't broke - don't fix it!

And if it is broke, find out how to fix it before fixing it!

PS Am expecting to change this shock for something thats not 18 years old once the bike is up and running (getting it unSORNed, taxed + MOTd being my priority now) so am not too worried about the old dear of a Showa that's there now as long as its MOT worthy.

Attempting to keep the rebuild momentum going, I am parking suspension problems for now and moving onto the fuelling side of things.

Having been brought up on Japanese 2 strokes back in the late seventies (GT250 Suzuki, RD350LC Yam, KH500 Kawasaki and a couple of trail bikes) I am aware that any changes to the air intake or exhaust sides of the engine may (will) require changes to the carburation.

These are my intake and exhausts. (Similar "silencer" on both sides)





Does anyone here have any thoughts on where I need to go with regard to jetting, needle positions etc?

Would love to go the flat slide route but my budget does not allow such extravagance.

PS Mr G, am still planning a swept path diagram for the rear suspension, and will use the dimensions you are getting for the rocker and shock length in your other thread. Will post as soon as done.

[Darren69]

I would suggest that maybe the standard Dynojet kit for Open exhaust and airbox or pod filters would be a good starting point. Dynojet Stage 2 or 3 if you can get one.

http://www.dynojet.com/jetkits/