NC30 damper rod forks part identification

[28hodge]

Need some help please,

The gold part on the top of the damper rod, has anyone seen one and know what it is?

I was going to buy some RaceTech emulators, however im not sure what the gold part is, its NOT a RaceTech emulator but its sitting where and emulator would sit, and as the holes are drilled in the bottom of the damper rod I'm wondering if i already have some sort of emulator set up in there.

When I bought the bike I was told it had maxton modified forks, the bike was club raced in the late 90's then sold to a guy who did one trackday on it and then left it in his garage for 10 years before I bought it, so whatever was done to it was done a long time ago.

Any help?

[lukemillar]

Have you got a pic of the emulator by itself?

I'm pretty sure though that single compression hole will still have an affect on compression. I'm kicking myself as I didn't take any pics of my forks when I did mine to refer back to now.

[28hodge]

I have but i am at work so cant get onto photobicket to put them up.

Its not an emulator though, it basically seems it is the top of the damper rod so im not sure what its purpose is, it is attached to the damper rod and won't come off. The forks do feel pretty good until heave braking when i seem to get quite a lot of tyre squish and it all feels a bit unstable, i never use more than half the fork travel.

[28hodge]

[lukemillar]

That first pic is interesting. Correct me if I am wrong but it looks like there is no valve in the emulator i.e I can see straight down to the bottom of the damping rod?

The standard rods have a collar and spring where that brass thing is which sort of self centres. I'm wondering if they just swapped that out for a solid bush? Even though I did my own forks with Racetech emulators, I chatted a fair bit with the suspension tuner who supplied the kit and built my shock. He said that they often have to machine the damping rods to ensure that they sit squarely in the fork tube. I wondering if this solid bush is another way to achieve that?

An emulator would actually sit on top of that bush. If you could confirm that there is no valve or bleed holes in that bush except for the large one the is in the middle, that would be good!

[28hodge]

Nope your dead right Luke, its a clear path from the top to the bottom, so either that brass bush is like you say there to act as a method to keep the damper rod central, or its a emulator that has had the valving removed. I doubt i will ever find out.

There is no bleed hole or anything on the brass piece it is just a bush, all compression damping is controlled by the small hole at the base of the damper rod and then the small rebound hole thats at the top. I did find these though which look promising....
http://www.debrix.com/41mm-Fork-Damper- ... 361-vt.htm

Having done some measurment and som half arsed technically drawings they should sit into the top of the brass bush that are at the top of my current damper rods and are a cheap option compared to the racetech ones, they also fit straight into the mk1 sv650 forks and by all accounts are just a direct copy of the racetech part.

[lukemillar]

Yep - you should easily be able to fit emulators. Might need to machine the ID of that bush but if it follows stock dimensions, it'll probably just fit. The overall height isn't important as you just modify the spacers to suit. Just need to make sure that the emulator can sit squarely so the top of the bush must be true.

Have seen those Racetech copies before - I think they are ok. When I owned an SV, a few of the guys in the UK fitted them and from what I remember got pretty good results.

I would definitely recommend emulators though as damping rods are always a compromise between high and low speed compression. Looking at the setup you have, it is biased towards low speed compression (obviously for track riding), but if you hit a bump, then it would probably be pretty harsh!

Racetech wrote a great book on suspension and principles in which they talk about emulators. I just found this link, which is the exert from that book and a worth a read if you haven't seen it:

http://www.racetech.com/page/title/Emul ... hey%20Work

[28hodge]

Cheers Luke,

Yeah ive got that suspension document saved on my PC its a good read though.

I think i may need to get a machine shop to square up the top of the damper rod a little to make sure everythng sits flat and level but im going to have to wait till next year i think.

Got Cadwell with BEMSEE on the 14th&15th of Sept then thats probably all ican afford to do for the season, so i'll get it all swapped out over winter ready for some feb/March trackdays hopefully it'll go ok.

Yeah its only ever been a track bike so its set up for that, i cant say i have ever felt any pain from hitting and bumps but then again you dont get the same bumps on track as you would encounter on the road, i just never seem to use anything like full travel even under real hard breaking.

I've been looking at pictures of myself braking into corners and the front isnt dived as others when tipping in, guessing this all effect the geomentary of the bike entering the corner, I only use 10W oil in my forks, dont really want to drop to 5W but it may be worth a try.