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420 Chain

1619 Views 25 Replies 5 Participants Last post by  Barnesjaca
Has anyone ever put a 420 sized chain on their bike? I’m under going a large project to lighten my 500 as much as I can while a) staying practical and b) not breaking the bank. I think my full wet weight (full tank of gas) should be around 350. I would love to get it below 300, it would help to run a lighter chain and sprockets. Also I’m not concerned about longevity right now this is purely a, would it work kind of question
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TBH, not that I know of, seems a bit weedy to me sort of chain you would run on a pit bike, of course the big issue is getting the sprockets for that size of chain to fit the bike. you could look at the EN models they run a rubber belt and alloy sprockets. but the weight saving of a lighter chain wouldn't be that great given there are plenty of other measures that would lose far more. but as the saying goes it's your bike. if you want to have go there is nothing stopping you.
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Ok I might give it a go and see what happens I’ll definitely try to post results if I do. I’d be curious to hear what areas you’d suggest to lose weight. I think I’ve pretty much covered most but I’d be nice to get second thoughts to see what I might be overlooking
https://static.nhtsa.gov/odi/tsbs/2018/MC-10152834-9999.pdf

I'd suggest a full read, oriented to all chains, though written by Ducati

I'll go on record and say this idea (downsizing) is ill advised. Period.
To be realistic how much weight do you think you going to save going to a lighter chain?

One could save even more weight by maybe losing 5 or 10 lb like I do.
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Ok a few things, I read over the pdf sent by Ducati man and I don’t see what you were trying to point out. The only thing I saw that was applicable was on the last page we’re it said that a chain could break due to excessive violent load which pardon me is a duh. Just asking for clarification.
a

Ghostt as for your comment I find it well intentioned but lacking in any actual help. The fact is I’m 5’10” and I weigh 145 soaking wet with my clothes. I don’t have weight to lose on my body without becoming malnourished hahaha I’d appreciate if no one else makes these comments. The point of the threads I’m making are about real engineering questions and pushing this bike to some new and interesting limits
Ok I might give it a go and see what happens I’ll definitely try to post results if I do. I’d be curious to hear what areas you’d suggest to lose weight. I think I’ve pretty much covered most but I’d be nice to get second thoughts to see what I might be overlooking
depends what you have done already. there is a limit to how much can be shed and still have a functioning bike. convert to Cops, single seat or alloy/GRP base with race foam. a guy on the old UK forum did the full monty stripped everything out lightened everything basically he saved around 20kg IMHO a complete waste of time as he weighed around 100kg at the time.
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To be realistic how much weight do you think you going to save going to a lighter chain?

One could save even more weight by maybe losing 5 or 10 lb like I do.
Shoot I also forgot to say that if I’m going to strive to make the whole bike lighter it would become a frivolous exercise to take this ideology weight is weight and if it can be lost in a practical way I’m going to go for it
depends what you have done already. there is a limit to how much can be shed and still have a functioning bike. convert to Cops, single seat or alloy/GRP base with race foam. a guy on the old UK forum did the full monty stripped everything out lightened everything basically he saved around 20kg IMHO a complete waste of time as he weighed around 100kg at the time.
Ok I like where this is going! (Do you have a link to the old thread?) I have considered doing something like this, going to a single seat and a lighter aluminum rear subframe. The sub-frame is probably going to be saved for next year. I do wonder how comfortable race foam padding is. It looks really thin, I do want the bike to still be my daily so there is a line to draw some where
afraid the old (private) forum is defunct the mainframe it was on deleted (moronic owner) so no longer viewable.
my memory isn't as good as it once was but basically he stripped out the whole bike and rebuilt it from the ground up chopped the frame to an engine carriage fabricated everything in alloy. custom made forks and swingarm. custom made fuel tank, stainless exhaust. stripped out the electronics to a single box. run it on a rubber belt. and CR carbs,
there was some talk of him converting the engine to air cooled and dumping the cooling system, but the forum shut before any results were known. sorry.
All good, that definitely sounds like as insanely cool project, way out of my league though hahaha
Did this once on a race bike. Removed all un used brackets remove the in tire rear frame. Hold the seat up with a monocot sheet metal hoop replace the tank with a smaller one from a Honda thingy( had to have a metal one ).
Result. The bike handled like $hit and I junked it

Fog
Fog did you try out different suspension set ups? Raising or lowing front end, rear end, different springs/shocks? Could you elaborate more what you mean by $hit? Was is squirrelly or hard to turn in? Was it just crap on the track or on the street as well. I apologize for all the questions I just haven’t gotten to really talk to anyone who has done this yet
Did this once on a race bike. Removed all un used brackets remove the in tire rear frame. Hold the seat up with a monocot sheet metal hoop replace the tank with a smaller one from a Honda thingy( had to have a metal one ).
Result. The bike handled like $hit and I junked it

Fog
Fog I also had a question specific to the air box mod. Would removing the air horns on the right air box pod do something similar to drilling the 1” hole? On the left pod? Because removing the horns would slightly increase the diameter of those two holes. I understand this wouldn’t due the exact same thing because the mod creates better flow through the mostly stagnant left pod. Also has anything ever been tried with custom air boxes and ram air flow. I know you’re a huge proponent of keeping the stock air box and for the time being that is my plan I’m just curious about improvements
All good, that definitely sounds like as insanely cool project, way out of my league though hahaha
yeah afraid most of us will never be a Allen Millyard although some aspire to be.
I tell you what happened The bike was so light the wheels overpower the thing (too much un sprung weight_) then it meant much lighter wheels and full race tires. and then the cost was over budget, and my box stock was much faster.
SO I abandoned it.

Save you money and ride it stock

FOG
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I tell you what happened The bike was so light the wheels overpower the thing (too much un sprung weight_) then it meant much lighter wheels and full race tires. and then the cost was over budget, and my box stock was much faster.
SO I abandoned it.

Save you money and ride it stock

FOG
I really appreciate the reply how ever this didn’t help me understand much. So you are saying the bike was hard to turn in for cornering? Also what are you referring to when you say your “stock box” was faster. Do you have additional input on the other questions I asked?
may be I could help out a little here. Fog was an out and out racer having a lot of success both as a rider and team owner. in the motorcycle class that covered the 500 EX, he was still racing @65 and winning races hence his nickname FOG (fast old guy) fog's philosophy is all about racing these bikes. I am sure if any modification was possible he would have done it at some point in time.

but if it didn't make it faster handle better or reduce lap times it made no sense doing it. so only the mods that actually worked were passed on to the forum. these are well documented within this forum, I cannot speak for everyone but I personally admire Fog for what his achievements are on this bike.
so when he states that a standard (stock) bike straight out of the box (packing case the manufacturer put it in) is better than (for racing) a modified one. take notice.

I may not agree with all his comments as I'm no racer (never have been) but look at the bike in terms of road only use, shaving a few seconds off a journey is less important than getting there safely. getting round a tight corner faster is less important than how it is done.

on a side note the hole in the airbox was not (I assume) arrived at by chance, he has never said but have often wondered how many airbox's were scrapped before the 1in hole was arrived at. and indeed how much time and effort went into modifications deemed unworthy I can only imagine.

unless your intending to build a lightweight racing bike stripped of all the comforts you need on a road bike I would suggest you think long and hard what the end result is intended to be. white elephants are expensive to build (don't ask how I know) and worth far less than the money put into them.

the guy who did the ultra lightweight bike did it because he wanted to (money and time no object) it wasn't any faster any better to handle or anything of benefit. he spent the best part of 3 years making scrapping and remaking parts.
for no other reason than he wanted to. a sort of never ending project, never to be truly finished.
I wish you luck and good fortune because your on a mammoth road that never ends.

Yorkie.
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my box stock bike was faster . the lightened bike coulden't damp the wheels properly so it wouldn't track with confidence,
I can't testify as to the thousand of air box ideas you may think of as my (Fog's air box) was stumbled upon during a dyno run. and I did not test any other

FOG
A little Fog story,
In about 1997 or so, the race school at the track in Loudon NH was sponsored by Kawasaki. and they got 2 new EX's every year. These bike were fitted with Penske Shocks and Race tires only.
Jeff Woods testing one, did a lap time 1:16 I think that was at least 5 Seconds better than the average race winning time for the class, and would have put him 5th on the pro grid for the last super bike race at that track.
Jeff was the son of school owner Gerry and worked as instructor for the school, as such had more hours than most.
Loudon was a short track that didn't;t reward big power much.

FOG
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