Chain - .420 vs .428?

[viclioce]

I have 2, 1975 Road Toads. I bought 2, .420 chains. The .420 fit the Red Toad just fine. But the .420 doesn’t seem to fit the Green Toad. How, besides trial & error, do you determine which chain will fit? The .420 seems like the links are not properly spaced for my countershaft sprocket, but it seems to fit my rear sprocket just fine! Someone please explain the differences! Do I need to order a .420 countershaft sprocket? Victor

[Bruce Young]

Hello, if the counter shaft sprocket is flat both sides its a 420 chain type, and if its dished a little on one side its the 428 type. Hodaka orginally used 420 chain on most early bikes then later on, sometime in the ACE 100 era they went to 423, 1973 aprox. they went on to 428 chain and sprockets, the 423 chain will not fit on 428 sprockets. It was an attempt to conform to the industry standards of the time. , but shortly there after until the last bike where produced they started using 428 sprockets, but thru the years lots of things happened out in the field. bruce

[Bullfrog]

All Road Toads left the factory with 428 chain. It looks like some DPO activities suckered you into going backwards on chain size. 428 would be the preferred chain to use.
Ed

[matt glascock]

[youtube][/youtube]Hi Victor, yes, the sprockets have to be exactly the same and both matched to the pitch and width of the chain. Chain/sprocket combinations have to have the same pitch and width without exception for safe operating. The three digit chain or sprocket number gives both of these designations based on the "rule of eighths". First some basic definitions. The chain pitch is the measurement of the center of one pin to the center of the next. You can determine the pitch of a sprocket by measuring the center of one "valley" of the sprocket to the center of the next "valley". The width is the measurement of the space between the inner link plates (the space where the sprocket teeth index with the rollers) or the base of a tooth. Now to dissect the meaning of the three digit number. We'll use your 420 chain for illustration. The first number "4" gives the pitch. The rule of eighths represents the fact that these measurements are based on 1/8" increments (thus the "rule of eighths"). The 4, in this case becomes the numerator while the number "8" is always in the denominator. Therefore, the pitch becomes 4/8 or 1/2 inch. So all chains with a three digit number beginning with 4 have a 1/2" pitch. 500 series chains have a 5/8" pitch, 600 series chains have a 6/8" (3/4") pitch and so on. The second and third number of the 3 digit number answers the question of width. Again we have a "rule of eighths" with slight modification. Again, lets use the 420 chain. The trick here is to place a decimal point between the first and second digit so that "20" becomes "2.0". The numeral "8" remains the denominator so that a X20 chain has a width of 2.0/8 or 1/4". Therefore your 420 chain has a 1/2" pitch and a 1/4" width. For certain chains, it gets a bit messy. For example, a 415 chain has a 4/8" (1/2") pitch but the width becomes 1.5/8 so in this case, you have to multiply both numerator and denominator by 2 to get rid of the decimal resulting in a width of 3/16". The messiest one is the 428 chain. Again, the pitch is 4/8 (1/2") but 2.8/8 when both numerator and denominator are multiplied by two would become 5.6/16". For whatever reason, this one is rounded down to 5/16" width. Just for an example, a 630 chain would have a 6/8" (3/4") pitch and a 3.0/8" (3/8") width. These measurements have a fair bit of tolerance to prevent the chain from binding but this underscores the importance of pitch/width consistency in chain/sprocket sets and as accurate as possible countershaft/drive sprocket alignment.

[givergas]

think i might just print this one out and put it in my folder, very good... albert

[givergas]

think i might just print this one out and put it in my folder, very good... albert

[matt glascock]

Hi Albert, Here's a table I made years ago for instant reference. All fractions are in inches.

Chain Pitch Width
415 1/2 3/16
420 1/2 1/4
428 1/2 5/16
520 5/8 1/4
525 5/8 5/16
530 5/8 3/8
630 3/4 3/8

[matt glascock]

I can't get the table to look neater, but you catch my drift.

[givergas]

i will print out your " supplement " also...albert

[matt glascock]

Cool! Thanks Albert. I hope it helps.

[viclioce]

OK. So I need to know. Does this mean my rear sprocket is a .420 sprocket, based on how this chain fits it in the rear (see photo below)? Does this mean I should stay with the .420 chain and get a .420 countershaft sprocket? I want to do this the most cost effective way possible!

I just ordered a .428 chain from Terry. Is the .428 chain going to work with this rear sprocket? Victor

[viclioce]

OK. I was able to get a hold of Terry BEFORE he shipped my order! He is going to substitute a .420 countershaft sprocket instead of sending me a .428 chain! This will be the most cost effective way to remedy the mismatch! Thanks everyone for the input!

And Matt, I saved your chain chart too! Victor

[Bruce Young]

Hello, Hodaka world, concerning chains and sprockets, do your home work as as Matt said measure the chains before you go and order. Its best to replace all three items at once in a matching set. Also, most modern chain manf., for a long time, mark on the side plate of the chain its size. Look for it. Don,t guess, get professional advice, ask your local dealer or engine or bike builder. It can be costly. Bruce Young

[SuperRat01]

I was considering replacing my old chain on my Road Toad as well. I am thinking about ordering an "o-ring" chain instead. Do any of y'all run this type of chain? Linc

[SuperRat01]

I was considering replacing my old chain on my Road Toad as well. I am thinking about ordering an "o-ring" chain instead. Do any of y'all run this type of chain? Linc

[taber hodaka]

I went to 428 chain on the old racing ace 90 and that ended chain problems for me. --------------Clarence

[JackM]

Good info to know, Matt. Thanks for that.
Jack

[matt glascock]

Linc, O-ring chains are designed to keep dirt, grit, sand, water, and chemicals out of the articulating surface of the roller and pin by interposing a rubber o-ring seal between the inner and outer plate at each roller. They also seal in a durable lubricant at each pin/roller set. Literally all of the tracks I run (MX, hare scrambles, XC) feature heavy sand and water/mud. I can honestly say that o-ring chains last me 2-3x longer than standard roller chains. I also ride 4 seasons so many of my bikes see road salt and water. If all you will be doing with your bike is fair weather riding on clean, dry streets, the additional expense of an o-ring chain may not be worth it. If the bike will see dirt, sand, mud, grit, salt, or other road chemicals, an o-ring chain is worth considering. I agree with Bruce regarding maintaining chain and sprockets as a set. They will wear in together and last a lot longer. Probably not a big deal if the bike is rarely ridden. Also, just a few tips on o-ring chain maintenance. Make sure all chain cleaning chemicals and lubes are o-ring chain compatible to avoid damage to the rubber o-rings and destruction of their protective features. Also, don't go nuts with the power washer or air gun or you can blow grit past the o-ring into the pin/roller set and displace the indwelling lubricant. After a gritty ride, hose it off, use a soft brush if necessary to loosen up grit, towel dry it, give it a good blast with an o-ring compatible lube then run it up and down the drive way a couple times and you're good to go. Easy to do trackside between motos with a grunge brush and o-ring chain cleaner. Takes less than five minutes.

[matt glascock]

You're very welcome, Jack.

[BrianZ]

Not sure about the Toad, but on earlier models I have found that there is not enough clearance around the countershaft sprocket for an o-ring chain. They are a little wider and wear into the inner shifter cover.

Brian

[matt glascock]

I run o-ring chains on my '72 SR, both '73 CWs, both 94 Wombats and a 99 Road Toad. No issues. I have never tried one on the Ace 90 or 100s but they are fair weather bikes only.

[Bruce Young]

After working in the motorcycle industry for over 30years, now retired I have sold lots and lots of chain and sat thru lots and lots of chain manf. presentations, and I concur with Matt,s statements. Bruce Young

[BrianZ]

I run o-ring chains on my '72 SR, both '73 CWs, both 94 Wombats and a 99 Road Toad. No issues. I have never tried one on the Ace 90 or 100s but they are fair weather bikes only.

Interesting... I wonder if there are differences in the widths from manufacturer to manufacturer. What chain are you using?

Brian

[matt glascock]

D.I.D

[SuperRat01]

Matt, I should have stated my question better. I use o-ring chains on my street bikes and I am a huge fan. I love the fact that they do not sling grease all over the place and they last a lot longer. However, I have never put one on any of my dirt bikes. I was wondering if there are any issues with that for dirt use and if it would, in fact, fit on a Road Toad. Linc