HAWK 520 chain help

[China Rider 27]

So upgrading to the 520 chain with 13T front and 35T rear. Two issues I want to kick around with the experts. Let me say I watched Dan's sprocket issue video.

1st issue. Chain on the front sprocket rubs the engine case at about the 11 o clock position on a round 1/2 in bump in the case. Looks to have been rubbing slightly with the 428 chain too. I reversed the sprocket and keeper no difference and clearly needs to be taken down. Looks like 1/8 inch should might get it, but I am leery of grinding on the engine case. It is tight all around with that chain. Whats the fix here?

2nd: I replaced the rear sprocket bolts with a Honda part and the shoulder on it is thinner than the factory. When assembled I see that two of the four bolts do not touch the wheel housing and two do. The clearance is probably little less than 1/8 inch. The side that touches the wheel housing has a space away from the snap ring and the other side is close to the snap ring. There is no play in the sprocket, it is tight but I believe it is held in position by the tight fit on the shaft. Can't really see that the sprocket run out is far outa whack but must be slightly. What is the proper relationship for the sprocket? Should it be as tight as possible to the snap ring or is space acceptable on the shaft. Is a space acceptable between the sprocket and wheel housing? Or a space between the sprocket and snap ring?

[Alaskaalaska]

What chain did you use? I wont say my clearance is huge, but I have 0 rubbing with 13T 520.

[Megadan]

So upgrading to the 520 chain with 13T front and 35T rear. Two issues I want to kick around with the experts. Let me say I watched Dan's sprocket issue video.

1st issue. Chain on the front sprocket rubs the engine case at about the 11 o clock position on a round 1/2 in bump in the case. Looks to have been rubbing slightly with the 428 chain too. I reversed the sprocket and keeper no difference and clearly needs to be taken down. Looks like 1/8 inch should might get it, but I am leery of grinding on the engine case. It is tight all around with that chain. Whats the fix here?

2nd: I replaced the rear sprocket bolts with a Honda part and the shoulder on it is thinner than the factory. When assembled I see that two of the four bolts do not touch the wheel housing and two do. The clearance is probably little less than 1/8 inch. The side that touches the wheel housing has a space away from the snap ring and the other side is close to the snap ring. There is no play in the sprocket, it is tight but I believe it is held in position by the tight fit on the shaft. Can't really see that the sprocket run out is far outa whack but must be slightly. What is the proper relationship for the sprocket? Should it be as tight as possible to the snap ring or is space acceptable on the shaft. Is a space acceptable between the sprocket and wheel housing? Or a space between the sprocket and snap ring?

My sprocket issue video was on a 428 chain series sprocket. The 520 sprockets are just a hair thinner than the 428 sprockets. I still used the same trick with my new sprocket as I did the old one, but with one change. I used a 10mm I.D. shims between the stud and the sprocket that I actually sanded to match the profile of the shoulder on said studs so that they fit within the recess of the sprocket. The easiest way to know how thick you need to go is to install the sprocket and snap ring, then using a feeler gauge set, measure the gap between the sprocket and snap ring at multiple points and average the numbers out. Then try to find a shim close to that number to take up as much space as you can. I used wave washers on my last bike because I couldn't quite find a thickness that would work, so the spring effect from said washers helped take up the difference. Ideally, you want the sprocket as close to the snap ring as possible. It doesn't have to be tight, but the less deflection the sprocket can have, the better.

The issue you are having with two studs seating and two not is one I also ran into. In my case the bushings in the hub where the studs insert were pressed in at different heights. I used a bearing/seal installer and gradually tapped them in until I had them all as close to flush as I could manage.

One thing you could try that I didn't would be to simply flip the rear sprocket so the recess faces outward. The downside to doing this is that tightening the nuts onto the studs will be damn near impossible unless it is done before installing it on the wheel, which may then make installing the sprocket a royal pain if the studs are even slightly out of alignment.

As far as the front sprocket/chain rub goes. I don't have this issue. Dimensionally speaking a 520 chain is actually narrower than a 428 by about 2mm when comparing like for like. My 520 VX2 X ring chain is still slightly narrower than the standard 428 chain that my Hawk came with.

Could you get a picture of the area the chain is rubbing?

[NzBrakelathes]

I once read in China the 14T 520 chain might rub a little and will create its own space, kind don't suggest that but in your case can you gently trim or grind some and gain what you need?

[China Rider 27]

So today to re-engineer the drive train. The issue of the front sprocket is perplexing. The new 520 chain is a Unibear and measures .829 inch from rivet end to rivet end and the stock chain .733 inch rivet to rivet. Searching last night, I found a post from Jerry about someone with 17T 428 sprocket rub and it happens to rub in the same place as mine.

http://www.chinariders.net/showthread.php?t=23005&highlight=grinding

The chain guide from day one never seemed to line up with the chain. Appears the rubber groove should ride in the center of the chain? Maybe the sprocket retaining clip channel is cut in the wrong place? And I need to reverse the retaining clip moving the sprocket out? The clip channel begins ½ inch plus 1/16 or 14 mm from the end of the shaft.

Looking at the rear sprocket this morning with fresh eyes, the spacing against the snap ring is not off a lot but Is significant. Thinking about how the sprocket is retained, it appears to me that the tightness of the sprocket is completed when the four bolts are torqued tight and thus “wedging” the sprocket in the cush (correct?) bearing of the wheel. So maybe if I loosened it and pulled it flush and re-tightened it would provide a better relationship. I am thinking that under torque the sprocket would just slide up to the snap ring anyway. There is still the gap between the sprocket bolts and the cush bearing or wheel housing. But does this really matter? I mean the bolts slide into holes that bottom into space and there is no lateral retention. Granted a tight fit will reduce some flex. I may look at shimming on the cush bearing wheel side to reduce any movement. Sound reasonable?

[China Rider 27]

I don't think the retaining ring is cut in the wrong place at 14 mm as I measured the Magician and it is 13mm or so. There is alot of side to side slack in the front sprocket as a rule and the chain and reversing the clip does provide alot of case clearance and the cover fits but don't know if it rubs on the chain yet. Clearly the stock 428 chain rubbed. Any downsides to moving the sprocket out with reversal of the retaining clip?

[Megadan]

I don't think the retaining ring is cut in the wrong place at 14 mm as I measured the Magician and it is 13mm or so. There is alot of side to side slack in the front sprocket as a rule and the chain and reversing the clip does provide alot of case clearance and the cover fits but don't know if it rubs on the chain yet. Clearly the stock 428 chain rubbed. Any downsides to moving the sprocket out with reversal of the retaining clip?

The rear sprocket gap to the snap ring that you have is actually not that bad. You could probably leave it be and be fine.

The only downside to flipping the front sprocket is getting to the bolts to tighten them. It can be a bit interesting. Other than that, it may throw the chain alignment off a hair, but not enough to be too concerned with. On my first Hawk I flipped it and it actually improved it.

[China Rider 27]

It is a game millimeters my friends and the sprocket swap that close but the cover will not go on. Appears to be hitting right at the edge on the chain to turn the corner in. I'm gonna swap it back to check the clearance since I have the chain to length now. On a side note, that Unibear chain has some serious hardened steel link pins. Took me an hour and half to get that pin out.

As far as the rear sprocket. I loosened two bolts on the side that had space to the snap ring and pulled it up snug and re-tightened the bolts. You can't get a feeler gauge under it. That evened up the spacing on the wheel side of the stud. Pix of reversed sprocket clip, sprocket, and chain.

[China Rider 27]

Here pix

[China Rider 27]

Got it! 520 chain reverse sprocket keeper 13T install. I ground on the lip of the sprocket cover but no dice on fit. I took the 13T back to the standard keeper arrangement to see how much it rubbed and to think about grinding the case and it still rubbed. The clearance to the chain all the way around had not changed from the reverse keeper setup, tight maybe 2 or 3mm. To have any chance at all of running this 520 I had to get the cover on. I noticed it always hit in the upper right corner where it is squared off. Took it down slowly little at time then bang she went on!

Changed the sprocket set up to inside clip retention and put the chain back on and tried the cover. No dice. Took down the the top corner some more and bang on she went! Whew! Saved me some money. Chain looks good out away from case and chain alignment doesn’t look to bad. You can see the kink in it where chain guide crooks it. Truth will be in the running. Some pix to save time for others. I took some off the inside of the cover you can see in one pix don’t know if made difference or not. Thanks Dan and NZbrakelathes for the support!

[pete]

The front chain cover is the first thing I remove
from my dirt bikes...
It is only there to collect mud and make it harder to
clean the bike...

then it still looks nice and pretty when you sell the bike...



..

[China Rider 27]

Now there is some wisdom! Instead of buying a new chain or sprockets because your sprocket housing doesn't look pretty just run it! I forgot where I needed to be, China Rider way! Got any wisdom about that chain guide?

[China Rider 27]

Runs good no issues, no rubbing works fine and I am glad to not have to be thinking about how my sprocket is doing up against that case. The ratio 13T and 35T is definitely a street ratio, I found myself going down one gear in any given circumstance from what I would use in the 15T 50T. I may need to consider the 12t or 11t as a swap out for the hills. The 520 chain is definitely a massive piece of strength. Before I do another one I will get a chain breaker.