nobackhair
XS650 Enthusiast
Did the drilling suggested to the upper hole in fork damper from Mintons Mods. I'm plugging it up and redrilling to the stock hole size. Anyone know what that is?
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stock hole size
- Thread starter nobackhair
- Start date
yamaha_al
yamaha_al
I did the same mode but haven't ridden my bike yet. Did you not like the suspension feel?
nobackhair
XS650 Enthusiast
the bike I'm doing the mods on has been down for months while i struggled to make decisions on what route to take based on the never ending topics throughout the web on front fork upgrade. Makes your head spin. PLus the phone calls and visits to shops. No matter how experienced mechanics and guys that do their own work, you can't seems to get any 2 guys to agree on details on mods. There obviously isnt a perfect way to go about it.
I'm close to closing it up and giving it a whirl. I'll let you know. Still trying to figure out the hole size at top of damper for return.
I'm close to closing it up and giving it a whirl. I'll let you know. Still trying to figure out the hole size at top of damper for return.
That would depend on the year of the damper rod. I'm only familiar with the '77 and newer forks, the 35mm ones. That small hole is about a #45 drill bit size on the '77 damper rods, about a #49 drill bit size on the '78 and later rods.
That being said, I've done the Minton Mods to several sets of the 35mm forks and I like the results. I used a #45 bit at the top, drilling through to create a second hole opposite the first original one. At the bottom, I enlarged the 4 existing holes using a #1 drill bit (just under 1/4"). The original size for them was about 3/16" or a #9 drill bit size. I did not add any additional holes at the bottom. Stock was 4 and there are still only 4, just slightly bigger.
That being said, I've done the Minton Mods to several sets of the 35mm forks and I like the results. I used a #45 bit at the top, drilling through to create a second hole opposite the first original one. At the bottom, I enlarged the 4 existing holes using a #1 drill bit (just under 1/4"). The original size for them was about 3/16" or a #9 drill bit size. I did not add any additional holes at the bottom. Stock was 4 and there are still only 4, just slightly bigger.
nobackhair
XS650 Enthusiast
Thank you sooo much for having this info. I just didn't want to go out and buy a bunch of bit I don't need. I reached out to quite a few sources to get this info. Fortunately I do have 35mm ('78). Going to buy a #49 to start with. If it doesn't match up at least I have a close starting point. I was going to do exactly what you've done w/ just drilling the damper based on that M.Mod. With the RT emulators the Instruction sheet for this type wants us to continue the lower pattern w/ another set of 1/4" giving us a total of six obviously making compression on them useless. I was under the belief that the emulators were assisting in reboung as much as comp. but they don't suggest even touching that upper hole or adding one. Kinda suggest the emulators does not assist w/ rebound. I have another XS650 I'm not in any hurry to build but I'm going to try your mod and see if I like it. I like the #1 bit idea instead of the 1/4" bit.
nobackhair
XS650 Enthusiast
I got lucky at an Ace Hardware. They had a few bits that were returnrned in little zip lock bags. I only had to try 3. Since you mentioned #49 I tried that one first. It was to big so I tried a #50 which fit perfect.
If you read the Minton Mods and compare them to a 35mm fork damper rod once you have it out and in hand, you'll notice some discrepancies or errors in the article. Minton calls for slightly enlarging the small upper hole and drilling through the rod to create a second hole, all using a #54 drill bit. As you (and I) discovered the stock little hole is already bigger than a #54 bit size. All I can figure is the bit size numbers got transposed or switched from 4-5 to 5-4 when the article went to print. Well, that's my theory anyway, and I'm sticking to it, lol.
The other error concerns the larger bottom holes. Minton says you'll find two 1/4" holes and instructs you to drill two more so you end up with a total of four. Well, there are already four there, at least there have been on every 35mm damper rod I even saw, but they are a little smaller (near 3/16"). I decided to use a #1 bit because it is slightly smaller than 1/4" and I happen to have a good supply of them (we use them at work). I figured I could always easily go bigger if need be but it's much harder to make the holes smaller again. Well, it seems the combination worked well, so I feel no need to change it. I guess I just got lucky, hitting on the ideal, or near ideal hole sizes.
Minton says that these later 35mm 650 forks aren't too bad for the most part but they don't respond well to little bumps or just one bump. Once you get them pumping they're fine, they're just a bit reluctant to get started. Little stuff jolts you through the bars instead of the forks soaking it up. The Minton Mods fix this. The forks become much more supple and now work over the little bumps better. This makes normal, every day driving much smoother. I can't say I notice much, if any, change or improvement during high speed or aggressive riding, but it's no worse either.
I know 3M has said he doesn't approve of these fork mods anymore and is even considering taking the whole Minton Mod article off his web site. Maybe they're not the best choice for racing but for daily driving, I quite like them. I'm sure spending like $200 on emulators and custom wound straight weight springs gets better results, but this mod is basically free - and it does help.
The other error concerns the larger bottom holes. Minton says you'll find two 1/4" holes and instructs you to drill two more so you end up with a total of four. Well, there are already four there, at least there have been on every 35mm damper rod I even saw, but they are a little smaller (near 3/16"). I decided to use a #1 bit because it is slightly smaller than 1/4" and I happen to have a good supply of them (we use them at work). I figured I could always easily go bigger if need be but it's much harder to make the holes smaller again. Well, it seems the combination worked well, so I feel no need to change it. I guess I just got lucky, hitting on the ideal, or near ideal hole sizes.
Minton says that these later 35mm 650 forks aren't too bad for the most part but they don't respond well to little bumps or just one bump. Once you get them pumping they're fine, they're just a bit reluctant to get started. Little stuff jolts you through the bars instead of the forks soaking it up. The Minton Mods fix this. The forks become much more supple and now work over the little bumps better. This makes normal, every day driving much smoother. I can't say I notice much, if any, change or improvement during high speed or aggressive riding, but it's no worse either.
I know 3M has said he doesn't approve of these fork mods anymore and is even considering taking the whole Minton Mod article off his web site. Maybe they're not the best choice for racing but for daily driving, I quite like them. I'm sure spending like $200 on emulators and custom wound straight weight springs gets better results, but this mod is basically free - and it does help.
