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My question is Erik, after reading how you barely discern a difference with sub 6 and even 5 pound flywheels
Did I say that?
BETWEEN the two a sub 6lb and a 5lb, say 4~10 oz difference in that range perhaps not a lot of seat of the pants.
But between stock and 4lb 6oz
or between 6.x anything and 4lb 6oz yes I think you will "feel"
a difference if you were to try them back to back.
Originally Posted by skokievtr
will I be able to feel an appreciable change? So before I install it should I have you trim it some more? ..
Up to you, but id say keep what you have and if you want another, do like we did before , buy in the US, ship direct, have it sent to you. Sell the one you do not want to keep.
|I think you'll get more return of $$ that way than shipping two ways and paying for the new cut.
Erik can i ask on the basket side of things whats the smallest dia you have went to?
135.5mm is the smallest diameter I have cut to.
I am not confident every flywheel out there is the same, as in they come from different vendors over the years, different runs for the manufactures supply chain, and while Im sure they all have a final spec to be made to, Ive seen enough variance in the ones I have cut to think there is some manufacturing differences in how the individual part maker got to that final spec.
So use caution and have a spare if you cut the basket OD smaller then 136mm
Cheers Erik.. that is some material removed. i have a spare here to practice on myself and im gona run it on my yellow bikes engine to see what kinda results iv got.. still have to get tooled up mind you but it will give me something to play with over the winter..
Target weight was "about 5 lb" as rider wanted a "not your lightest version" I weighed swarf as it came off the flywheel for a guesstimate on what i had removed and got close...
Finished weight is 4 lb 12 oz
This one drew blood ..........
think of it as razor sharp confetti
Last edited by E.Marquez; Nov 29, 2017 at 03:37 PM.
Yesterday I found an interesting and new issue..
I cut the basket of one yesterday to my standard 135mm diameter ..And found the area of the basket that is "stamped" actually caused the steel to fracture and once the deformed steel was cut away, the fracture reveled itself.
The fracture you see was visible at 138mm which is the diameter of the area on this one that is smooth and finished cut. After finding the fracture I did a rough cut to 133mm just to confirm it was a fracture and not just a scratch from dragging a tool across the surface. You can clearly see the fracture in that pic.
At first I thought I had cut too far and it was undersized..but no...the dia was 135.43 mm so almost 1/2mm above my general target..
This is the first time I have seen this issue and I cut two more last night to confirm it was not something "new" I was causing .
The next flywheel i cut at 139mm looked like this
the deformed stamping is still just visible.
At 138mm its gone and you can just see a shadow of where it was
So just another item to inspect on a provided or bought flywheel that might make it junk for this MOD ...like the ones I get from ebay that were removed with a 3 jaw puller, or the key way / taper is damaged... flywheel has been dropped and the basket is deformed. 1 in 4 flywheels i look at on ebay are rejected for purchase because of these type of issues and I've been burned a few times still with what shows up.
So look well before you purchase and if your doing this MOD be on the look out when you cut it down for these fractures..... I found them at all stamping locations on that one flywheel..
good advice Erik,,, i have went through the records of any i have done and as yourself im in around the 135 dia but so far no cracks, iv an old one here im gona cut down down and see when it gets to the point of failing and see how much meat is on the bone.. as you say they all seem to be slightly different weight/size wise..
I cut this one flywheel to the point of failure to re confirm basket material thickness. At 136mm Im absolutely unconcerned with cutting down to that point.
Theses fractures..there has been only ONE flywheel in all i have done that I found this issue, and the fractures were observable long before 136mm..
Bottom line, as long as your looking for them, you will see them as soon as you clear the last of the stamping from the basket. If not there, it's not an issue for that flywheel.....finish the cut as normal.
Originally Posted by fabiostar
good advice Erik,,, i have went through the records of any i have done and as yourself im in around the 135 dia but so far no cracks, iv an old one here im gona cut down down and see when it gets to the point of failing and see how much meat is on the bone.. as you say they all seem to be slightly different weight/size wise..
And my Christmas wish has been delivered (Actually that wish really was delivered, one of our pups needed surgery and she came though plus healing well..... )
But anyways .. have a source for balancing flywheels... or at least a commitment to give it a shot.. Im not convinced there is enough material remaining to insert balance weight, or remove same as needed. But the company has extensive experience in doing motor sport balancing to include turbo rotors spinning 30-40k RPM's
I cut one last night as a test and shipped it off today for their review and work.
And my Christmas wish has been delivered (Actually that wish really was delivered, one of our pups needed surgery and she came though plus healing well..... )
But anyways .. have a source for balancing flywheels... or at least a commitment to give it a shot.. Im not convinced there is enough material remaining to insert balance weight, or remove same as needed. But the company has extensive experience in doing motor sport balancing to include turbo rotors spinning 30-40k RPM's
I cut one last night as a test and shipped it off today for their review and work.
Interesting! I can't wait to see what they find out while balancing one.
Sorry to hear about your puppy dog. Glad she's doing okay.
Was asked to do a Moriwaki cut on a flywheel this week..not something I normally do anymore, but as I was already set up for flywheels this week it was an easy deal to knock out.
I was a little surprised at how little weight it removed.
Started at 7lb 3 oz
Removing 0.50" of OD from the weight disk only finished at 6 lb 8 oz
Reduced by 11 oz
Its what the rider feels works best for his riding style, and I cant fault that, we all ride differently, and what "feels" best for one is not the same as for another.
My 2 Cents, I recently cut mine which was around 7 Lb stock. I took off 1 Lb ish and it balanced with no issues. By far it was one of the best mods I've ever done. It did idle slightly lower, which I did not mind, but it picks up revs in between gear changes so quickly that it has the feeling of not falling at all. I really love the way gear changes have been altered. Snappier, yes, but the real difference for me was the shifting. Basically stock 2005 with 2 bros slip ons.
My 2 Cents, I recently cut mine which was around 7 Lb stock. I took off 1 Lb ish and it balanced with no issues. By far it was one of the best mods I've ever done. It did idle slightly lower, which I did not mind, but it picks up revs in between gear changes so quickly that it has the feeling of not falling at all. I really love the way gear changes have been altered. Snappier, yes, but the real difference for me was the shifting. Basically stock 2005 with 2 bros slip ons.
B
Sounds like you could really appreciate a fully lightened one.. Chuck that flywheel back up and try a target weight of 4lb 9oz bet you will like it.
I know there hasn't been activity on this thread in a long time but I'm looking for some info. I'm planning on having my flywheel lightened by a local guy but I was hoping to find some specs to give him to turn it to. I see Erik did the baskets to 135mm with a 4mm edge to retain the timing marks but the main weight I'm looking for a thickness (possibly 10mm?) and a diameter of that weight. Or even just how much to take off the OD of that weight.
