TRX250R.ORG
Workshop => Engine and Bottom End => Topic started by: The norm on February 16, 2020, 12:18:07 PM
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Talking with Pete the other day, he mentioned that I might enjoy a flywheel weight on the 391 as I am big for my age lol. He talked about using aluminum and machining the largest diameter weight that will fit under the stator cover. He also said that I should keep the CR flywheel with the weight at roughly the same weight as the trx flywheel. So basically I will be adding more leverage with the larger diameter, but keeping it close to stock weight.
So my question to you fine gentlemen is this.... If you are running a CR ignition system on your big bore R are you also using a flywheel weight? If so what weight size/brand/style are you using?
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bought a 14oz stealthy. Cant comment on if it made a difference or not I never rode this engine before I installed it.
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If I recall 10-12 oz. weights are what guys typically run on Big bores. I think the preferred weight is a Moose/MSR.
Joe
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I have not been running a weight. I did years ago. But didn't really notice a difference.
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No weight for me in a stock jug. Revs were definitely a noticeable difference from stock. I'll find out this year as far as big bore and report back
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I think Kyle burnham uses a weight on his Mx 363. Not sure about his xc 370. He said it was to “tame it down”
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LED recommends a flywheel weight for the hpi ignition on 350cc and up
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Pete was saying I would like a weight because of how I ride. I love going down in those gnarly tree shots at the dunes and I always ride a gear high. So I think a weight will reduce clutching it in the trees.
I have a 96 cr250 that I ride in very tight nasty single track trails. It has a 12oz flywheel weight. In switchbacks a cr250 would suck without a weight.
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I run weights on my CR setups. I think i have a stealthy 10oz on my 370.
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I run weights on my CR setups. I think i have a stealthy 10oz on my 370.
Do you feel it makes the engine not rev? I saw your vids of nailing the hole shot so probably not... I think a weight would help rolling on throttle out of corners or in my case dodging trees on crappy hillclimbs lol
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I was having trouble in those three shots last year. Normally I’d go down in second gear clutch a little and climb out in second or even up shift to third. Last year my bike just felt dead on the bottom end and I was having to shift down to first and even stay in first sometimes. Not sure what is going on. Maybe I’m just getting too fat.
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Too fat lol!
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Those that have the cr flywheel weight... Can someone measure the od and the thickness? If I go with a weight I want it to be the largest diameter that can fit inside the cover
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Flywheels are designed to provide momentum, and high reving motors generally use/need less flywheel, then a similar motor. A heavier flywheel should help with holshots, tree shoots ,and the like, Heavier is good, unless it comprises the ability to rev. Larger displacement should require a heavier flywheel, but in some instances it isn't as important. We use lighter flywheels on short tracks, autocross, gymkhana events where acceleration out of the corner is paramount, heavier flywheels on heavier vehicles, and more street type use. I would think that on a single cylinder engine, that flywheel mass is very important, but limited because of placement with-in the assembly.
desertR
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I did a lightened flywheel on my Banshee years ago and did not like it. Was easy to stall. Locking up the rear brakes to slide into a corner, if I was not heavy on the clutch, it would insta-kill the motor.
It made the motor light switchy...but at that time in my life, I enjoyed that. However my small forearms could not keep up with all the extra clutch work.
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Just remember you loose alot of mass going to a CR250 flyshweel. Even with the added weights, to the CR250 flywheel, you are no where near the rotational mass of the stock 250R.
For those of you that worry about not wanting to rev. I will leave you with these.
https://www.youtube.com/watch?v=eTSrbfANv54
https://www.youtube.com/watch?v=ij6qlC-x9F0
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And just to top it off, Holeshots for days.
https://www.youtube.com/watch?v=W2Gcx2NKcf4
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Love the wheelie after the holeshot. Looks like a heck of a lot of fun!
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I run Steahly's on cr ignitions.