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Author Topic: Gearing help/suggestions  (Read 4049 times)

Offline jto1

Gearing help/suggestions
« on: July 14, 2016, 12:44:30 AM »
Ok, so looking for some opinions on gearing. Here is my set up 86 short rod, 86 trans, stock jug 72.25mm bhp mx port, great bottom end, and arm ripping mid that I  have never got to fall off the pipe on top, it still winds great on top.38mm pwk a/s,Vf2 reeds, esr trx6 pipe 01 cr250r ignition , 86 leanth swinger, 280 lb rider.
So before I had pj 38mm carb, and stock ignition, ran 14/38 and 13/38. 14/38, was good off the line, and topped out at 86.2 mph on police radar I liked it, but I  loved the 13/38 better. Jumped off the line a hell of a lot harder, and still had a great rev out and toped out at 82.6 mph on the same radar.

Now with the carb change, and ignition change, I tried the 13/38 only for a short run and with feilds in, really have no where to test what I like better. The 13/38 seems to unbelievable  from a dig, and being a big boy, I love it. My concern though about it is how fast the cr ignition revs.
I'm a recreational rider, so it doesn't have to jump so hard off the line, but I  do pick a lot of races, and with the extra weight like the holeshot of the gearing. I do climb a lot of hills, and am concerned that with the 13/38 the shift points will be too close, and think the 14/38 would be better  in that area, giving me a little longer for the shift points. I also do a bunch of woods riding, and like how hard and fast the 13 pulls out of the corners.
Would I sacrifice a bunch of my bottom end going to the 14, or will the 14 feel more like the 13 did before I  changed carb and ignition.
It does feel with the new ignition and the 13 like it hits harder off the line than it did with the stock ignition but may be all in my head. So I just wonder if going with the 14 it will seem more like it did before with the 13 and stock ignition. If that makes any sense at all, lol.

Offline rablack21

Gearing help/suggestions
« Reply #1 on: July 14, 2016, 07:56:13 AM »
Well, that was a bit confusing. So let's clarify this a bit. lol.
First of all, what conditions are you gearing it for? MX, trail riding, hill climbing? The best gearing is going to be different for each of these. So give us some more information on how you are primarily going to be using this machine, so we can tell you the best setup for what you will be doing.

Yes, the CR ignition will rev quite a bit faster than the oem ignition. So you may want to account for that in the gearing that you like.

Offline jto1

Gearing help/suggestions
« Reply #2 on: July 14, 2016, 09:02:19 AM »
Haha, sorry I was babbling a little there, I was half asleep.
Main riding will be a combination of trails and dirt hill climbs. Guess I  should add tire size 21-11-10, but will be changing to a 9" rim soon with the same tire size.

Offline rablack21

Gearing help/suggestions
« Reply #3 on: July 14, 2016, 09:11:30 AM »
Quote from: jto1;68774
Haha, sorry I was babbling a little there, I was half asleep.
Main riding will be a combination of trails and dirt hill climbs. Guess I  should add tire size 21-11-10, but will be changing to a 9" rim soon with the same tire size.

Alrighty, now we are getting somewhere. lol. Ok, so what are you looking to get out of your machine?
13/38 is roughly the stock gearing depending on your year model. This will give you lots of bottom end pull. The motor will pull harder at a slower speed. This gearing is great for woods and should be good for hill climbs as well. With the cr ignition you will find yourself getting to the max rpms in each gear even quicker than before requiring you to shift more often. My recommendation would be to try both sprockets (13 & 14) and see which one YOU like better for what you are doing. It really difficult for someone else to determine for you to a certain extent. It all depends on what you like.

Offline havinnoj

Gearing help/suggestions
« Reply #4 on: July 14, 2016, 05:48:30 PM »
If you want quantifiable differences, see our handy gearing calculator:
http://trx250r.org/threads/3006-Honda-TRX250R-Gearing-Ratio-RPM-Speed-MPH-KM-H-Calculator

Offline Michael88R

Gearing help/suggestions
« Reply #5 on: July 14, 2016, 07:35:40 PM »
I prefer the 14 in the front. Seems to last longer and when u throw a chain it doesn't get bound up as bad as the 13.  I adjust the rear accordingly.
88’ R Esr 350 CEO, Esr trx5 pipe
88’ R Esr ported stock cylinder, waiting for rebuild when my son gets a little older

 

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