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Discussion Starter #1
Did you gain anything in the spread for the gear ratios? Can you have a creeper like the TW first and a taller sixth gear than what the TW offers in fifth?

How much taller? Is it worth it?

I found a 03' TTR225 for $850 and was thinking I could get the motor for darn near free after I part out the rest of the bike. Will I gain anything in a wider spread from first through sixth compared to the TW five speed?
 

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Not appreciatively different according to Ronnydog, I believe he reported more overlap, not extended range of ratios unfortunately. However If I recall Ronney has a larger diameter Duro or Bighorn2 tire shoe-horned in there being driven by gosh knows what sprockets so your experience might differ.( How's that for a disclaimer?)
TWBrian is about to unveil his 225 six speed conversion if only he can get his shoehorn to work getting his engine back in the frame.
 

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I suppose those who seek accurate answers can always look up specs for ratios of both machines.
 

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IIRC there was a post from lizrdbrth stating that you could get a lower granny gear AND a higher top gear... but i saw others that said the opposite. ??
 

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If I remember right 1st and 5th of the TW is about the same as 1st and 6th of the 6 speed.
 

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Discussion Starter #7 (Edited)
OK. I think I have this figured out. If someone who knows more than I has any input I welcome it.

For the TW200 from the parts list:

First gear; First gear Wheel is 34 Teeth. Main Drive is 12 Teeth. First Gear = 34/12 = 2.8333.
Fifth gear; Fifth gear Wheel is 28 Teeth. Fifth Pinion is 23 Teeth. Fifth Gear = 23/28 = 0.8214.
Difference; ........................................................................................................ 2.0119.

TTR225

First gear; First Gear Wheel is 37 Teeth. Main Drive is 15 Teeth. First Gear = 37/15 = 2.466. Slightly taller than the TW.
Sixth gear; Sixth Gear Wheel is 29 Teeth. Sixth Pinion is 22 Teeth. Sixth gear = 22/29 = .7586. Again, taller that the TW
Difference;.................................................................................................................. 1.707.

The TW has a wider range of ratio with five gears than the TTR225 does with six. If you change gearing on the TTR to get it as low as first on the TW you would have to reduce it by 14.88%. This would but your sixth gear at .8715 which although the number is higher the ratio is lower than the fifth of the TW.
 

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dont forget the ttr has a change in wide ratio to narrow in 04 I believe. the xt225 and the earlier ttr tranny are the same. My conversion is about done as well and per my math its getting a 15t front sprocket. that should bring the 6 speed first up to the stock tw 5speed. I should net a slightly taller 6th, but I doubt its gonna have anymore high speed. Im really looking for the old 4-5 drop to be better.
 

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Discussion Starter #9
I was looking at the fiche from 2003 model TTRs. That's the year I found and can get a deal on. Going back to 2000 the first for the TTR goes to a 34 tooth and sixth pinion goes to a 34 tooth. That makes it even closer, 1st to sixth.

Am I doing this right?
 

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I am running the six speed with stock final gearing as are my buddies with their 5 speeds. My first gear is slightly lower than theirs and 6th is slightly higher than their 5th....not much difference really but in combination with the extra displacement it makes the conversion worthwhile. It is not wide enough for a granny first offroad and an overdrive 6th on road, but it is an improvement. I just finished my second 6speed motor and I am looking for a home for it. Find a low hour and maintained ttr225 as your base and it is an easy conversion. I did not even install new rings on either of these motors I converted....almost no signs of wear on the pistons or the bores, barely broke in really! I suggest using the early style carb as they make great/responsive low end power in the stroked motor. My bike has lost about 20 lbs and the bike feels more like a real dirtbike than a compromised dual sport.
 

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Discussion Starter #11
Can you point out where I'm going wrong by using the gear teeth as listed on the parts diagrams.

I have two options. I have a spare TW motor that I have already built the head for with Web Cams, cam. I plan on getting a 225 crank and run a couple more CCs but with a 10.5:1 compression ratio. Together these should really boost the torque and low end.

Then I stumble on the tail shaft conversion and thought what I really need is a wide gear range. I could get a cam for the 225, high compression piston, have more grunt AND six gears. BUT! what good does the extra grunt give you if you still are either winding 15,000 rpm to do 60 mph or can't walk up a blown down tree in first.
 

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Discussion Starter #12
IIRC there was a post from lizrdbrth stating that you could get a lower granny gear AND a higher top gear... but i saw others that said the opposite. ??
This is what's causing the conundrum.

From the TW Service Manual, page 2-2;

TW200 Gear Ratios 001.JPG

Look at the top and bottom numbers and compare to my previous post.

Can anybody find the same data from a TTR225 or XT225 Service manual to refute my claim that the TW200 has a wider gear ratio?

I have some real work to get done here this morning but I'll get on it if no one else finds it by the time I get back.
 

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Discussion Starter #13 (Edited)
The plot sickens....

From a 1998 XT225 Service Manual:

1998 TTR Gear Ratios 001.JPG

This is born out by checking the parts list.

So the answer to which has the wider gear ratio, the TW200 or the TTR/XT225, is YES! ....depending on which year you are talking about.

Edit to add that the XT225 has a wide range over the TTR225 for the same year for 2003.
 
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