A forum for owners of Yamaha TTR250 trail and enduro bikes!

TTRfan · Super Guru

Wondering about model differences or year model????

DC · Veteran Member

RE: Model names and codes and catalogue numbers

barra8 · Guru

Wondering about model differences or year model????

barra8 · Guru

Thought i would share some info that i have acquired from mechanics,yamaha etc. So far the only differences yamaha made to the motors are eg:

Clutch plates/boss and basket some have 6 some have 5 & some 7 friction plates. Both are interchangable provided you use the whole cluch assembly & 99 clutch cover. The clutch plates all interchange.

Electric start on some models can be interchanged using all the electric start components.

Compression ratio on Raid models although any head is interchangeable.

Other than that i have'nt found any differences between any model ttr 250. If anyone would like to add to this or enlighten me feel free to do so.Cheers

-- Edited by barra8 on Saturday 2nd of February 2013 07:42:04 PM

TTRfan · Super Guru

The bit about different compression ratios surprised me. I hadn't noticed that on the specifications before - see http://www.ttr250.com/#Specifications

The part number for the cylinder head for the first 4GY1 and 4GY3 models are different to the 4GY5, 4RR1, 4RR2, and 4WA1 but I have no idea what the difference is! The valves all have the same part number.

So, if you have a very early TTR then the best way of tuning it is to put on a later cylinder head wink

Brian

barra8 · Guru

TTRfan wrote:
Model differences:
Most white metal-tanked TTRs have a digital speedo and therefore have a gearbox with an extended transmission/sprocket shaft to take the speedo magnet.
They also mostly have 6-plate clutches and a narrower clutch cover and therefore less oil than later 7-plate models. Easy to tell the difference as the later covers have Yamaha stamped on it them.
6-plate cover (stamped 1000cc) below:

7-plate cover (stamped 1100cc) below:

Oh and if it had a less aggressive cam (and cam timing) would'nt that change the ratio as the valves would be opening for a shorter period and not as far open???? Just going off the capacity of what it can suck through.

Your theory on the ports is a good one and what i think it must be. Don't know why i didn't think of that aww

barra8 · Guru

I wasn't counting the plates on the boats site as it's the same pic for all ttr's. I was looking at the number of clutch plates needed for assembly as it tells you this under the pics.

I have a pic of my clutch plates (white bike) and there is 6 so not sure who is right on tthe clutch subject.

On the cam subject i just thought that maybe on the down stroke the valves would open more or less with different cam letting more or less air through. Maybe i'm on the wrong track though smile

-- Edited by barra8 on Monday 23rd of July 2012 11:04:30 PM

barra8 · Guru

TTRfan wrote:
barra8 wrote:
I wasn't counting the plates on the boats site as it's the same pic for all ttr's. I was looking at the number of clutch plates needed for assembly as it tells you this under the pics.
I have a pic of my clutch plates (white bike) and there is 6 so not sure who is right on tthe clutch subject.
I think we are actually agreeing
White TTR - 6 friction plates (your pic confirms) and narrower clutch cover
Blue TTR - 7 friction plates (my pic confirms) and wider clutch cover
Brian

Oh sorry brian i should have read your mesg better. Just counted your plates and missed one lol. That's weird that you have 7 as i have'nt found this info on the boats site. Have'nt checked all models yet though.Who knows maybe there listing is wrong??? You would think that they would have it right by now though???

So did you get my point i made about the cam or do you still think i'm off with the fairies? biggrin

My clutch is aftermarket so maybe why it's thinner on the pressure plate??

Oh i think i know why you have 7. Is one of those plates a friction plate???

Ps. hope i'm not getting on your nerves Brian just trying to get to the bottom of it all.

-- Edited by barra8 on Monday 23rd of July 2012 11:37:06 PM

-- Edited by barra8 on Monday 23rd of July 2012 11:41:54 PM

TTRfan · Super Guru

Model differences:

Most white metal-tanked TTRs have a digital speedo and therefore have a gearbox with an extended transmission/sprocket shaft to take the speedo magnet.

They also mostly have 6-plate clutches and a narrower clutch cover and therefore less oil than later 7-plate models. Easy to tell the difference as the later covers have Yamaha stamped on it them.

6-plate cover (stamped 1000cc) below:

7-plate cover (stamped 1100cc) below:

barra8 · Guru

Yeah it's weird how the valves seem to fit all models but the compression ratio is different on the raid model???? confuse How can that be?? cam timing??? shorter stroke? That subject has me fooled lol biggrin Wonder if anyone here knows???

TTRfan · Super Guru

The bore and stroke of all TTR models is the same so it is likely that the lower CR of the early models is achieved by there being a bigger combustion volume in the cylinder head. Cam timing wouldn't affect the CR.

The wiring looms on the Raid and white metal-tanked OEs are different to the plastic tank models. They incorporate connections for the digital speedo head and sender unit. Also the headlight connection on the loom is different at least as far as the European blue model is concerned as it incorporates an extra wire for the parking light in the headlight.

At least one Raid model has a clever relay circuit that only allows power to the lights when the engine has started. I wasted a lot of time trying to get a headlight to work on of those models until I sussed what was happening. I am not particularly confident with bike electrics disbelief

TTRfan · Super Guru

barra8 wrote:
I don't like to correct you brian but it seems the earlier models had 6 clutch plates eg
1999: http://www.boats.net/parts/search/Yamaha/Motorcycle/1999/TTR250LC/CLUTCH/parts.html
The 2006 model used 6 too eg. http://www.boats.net/parts/search/Yamaha/Motorcycle/2006/TT-R250%20-%20TTR250V/CLUTCH/parts.html
The difference i have found so far is the 2005 model with 5 clutch plates eg. http://www.boats.net/parts/search/Yamaha/Motorcycle/2005/TTR250%20-%20TTR250TC/CLUTCH/parts.html

Oh and if it had a less aggressive cam (and or cam timing) would'nt that change the ratio as the valves would be opening longer???? Your theory on the ports is a good one and what i think it must be. Don't know why i didn't think of that

I don't mind being challenged wink

If you count the friction plates in the fiche pics on the boats.net links you will see that they are all 7 plate. See the pic of a clutch assembly from a blue TTR below showing clearly the 7 friction plates:

I haven't got a pic of a white TTR clutch assembly but I promise that they only have 6 friction plates.

Regarding valve timing, all valves on a 4T will be fully closed at TDC on the combustion cycle.

Brian

TTRfan · Super Guru

barra8 wrote:
I wasn't counting the plates on the boats site as it's the same pic for all ttr's. I was looking at the number of clutch plates needed for assembly as it tells you this under the pics.
I have a pic of my clutch plates (white bike) and there is 6 so not sure who is right on tthe clutch subject.

I think we are actually agreeing biggrin

White TTR - 6 friction plates (your pic confirms) and narrower clutch cover

Blue TTR - 7 friction plates (my pic confirms) and wider clutch cover

Brian wink

TTRfan · Super Guru

barra8 wrote:
That's weird that you have 7 as i have'nt found this info on the boats site. Have'nt checked all models yet though.Who knows maybe there listing is wrong??? You would think that they would have it right by now though???
So did you get my point i made about the cam or do you still think i'm off with the fairies?

Boats.net have the number of friction plates right for the blue model - see screen print below:
Boats extract.jpg

The CR is measured at TDC when all valves are closed - see the formula below. The only way the early models can have a lower CR is that they have a deeper combustion chamber in the head wink

Formula

The ratio is calculated by the following formula:

$\mbox{CR} = \frac { \tfrac{\pi}{4} b^2 s + V_c } {V_c}$ , where

$b\;$ = cylinder bore (diameter)

$s\;$ = piston stroke length

$V_c\;$ = clearance volume. It is the volume of the combustion chamber (including head gasket). This is the minimum volume of the space at the end of the compression stroke, i.e. when the piston reaches top dead center (TDC). Because of the complex shape of this space, it is usually measured directly rather than calculated.

I think we have probably got to the bottom of it now biggrin

Brian

Cubber · Super Guru

TTRfan wrote:
The only way the early models can have a lower CR is that they have a deeper combustion chamber in the head
Brian

That ain't necessarily so, Brian.

The depth of the combustion chamber certainly has a bearing on the compression ratio of an engine, granted.

However, the MAIN method of altering an engine's CR is by fitting a different piston. confuse

An engine manufacturer makes one engine that is suitable for many uses. For example, BSA Gold Stars were made and used for trials, scrambles, road, racing, sprinting, etc. A buyer could specify the tune of an engine when ordering to satisfy his demands. BSA would have a selection of different pistons that altered the compression ratio by the shape of the piston head. The distance between the centre of the little end and the top of the piston crown can be quite different to give a variation of ratios. A high compression racing piston may have, say 100mm height, a low compression trials piston may have a mere, say 90 mm height. The 10 mm difference gives a different CR for each piston. The "swept" volume is being altered by the piston shape.

My T100 started originally on 8:1, but pistons giving ratios between 5:1 and 10:1 were readily available from Hepolite and others. The cylinder head and valves were the same on all CRs. smile

Martyn (pedant)

TTRfan · Super Guru

Sorry Martyn - I didn't make myself clear - so what's new eh?

I was working from the basis that all the TTR pistons are the same.

So the first TTRs with the apparently 8.5:1 CR have a piston with part number 4GY-11631-00-C0 - for the OE see http://www.megazip.ru/ru/bike/yamaha/view/1086/2710/51744#g51746

For the Raid see: http://www.megazip.ru/ru/bike/yamaha/view/1086/2716/51744#g51746

And the later blue models have the exact same part number - see http://www.boats.net/parts/search/Yamaha/Motorcycle/2003/TTR250%20-%20TTR250R/CRANKSHAFT%20PISTON/parts.html

If I am right that all TTRs use the exact same standard Yam OEM piston then the different CRs can only be explained by a difference in the combustion chamber in the head.

As always, I am happy to be corrected wink

Brian

barra8 · Guru

Okay well i see what you mean about the cylinder volume capacity wont change by fitting a different cam. Just thought it may let less or more in with a different cam. Maybe i'm on the wrong track as i guess the capacity would be the same,it would just change the flow of the engine. Thanks for the ideas and solutions to questions Brian and others...

Haggis Hunter · Veteran Member

I am a bit late with this Barra8. But worth a look http://en.wikipedia.org/wiki/Compression_ratio

Sorry I have not linked it, having computer problems, I am knackered and I want to go to bed. Nite Nite.

-- Edited by Cubber on Tuesday 24th of July 2012 10:39:36 PM

barra8 · Guru

Thanks for the info,but maybe time to get back to the subject.

So far the differences are

Clutch plates,boss & basket some have 5 some 6 some 7. Both are interchangable provided you use the whole clutch assembly with the 99 clutch cover.All clutch plates interchange.

The 1993-1998 electric start can be interchanged with 99-2013 parts

Compression ratio on Raid models.

Most white metal-tanked TTRs have a digital speedo and therefore have a gearbox with an extended transmission/sprocket shaft to take the speedo magnet.

They also mostly have 6-plate clutches and a narrower clutch cover and therefore less oil than later 7-plate models. Easy to tell the difference as the later covers have Yamaha stamped on it them.

The obvious eg. wiring,plastic tank-metal ect..

Other than that i have'nt found any differences between any model ttr 250. If anyone would like to add to this or enlighten me feel free to do so.Cheers

-- Edited by barra8 on Saturday 2nd of February 2013 07:20:02 PM

barra8 · Guru

Oh... maybe someone removed it or it is from an EARLY model as my old 1994 0r 1995 (originally purple frame)has the strenghtened frame also. I just checked.

......................

Jarrah.

-- Edited by barra8 on Saturday 2nd of February 2013 08:32:04 PM

barra8 · Guru

Engine differences between 1992-1999 and 1999-2006

All cylinder barrels are the same

All heads are interchangable (raid model different compression ratio but still fits). Also the breather pipe is on the 1999-2006 head but not hard to fit a two piece joiner and pipe (if fitting the 1993-1998 bottom end to a 1999-2013 head) or the 1992-1999 head cover plate. *Edited Also while on the head cover plate i forgot to mention that the older models don't have the bump stop fitted.

The only differences with engines between any model from 1992-2012 is mentioned below.

You can order 1999-2006 parts unless its clutch boss & basket as these are different with the engines ie. 1999-2012 TTr 250 has 7 clutch plates 1992-1998 has 6.

All clutch and friction plates are the same in any model mentioned and will interchange.

Note: Some early models had 5 clutch plates

Interestingly enough if you fit all the components from the 1999-2006 eg. clutch boss and basket,clutch cover (pictured below) you can upgrade to the 7 plates no problem.

The good points to this would be that you would get the higher oil capacity (see below) and the added bonus of an extra clutch plate or two.

1992-1999 cover stamped 1000 cm/3 (see below)

1999-2006 plate cover (stamped 1100 cm/3 below:

1992-1999 6 clutch plates (see below)

1999-2006 7 clutches plates (see below)

The rotor casing is different from 1993-1998 & 1999-2013 but all starter components interchange aswell as the casing.

Also the white metal-tanked TTRs have a digital speedo and therefore have a gearbox with an extended transmission/sprocket shaft to take the speedo magnet.

..........................................................................................................................

Frame differences:

The 1993-1998 frame has two rubber mounts at the front & bolts on at the rear,whereas the 1999-2013 has a rubber mount underneath the tank,bolts on at the front & has a rubber holding it down.

As Brian brought into light ''some'' 1993-1998 frames do not have strengthening fillets at the rear shocky mount. All 1999-2013 on the otherhand have the strengthening fillets.

.................................................................................................................................

Carby differences:

In Australia the 1993-1998 carb has #48 pilot & #147 main jet. Whereas the 1999-2013 models have #50 pilot & #147 main jet. It has been suggested by Brian that the change to #50 pilot was around 1996 for the UK.

The slider arm on the 1993-1998 & 1999-2013 carby is slightly different but is still interchangable.

The top cover on the 1999-2013 carb has lipped edges whereas the 1993-1998 does'nt. Both are interchangable.

...............................................................................................................................................

Front axle difference:

The 1999-2013 has a different axle than the 1993-1998 as the 1993-1998 has to accomadate the speedo drive.

.........................................................................................................................................................................

Headlight:

Headlight bracket...

Note: Any speedo bracket from 1993-2012 should fit but i used a 1994 one as it was lighter. You can see this in the pic below...

...................................................................................................................................................................

Wiring:

Some blue models have a different headlight capacity so therefore seem to have different wiring harness.

Speedo wires fitted to the 1993-1998 models

.................................................................................................

I think that's all or i will start to go into different country differences.

The US model has a different headlight plug than the Australian or UK models but can be chopped & joined.

Brake light, blinkers ect. not fitted to US models (obvious).They still have the wiring needed in the harness (as far as i can tell)

The US headlight... aww aww aww aww aww ...

Note: You will notice i left colour changes out as these are'nt important. (to me anyway)

............................

Jarrah.

-- Edited by barra8 on Saturday 2nd of February 2013 11:43:49 PM

TTRfan · Super Guru

First time I have spotted this frame difference! You can see from the first pic of the purple frame where the frame had cracked and been re-welded. This must have been a problem for Yamaha to have added the fillets on the later metallic blue frames.

Brian

Frame differences - purple frame.jpg

Frame differences - metallic blue frame.jpg

barra8 · Guru

Ahr yes that is another difference that went unnoticed. Good spotting Brian

I have not looked at this thread in ages smile

........................

Jarrah.

TTRfan · Super Guru

Maybe some geographical differences?

Just looking back through my photo albums and found a 1994 Raid frame without the fillets.

Raid frame.jpg

But the other purple frames are about a 50/50 mix. Some have fillets others don't confuse

I jumped to a wrong conclusion based on one frame disbelief

Brian

barra8 · Guru

It's okay Brian we can't always be right the first time lol i edit all the time hahaha biggrin

I like how the frame in the pic above has been sprayed, why did'nt i think of that when i sprayed my frame lol it may have saves some work biggrin biggrin biggrin

I might add a few things to this as there is heaps of other differences. It can wait though,in the meantime anyone else want to add to the topic??

......................

Jarrah.

barra8 · Guru

If anyone wants to add the Raid differences be my guest but i'm not interested in them personally.

.........................

Jarrah.