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HOLY CRAP! My Tmax is now a friggin' MOTORCYCLE!!!

39K views 93 replies 24 participants last post by  pellicle 
#1 ·
Finally took the time and installed my Dr. Pulley Sliders & Sliding Pieces. Used four 18gm Sliders (Dr. Pulley recommended for Tmax) and four 15gm Sliders (recommended for Majesty 400): Average Weight is 16.5gms. The RESULTS:

1.) Hesitation off the line is GONE. Acceleration from stop is seamless and MUCH faster than stock.
2.) Midrange acceleration (e.g. NAIL it at 30 and keep it down till 65) is ASTONISHING!!! Literally a different bike.
3.) Idle is QUIETER...rattling of the stock variator is GONE...only had 3,500 miles on the rollers & sliding pieces. And the sliding pieces were quite WORN.

I thouight that the Dr. Pulleys had transformed my Majesty; just as much of an inprovement as THAT on my Tmax. For LESS than $75.00. Amazing.

I recently test road the BMW C650GT...my Tmax will now WALK AWAY from that BMW.

WHY such an improvement? The Tmax is now in it's SWEET SPOT at full throttle, with max torque and 90%+ horsepower. Again, Wow.

Thanks, BWT, for the Variator Tool drawing. Made one and was able to torque it to the factory 115 ft/lbs no sweat
(FYI...I marked the nut/crank positions with a scribe. When I reinstalled the nut, at full torque it was PAST the original mark)

(There were a few caveats with the new Sliding Pieces and the HORRIBLE ROUGH CASTING on the variator that they slide against, which is why my factory sliding pieces were worn and loose. If you are interested I'll do a follow-up post.)

Tmaxers: you GOTTA DO THIS MOD!

Neil
 
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#79 ·
I think it would make a good tourer, but I have certain back and neck issue that doesn't make me want to sit on any bike for long period of time, but if I have to, probably a bigger sport tourer would be ideal. Or a B650.

I made $750 plus accessories off that DCT bike, got lucky on that deal. :D

Just sold the clutch Nc700x also, not a bad bike at all.
But got a deal on a FZ07, very light and nimble with fairly upright ergo. I do want want to try a cb500x also.

Btw, why not tour with the Tmax? U put many miles on it so far. Not enough power?
 
#81 ·
sk8norcal said:
Btw, why not tour with the Tmax? U put many miles on it so far. Not enough power?
I have made many tours on my TMAX...some in the 4500-5000 mile range. It has plenty of power in terms of getting up the road. What it lacks is electrical power. It barely has enough for its own needs. If you turn on heated grips, heated seat, heated gear and start charging anything up - forget about it. Definitely forget about adding any auxiliary lighting. So that's my chief complaint.

Secondly, I'd like to put hard bags on it, but there are no good hard bag solutions available. I could have some custom rack mount things made for it - and I would - if not for the electrical weakness.

I do have an aftermarket stator sitting in my garage. Supposed to be better than OEM. But I'm not going to tear into it and try to replace it until it just craps out, or I have a second bike to ride in the meantime...whichever happens first :)
 
#82 ·
Armed with my new sheave tool (and some time) I got around to having a better look at the actual Torque settings, see how the new sheave is doing and putting in the new belt.

So, rather than repeat it all here its on my blog link here.

Summary findings
Now even better (lower) revs at 100,
Discovery of a non standard spring (perhaps replace it?)
Wondering if I'll be able to avoid spending nearly $800 for the secondary sheave and keep using what's there ...

 
#83 · (Edited by Moderator)
alaskaguy said:
sk8norcal said:
Btw, why not tour with the Tmax? U put many miles on it so far. Not enough power?
Secondly, I'd like to put hard bags on it, but there are no good hard bag solutions available.
You can modify the GIVI side mounts to take hard bags:

Rear View.jpg

Loaded-up.jpg
 

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#85 ·
Today I went for a 400Km ride down the mountain from where I live, off into a major city (population 700,000) and navigated everything from motorways (posted at 110Kmh but everyone doing 120 or more), tight mountain roads, country roads with long sweepers to heavy traffic.

I can say that after rebuilding my primary sheave, and throwing out the 17g Malossi weights and installing 19g Yamaha weights my T-Max has indeed transformed it from a buzzy little scooter (which revs its arse off but has no actual balls) to a torquey and competent mid range motorcycle.

I could sit on 120Kmh and still only see 5300rpm (it was over 6700 with the lighter weights), I could step out and overtake a line of trucks (from 90kmh) with good torque and acceleration ... better than one would normally get from a 500cc bike (but of course not what I'd get from a VFR750 or a XJR1300).

Fuel Economy has benefited and have moved from a reliable average of 4.8L/100Km to 4.1 L/100Km

Top speed is up so I can sit on 120Kmh and not feel like the motor is going to explode and I can see peak speeds which are well over 140

Its almost like Yamaha did a good job in designing the bike in the first place. But that can't be right ...

... can it?

So my take is "if you want to tune your T-Max to a specific race track" then the the lighter weights are the go for tuning in ratios, but if you want an excellent all rounder motorcycle ... leave it stock
 
#87 ·
pellicle said:
Today I went for a 400Km ride down the mountain from where I live, off into a major city (population 700,000) and navigated everything from motorways (posted at 110Kmh but everyone doing 120 or more), tight mountain roads, country roads with long sweepers to heavy traffic.
...
So my take is "if you want to tune your T-Max to a specific race track" then the the lighter weights are the go for tuning in ratios, but if you want an excellent all rounder motorcycle ... leave it stock
Thanks for this follow up. Al-rounder is what I'm after, so I appreciate the summary of changes with different weights.
 
#88 · (Edited by Moderator)
Umbrianissimo said:
Thanks for this follow up. Al-rounder is what I'm after, so I appreciate the summary of changes with different weights.
You're welcome.

I thought I'd attempt to provide balance in the "conversation" because its always vocally slanted towards the "oh my god" believers in the Kool-aid by the makers of spare parts.

To my mind everything is a balance, more of this means less of that. I believe that the CVT is at once the most important part of what makes the T-Max so much different (and better) and at the same time so "misunderstood".

Most people know how gears work, and expect that (as it does) power drives acceleration, however this isn't always true, as for instance with a CVT, where the acceleration is a product of the power the torque AND the CVT shifting gear (but mainly the last two).

Going back to first principles for a moment, on a regular gearbox the only way you change speed is by increasing RPM. When you run out of "grunt" (due to the design of the engine) you need to change a up gear and begin this process again.

The CVT in contrast often selects an RPM (based on how you twist that throttle, based on how much acceleration you (the rider) wanted. Often you'll observe that the RPM spins up to 5000 and sits there while the speed continues to rise (therefore acceleration occuring). This acceleration comes from the force of the CVT forcibly changing gears (at exactly the right balance) to keep stable RPM while accelerating.

Its a different concept and one that "throws" most riders expecting the usual rev rise -> change and drop rev -> repeat rise and explains why so many riders are at first caught out by what speed is on the dial when they look down. Too used to picking speed by the "sound" of the engine.

Many times I see that as I am approaching the speed I want (say, entering a roadway and wanting to come up to 100km/h fast) that I see 5500 on the dial, and note that I have to back off the throttle as the speed approaches 100 or it will go past that speed and then the revs and speed come back into balance.

Sounds more complex than it is ...

If you look at the power and torque curves its intereting what emerges (these are from a 2008 model I found published on the net promoting a "wow more power" set of inlet pipes to your airbox)

fig1.jpg


You see that the power rises slowly (its not a steep curve) and the torque is almost flat from low RPM to higher RPM.

If I overlay them (and keep the original size) you can see this more clearly:

Tmax-2008-TORQUE-HP.jpg


So if you've ever listened to a Diesel Electric locomotive hauling it usually applies RPM in a narrow range and balances the engine power output with the amount of electricity (power) being put into the rails to accelerate. The Tmax is just like that.

If you think of Torque as the amount of force you can apply to the crank (to attempt to stop it) and Power as the mount of work that can be done over time you'll see that this engine is designed to deliver different amounts of acceleration depending on the RPM you put it at.

You'll also see that after about 6000RPM torque drops off (meaning the motor is only making more power because of work done over the time : the revs per minute (time).

So when the primary and secondary are fully engaged (biggest it can get on the front, smallest on the back) you only then accelerate by increase in RPM. Based on my figures (readings) and those of another poster here some time back that occurs at about 120kmh (but can also drift down to 100 without head winds or hills resulting in me seeing 4800rpm on occasion at 100) and then you have RPM to take you to the higher speeds (if you were in Europe on an Autobahn or some other place where high speeds are permissable) like the 160kmh without revving the tits off it.

Recall also that the motor has a longer stroke than bore (meaning over square) and thus is designed to give more torque and rev lower. So that's why its redlined lower than some other (say FZR 600) bikes. Check the bore, stroke, power and torque of both these engines here:

https://en.wikipedia.org/wiki/Yamaha_TMAX
https://en.wikipedia.org/wiki/Yamaha_FZR600

and its power curve:
fzr600-yam.jpg


Thus you really need to be moving that engine around the RPM range to get it to perform ... its a totally different motor.

So bottom line for me is that I like it how it was made, and if I wanted a faster motorcycle I'd go buy another XJR1300
(like I used to have :)

But I'm really happy with the fact that the T-Max
  • costs me less to run[/*]
  • is super reliable[/*]
  • keeps me warm and (relatively) dry[/*]
  • is less likely to see me in prison[/*]
 

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#89 ·
Thanks for that very erudite exposition on how the TMax drive system works.
It has me thinking, but unfortunately, as yet I do not understand sufficiently to think coherently and reach a conclusion.
I thought that I was going in the right direction choosing the 16gm weights, but with your recommendation of the 19gm, I am more confused than ever.
I have yet to install them, so I am not committed to any direction … yet.
My riding will be mostly commuting, and on the back roads for day rides, I seldom exceed 90 kph. Very occasionally, I will venture onto highways at 100 kph.
Given this riding behaviour, and that I will likely do no more than 4000 kms per year over the next six years, before celebrating my 80th birthday and re-evaluating my riding career, any thoughts on which direction to take.

All comments, useful or otherwise, much appreciated. :bigsmurf:
 
#90 ·
WayneTalbot said:
I thought that I was going in the right direction choosing the 16gm weights, but with your recommendation of the 19gm, I am more confused than ever.
no harm had in trying them ... besides you get good at taking it apart ;-)

I built a small slide hammer (threaded rod, bit of steel water pipe) to make the job of encouraging the case off.

I myself believe strongly in the Maxim of Nullius in Verba

https://en.wikipedia.org/wiki/Nullius_in_verba

If you try them you may like them. If you don't do highway work (like all around town) the lighter weights are probably fine. Myself I tend to think they're a bit light, but I've seen other folks here try different combinations (even mix n match).

What works for me may not work for you :)
 
#91 ·
for those interested in the T-Max engine (and its undersquare design) I suggest this good read:
https://www.thenakedscientists.com/foru ... ic=34958.0

I'll quote from it below:

Undersquare engines

These produce strong torque at low to mid range rpm's because of the "leverage" advantage of a longer stroke. But, undersquare can be a negative trait, since a longer stroke usually means greater friction, a weaker crankshaft and a smaller bore means smaller valves which restricts gaseous exchange; however, modern technology has lessened these problems.

An undersquare engine usually has a lower redline, but should generate more low-end torque. In addition, a longer stroke engine can have a higher compression ratio with the same octane fuel compared to a similar displacement engine with a much shorter stroke ratio. This also equals better fuel economy and somewhat better emissions. Going undersquare can cause pistons to wear more quickly (greater side-loads on the cylinder walls) and can cause ring seal problems and lubrication problems; with increased loads on the crankshaft, pistons, the piston pins, connecting rods, and rod bearings (due to piston speed). In general, a longer stroke leads to higher thermal efficiency through faster burning and lower overall chamber heat loss.

A longer stroke will have greater port velocity at a given RPM, more torque due to more leverage on the crank, will achieve it's greatest efficiency at a lower RPM. Smaller combustion chambers are also more efficient, with the flame front having a shorter distance to travel- this leads to being more detonation resistant, and having an advantage for emissions.
and as an update on my 500Km journey the other day I got 4.1L/100Km (filled tank twice) which is an improvement over the previous (many journeys on that road) of 4.7 or a bit more than about 10% better fuel economy. (not that such is important to everyone)

From Wikipedia:
 
#92 ·
thanks for all these info.

the NC700X is also an over-squared engine. I didn't particularly like the low rev limiter, but I got used to it. Not safe for passing cars on backroads.
 
#93 ·
@pellicle,

Wow, that was brilliant. Thanks for all the effort you put into the two excellent posts above. Beer is on me if you fly across the ocean!
As well, I'm certainly pleased to read so many posts that speak highly of the TMax durability. I'm still in my first year of ownership of the 2012 NOS scoot, but I really like it. Good to know that miles are no problem for these bikes.

I'm getting similar highway mileage, but generally 5.6 l/ 100 kms in my commuting riding. I did a ride around the southern tip of Vancouver island a couple of weekends ago; Sidney (ours, not yours), Spoke, Port Renfrew and across the island to Duncan. Wonderful twisty roads and great scenery. The best way to spend a weekend.
 
#94 ·
Hi

Umbrianissimo said:
...Beer is on me if you fly across the ocean!
hah ... I'd love to have an ale with ya. I've got mates in Alberta (been there once for a month in 2002) and intending to go back and do a bit of "deer population reduction" with my mate (or if we luck out he's got some in his freezer anyway). So its possible

...but I really like it. Good to know that miles are no problem for these bikes.
my view is that if you do the basics (oil and filter changes as specified) they will yeild high miles. I sold an FJ1100 to a mate who remarked looking at the ODO that "wow, its in really good condition for a bike with forty thousand kilometers on it (as if that was big). So I told him the truth (cos he's a mate right) and said that it had gone around the clock and it was 147,000 not 47,000 km (it was about 3 yeas old then)

Oil changes at 5000 is the only big deal...

A few notes from the "Technical Orientation" guide of the first model (which has essentially the same engine as my 2006 model):

"Shim-under-bucket" valve adjustment for long maintenance interval (same as YZF-R1/YZF-R6)
and that bike is designed to do nearly double the RPM, which means that (as friction scales at a square of RPM) I would expect to get at least double the mileage from the T-Max valvetrain.

Ceramic composite cylinder coating for increased cooling and longer wear life
can't be a bad thing ... especially if you keep those RPM down ...
Dual stage oil pump brings oil from oil tank to respective areas of the engine, including a spray bar
over the starter gears and the stator assembly.
The oil pump also has a scavenging pump that returns the oil to the oil tank.
The scavenged oil fills the tank until it is full and then overflows back into the sump area to maintain
a constant level in the sump
I'm expecting to get 200,000 out of one ... I would have with the first one I owned (which I was the second owner of and had 39,000 on it when I got it), but I sold it at ~140,000 (IIRC) (still wish I didn't)

I'm getting similar highway mileage, but generally 5.6 l/ 100 kms in my commuting riding.
good to know ... that's what I see when tootling around Brisbane for a few days too.

I did a ride around the southern tip of Vancouver island a couple of weekends ago; Sidney (ours, not yours), Spoke, Port Renfrew and across the island to Duncan. Wonderful twisty roads and great scenery. The best way to spend a weekend.
of course its yours, ours is Sydney ;-)

love touring on the T-Max
http://cjeastwd.blogspot.com/2018/05/da ... aween.html

:)
 
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