The cheater MX85 argument. I might be changing my mind.

[steamroller]

Nothing wrong with a TF125 at all, it's a very nice engine, glad you enjoyed it as much as I do,
Reliable as clock work and lots of bottom end power, it's served me well with a NI championship and 3x 2nd places, it's leading the Auckland points at the mo, what more do you want ?
Cheap, reliable, abundant and still being made today.
Maybe it's just not cool because it started life as a farm bike !!

To me thats what makes it so cool look at it now i loved riding it and the power was great

[TZ350]

Yeah, it would be so awesome, think of all the hot motors running around and performance potential limited to 30HP

Not so long ago 20rwhp was considered remarkable, now its 30 with most race winning bikes in the mid 20's. A hot MX85 should be able to do that and maybe someone could even get one to 30. Un-limited, I think they could be a very handy little engine.

[steamroller]

I have no plans to built one. Can you not read?


If it ain't smokin', it's broken.

skunk if 85 come in should they stay stock?

[Sketchy_Racer]

Not so long ago 20rwhp was considered remarkable, now its 30 with most race winning bikes in the mid 20's. A hot MX85 should be able to do that and maybe someone could even get one to 30. Un-limited, I think they could be a very handy little engine.

How do you think the power curve would look with a 85 at 30hp?

The reason I ask is that I have recently learnt how important the area under the curve is. Having put both my 85 and kyles FXR150 on the dyno anyone would swear looking at the two curves at a glance the 85 would be the clear winner, however on the track the they are exactly the same.

It would not surprise me if a 25HP 150 with a good spread would kill any 85 with 30HP.

I agree with your sentiments of 20hp used to be the bench mark of a fast bucket, but now it's not even in the ball park.

[Bert]

Or easy.

I thought this was an idea to OPEN the class up to MORE riders. Instead you either ride a diesel or have be rich or an engineer. I don't like the options and the attitude that everything is ok. It's not.

Over and out. Can't be fucked with old school thinking. Some of you should be on the MNZ Board. No changes unless it suits you personally.


If it ain't smokin', it's broken.

settle petal; no need for the aggression and the view that everything is broken.

And for the record; despite the some from team declaring that the entire team is against this... I'm in the other camp..
So I'm guessing I'm out of the team...

but, primarily for the purpose of expanding the possibilities and following other classes of similar elk.



This entire tread has degraded into a stack of personal opinions and attacks; and some are refusing to look at questions poised.

if the 85cc were let in, what controlling rules are needed to to ensure that no significant advantage is gained ?

SWOT anyone.
Strengths:
1. the supply and availability of parts
2. reliability and maintenance of Hp over duration of a race (24 to start, 24 at the end)...
Weakness:
1. motors likely to be flogged out so a bit of work required.
2. people perception of cheating...
Opportunities:
1. potential for more riders or more at the pointy end.
2.
Threats:
1. potentially out perform current bikes
2. no controls in place to ensure the class doesn't loose it appeal.

this has to be explored before any submissions are put to MNZ.

So open discussions (rather than shit throwing); and testing is the only way forward.

Dave has brought forward a couple of really good simple controlling measures.
my two cents: open engine work, controlled exhaust, stock ignition & restricted Carb.
(& 25kg of lead if the rider is less than 70kg- - eat some food you little buggers).
we are never going to see a 30Hp 85cc MX here in NZ (unless some very trick aftermarket parts are thrown at one; so stop that from happening)...

where is the harm really. Start adding the the SWOT list (I'll keep amending it)..

[steamroller]

How do you think the power curve would look with a 85 at 30hp?

The reason I ask is that I have recently learnt how important the area under the curve is. Having put both my 85 and kyles FXR150 on the dyno anyone would swear looking at the two curves at a glance the 85 would be the clear winner, however on the track the they are exactly the same.

It would not surprise me if a 25HP 150 with a good spread would kill any 85 with 30HP.

I agree with your sentiments of 20hp used to be the bench mark of a fast bucket, but now it's not even in the ball park.

When your on the track racing your not riding half throttle its all top end. again the the 85 is 24 hp fxr150 25hp my bike coud not do a thing in a straigt line i think the 85 just had a bit on me give it 30 hp and yeah

[Sketchy_Racer]

Strengths:

1. the supply and availability of parts
2. reliability and maintenance of Hp over duration of a race (24 to start, 24 at the end)...
3. good starting platform for engine development
4. race ready for mid level power output
5. light weight


Weakness:

1. motors likely to be flogged out so a bit of work required.
2. people perception of cheating...
3. not the easiest to mount in road chassis
4. porting the plated cylinder might cause chipping


Opportunities:

1. potential for more riders or more at the pointy end.
2. opens the doors to mx based riders who know and like the motors



Threats:

1. potentially out performance
2. no controls in place to ensure
3. upset others with half developed motors

[goose8]

Not so long ago 20rwhp was considered remarkable, now its 30 with most race winning bikes in the mid 20's. A hot MX85 should be able to do that and maybe someone could even get one to 30. Un-limited, I think they could be a very handy little engine.

Nathaniel's bike had 23 maybe 24 at the gp and Dave's bike had 22.5hp mb100 and it weights 90kg and he set a new lap record with it , and the same bike still holds the out right lap record at mt welly With me at 85kg on it so hp is not everything but I can't wait to ride it again when mike gets it back to 30hp and you can buy new cylinders and cranks for about $40 a piece so personally don't think mx85 are needed. But then I don't think gp chassis should of been allowed either.

[mr bucketracer]

When your on the track racing your not riding half throttle its all top end. again the the 85 is 24 hp fxr150 25hp my bike coud not do a thing in a straigt line i think the 85 just had a bit on me give it 30 hp and yeah

thats a fair call from 2 fast riders , if it was not for f5 dave with his new 50 gettting near 14hp with such little work ( knowing once apon a time )pete sales it took years to get there, i may have a diffient view on it

[husaberg]

all good options. 50mm stroke.

also suzuki TS125r, TDM150, TZR150, DTR150...

while they turn up now and again they aren't common...

Yeah you would be pretty silly to choose a 54mm streoke NRS125 aye

settle petal; no need for the aggression and the view that everything is broken.

And for the record; despite the some from team declaring that the entire team is against this... I'm in the other camp..
So I'm guessing I'm out of the team...

but, primarily for the purpose of expanding the possibilities and following other classes of similar elk.



This entire tread has degraded into a stack of personal opinions and attacks; and some are refusing to look at questions poised.

if the 85cc were let in, what controlling rules are needed to to ensure that no significant advantage is gained ?

SWOT anyone.
Strengths:
1. the supply and availability of parts
2. reliability and maintenance of Hp over duration of a race (24 to start, 24 at the end)...
Weakness:
1. motors likely to be flogged out so a bit of work required.
2. people perception of cheating...
Opportunities:
1. potential for more riders or more at the pointy end.
2.
Threats:
1. potentially out perform current bikes
2. no controls in place to ensure the class doesn't loose it appeal.

this has to be explored before any submissions are put to MNZ.

So open discussions (rather than shit throwing); and testing is the only way forward.

Dave has brought forward a couple of really good simple controlling measures.
my two cents: open engine work, controlled exhaust, stock ignition & restricted Carb.
(& 25kg of lead if the rider is less than 70kg- - eat some food you little buggers).
we are never going to see a 30Hp 85cc MX here in NZ (unless some very trick aftermarket parts are thrown at one; so stop that from happening)...

where is the harm really. Start adding the the SWOT list (I'll keep amending it)..

Right the weakness for the current rules is the fuzzyness arround the parts. The dreaded SSSSSSSSSSSSSSSSS in motors.
Not being able to use a competition rod and bearing or crankshaft is trite.
I think gearboxs and clutch should be open.
The general lack of decent pistons for the 100's without expensive destroking. (submission in place)
if the 85 have to come in they have to be restricted to std cc and Pipe diameter is a great idea plus put a year cap on them to exclude the check book racers buying late model KTM's say 05 or something?


PS anyone able to send me a drawing of the transfer and stud positions of a TF125
ie a scan of the base gasket with a ruler?

[TZ350]

How do you think the power curve would look with a 85 at 30hp?

The reason I ask is that I have recently learnt how important the area under the curve is. Having put both my 85 and kyles FXR150 on the dyno anyone would swear looking at the two curves at a glance the 85 would be the clear winner, however on the track the they are exactly the same.

It would not surprise me if a 25HP 150 with a good spread would kill any 85 with 30HP.

These questions and the answers and the reasoning behind them have all been well covered by knowledgeable people in the ESE thread, if your at all interested in 2T's it might be worth a look .....

[TZ350]

if the 85 have to come in they have to be restricted (Pipe diameter is a great idea)

Wob may correct me, but I think that all things being equal a fat pipe design gives more torque and a smaller diameter pipe more hp (albeit peaker). So one will just have to use the clutch and gear box a bit more, I recommend Kevlar clutch plates for that snappy 30hp zing out of the corners.

[husaberg]

Wob may correct me, but I think that a fat pipe gives torque and a smaller dia pipe more hp (albeit peaker).

i thought the fatter is the betterer for both in'it? up to a point? torque is HP its just at its speed of effort...... or something frits would tut tut you Rob.............

[Sketchy_Racer]

When your on the track racing your not riding half throttle its all top end. again the the 85 is 24 hp fxr150 25hp my bike coud not do a thing in a straigt line i think the 85 just had a bit on me give it 30 hp and yeah

I'm sorry but this is simply not the case.


If partial throttle wasn't used why don't you replace your throttle with a switch? If you had ever looked at a data log of throttle % over the course of a a lap you would start to understand the importance of it and why engine tuners are for even in search of flat torque curves. Unless you have a CVT.

By your statement there you are suggesting the RPM does not change for each gear? So my 85 has 16HP the whole time I have the throttle open? I don't think so. Keep in mind that in the time that it's taken the FXR to shift 1 gear, the 85 has shifted 3, and that's three gears shifts of power not on the ground.

The dyno comparisons don't lie. Both bikes, same dyno same conditions.

[TZ350]

i thought the fatter is the betterer for both in'it? up to a point? torque is HP its just at its speed of effort...... or something frits would tut tut you Rob.............

Not really sure as I am just starting to think about this pipe business. But when you think about the energy in the pipe I think a smaller diameter will have greater reflected energy plugging the exhaust port but over a smaller rpm range. And with a fat pipe you sacrifice some peak hp by using the pipe to broaden the rpm range of deep suck at BDC.