COVID19: WE ARE CURRENTLY OPEN FOR BUSINESS AND TRADING NORMALLY!
$0.00 / 0 items
0
0

Yamaha YZ

yz85 2017

YZ85:

Jetting:

……

These are ballpark specs only. We do not accept any liability if you choose to run these specs, however we have safely used them on a number of bikes.

Head:
Run a TSP head for more power everywhere over stock and less risk of detonation. See SHOP for prices and details. Our heads perform better and cost less than anything else on the market.

Carb:

Porting:

The cylinder needs porting to be competitive in MX. See SHOP for prices and details.

Exhaust:
Stock system is fine for trail riding.  For more serious racers we suggest an HGS, DEP, or FMF. All of these add extra top end power.

Ignition:

Rebuild intervals:
Top end: Every 30 hours for trail riding/club MX. Every 10 hours for A grade MX

Bottom end: Every 100 hours for trail riding or club MX. Every 40 hours for A grade MX

Fuel/Oil:
Run 30:1 for A grade MX and 40:1 for trail riding. Normal 98 unleaded is fine for a stock engine and for our modified engines. Race fuels wont add extra power to a good engine setup, but they will be more consistent in quality. They may add extra power to a badly setup engine.

Suggested Mods (in order, first to last):

– Head setup

– Cylinder porting

– Different pipe

– Case mods

– Long rod conversion

Notes:

The YZ85 is way behind the competition in power. In order to make it more competitive it needs a lot of work… head setup, cylinder porting, long rod conversion, case mods, etc

 

 

yz125 2017

YZ125:

Jetting:

40-42.5 pilot, 6BFY43-74 needle 3rd clip, 430-450 main, AS 2.0 turns out

These are ballpark specs only, for stock or lightly modified bikes. We do not accept any liability if you choose to run these specs.

Head:
Run a TSP head for more power everywhere over stock and less risk of detonation. See SHOP for prices and details. Our heads perform better and cost less than anything else on the market.

Carb:
Carb oval boring adds extra mid/top end performance. See SHOP for prices and details.

Porting:
Dont bother for trail riding. For racers we can get a lot more mid/top power with correct porting. See SHOP for prices and details.

Exhaust:
Stock system is fine for trail riding and most forms of offroad racing. For more serious racers we suggest an HGS, DEP, or FMF. All of these add extra top end power. The stock silencer is absolutely fine for all levels of racing.

Ignition:
The stock CDI is fine.

Rebuild intervals:
Top end: Every 40 hours for trail riding. Every 15-20 hours for A grade MX.

Bottom end: Every 200 hours for trail riding. Around 100 hours for A grade MX

Fuel/Oil:
Run 30:1 – 40:1. Normal 98 unleaded is fine for a stock engine and for our modified engines.

Suggested Mods (in order, first to last):

– Head setup

– Rejet the carb

– V Force reed cage

– Cylinder porting (adds mid/top)

– New pipe

 

Notes:

The YZ125 engine hasn’t changed since 2006 and its still a great package. This is actually one of our favourite bikes of all time! They are very prone to detonation due to the head design and the lack of centering dowels in the head. The stock jetting is also too lean on the main jet. Some basic mods to the head, rejetting the carb, a new pipe and some cylinder porting will add about 3hp more than stock and make it very competitive. Its still down on power compared to the new KTM engine but the chassis and handling are great and make it a competitive bike. It also makes a great offroad racer or trail bike. A stock YZ125 makes 34.5rwhp on our dyno. Doing the head, cylinder porting, pipe and reed cage will see it hit 37-38rwhp.

 

 

yz250 2017

YZ250:

Jetting:

45 or 48, N3EW clip 3, 175 main. These specs will only work with our head setup.

These are ballpark specs only, for stock or lightly modified bikes. We do not accept any liability if you choose to run these specs.

Head:
Run a TSP head for more power everywhere over stock and less risk of detonation. See SHOP for prices and details. Our heads perform better and cost less than anything else on the market.

Carb:
Carb oval boring adds extra mid/top end performance. See SHOP for prices and details.

Porting:
Dont bother for trail riding. For racers we can get a lot more mid/top power with correct porting. See SHOP for prices and details.

Exhaust:
Stock system is fine for trail riding and most forms of offroad racing. For more serious racers we suggest a GYTR, HGS, DEP, or FMF. All of these add extra mid/top end power. The stock silencer is absolutely fine for all levels of racing. If you want more power spend your money on head setup first and rejetting first… its much better value for money.

Ignition:
The stock CDI is fine.

Rebuild intervals:
Top end: Every 50 hours for trail riding. Every 30-40 hours for offroad racing or A grade MX. Reduce these intervals by 25% if youre running the stock head.

Bottom end: Every 200-300 hours for trail riding. Around 100-150 hours for offroad racing or MX.

Fuel/Oil:
Run 40:1. Normal 98 unleaded is fine for a stock engine and for our modified engines.

Suggested Mods (in order, first to last):

– Head setup (adds more power everywhere, runs much more smoothly)

– Rejet the carb

– V Force reed cage

– New pipe (GYTR/FMF work very well and give good midrange)

– Cylinder porting (adds mid/top)

Notes:

The YZ250 is a great engine and hasn’t changed since 2006. For trail riders the only mods you need to do are setup the head and rejet the carb. For more serious riders also fit a new pipe… FMF/GYTR both add mid/top without losing too much bottom. The Pro Circuit pipe adds lots of top end but loses a lot of midrange. V Force reed cage works well. Theres no need to do cylinder porting unless you want maximum top end. A stock bike makes approx. 48rwhp on our dyno. Basic mods (head setup, reed cage, pipe, rejetting) will see it hit 51rwhp with awesome midrange… this is plenty for most riders. Add cylinder porting to this and weve had bikes make 55rwhp.

The stock head design is very bad and leads to detonation and short top end life. Best mods: head setup/rejet.