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Need to know the exact dimension from the side of the piston to the end of the exhaust spigot for a 1998 YZ 250 two stroke.

Building an expansion pipe for a Yamato outboard racing motor using expansion chamber components from 1998 Yamaha YZ 250. To get correct total overall length of the modified pipe I need to know the exact length from the side of the piston to the end of the cylinder exhaust spigot. This dimension was probably the same for several different years so information for any years would be appreciated. Thanks Lar

Posted by Larry Stenander on

  • Larry Stenander Mar 03, 2013

    Mark,

  • Larry Stenander Mar 03, 2013

    If I had a yamaha YZ 250 cylinder I would measure it myself.

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1 Answer

Mark Jones

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  • Contributor
  • 33 Answers

Lar get something to measure it with

Posted on Mar 03, 2013

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5 Related Answers

tombones

  • 3567 Answers

SOURCE: Maintenance schedule 2008 yz 250

How about an complete factory service manual instead of just a maintenance schedule? Go to the site below and do a free download of the manual AND a parts fitch manual. These manuals are about 4 years old but 95% of what is there is still accurate for your 2008.

http://www.carlsalter.com/motorcycle-manuals.asp

Top rating due on this one! Thanks!

Posted on Apr 24, 2009

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Anonymous

  • 1 Answer

SOURCE: 01 yz 250 2 stroke leak out left side black hose???

i have 03 yz 250 told that the hose you are talking about is drain for powervalve and when bike is ran in low rpm are not warmed up before its shut down load up of premix will drain from hose .i found that mine does not leak anything after hard rides on track.

Posted on May 05, 2009

tbrat44

  • 86 Answers

SOURCE: how much is my yz 125 worth?

the retail value in good condition is approx $1,500. meaning it looks good, runs good, good tires, breaks,chain and sprokets. but with the extras you have and the after market up grades, i would start with a little higher price.

Posted on May 21, 2009

Anonymous

  • 1 Answer

SOURCE: YAMAHA TTR 250 cherry red exhaust

I have a TTR-250 2005 that I bought new. Exhaust has slowly been getting hotter/redder over the last couple years. It quit running and idling smoothly just recently. I used some "Sea Foam" gasoline additive and it helped a little. After talking to guys at the Yamaha shop, the problem is most likely too lean a mixture due to deposits on the needle valve or build up in the carb somewhere. The sea foam did help but I'll be taking my carb apart soon to fix it totally (I hope).

Posted on Nov 10, 2009

SOURCE: yamaha yz80 2 stroke or a4 stroke

2001 Yamaha YZ80 Specifications Engine Engine Type
2-stroke Displacement
83 cc Bore x Stroke
47 mm x 47 mm Compression Ratio
8.2:1 Engine Cooling
Liquid Carburetion Carburetor
26mm Mikuni Transmission Transmission
6 - speed Chassis Wheelbase
49.5 in Ground Clearance
13.7 in Seat Height
33.6 in Fuel Tank Capacity
1.3 gallons Forks Forks
33mm Kayaba Fork Travel
10.8 in Shock Shock(s)
Kayaba Shock Travel
11.1 in Wheels and Tires Front Wheel
17 in Rear Wheel
14 in Brakes
disk/disk Other Information Intended Use
Motocross Color Scheme
Blue Cost when new
$3199

Posted on Jul 19, 2010

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I would suggest a 250 2-stroke or a 4-stroke. Lots of power, lots of pull and the motor would likely last you for years. I've raced both the 125 and the 250 2-stroke at the pro-am level (A-class) and the difference in engine life is tremendous. I would re-ring a 125 every week (running 26:1), while with a 250 I could go for 2-3 months or more without doing the top end while running 32:1.

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This is a two-stroke, right? If so, the original pipe was designed with a restriction (the pipe gets much smaller) at the end of the expansion chamber which caused a backwave from each combustion chamber explosion. The length of the pipe was precisely calculated to cause the backwave to arrive at the cylinder at the bottom of the piston stroke.......when both the intake port and exhaust port are open. The backwave keeps the fuel-air mixture from going out the exhaust pipe. If the aftermarket pipe is not designed right, a lot of raw unburned fuel and two-stroke oil will be dripping out of the pipe and your power and fuel efficiency will drop. In that case you might be better off with your original pipe. It was designed to give you good power and efficiency for that engine.
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