Clearance for kt100.. and a few questions

[Magice]

I've just bought a kt100 for $100. Picking it up Wednesday.

Now as you know the pto is on the other side with a 2 cycle, so I'll have to mount it pto right, away from the kart.

There is very little clearance between the wheel and the frame for the sprocket, so I was wondering. Should I mount it with like about 1cm of clearance on either side after the chain, or should I invest in a jackshaft setup.

My other question was does the kt100's crankcase come tapped for a pulse fuel pump, and does the walbro carb have a pulse fitting.

Also, on a side note, 2 strokes get power from compression in crankcase, wouldn't a pulse pump bring compression down?

[Russ2251]

Now as you know the pto is on the other side with a 2 cycleThis is true of KT-100's, not 2 cycles as a whole.
does the kt100's crankcase come tapped for a pulse fuel pump, and does the walbro carb have a pulse fitting.Crankcase is tapped for diaphragm carburetor as standard for this engine. Carb has nipple for this reason. Probably a WB-32 or WB-3a Walbro.
2 strokes get power from compression in crankcaseThis is incorrect. 2 cycles get power from fuel air mixture in combustion chamber, same as a 4 cycle. Pressure in crankcase is necessary to get fuel/air mixture into combustion chamber via ports in cylinder wall/piston.
Typically, these engines are race ready and require rebuilds every 100 miles or so. Definitely not for the inexperienced builder. Many books out that cover this engine. I strongly recommend you check them out.
wouldn't a pulse pump bring compression down?Insignificant. Too small to measure.

[Kenny_McCormic]

Should have enough by the sound of it, most minibikes are setup that way.

[Magice]

Russ being the 2 stroke expert you are what kind of decreases would I see in the engine if it wasn't rebuilt?

I'm not sure if I'm going to put this on my kart or not. I'm not going to be racing.. But for $100 and close I couldn't resist the kt100 + clutch.

[Magice]

Any particular book you recommend?

[Russ2251]

being the 2 stroke expert you areThanx, but still learning just like you! I'm just on a different level.
what kind of decreases would I see in the engine if it wasn't rebuilt?Expect mushy compression. Rings are first thing to suffer wear. May be fine the way it is but will not be giving you the 9 or so horse power it's rated at.
Any particular book you recommend?The factory service manual for starters. Contact Yamaha or go to their website and see if they have a manual for download.
If you do contact them, have serial number ready. These engines are subject to new revisions year to year.
A '92 model might have different specs than a '96.
Side note: Surprises me that this is a piston ported engine when it is well known that reed inducted engines rev higher with better response time.

[Magice]

What's the difference between piston ported and reed inducted?

[Kenny_McCormic]

What's the difference between piston ported and reed inducted?

How the intake is closed off from the carb to produce pressure that pushes fuel into the jug. Piston ported:the piston covers the port its cheaper and more reliable, reed inducted: uses a one way reed style valve. Im curious how they designed a engine that only lasts for 100 miles? Lean running or crap materials?

[Russ2251]

On piston ported, shirt on piston acts as a valve to open and close intake port.
Reed valves are metal leaves (or petals) that open in the presence of negative pressure or partial vacuum as piston moves upward in cylinder (intake stroke).
When piston moves downward, it pressurizes crankcase forcing reed valves to close.
Open in one direction and close in other direction.
Vacuum opens. Pressure closes.
Most 2 cycle engines use metal reeds while high performance engines use carbon fiber.
pic 1: reeds in partial vacuum.
pic 2: piston ported. blue = intake red = exhaust

[Magice]

How the intake is closed off from the carb to produce pressure that pushes fuel into the jug. Piston ported:the piston covers the port its cheaper and more reliable, reed inducted: uses a one way reed style valve. Im curious how they designed a engine that only lasts for 100 miles? Lean running or crap materials?

Well it can spin 18k rpm..

[Russ2251]

Full size dragster engines good for 1 1/4 miles or 5 races if they manage to stay together at all.
"The light that burns twice as bright, burns half as long" Eldon Tyrell

[Magice]

I might play around with this a little.. Then see if I can sell it / trade it for a 125cc shifter engine or something like that. It seems to be tooooo fragile.

I might consider direct drive though.

[Russ2251]

Just a question out of curiosity. Did you get a starter with this engine? If so, what is it?
Kick?
Electric?
What is compression (psi) ?

[Magice]

I know nothing about the engine except that it runs and it comes with a clutch.

[Russ2251]

Mount it on something just for S & G's!!!

[Magice]

I have a friend who's picking it up today. He isn't home, I'll probably have it tomorrow.. I'm excited :)

I wish I had a place to take it to top speed. The main road is just too dangerous.. People pulling out of driveways ,etc.

[jr dragster Tyler]

Full size dragster engines good for 1 1/4 miles or 5 races if they manage to stay together at all.
"The light that burns twice as bright, burns half as long" Eldon Tyrell
They last longer than that, russ. your refuring to like 4000 horsepower blown alcohol that MAYBE last 5 runs. Or top fuel engines are REBUILT every run within 2 hours.

[kibble]

They last longer that that russ. your refuring to like 4000 horsepower blown alcohol that MAYBE last 5 runs. Or top fuel engines are REBUILT every run within 2 hours.

LOL! You need to use a comma between "They last longer than that" and "Russ". The first time I read it, I thought you were saying that it lasted longer than Russ. I had to go back and read it again.

I wanna see pics of this engine when you get it! :drool5:

[Russ2251]

They last longer that that russMakes no difference. You're missing the point of post.
I wanna see pics of this engine when you get it![/URL]Here's Yamaha's website:
[URL]http://www.yamaha-motor.com/sport/products/modelhome/464/0/home.aspx (http://www.yamaha-motor.com/sport/products/modelhome/464/0/home.aspx)