First Kart and new to forum!

[scooby44]

Hello, my name is Steven! only experience I have with karting is riding a friends years ago. Finally found a good deal and in good shape kart, so I pulled the trigger.
I Picked up an energy wave evo kart with rebuilt kt100 yellow fin.
with mychron 4 new dunlop tires, stand and starter.

only issue I have ( assuming it's an issue) I start it up, it revs to 7500, sounds like its screaming!!! after a few minutes it dies down to about 2200 and seems to have a good healthy idle. but man that first few minutes it screammmsss. I don't like it reving that high not warmed up.
is this normal?

thanks for any help! and can't wait to take her out for first track practice !

 

[Poboy kartman]

to the forum!

 

[OzFab]

We tend to deal mostly with 4 stroke engines like honda GX (& clones), Briggs & Stratton, etc; very few deal with KT engines but, there are some, it may just take them a while to respond... hang in there...

 

[Hellion]

...only issue I have ( assuming it's an issue) I start it up, it revs to 7500, sounds like its screaming!!! ...I don't like it reving that high not warmed up. is this normal?

Not normal and not good for a cold engine or an engine in any state for that matter. When first starting it should (generally) take some time to start unless it's one of those engines known for starting on the first try. It should have a nice, slow irregular idle at first like most engines.

The thing I find most bothersome is the high RPMs at the beginning. Think of where all the oil is when it's first started--> in the sump. Then this engine over-revs right from the start with basically no lubrication. You could be getting some alarming wear-and-tear right from the get-go. Yikes.

I'd get the specs on that engine just to know where it redlines and its proper idle.

And welcome.

EDIT: I know about 4 strokes and 2 strokes but was guessing about what you had.

 

[Denny]

Pay no attention to Hellion for he knows not of which he speaks. KTM should be a 2 stroke engine, there for make sure the float level is ok and the needle is seating. You may want to install a fuel shut off valve in line also. It sounds like what may be happening is extra fuel may be puddeling in the crankcase. When you shut the engine off fuel leaks into the crankcase then when you start it again it goes WOT until that fuel burns off. Good luck.

Denny

 

[landuse]

Welcome. Check that the throttle isn't pulling it open for some reason when you start it

 

[Kelly Wood]

I raced Karts & had a KT100. For those watching, the KT100 was introduced by Yamaha in the early 70's and is a specific kart racing engine still used today in many places.

Even though the kart it came on (The RC100) was a complete failure because of it's "dead frame", the engine became part of numerous racing circuits.

KT100's are finicky turds but are fun to drive. Common racing RPM's can get well above 10,000 and mine was around 12. Temps on the engine get to 400+ degrees but watch it, if they go much further, it'll blow. Make absolutely sure your temp gauge in the onboard computer works.

Yes, on start they usually go way up in idle for the first little bit but then come back down. If it's way up there for MINUTES, there is something wrong. Clean that carb & check things. Don't worry about the high rev too much as the gas and oil are already lubing the thing, it's a 2 stroke.

There is no float in the carb, could be a vacuum leak, all kinds of things.

Does it perform just fine?

Keep in mind, racing one of these things requires maintenance. Rebuilds during the season are common. Start of season, fresh rebuild. Half way through, piston rings, possibly a piston & head gasket. Find the rule book on this class because once the engine has been punched out so many times, it'll become illegal to race & you'll need a new cylinder. (or can as they call it)

If you want the fastest KT there is, send it to Woltjer, and you're gonna pay for it... but she'll come back quite fast.

Racing notes:
It looks like you're in the "can" class. Probably 3 or 4 hole can (muffler, 3 or 4 holes) That'll be fun. Make sure the thing is bolted on good. Those can's love to come off.

The clutch, commonly the Horstman HDC is used. 1, 2 or 3 Disc dry clutch. Maintain that thing, it's a 300 dollar clutch. In specific, that inner thrust ring (the little ring between the clutch and the engine... lube it every time.)

Tire pressure & tires. I know you said you got new ones... but in the racing world: New OLD tires do not work for racing. If the tires are old, you're gonna spin out, period. If you have the means, buy new tires. Tires are everything and slides in corners=loss of speed, you're supposed to stick. Tire pressures on cold days, start at 14 up front, 15 in the rear. HOt days, go 11 up front, 12 ish in the rear.

Chains: Commonly a 219 chain is used. Get a spare. You WILL break one. Buy a chain breaker too.

Frame: Look down the rear rails, see if they're straight. If the left side is bent up a bit, get it fixed because it'll cause left turns to fail. It also means it's been in the air at one point. (very likely)

I see a chain guard there, good! Make sure it stays there. When one of these comes off or breaks, pray it doesn't hit you.

The carb: That T-Handle thingy. Turn it in all the way, then out 1 to 1.5 turn to start. After a minute & warm up (maybe half track), turn it out a little more. Play with that.

Alignment: Start at 1 degree toe out & go from there.

 

[scooby44]

I raced Karts & had a KT100. For those watching, the KT100 was introduced by Yamaha in the early 70's and is a specific kart racing engine still used today in many places.

Even though the kart it came on (The RC100) was a complete failure because of it's "dead frame", the engine became part of numerous racing circuits.

KT100's are finicky turds but are fun to drive. Common racing RPM's can get well above 10,000 and mine was around 12. Temps on the engine get to 400+ degrees but watch it, if they go much further, it'll blow. Make absolutely sure your temp gauge in the onboard computer works.

Yes, on start they usually go way up in idle for the first little bit but then come back down. If it's way up there for MINUTES, there is something wrong. Clean that carb & check things. Don't worry about the high rev too much as the gas and oil are already lubing the thing, it's a 2 stroke.

There is no float in the carb, could be a vacuum leak, all kinds of things.

Does it perform just fine?

Keep in mind, racing one of these things requires maintenance. Rebuilds during the season are common. Start of season, fresh rebuild. Half way through, piston rings, possibly a piston & head gasket. Find the rule book on this class because once the engine has been punched out so many times, it'll become illegal to race & you'll need a new cylinder. (or can as they call it)

If you want the fastest KT there is, send it to Woltjer, and you're gonna pay for it... but she'll come back quite fast.

Racing notes:
It looks like you're in the "can" class. Probably 3 or 4 hole can (muffler, 3 or 4 holes) That'll be fun. Make sure the thing is bolted on good. Those can's love to come off.

The clutch, commonly the Horstman HDC is used. 1, 2 or 3 Disc dry clutch. Maintain that thing, it's a 300 dollar clutch. In specific, that inner thrust ring (the little ring between the clutch and the engine... lube it every time.)

Tire pressure & tires. I know you said you got new ones... but in the racing world: New OLD tires do not work for racing. If the tires are old, you're gonna spin out, period. If you have the means, buy new tires. Tires are everything and slides in corners=loss of speed, you're supposed to stick. Tire pressures on cold days, start at 14 up front, 15 in the rear. HOt days, go 11 up front, 12 ish in the rear.

Chains: Commonly a 219 chain is used. Get a spare. You WILL break one. Buy a chain breaker too.

Frame: Look down the rear rails, see if they're straight. If the left side is bent up a bit, get it fixed because it'll cause left turns to fail. It also means it's been in the air at one point. (very likely)

I see a chain guard there, good! Make sure it stays there. When one of these comes off or breaks, pray it doesn't hit you.

The carb: That T-Handle thingy. Turn it in all the way, then out 1 to 1.5 turn to start. After a minute & warm up (maybe half track), turn it out a little more. Play with that.

Alignment: Start at 1 degree toe out & go from there.

Thanks for all the information!
So, you recommend the low adjustment for carb to be 1-1.5 what about the high portion?
I attached a picture of the clutch, not sure where I should lube or with what. Also, one more question! What do you use as in mix ratio go fuel. I have racing castor