Question for Dirt Bike Guys/Girls

AKBill

AKBill

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AKBill
So I have an old IT125 Yamaha dirt bike, I think it's a 1980 model. It has a 2 stroke 125cc engine. The engine runs sometimes, it's loud. It is a PITA to keep going. Thinking of putting a 4 stroke engine in it. The bike has no lights and I would like to at least install a head light and a tail light on the bike.

My plans are to build the bike, then take it apart to transport to a different location (Gustavis, AK). I would use the Beech Sport to move the bike to Gustavis, and leave it in a hanger at the airport so I can get around town when I fly in.

Any suggestions for something less than $500.

Thanks
Bill B
 
Its never worth doing a custom build, just buy the 4 stroke bike you want. Something like an older Honda XR or XL is what it sounds like you want.
 
G-force said:
Its never worth doing a custom build, just buy the 4 stroke bike you want. Something like an older Honda XR or XL is what it sounds like you want.
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Well the frame is in great shape, lots of new parts. I just want to put a reliable 4 stroke in it so I can run around town. Heck you don't even need to license it in Gustavis, AK. Cars, trucks, bikes running around town with plates that expired in 1990.
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I bet it just needs a new carb....seals go bad and they can get gummed up from sitting. It's easier just to get a new vs. clean the old. It can be done...but there is more trial and error in DIY.

$30 and go.....
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Checkout_my_Six said:
I bet it just needs a new carb....seals go bad and they can get gummed up from sitting. It's easier just to get a new vs. clean the old. It can be done...but there is more trial and error in DIY.
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Went through engine, bored 1 size over with new piston and rings. Having compression problems. Blow by at cylinder head. Even made a custom head gasket. I'm tired of F****** this engine. I want to use it to ride to the beach and a friends cabin. Maybe use it to get me to a spot to hunt moose...:)
 
Echoing the others, sell it as-is and buy a 4-stroke. If you really just want something ride down to the beach with gear, get an ATV/4-wheeler. You’d probably only have to spend $500-1,000 on top of what you sold your bike for to get something decent used, which is essentially what it will cost to shoehorn a 4-stroke into a frame that wasn’t designed for one. Not to mention the power loss.


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I bet it needs a top end at the very least if it’s been a while.. I used to race 2 strokes
 
SoonerAviator said:
, get an ATV/4-wheeler
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No way I could get a 4 wheeler into the area to moose hunt. Might get a 4 wheeler for the wife to ride around on. Leave in hanger for a friend to use from time to time.

ktup-flyer said:
I bet it needs a top end at the very least if it’s been a while.. I used to race 2 strokes
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I have access to a mill and lath. Thinking of the noise level for the locals. Don't think they would like a bike 125db+ running around.
 
A little old two stroke dirt bike won't make a very nice ride on the roads, even if you go to all the expense of updating the engine and adding lights. You can buy a not too old smallbore street bike or dual sport for a couple of AMU, and it will give you years of good service.

A 125cc or bigger scooter would work for in town use as well.
 
It's a 40 year old bike. Resist that terrible urge that wants you to spend hundreds of dollars on something that will break while you're riding it around Gustavis, AK and buy something built in this century.

I'm not trying to be preachy and annoying, but surely you have better things to do than trying to put a different engine in a motorcycle that's not worth $200. What will you do after you buy the engine, put out the labor to force it into the frame, and find out the width of the engine places the primary sprocket 3/8" out of line with the rear sprocket? Will they use the same size chain?

You'll also have to buy different throttle and clutch cables, buy and modify an exhaust system to fit, install new fuel lines, buy and install a wiring harness and lights, a battery, a chain, and other things I can't think of right now.

Edit: And a kickstand. Or, you could just buy two bungee cords and take the milk crate everywhere with you. :D
 
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AKBill said:
So I have an old IT125 Yamaha dirt bike, I think it's a 1980 model. It has a 2 stroke 125cc engine. The engine runs sometimes, it's loud. It is a PITA to keep going. Thinking of putting a 4 stroke engine in it. The bike has no lights and I would like to at least install a head light and a tail light on the bike.

My plans are to build the bike, then take it apart to transport to a different location (Gustavis, AK). I would use the Beech Sport to move the bike to Gustavis, and leave it in a hanger at the airport so I can get around town when I fly in.

Any suggestions for something less than $500.

Thanks
Bill B
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Part of the problem you'll face is that there are so few motorcycles in Juneau to scavenge an engine from. If it were me, I'd get a Yamaha 125 Zuma to leave over there. Seattle dealers happily ship to Juneau. It would be a great little scooter for both Gustavus and Juneau. I had one for several years. Sold it last year just before I left for Juneau. Should have brought it with me.

BTW, I didn't make it to Juneau for the Summer this year due to my 90 yr old mother's health issues. I'll be back soon enough though.
 
You can buy a new Chinese 250 dual sport for $1,500 and have it shipped from Seattle. The have a one year warranty and putting around town isn't going to break it.
 
I tried to go down this path with an old YZ250 I had.

You’ll need to find a 4-stroke that’s dimensionally similar and weighs about the same, or it’s significant fab work to the frame. If you can find something, then you’ve to solve for drive chain alignment. Then, power to weight will make you want to consider new front/rear sprockets.

And then, when you go to change the oil the first time, you’ll remember you never figured out Access for the drain plug and it’s pull the motor to change the oil.

And breaking it down won’t be easy like a bicycle. Front forks is about all you’ll want to take off unless there’s a removable subframe, so it’s not going to be much more compact/portable.
 
3393RP said:
You can buy a new Chinese 250 dual sport for $1,500 and have it shipped from Seattle. The have a one year warranty and putting around town isn't going to break it.
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You'd be better off buying a used Honda or Yamaha for about the same.

It's one thing to buy a pair of socks made in china, it's another to buy something that can leave you stranded made in china
 
The WR is the best Japanese trail bike out there right now. That’s the route to go if you want a 4 stroke
 
He has to transport what ever he buys in his Beechy, so size is a big factor.Most of these tall dirt bikes won't work.
 
2 smoke is going to be loud no matter what. I echo new rings and hone, new carb, new reeds, a new plug and she will run fine. And make sure the air filter is clean. Not much to a 2 smoke at all.

Otherwise cut your loss and just buy a reliable 4 stroke and be done.
 
simtech said:
2 smoke is going to be loud no matter what. I echo new rings and hone, new carb, new reeds, a new plug and she will run fine. And make sure the air filter is clean. Not much to a 2 smoke at all.

Otherwise cut your loss and just buy a reliable 4 stroke and be done.
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Isn't there new cylinder kits for these?
 
A $500 4 stroker dirt bike seems the impossible task.
 
Tom-D said:
A $500 4 stroker dirt bike seems the impossible task.
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Searching on the local CL for bikes $500 max price nets one XR70 minibike that looks like it probably runs, and several "It ran great in 1980 when I put it in the barn" type ads.

Nothing that looks like it would be suitable for dependable everyday transportation.
 
Tom-D said:
Isn't there new cylinder kits for these?
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Im sure there are somewhere. Back when I raced 125's if the cylinder got too rough I just had it bored next size. Only had to do that once otherwise a hone and new rings usually did just fine. I think on the 2 stroke's lots of people neglect the reeds and an old sitting bike they are brittle if not broke. They will make a huge difference.
 
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