1984 IT490 Rebuild thread

[jr dragster T]

Thats too bad, But all you had to do was pull a side cover like my 250. I removed the right side cover off my 125 to do the clutch plates and if I needed to get at the kick starter gears I'd have to split the cases.

 

[crazycart]

Do the 125 cases split vertically or horizontally? Horizontally its real easy to do.

 

[jr dragster T]

The 125 cases split horizontally. The 250 cases split vertically. I thought that was easier? But say if I split the cases if the 125, Isnt like half of the transmision lay shaft if one bearing on one side of the case and the other in the other side? I dont want the shafts just to fall out if I split the cases. With the 250 you remove the top end and remove like 10000 bolts then give the cover a tap to keep the crank/layshafts down then just remove the cover. This is a picture of the 250.

Sorry 'bout the highjack.

 

[crazycart]

You got horizontal and vertical mixed up tyler! If those are the 250 cases in the pic, that's horizontal (ex.. Horizon) split. I don't mind the 'hijack', as long as its about bikes! My 400 Yamaha trike splits like your 250. its nice.

 

[jr dragster T]

But crazycart the cover on the 250 pops apart upwards, Wouldnt that be vertical? I dont split the cases with the engine on its side soo....So If your correct my 125 splits vertical. It would appear one bearing boss is in one half of the cover and the other is in the other half of the case. Sounds like a PITA to split.

 

[crazycart]

Oh i get what your saying. I mean the actual split in the cases, the line is horizontal.

 

[jr dragster T]

Ohh ok.

 

[88s10Durango]

What was your stock compression ? What did you go up to with the Weisco ?
Oh and on the story of the My Space girls , its nothing a 24 of and a >> I Did Her For My Country << situation can`t fix , lol

 

[crazycart]

Dont know, but the head mod i did lowered comp so it should be about the same.

 

[88s10Durango]

I see , generally a Weisco will up the compresion from 2 to 3.5 ratio`s , I know the Weisco for my little 185 Honda brings it up from 8.0 to 1 to 10.25 to 1 , or I can go up again to 13.5 to 1 , which requires Race fuel only though , I`m gonna settle on a stock piston out of a ATC 200X , will give me 9.6 to 1 ratio , and bring me up to 192cc`s , your 490 with a couple points higher on the compresion would be Killer !! Would make a nice Kart engine

 

[crazycart]

Ive seen 490's used in dune buggy's and race carts. There used to be a company that made high comp water cooled race heads for them also.

 

[jr dragster T]

Just a question crazycart. After adding aditional compression to a 490 engine and say its in a race kart. How do they start them?

 

[crazycart]

I'm sure they still use the kick start, but i cant verify it. Push start?

 

[EagleTalons]

I'm sure they still use the kick start, but i cant verify it. Push start?

Cheater kick starter bar!!!

 

[crazycart]

490 is fixed finally. Picked up 40$ worth of race gas, its Leaded 110 octane. Runs just perfect. I even put it in my little KD100, i was amazed at the power it has now, not to mention how smooth it revs out.

 

[jr dragster T]

Dont you love the smell of race gas lol.

 

[crazycart]

It does have a unique smell to it. The yamalube covers a lot of it up though

 

[jr dragster T]

Well I mean raw race fuel. You mean you dont open the fuel cap just to take a wiff in the morning. Maybe I'm mixing up race gas and normal racing fuel. Not sure what exactly you have. Racing fuel will not smell like gasoline at all. Ohh also watch out when you buy racing fuel, Methanol and so on from a large drum. Sometimes they will give you realy old stuff that probably has water contamantion.

 

[crazycart]

I get it from a place called Kath. They have a regular pump for it. I guess i didn't know there was a difference between race gas and race fuel?