IT 490 Blaster Build

[Dassie]

Hi
I'm new to the forum. I started with my blaster 490 build a couple of months back and was hoping someone could give me some advice on if I should bolt or weld engine mountings on and if I must use polyurethane bushes for the vibration?

 

[yamaha28]

weld, much easier in my opinion. Thats a nice looking blaster too!

 

[Paulie B]

Welds will break, bolts will not.
I would also scrap the rubber/poly mounts altogether. Yes they will dampen some vibes but also create another problem- movement.
The motor will shake more and vibrate less if that makes any sense to you.
That particular motor is especially bad with the vibrations.
Pick up some extra needle and seats for the carb even mine tends to wear them out faster then normal from vibes.

 

[YZ Otis]

Welcome to the forum:

IMHO ... lol ... Long welds along the tube, not around the tubes. If you weld, don't use heavy metal ( like 1/4" plate), you'll kill the surrounding tube metal trying to weld it and it will break. If you go with bolts, use them to clamp to the tubes, don't drill the tubes. they will crack. Most folks say rigid metal to metal mount is best. I'm still undecided on that topic but it's the best place to start.. Post lottsa pics and get ready to shake, rattle & roll I:I

 

[Dassie]

Thanks for the advice guys,thanks yamaha28. I'm only waiting for a kick starter shaft, because my one’s stop broke off. The motor now has a 1mm oversize wiseco piston, new small end bearing, big end bearing, crank bearings, crank seals,every gasket was replaced with Yamaha ones.The motor was also ported. Rewinded the stator, redid all the cdi's wiring and also bought a new woodruff key and clutch plates.I know the vibes are real bad that's why I had the crank balanced, hope it helps! When the motor is back together I'm going to fit it in the frame and make up some mountings and gusset the frame and have it powder coated.I am also going to measure the port timing to build my own pipe out of 0.6mm plate that we are going to blow up.I will post some pics as the build goes along.

 

[vspec]

Definitely watching this build, I have a yz490 motor sitting around that i want to put in a blaster frame.

 

[Dassie]

The IT490 that I bought for the build.

Stripping the bike.

IT piston vs Blaster piston.

 

[Dassie]

Custom 110mm swing arm extension.

New Airtime front bumper. Laser cut and welded stiffeners into the rims. Powder coated the rims and put stainless steel valves in. Made a new grab bar with a tool bag on.

Made a 6mm aluminium disc and sprocket guard.

My two blasters. I put 22's on the one that is getting the IT motor for dune and trail riding.

 

[cole454]

Those rims are sweet. Cheap way to get baja style rims if you have the equipment.
Props for all the custom fabbing.

 

[Dassie]

IT's clutch cover was broken.

Bought a 1981 YZ 250 cover from ebay. The 81 air cooled YZ 250 and IT use the same cover.

 

[Dassie]

Thanks man. It added a tiny bit of weight to the rims but its worth the look

 

[1995blaster]

Thats a reallly great looking Blaster you have there. Wish i had the equipment to build these things. I really like the rims. Never seen anyone make a swingarm extension i know they sell them but most just extend the swingarm. Also That swinger skid looks indestructable.

 

[Dassie]

Thanks man.
Got my motor done so now to make up some mounts.
Does anyone know which side of the swing arm you grind of to fit the motor?

 

[Awk08]

all good stuff dassie
nice thick swinger gaurd !!!
keep the pics comin

2 things caught my eye, the piston size comparison....holy shizzle !!!!
and the length of the kicker on that 490 to aid kicking that beast

 

[Dassie]

Cut the swing arm and machined the bush on the inside to fit the IT motor.
The IT motor is 14mm wider than the blaster motor. Also machined a new visconite bush and bought a new dust seal.

The motor fits perfect. Kick starter clears nice and the spark plug clears the tank.
Making up some engine mountings now.

 

[Dassie]

Thanks awk08. The IT's are quite difficult to start!

 

[PikledBeats]

looking great, loving the fab work ... and rims look sick as well

 

[lowkhalbalr]

Omg this is intense. Keep up the sickness and dont
forget to take pics!

 

[Dassie]

Hey guys, the IT kick starter touches the rear plastics. Don't know if I should cut the plastics or look for a shorter starter. The IT's are are real difficult to kick so I think it would maybe be better to cut the plastics. What kick starters do the other IT/YZ hybrids use?

 

['blanshee'man]

Just ditch the rear plastics lol others will tell you otherwise but i dont run a set. And besides its not like your gonna be running a stock airbox anyway right?