Niche Industries Top End Kit

[Logan]

I recently purchased a top end kit from niche industries. I have read the stuff posted on here about it and wanted to give some details about it. I'm not a mechanic by any means but I do know a little about casting and why these kits are so cheap. Mine is from parts discounter on eBay for $135. The cylinder seems pretty good. The holes for the head bolts and exhaust flange need to be cleaned. As many of you have also stated, all of the ports must be chamfered. There are some small casting defects inside the ports but nothing too serious.
The piston looks like crap. The best description of it I could give is that it looks like it is made of recycled matchbox cars. It is also very light in comparison to the bad piston I took out. All of the other parts appear to be fine.

I will be installing the kit this coming weekend and will give updates. I will probably be using a pro x piston.

 

[Awk08]

good info Logan, keep us posted with your results


are you getting ready to drop that piston in the recycle bin in this pic

 

[Logan]

Haha yes. That is probably the best place for it, but I'll probably turn it into a pencil holder or something for my desk.

 

[Larry's Shee]

Make sure the ports have good champhering, if in doubt google it.

Be sure to wash clinder real good. Best "at home" way is Dawn dish soap, keep washing until a white towel comes out white.

 

[Logan]

Make sure the ports have good champhering, if in doubt google it.

Be sure to wash clinder real good. Best "at home" way is Dawn dish soap, keep washing until a white towel comes out white.

Thanks for the advise. I'm still in the process of installing the kit. A few things have gotten in the way.

 

[Larry's Shee]

Those tips are pre-installation.

 

[Logan]

I realize this. It was nice and cleaned up when I put it in. Everything installed pretty easy. The base gasket and reed cage gasket seemed very thin and crappy. Luckily I had a spare set so I used those instead. The copper head gasket seemed just fine so I used it. The fourwheeler is completely together now but is leaking fuel from the petcock pretty bad so I won't be able to test it out till I get that fixed. I'll post an update when I fix it.

 

[79 bronco]

Nice info!

 

[Logan]

Just an update on the kit. Motor starts and barely idles but can not rev up enough to drive the fourwheeler. I believe it is low compression. I'm getting A compression tester to check this. When I put my hand behind the exhaust I can barely feel anything coming out.

 

[MURPH]

Make sure ur exhaust is clear and free flowing....critters like to make nest's in there

 

[Herpderplol]

mass produced cylinder + mass produced piston = messed up parts.

im sure the clearances are off

 

[Larry's Shee]

mass produced cylinder + mass produced piston = messed up parts.

im sure the clearances are off

And you don't think Yamaha "mass" produced them OEM?? Sure wasn't one at a time.

The real issue is quality control. When you're paid three bowls of rice a day, you're to hungry to give a fugg.
Casting flash is a different subject though, even stock can be cleaned up better than factory.

Were I to need one, I would probably just get the cyl, 1st over piston of my choice and bore to fit.

Still say "someone" said they were going to get one and "Check it out"

 

[jus_me]

Instead of all this back n forth on these things. Why dot we hold donation/raffle type thing where members can donate and once we hit the cost of the top end, it gets sent out to someone so it can "Really" be checked out and spec'd. Then after that hold a raffle for all who donated and have a chance to get the cyl or give it to someone who does. ? I am willing to donate a few bucks to get it started this way we all know what is going on and if we ever do need one of these cyls we all know what to expect and what does or doesnt need to be done..

 

[Herpderplol]

And you don't think Yamaha "mass" produced them OEM?? Sure wasn't one at a time.

The real issue is quality control. When you're paid three bowls of rice a day, you're to hungry to give a fugg.
Casting flash is a different subject though, even stock can be cleaned up better than factory.

Were I to need one, I would probably just get the cyl, 1st over piston of my choice and bore to fit.

Still say "someone" said they were going to get one and "Check it out"

mass cheaply produced...

 

[Logan]

Make sure ur exhaust is clear and free flowing....critters like to make nest's in there

That honestly doesn't sound like a bad idea. I Shook it but do not have an air compressor. I'll check that. Thanks. And why is herpderplol always so negative? But he is right about the cheapness of the parts. I'm currently using the piston that came with it as a paperweight.

 

[Logan]

Make sure ur exhaust is clear and free flowing....critters like to make nest's in there

You were right. I had a big chunk of something blocking the front of the header. It looked like a giant booger so I am assuming the mouse died right there and got stuck because it took a pressure washer to get him out. But the blaster runs now. It feels a little low on bottom end though. I expected a little bit more power. There may be other issues in the bottom end that I will look into. So my initial report is that the piston, base gasket, and reed gasket look crappy so they were excluded. I did run 40:1 for the first tank to be on the safe side. Hopefully I will get a chance to break it in this week sometime.. Is there anything else that people are interested in knowing?

 

[MURPH]

Good to here its running but you should mix it 32 to 1

 

[Logan]

I really should have looked that up. I still have the injection system hooked up. I'm pretty sure that the previous owner also used premix. Does it the oil pump or whatever wear out if there is no oil in the tank for awhile?

 

[MURPH]

if you run the system dry it sucks in air and you need to bleed the system if you want to use oil injection but if you want to pre mix do it the right way and get the block off

http://www.ebay.com/itm/Yamaha-Blas...005&rk=2&rkt=6&mehot=pp&sd=191556732867&rt=nc

 

[Blaaster]

Do not run injection and pre mix at the same time, and mix at 32:1 if you delete the pump.