Added reply in a thread Piston crown erosion question 2/7/2021 1:38 PM

Yeah, we just picked this up from a guy, so no telling of the abuse, and neglect it suffered. In the process of the tear down and inspection, now. I’ve never seen a piston in this condition before. I’m sure it will be all good once we get done with it. ... more »

Added reply in a thread Piston crown erosion question 2/7/2021 6:46 AM

I’ll pull it off and look under it. I’m thinking you’re right, as heat is the only thing that would cause it to melt like that.

Added reply in a thread Piston crown erosion question 2/6/2021 6:59 PM

Yeah, I just figured out that it’s a plated cylinder. It does need replacing, so I’m having that done, and am replacing all seals and bearings and putting in a new top end kit. I’ll check out possible causes for a lean condition, as well.

Started new thread Piston crown erosion question 2/6/2021 11:53 AM

My son and I picked up a 1996 WR250ZH and are in the process of doing a partial restoration on it. It ran before tearing it down, but take a look at the exhaust side of this piston crown. It’s eroded and curved. I’ll be having the cylinder bored and

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This forum thread has 8 replies

Added reply in a thread Bell Moto 3 Helmets 1/29/2021 1:22 PM

Very nice! I like the black white combination!

Added reply in a thread Bell Moto 3 Helmets 1/27/2021 6:13 AM

Looks great!

Added reply in a thread Bell Moto 3 Helmets 11/23/2020 8:15 AM

Nice!

Added reply in a thread Build your own leak-down tester. 10/30/2020 7:16 AM

No need to be condescending...

Added reply in a thread Build your own leak-down tester. 10/29/2020 8:41 PM

So, high pressure air applied to the crank will blow the seals out. If I’m not mistaken, the transfer ports come into play when the piston skirt rises above their openings. Explain your concern.

Added reply in a thread Build your own leak-down tester. 10/29/2020 5:37 PM

Motion Pro’s 2 stroke crank leak down tester. This is why I made one. https://www.motionpro.com/product/08-0071

Added reply in a thread Build your own leak-down tester. 10/29/2020 5:34 PM

Yes, and that is for above the piston compression leakdown.

Added reply in a thread Build your own leak-down tester. 10/28/2020 6:45 PM

There are compression testers, compression leak down testers, and crank volume leak down testers. Mine is a crank volume leak down tester. It inserts in the carb boot, where you clamp it into place with the hose clamp. Then you plug the exhaust exit ... more »

Added reply in a thread Build your own leak-down tester. 10/19/2020 11:04 AM

Thanks!

Added reply in a thread Build your own leak-down tester. 10/18/2020 8:12 PM

Thanks. I wanted to use aluminum, but don’t have the equipment to do the machining. I did all of this with a hand drill and taps.

Started new thread Build your own leak-down tester. 10/18/2020 3:53 PM

I wanted a leak-down tester and they cost over 200 dollars, so I decided to make my own. I used a solid acetyl copolymer rod and drilled it out and drilled and tapped the holes for the brass fittings. I bought the gauge from Amazon for 20 dollars. Came

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This forum thread has 14 replies

Added reply in a thread HPI Ignition Systems 8/20/2020 6:04 AM

I had NGK B9EV that I used, but I recently crossed them to a new NGK number plug which is the BR9EIX plug.

Added reply in a thread 1981 YZ125 Front Number Plate/Air Scoop 3/15/2019 9:01 AM

That would be cool, but I've owned this bike since 1981. I bought it from the original owner that year. It is an interesting coincidence. I guess we have the same taste!

Added reply in a thread Setting timing on a 1981 YZ125 using a dual guage. 11/5/2017 3:39 PM

OK, thank you!

Added reply in a thread Setting timing on a 1981 YZ125 using a dual guage. 11/4/2017 11:27 AM

Thanks, I'll check into that!

Started new thread Setting timing on a 1981 YZ125 using a dual guage. 11/4/2017 8:25 AM

I'm having trouble setting the timing using a Motion Pro dial gauge following a restoration. After finding TDC, then moving to the appropriate mm advancement, the mark on the fly wheel is at about 7:00 o'clock and I can't rotate the stator plate far ... more »

This forum thread has 6 replies