80' Trailfire 440 rebuild! Advice and opinons welcome

[christoner2002]

I used Yamabond when I did my changing of seals, and orings on my 81' Trailfire. Also, I may have a airbox here for one if you are still in need?

[deerehunting]

I got an airbox coming thanks though, did you use yamabond 4? I ordered three bond but im not going to have the patience to wait for it another week after I get everything else , I'll probably run up to the Honda shop and get some hondabond, the Yamaha shop didn't have any for some reason oh well.

[deerehunting]

Ok I'm also having the 09-689 piston not being right issue has anyone found a solution to this, any OEM style available, will this piston work ok? Need help please, Matt any chance new breed will be getting the spi piston back in stock?
Thanks, matt

[Matt]

They're not available to me right now. I don't know when they will be. There is always the Wiseco option. At this point I still don't understand what the Trailfire issue is. I wish I still had a trailfire engine here to test fit pistons.

[deerehunting]

Yeah I just hate the wiesco price tag, but you get what you pay for, I just got the piston today and only had a second to look at it before work, my trailfire had two rectangle rings on each piston, not sure if the top may have been a half keystone. I would say without looking at it the top ring is about 1/8 to 1/4" down the piston, the new piston 09-689 has a L shape ring on top and a rectangle on the bottom and the top ring is at the top of the piston with a groove for the bottom of the L and a groove cut all the way around the top of the piston for the top of the L. I've seen where other guys are having problems with compression and breaking the top L ring, I believe the arrow on the piston is also wrong which has been discussed on here before. Like I said I didn't have time to really check it out so I'm not sure about the ring's orientation to the ports, but I will be looking more into that when I get home, like I've said this is all fairly new to me so i don't want to do something i shouldn't. If everything seems ok i will likely try it and see how the compression is and update from there, but again I'm at the end of my knowledge so if the rings are clear of the ports and everything fits good, what is the worst case scenario if i run this piston? Also i would like to get the right rings for my oem piston that I'm reusing I'll get more info and pics when i get home.Thanks Matt

[Matt]

Yeah I just hate the wiesco price tag, but you get what you pay for, I just got the piston today and only had a second to look at it before work, my trailfire had two rectangle rings on each piston, not sure if the top may have been a half keystone. I would say without looking at it the top ring is about 1/8 to 1/4" down the piston, the new piston 09-689 has a L shape ring on top and a rectangle on the bottom and the top ring is at the top of the piston with a groove for the bottom of the L and a groove cut all the way around the top of the piston for the top of the L. I've seen where other guys are having problems with compression and breaking the top L ring, I believe the arrow on the piston is also wrong which has been discussed on here before. Like I said I didn't have time to really check it out so I'm not sure about the ring's orientation to the ports, but I will be looking more into that when I get home, like I've said this is all fairly new to me so i don't want to do something i shouldn't. If everything seems ok i will likely try it and see how the compression is and updated from there, but again I'm at the end of my knowledge so if the rings are clear of the ports and everything fits good what is the worst case scenario if i run this piston? Also i would like to get the right rings for my oem piston that I'm reusing I'll get more info and pics when i get home.Thanks Matt

The Sportfire also originally came with the "rectangle" ring pistons too, but the L ring on the SPI piston works fine.

[deerehunting]

Ok that's my main concern is the different shape ring and the different placement height wise on the piston with the l ring on the very top.

[deerehunting]

I think what I will do is go home check it,( I'll post pics of my findings) if everything looks good I'll install it I'm reusing the old piston and rings in the other cylinder if they also check out, so ill get a comparison between the two compression wise, and I'll see how she runs, worst case in back at this point, and ill go with wiesco.

[deerehunting]

Is it possible, while I'm waiting on the other cylinder and parts to put this cylinder together, temporarily to check compression with the other cylinder off? Meaning put the case halves back together put piston and cylinder on and leave other cylinder off, just to check without putting everything back together? Or will it not work? Just trying to save some time.

[Matt]

Unfortunately I think you will need to put most of the engine together to get to that point.

[deerehunting]

Thanks that's what I figured.

[deerehunting]

ok from what I understand the pistons ring gaps should ride on either side of the exhaust port so as not to snag the end of the ring on the port correct? that's how the oem piston I have is anyway. what im finding is the placement of the ring pin on the top ring puts the gap right at the very edge of the exhaust port(sometimes snagging the corner of the port) and the bottom ring gap is dead center in the middle of the port(the two ring pins are within 1" of each other). With the piston turned around it is the same with the ring gap of the bottom coming out in the center of the teardrop of the intake. Not good right?

[deerehunting]

ok I think I got it like I said the arrow is wrong the ring gaps go towards the intake the top ring never gets close to the port on the stroke, the bottom ring gap is covered by the teardrop, it looks and feels good, setting the ring gaps tomorrow, I will try this piston and let you know what happens.

[Matt]

I just got this other piston that's P/N 09-688. I didn't know about it until last week. Can you take some measurements on the original piston to compare to?

[jjtt]

Tuned in as I have to replace pistons in my 79 Trailfire and waiting on this information before I order new pistons.