Cruzinimage GT550 Piston USA

[yeadon_m]

Question: other than breakage risk, would you hear a looser than ideal piston pin? what sound might that make?
Cheers,
Mike

[bill in okc]

I've had 1st over cruzin image pistons in my H1 for over a year now and no problems yet. I've got std GT550 pistons from cruzin but have not used them. The pins seem to fit fine though but I'm considering going 1st over.
I put cruzin brake lines on both the H1 and GT550. The 550 lines went on no problems, the H1 lines needed some adjustment - they leaked in two places at first - at the triple where the line from the master connects to the 3 way brake light junction - I used two crush washers on one side to fix that leak - the bend at the banjo was not sharp enough to clear a part of the 3-way casting. The other problem was the hard line shape and leaking where it connects to the rubber line near the caliper. I adjusted the bends of the hard line around the fork leg and just kept tightening that connection until it stopped leaking. No problems since. I guess it might be hit and miss with them but now I'm working a '71 CB750 and I've already bought cruzin brake lines and a brake caliper piston from them - I think the original engine bore/pistons are good so it won't need new pistons.
The shipping from cruzin image has gotten longer - it used to be 3 days from Japan like clockwork but the CB750 caliper piston was held up in customs for 3 days, 9 days total to get it.

[Vintageman]

Maybe I'm too fussy

I now have direct from Cruzin the junk man

GT750 1.0 Piston set
GT550 1.0 Piston set
GT380 1.0 Piston set

All unused, still in box and shipping package

Sell for 30% off his price + shipping USA actual cost
50% off the GT550s (IMO pin fit a little too loose... maybe try nos pins?)


Found OEM 1.0mm OS Piston and Rings coming from 3 different sources
These are very hard to find. Everything cost me $238 includes all shipping.

Paul Miller's wisecos @$299 would have been about same price once I get new wrist pins and small end bearing.
On the side of the wiseco box clearance is 0.0025" (not too bad) . OEMs as low as 0.00159"

[Coyote]

I ordered the 0.5 OS Wiseco pistons from Paul Miller. He sent me 1 correct piston and 2 standard pistons. I sent the whole mess back to him and he wound up sending me all the correct stuff. All Suzuki.. So I ordered Wiseco and received Suzuki. I was pissed at first. Then I realized I was probably just as well off with OEM parts. So I didn't raise a stink over it.. He also put a 20 dollar bill in the box to cover the shipping cost of returning the wrong parts.

[Vintageman]

I absolutely think you are better off with OEM. Those pistons are well proven for street use.

I asked him if the dome on the wisecos were the same shape as OEM. I have seen a few wisecos be less domed in the past and by quite a bit thus less compression. He said “he was no piston expert call Wiseco”. I did and they said he owns the design and call him

I also asked miller clearance, did not reply (sick of my questions or too many at once?) then realized if I zoomed in it was written on the box. Well, I am almost but, sure those wisecos are good pistons and would have bought if I did not find the 1.0 OEMs (still crossing my fingers they come in and are OK).

I could really find no flaw with the cruzin GT380 piston (pins is little loose too, OEM pin was little tighter in it) but, I bought OEM for GT380 for $20 each just today ($8 shipping). Saw that an grabbed it (man is my wife going to give me talking to again about $)

I am not sure what the clearance can be on the Cruzin's material. That aluminum seams a little different than OEMs. It reminds me of when guys were first buying the reproduction Yam R5 piston off HVCycle. If you held to the factory clearance 0.0016" (?) they would seize. I think he later stated to use more like +0.002” if I recall correctly.

[Coyote]

Forged pistons (wiseco) require a minimum of .0025 clearance. They expand more than a cast piston

[yeadon_m]

Repeated question, forgive me, but I'm interested if anyone can say, other than risk of piston breakage, what noises might a slightly less tight than ideal piston pin fit to piston make?
Cheers,
Mike

[Vintageman]

Repeated question, forgive me, but I'm interested if anyone can say, other than risk of piston breakage, what noises might a slightly less tight than ideal piston pin fit to piston make?

Nothing at first maybe or only briefly when engine not under load. What I was trying to say is that area is not intended to move really. There is no oiling provision for example. So that is a problem if is moves very easy. Also if there is a significant gap that will hammer egg shape, get pingy and just grow over time. So I suspect no real issue at first from what I see but for How long?

I have had loose pin bearing fit into small end rod eyes. Sounds like pinging. And, if little wear under load may not here it, until no load then sounds just like ping to me and I can't discern (can't adjust carb to get rid can be a clue). If I hear it at all its usually well worn . But, it only gets worse from there quickly sounding, more often and like a tin can with pellets in it.