Big Bore Kit Brands

[OhioYJ]

So already have a few things ordered for the DRZ for this winter. Was thinking about finally going Big bore. I know Cylinder Works has always been a favorite, but is this because of cost, or is it really the best? I was looking at Athena's documentation and noticed they are recommending piston replacement every 15 hours? Is this some leftover blurb from a 2-stroke document?

I won't necessarily say cost is a huge concern, I just don't want to give up reliability.

 

[LuckyLucky]

I picked the CylinderWorks kit for cost and the lower compression. I currently live in an area where obtaining anything better than 87 octane is a questionable prospect at best. If that wasn't the case, I might've just picked up the Athena and be done with it. In any case, both of those kits are tried and true platforms to go on.

[OhioYJ]

1 hour ago, LuckyLucky said:

I picked the CylinderWorks kit for cost and the lower compression. I currently live in an area where obtaining anything better than 87 octane is a questionable prospect at best. If that wasn't the case, I might've just picked up the Athena and be done with it. In any case, both of those kits are tried and true platforms to go on.

Generally where I am 92 octane is the lowest I will see, 93 is generally what I always run. So fuel shouldn't be a problem. I also looked at the ice cube kits. They are the more than either of the other two, but more displacement again?

[ohiodrz400sm]

The Cylinder Works was favorable over Athena due to the price advantage. The cost has gotten closer but you can still get a CW for a bit cheaper.

Whether you use a triple layer or single layer base gasket dictates the compression. Athena and CW are basically the same. I think Athena advertises a smidge higher and a larger water jacket. CW advertises stock 11.3 compression assuming you'll use the 3 layer gasket.

Ice Cube kits are billet and probably better choice of you want to build something larger than 462cc. The price reflects this.

[BillDirt1]

I got the Athena, like it, would do it again.

[Scottg07]

So back to the original question- Athena piston replacement every 15 hours?? Is this true?

[bucket list]

So back to the original question- Athena piston replacement every 15 hours?? Is this true?

That's if you supermoto racing it, a safe max performance interval. I know several guys that race 250f mx bikes and replace them 40-50 hours with out problems. I went over 400 hours on my last CW vertex piston 434, though it had a big crack down the middle of the crown, thats cruising around adv riding.

[ohiodrz400sm]

That's if you supermoto racing it, a safe max performance interval. I know several guys that race 250f mx bikes and replace them 40-50 hours with out problems. I went over 400 hours on my last CW vertex piston 434, though it had a big crack down the middle of the crown, thats cruising around adv riding.

Do you happen to know the miles you racked up in those 400 hours?

Vertex recommends 20 hours I think. It's to cover their own ass. You can't except a modified engine to have the same life expectancy of a stone stock. However, if built correctly it will still last quite a long time.

[BillDirt1]

Do you happen to know the miles you racked up in those 400 hours?

Vertex recommends 20 hours I think. It's to cover their own ass. You can't except a modified engine to have the same life expectancy of a stone stock. However, if built correctly it will still last quite a long time.

What's the old adage..."You Play, You Pay" lol. [emoji106]

Agree, installation & maintenance have alot to do with service life.

Mine looked fine when I had it apart in May, for the stroker install.

Anyone wondering/worring about service life, should just keep the OEM top-end. Without a doubt most durable.

[jjktmrider]

I don't think you'll notice any difference between the 2 kits , both have proven good . Maybe more down to which brand of piston you'd prefer but even that for std street riding it won't make a big difference . Now if you go to 13.1 or a bit higher compression, since you have better fuel, then piston choice will come in more . If you don't regularly bounce it off the rev limiter or run it high rpms for miles and miles down the freeway , hrs for piston replacement becomes a none concern ,as does reliability concerns,  just need to watch for compression loss as to when it's time .

 

.

Edited December 16, 2018 by jjktmrider

[habs]

My Athena 90 mm came with 2 base gaskets, single and triple layer. 

[hinksy]

I used the CW big bore with a vertex piston on my SM 8 years ago . Although I sold it 2 years ago , I still see the new owner and he has had no problems with it and it is his daily driver . A lot of the problems that used to occur , were the big end would fail if the motor had too much mileage on it . If you are going to race it , then maybe they wont last so long , but just general use they should last as long as the std setup ( if installed properly ) The best brands are athena , cylinder works and ice cube . If you use anything else it tends to be a cheaper quality and usually ends in tears , greg 

[bucket list]

11 hours ago, ohiodrz400sm said:

 

 

Do you happen to know the miles you racked up in those 400 hours?

Vertex recommends 20 hours I think. It's to cover their own ass. You can't except a modified engine to have the same life expectancy of a stone stock. However, if built correctly it will still last quite a long time.

 

24,000 kms that I know of, talking to P/O,  piston could have been closer to 40,000 kms and 700 hours.

Of course the piston manufacturer is going to go conservative on the intervals, but I believe how you maintain it and ride it has a HUGE influence on how long it will last.

[habs]

So how can you tell it’s time to change piston , compression and leak tests ? 

[BillDirt1]

When something brakes. [emoji106]

[ohiodrz400sm]

So how can you tell it’s time to change piston , compression and leak tests ? 

Do a test after break in and write the number down in the manual. Every season, birthday, February 29th or whatever other schedule to pick, take the reading again and compare to the original baseline.

 

[habs]

1 hour ago, Diverdown said:

When something brakes.

Yup , I was expecting that one ??

[bucket list]

So how can you tell it’s time to change piston , compression and leak tests ? 

Just before it gets to this point.[emoji27]

Actually i was up to 30% leakage and i knew it had alot of hours on it, also chasing an engine rattle, so i just threw a new BB kit at it. Didn't see the crack under that carbon on the crown, but the young guy in the shop with much better eye site than i have, saw the crack over the pin, so i cleaned off the crown and YIKES.
New kit sure quieted down the engine though.

[habs]

3 hours ago, bucket list said:

Just before it gets to this point.

Actually i was up to 30% leakage and i knew it had alot of hours on it, also chasing an engine rattle, so i just threw a new BB kit at it. Didn't see the crack under that carbon on the crown, but the young guy in the shop with much better eye site than i have, saw the crack over the pin, so i cleaned off the crown and YIKES.
New kit sure quieted down the engine though.

That’s not the original piston , is it ? 

[bucket list]

41 minutes ago, habs said:

That’s not the original piston , is it ? 

No That's a vertex , CW, big bore, but with alot of hous/kms on it. I've not heard of any piston breaking on these engines. Most engine failures seem to be valves, cam bearing or piston seizures. More maintinance and riding issues.