[CiscoSanJose]

Well as of today the new stock grom cylinder and check is on it's way to BrianS for his 170cc kit.

I assume I have to wait a couple of weeks to get the product.

Other items I need to get is the A/F ECU adjustment unit, not sure what brand I will be buying but I assume I will go with what BrianS has used for testing or the other tester has used in California.

I do have a spare stock Grom head that I was going to port and polish and flow, but I will run baseline test with the stock heads first.

I also have a spare new Grom cam and I was thinking of having it ground to what ever spec that will give the best HP.

In storage or waiting for install will be the lighten oil spinner and flywheel.

Right now in all stock form as far as grom engine goes, the engine has 1020 miles on the odm and it seems to run a lot better and maintain 60-65 and some times up to almost 70mph. Not bad with a 210lb rider.

I have not even touched the Air box yet for mods

 

[Ven0m0uS]

That's cool man. Should be a nice power bump from stock. I'm thinking of riding to Morgan Hill to get my stock Grom dyno'ed. Just curious to know exactly how much power it's making. Now that it's broken-in and everything. I had a few other bikes dyno'ed there no more than 2 years ago. The place is called EMF Motorsports. They have been tuning for years and have a good reputation. I still own the bike that I got checked there last. '09 Yamaha WR250X, made 29.8hp at the wheel.

 

[Maxacceleration]

Can a stock cylinder be bored to 170cc? Or does it require a bigger cylinder?
Brand of piston kit? As there are issues with another big bore kit on this site, his kit should not be taken for granted either.

 

[BiG Chris]

I believe its re-sleeved for a bigger piston, my yuminashi one appears to have the same thing done

 

[CiscoSanJose]

I believe its re-sleeved for a bigger piston, my yuminashi one appears to have the same thing done

yep you're correct, plus BrianS has been testing these 170cc kit on the East Coast and also had one shipped to San Diego for a Grom user to test. So far positive results but I have not seen any dyno sheet and also the various combo-sheet meaning what upgrades that a Grom user does to parts such as port and polish of Grom head or using stock head with no mods, variation in the exhaust system used, variation in cams used and airbox mod used and the variation ECU A/F adjustment system used.

I do know the baseline for the Grom HP is between 7-9hp so if I see a double in HP with the 170cc kit I will be happy for the price.