Planet Minis

Kurlon · 10-03-2008, 11:28 AM

Ok, so I'm drifting a bit outside the forum scope, but figured this is the best spot to get Z's attention. : )

Got a friend looking to hop up his S90. Powroll and Dr ATV both offer 54mm bore kits, Powroll offers a crank stroking service for the bike. Do any of the JDM brands offer hop ups for that motor?

fatcaaat · 10-03-2008, 11:40 AM

Honda ATC125M from 84 and 85 crankshaft is 52.2mm I believe and will drop in (so I heard).

Z · 10-03-2008, 12:09 PM

Quote:

Originally Posted by Kurlon

Ok, so I'm drifting a bit outside the forum scope, but figured this is the best spot to get Z's attention. : )

Got a friend looking to hop up his S90. Powroll and Dr ATV both offer 54mm bore kits, Powroll offers a crank stroking service for the bike. Do any of the JDM brands offer hop ups for that motor?

Email me if you need something, lazy butt...

There is no aftermarket part support in Japan for the CT90, ST90 or S90 that I'm aware of. Boat anchors.

If you want to build up a boat anchor, fatcaaat is your man.

fatcaaat · 10-03-2008, 01:16 PM

Quote:

Originally Posted by Z

Email me if you need something, lazy butt...

There is no aftermarket part support in Japan for the CT90, ST90 or S90 that I'm aware of. Boat anchors.

If you want to build up a boat anchor, fatcaaat is your man.

I have to be honest here...the best mod you can do to Honda 90 based motor is either keep it stock, or sell it to a restorer to fund a real motor.

And since they are different mountwise, you'll have to fabricate stuf to make a 70 base or china base work. So, unless you are interested in a lot of fab work, I'd say ditch the bike. If you want that style, find a CL70 to work with.

The forks and springs and things....I have no clue on.

I'd avoid it personally...its going to be a headache. Put it to stock, sell it, and then buy a vintage CL70.

Z · 10-03-2008, 01:23 PM

Take the S90 engine out and build one of these:

CUSTOM HONDA

I can't tell is that's a CT90 or a 50/70 based engine. Too bad nobody in their right mind would by that thing. It took some talent to build, but what's the point?

Dan

Kurlon · 10-03-2008, 01:24 PM

The owner uses it for vintage racing, mostly Giros on public roads, so I doubt I can convince him to move to something else, or swap in a modern engine. He was just looking for a bit more power for a couple of the mountain passes he was running up. He's also got an S65 he's running as well.

fatcaaat · 10-03-2008, 02:06 PM

Now an S65...that can be made into a really fun machine. I did one a while back and when completed was a whole bunch of fun. I used modern forks and shocks, and a 95cc motor.

The s90 if you want more power, you can do the following;

Cam...send the cam out to webcamshafts.com and have them hardweld a new grind on it. The number 3 won't work, but the one just below it will.

Carb...of course you can update the carb. Those vintage carbs are crappy compared to modern stuff. I personally like the mikunis.

Porting...send it out to be done correct. I am sure you know who they are.

Bore/Stroke. Again, pretty sure the atc125m crank will swap in. Pin relocation and welding is a lot of money but not a bad option. Bore...If I am not mistaken, the atc125m cylinder will fit on there as well...don't quote me on that. I have a cylinder and varous head components for one here if you want them.

Dratv used to have a 3mm bore kit for it but I think it uses a 15mm pin and therefore can run the atc125m set.

I have to believe that without some serious work, you won't pull more than 10hp.

10-03-2008, 11:28 AM	#1 (permalink)
Kurlon Baron Von BanHammer Join Date: Feb 2005 Location: Windham, ME Posts: 7,851	S90 parts Ok, so I'm drifting a bit outside the forum scope, but figured this is the best spot to get Z's attention. : ) Got a friend looking to hop up his S90. Powroll and Dr ATV both offer 54mm bore kits, Powroll offers a crank stroking service for the bike. Do any of the JDM brands offer hop ups for that motor? __________________ http://www.x386.net/TTR 2004 ST3 - 'Duckie'?!?! 2005 CRF70RR - MiniGP Weapon 2005 CRF70 - Dirt Donk 2008 Pitster Pro X4 Motard 1991 GS500E - LRRS/CCS #771

10-03-2008, 11:40 AM	#2 (permalink)
fatcaaat 3rd Gear Member Join Date: Sep 2004 Location: Arlington, VA Posts: 2,960	Re: S90 parts Honda ATC125M from 84 and 85 crankshaft is 52.2mm I believe and will drop in (so I heard).

10-03-2008, 01:23 PM	#5 (permalink)
Z 5th Gear Member Join Date: Sep 2003 Location: KANSAS Posts: 7,257	Re: S90 parts Take the S90 engine out and build one of these: CUSTOM HONDA I can't tell is that's a CT90 or a 50/70 based engine. Too bad nobody in their right mind would by that thing. It took some talent to build, but what's the point? Dan

10-03-2008, 01:24 PM	#6 (permalink)
Kurlon Baron Von BanHammer Join Date: Feb 2005 Location: Windham, ME Posts: 7,851	Re: S90 parts The owner uses it for vintage racing, mostly Giros on public roads, so I doubt I can convince him to move to something else, or swap in a modern engine. He was just looking for a bit more power for a couple of the mountain passes he was running up. He's also got an S65 he's running as well. __________________ http://www.x386.net/TTR 2004 ST3 - 'Duckie'?!?! 2005 CRF70RR - MiniGP Weapon 2005 CRF70 - Dirt Donk 2008 Pitster Pro X4 Motard 1991 GS500E - LRRS/CCS #771

10-03-2008, 02:06 PM	#7 (permalink)
fatcaaat 3rd Gear Member Join Date: Sep 2004 Location: Arlington, VA Posts: 2,960	Re: S90 parts Now an S65...that can be made into a really fun machine. I did one a while back and when completed was a whole bunch of fun. I used modern forks and shocks, and a 95cc motor. The s90 if you want more power, you can do the following; Cam...send the cam out to webcamshafts.com and have them hardweld a new grind on it. The number 3 won't work, but the one just below it will. Carb...of course you can update the carb. Those vintage carbs are crappy compared to modern stuff. I personally like the mikunis. Porting...send it out to be done correct. I am sure you know who they are. Bore/Stroke. Again, pretty sure the atc125m crank will swap in. Pin relocation and welding is a lot of money but not a bad option. Bore...If I am not mistaken, the atc125m cylinder will fit on there as well...don't quote me on that. I have a cylinder and varous head components for one here if you want them. Dratv used to have a 3mm bore kit for it but I think it uses a 15mm pin and therefore can run the atc125m set. I have to believe that without some serious work, you won't pull more than 10hp.

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