Surfriding Building a stock surf motor?????

[customride0105]

So I'm planning on building a limited motor for surf only... I'm unsure on what I'm gona use and wanted some input on it.

Motors got a fresh crank 62t bottom end
62t top end Ada head
Factory bpipe

Now from what I've read a 62t isnt good for bottomend
Should I use a 61x top end instead of a 62t top end???

Any help would be wonderful

 

[yamanube]

Just for surf? I think that 62t topend will be just fine, especially if you already own it.

 

[Big Kahuna]

bump your compression some, put a lower pitch prop and you should be ok. you could find a thinner base gasket and up your dome size and this would lower your port timing some also. This a trick that is used in stock class racing (Also in other classes also). to alter port timing.

 

[customride0105]

Already got 35cc domes and was planning on getting a hooker.

I've got a 61x top end I can get I just wanted input on who's built a motor

 

[kraqus]

Already got 35cc domes and was planning on getting a hooker....

That is it!
I would work on Handling mods after that......


Benny

 

[tightithrash]

What's the motor out of?

I'd say 35 domes. Stock lightened flywheel. Coldfusion billet couplers. MSD enhancer. 9/15 hooker.

 

[Freakrider]

I would go with the 61x cyl and sell the 62t on pwctoday...and a ported 61x cyl is fun in the surf too...

 

[customride0105]

So is the 61x cylinder better than the 62t.

 

[Big Kahuna]

Yes. The port timing is lower = better bottom end.

 

[customride0105]

Have u tried a 62t?

 

[Big Kahuna]

There are plenty of motors like yours that work and work well. If I were building a race motor, I would use the 62T cylinder. If I wanted something for more low end grunt, I use a 61x. Especially if it is unported.

 

[kevbo]

Yes. The port timing is lower = better bottom end.

Lower port timing = better throttle response = less power = less thrust as well. Just make sure NOT to over prop it and then only fan the throttle 5 times a second instead of 15.

 

[Screwy]

Yea really any motor that you ring out unloaded aint gonna last. I'm working on that same problem right now. I got a 61x top end and bottom. I was kinda in the market for a low priced set of 62t cases. Seems like the 61x bottom end is the red headed step child. Looking for an aftermarket intake and reed cages. I know a lot of the guys I ride with swear by the hooker 9/15 in the surf in nj. Food for thought.

 

[chriselmore_1]

my old 61x motor flat out ripped!i hit alot harder than some of my friends 62t/61x motors for sure. Set it up proper and spend some time tuneing. Nothin wrong with a 61x setup.

 

[Screwy]

Thanks for the vote of confidence. Too bad finding aftermarket parts is getting harder. I did some searching for intakes or reed cages and everything is for 62t. I already port matched the intake and carb mount. I was hoping R&D or Riva had one left in production. Ported the exhaust port and polished it. So we shall see what I hqve accomplished with those mods after i throw on a Bpipe and ADA head with 35cc heads for 180 psi compression.

 

[yamanube]

I run ported 61x cases with ported 760 cylinders in the surf and love it. Not sure why you would need an aftermarket 61x intake manifold?

 

[Screwy]

well cause when i looked at the intake it was not the smoothest thing in the world. but i fixed that problem, cleaned up the intake runners and smoothed everything, not polished. the air has to have some turbulence or the gas particles will separate....lean. found that out the hard way on a CR125 i did a few years back. just dont wanna hit the throttle and go where's all the power!!! i figure i'd build it once and just ride

 

[Idok]

61x/61x..punch it to 84, 48mm carb, 2mm static advacnce w an enhancer, LTD B and a head


voila...a st. augustine special