Porting specs for 61X - please advise...

[Polish jet pilot]

I wonder whether anybody could share some porting specs (height of exhaust window from top edge of cylinder to top edge of exh. window). I will be using 35cc domes, factory pipe, probably will stay with 701 or max 735cc. I got racelogic's porting template, but wanted to increase port height, just not sure what would work best for bottom end...

All help appreciated.

Andrew

 

[jetski9010]

I would just stick with the porting template from racelogic. If you wanted to do any kind of different porting specs I would just send it to a pro that has a proven porting spec. Just my 2 cents. I am getting sick of wrecking parts and wrenching on the beach.

 

[Polish jet pilot]

jetski9010...I completly agree that it is better to send,....but I live in Poland, nobody does freestyle here, only racing - they have no experiance in that...

 

[lmi-step]

jetski9010...I completly agree that it is better to send,....but I live in Poland, nobody does freestyle here, only racing - they have no experiance in that...

why you dont ask martin schaub in Germany (Cologne -Köln)!
http://www.martinschaub.de/

 

[lmi-step]

this is the guy making marc sickerling engine...:brap:

 

[jetski9010]

jetski9010...I completly agree that it is better to send,....but I live in Poland, nobody does freestyle here, only racing - they have no experiance in that...

Are you trying to port them for freestyle? If so why are you trying to rise the port higher then the sport port kit. How hard is it to send parts to the USA to get work done.

 

[kevbo]

Do you want more thrust, better response, or some of both? What gas do you plan to use? What is your pump configuration and are you willing to change your prop.

 

[Waternut]

I got racelogic's porting template, but wanted to increase port height, just not sure what would work best for bottom end...

If you want to maintain good bottom end, don't raise the port at all. In fact, don't even clean them up. I used the newer super stock (I think that's what they were called) templates and they are really nice and produce very good power. I don't spend much time in the upper rpms but it does still pull strong when you're up there.

 

[Polish jet pilot]

Thank you for all your comments and the link. I am not a small guy @ 90 kgs (200lbs). I will not have the bucks to buy a pro engine for next season, but I see a great future in promoting this sport, even here. I want to have a relaiable engine, which has the right bottom end to get some air. Not sure what is needed for that (thrust or response, I guess thrust would be more important, however maintaining response is also important in any freestyle riding). The bpipe woke the engine considerably, but more brrapp is needed. I went the "safe" way and got the racelogic as primary porting instruction to an unexperianced builder, but wanted to "extract" as much as possible from this 701 while I am at it. Gas wil be best "pump gas" @ 100 octanes (European octane rating), which I think is about 92 octanes in US... I am willing to change other components (such as prop)to make this work, just not ready to spend big bucks yet on high dollar parts/setups. I know I will need a hooker for sure, head @ 185psi, and rejet the carbs. I also shed as much weight as possible from the ski (deofoamed, light hood, carbon reinforced, small tank, etc). I was hoping to leave the current top end (no rebuild and overboring) but if it turns out that they are not too fresh I will go a bit bigger..maybe 735cc..but just if this is really necessary..keep it simple, relaible and cost efficient. Thank you once again for helping me out on this one!

 

[Polish jet pilot]

BTW my pump confi is: cone, 08 SJ prop, inatke grate, freestyle nozzle. Not sure how much the nozzle should be bored...

 

[D-Roc]

i did the racelogic sport port, it was the newest spec for freestyle. It made a great difference in the attitude of my engine. It worked even better when i bored to 83mm pistons/35cc domes. that made the compression 195ish and really made the motor run pissed off.

 

[Waternut]

The really nice thing about sport port templates is you don't have to change the jetting. I've done a 750 and a 701 with those templates and after 10-20 minutes messing with the adjustment screws, it's good to go.

Just make sure you chamfer the ports and I would highly recommend honing the cylinder and getting new rings while you're in there. Of course, you should also evaluate the condition of the bore to see if it needs stepping up. I reused the old pistons in my 750 but the bore was out of tolerance on the 701 and needed the next size.

You already have the b pipe. If you do this porting with 185psi and add total loss to your setup, you'll have an arm ripper you can be proud to show off to your racing buddies. I have that combination and love it.

 

[lerott]

I think it's the best way you can choose :

http://www.x-h2o.com/threads/63652

 

[D-Roc]

that is alot more than sport porting yourself, he could afford the TL or the new bore/wiesco top end. sport port is cheap, a bunch of work, but yeilds great results.

 

[Polish jet pilot]

Ok so lets starighten things up and see if everybody agrees:

- I will use the sport port templates. I will not alter the window height. I was thinking to do something to the boost ports (the ones that transfer the mixture from crankcase to cylinder), but what? Widen them?

- I will verify the top end of my engine. I will replace the crank seals (the engine is about 8-9 years old, never opened)? I will certainly hone the cylinder and provide new rings, and replace pistons and do overbore to 83mm if really needed.

- I will add a hi comp head @ 185/195 psi

- I think MSD enhancer would be mandatory if above steps are done

- Intake: stuffers + carbon tech low tension reeds? I already have the R&D angled mani spacer. Should I fill the void in the intake manifold?

- Pump: hooker (not sure of pitch), bore the nozzle to about 83mm? Or other diameter?


Please add your comments to the above steps.

Thank you.

Andrew

 

[D-Roc]

i don't use a stuffer in the intake or epoxy fill the ramp on the intake of the case. i did finger point the cases to allow a more direct flow to the transfer. I also cleaned up my transfers, didn't make them bigger just smoother. i use a c-75 scat with the tbm superpump cone

 

[waxhead]

The sport port i saw made a really wide flat exhaust port , be careful not to make a ring eater

 

[Polish jet pilot]

The instructions says to chamfer them, but thank you I will certainly remeber about eating those rings.

I started to roughly calculate the cost and building up a ported 701 (701-to about 735cc) costs SIMILAR to going big bore (In case I would have to replace the pistons). Yeh, you need to add the cost of sleeves, a bit pricier pistons and machinning, but all that would add up to maybe + 400 usd?? Maybe I am making a mistake thinking about porting what I have? Maybe I will get used to the power after 4-5 rides...? Decisions, decisions....

 

[Waternut]

The big bore would cost a lot more than $400. A single size bore/hone and 2 piston kits is going to run a minimum of $250 if you shop around but more likely $300-$400.

The two big bore sleeves are around $115 each ($230 + shipping) last I saw plus some really nice big bore pistons like RIVA or Wiseco's are going to run nearly double that of normal WSM or Pro-X pistons so another $200 a kit for RIVA's ($400 + shipping for pistons). Then you have to remove the sleeves, bore the inside of the cylinder, and bore the cases so go ahead and factor in another $100-$200 for the machine work. Don't get me wrong, a big bore will be excellent but you're going to pay for it. It's not compareable in price to rebuilding a normal engine. Figure 2-3 times the price of a normal rebuild.

IMHO based on personal experience... Do the sport port thing, get a girdled head, look for a good used total loss system (there are plenty floating around on here), skip the reeds, use a 9/15 hooker impeller, bore the nozzle to 83-85mm, and rip it up!

The sport port template is very good and exceptional value for money. Only touch the items involved in the template kit. If you don't know what you're doing, don't touch the intake ports or you'll mess it up. I've never been a fan of MSD enhancers. They're expensive, only adjust timing while maintaining a big heavy flywheel, and it seems like every week I see another post about one crapping out.

 

[Polish jet pilot]

That sounds reasonable, I am just afraid that I will dump some money and will be sorry that did not dump "a bit more" and get a LOT more power. I was really surprised at first how much difference the Bpipe made. Do you think porting , head, etc will make the ski as "strong" in feeling as after installing a bpipe to oem engine? Or more? I know a ski which is too strong is no good, it will wear you down, and you will not learn too much on a beast, but worried that this winter's effort will not pay off enough...?