WHICH IS FASTER THE MAX 540 OR THE SRX 440

[chrisrider63]

Im gonna start this debate again because im at a crossroads between putting a 540 engine together in my 81 SRX 440 chassis or I will put the 440 in it which has more power but many guys say its not as reliable, BUT a few guys on here say they can work very well...I never tried a SRX 440 but my buddy said it was a rockey ship when they are tunned. I really do like the low-end pep that the v-max has though epecially when im just riding in fields and trails, i thought from riding last year that the v-max was almost too-much sled to have for the riding I do in fields and small trails but was nice to have when you run into a mach-z or 2 and they do a double-take when they see her take off.

[tyler440]

dude! you were the one that asked then too.... http://www.vintagevmax.com/vvforum/view ... highlight=

[chrisrider63]

I am aware of this Tyler, I didnt really get a straight answer I just want information from the people on this great site........SORRY.

[Bob Vehring]

Chris, don't take this the wrong way but, I think your looking for a definitive answer to a very relative question.
So what is fast, or, too fast. Years ago we used to take the drag sled out at the beginning of the season. It would scare the crap out of me, but two weeks in, you were trying to make it faster. It didn't get any slower, I just got used to it, now it seamed slow.

I don't have a SRX 440, stands to reason if it as fast or faster then a 540, its going to be wound alittle tighter, its a 100 cc's smaller. Yes that means you'll probably give up some low end to get that top end. Really to get that level of performance at both the low and the top, is why sleds are now 800 cc's. They can use mild port timing to keep the low end, and rely on bigger size to give you the the top end.
You have to decide what you want. For me, my VM is ported to far.I just picked up 4 more jugs, 2, I think are usable the way they are, a few scratches in the bore, but should be ok. I hope to get them on next week. The other 2, I am going to have the plating stripped off and lower the ports then bore it out for bigger pistons and have it replated. That won't happen until summer.
It seams like a fair amount of people here have good running SRX's, If your careful with jetting, and use good oil, I don't see why it won't last and run fine.The key to a high strung engine is simply knowing where its limits are and staying below that. I'm willing to bet most of the bad things you hear, are from people that have crossed that line

[chrisrider63]

Thanks for the post Bob, makes a lot of sense.. Im gonna put together an SRX i think and just keep my 540 stuff for spare parts as its hard to find good jugs for these things around here, ive had a hell of a time getting SRX jugs. I could just have my VMAX as a trail sled as it is and have the SRX for really goin fast which seems like a good fit...I got the VMAX running real nice just stock with sanded BUT used pistons it runs great.

[vmax-540]

As you can see I have both sleds. Line the two up and if both are in perfect shape and both BONE stock the Vmax is faster off the line and up through mid range but on top end the SRX is a little faster by a couple MPH. Which one is a better sled to drive, Easy the Vmax . All around better sled.I like to describe them like this,the SRX is like the lake racers of old, little to no suspension and a very high strung engine. The Vmax is like the modern muscle sleds ,good ride well mannered power curve and a sled you can ride the trails all day and be happy.

[chrisrider63]

THanks for the input, my friend said if you tighten up the spring and get them to engage around 5000 they want have the low end bogg. I have the polaris clutches on my max and really like them.

[Bob Vehring]

Well thats true, but it invites a whole different set of problems. Right now, my SRV has its old race clutch on it. It engages very hard at 5200. Its very hard to get moving politely, which means throwing snow in the face of the guy behind you each time Beyond that if you have to drive slow for towns or people its hard to keep it engaged and it tears up belts quickly. As soon as I can get to it, I'm going to change that clutch.

[vmax-540]

Here is a link to a speed calculator, if you put in the values for the SRX or Vmax you will see that on paper the SRX has a higher top speed. http://www.cmsaracing.com/calc.htm

[vmax-540]

Bob you are right about the SRX it is a very high strung motor and you are also right about the trouble people have with them. If you leave them alone and just keep them tuned properly then they will last a long time. I think because of the trouble Yamaha had with this sled in the beginning that to many people try and reinvent the wheel, I have seen people try porting them because " they know what they are doing" only to screw them up, they change this ,change that ,only to make them worse.
They weren't that bad of a sled when they were new and they aren't a bad sled today,sure they had some problems but Yamaha stood behind them and corrected what problem they had. All I can say is I love mine,and everyone that I have talked to that has owned or driven one says the same thing,it took me twenty five years to finally get one and it sure was worth the wait.

[chrisrider63]

Would I be loosing HP putting 38 round slide carbs on instead of the hard-to-tune butterflies??