We are not talking about modified engines such as your drag sled. If engine porting or other mods have been made a larger carb will definately be beneficial in getting the new flow which is required. You have changed the flow requirements with the mods and now the carb is the restrictive element.What about the case of my SP600, it has the same size 34mm carb as the 700, which makes it 17% bigger when compared to the 700's theoretical fuel/air mixture requirements. This would mean the 700 carb is severly undersized. By the way, the SP600 gets almost the same milage as a 500HO unless you call 25 cents difference a large amount when refueling an almost empty tank. I know this to be a fact because my riding buddies own 500HO's and we have compared fillup costs on numerous occasions while riding together. Needless to say, they were impressed. The 700 on the other hand is a pig in comparison and obviously can flow the fuel through the 34mm carb. Do you honestly believe all manufacturers put on restrictive carbs and hinder performance. To put on a larger carb during the manufacturing process would cost the manufacturer just a few $.

 

Reguardless if it's a modified engine or not it's a proven fact that larger carbs provide more HP over stock. We may be only talking a a couple of HP but there is an increase. But to gain that increase you need more fuel added to even out the air to fuel mixture through the carb. That is why I made the original statement about not having the 40 (or even a 38 for that matter) on the SP6 and 7 vs the 34. As far as gas milage between you and your buddies quads that would all depend on riding style. All it takes is a little harder jump on the throttle out of each corner to make a big difference at the end. I've noticed this when riding trail sleds. I on purpose tried to ease in and out of the throttle a little more while staying right with my other buddy when riding and noticed over an 1/8 tank less gas used vs my previous fill up. As far as the 700 being able to flow the fuel, absolutly. You can flow as much fuel as you want through a carb as the jetting will allow. But won't make power unless you get the proper air mixture to it. This may be why I've heard so many people make a statment about the 7 hundo's running rich... and that is why I made my original question asking if anybody has messed with jetting on these quads.

 

I agree on the fact that the early 700's were runing rich and that's why Polaris reconfigured the carb by dropping the main jet from 162.5 to a 155. They also changed the needle jet, jet needle and pilot jet to correct their mistake or maybe it was an attempt to address the bad gas milage.

 

What size jets are used on the 6'er? Have your rode your buddies 500 HO much? Curious on the difference between the 5 and 6 powerwise. Am looking at upgrading to a 6 or 7 in the near future. Am using a Mag 500 right now and have rode a '01 HO and there was a decent noticable power difference between the 2. How does your 6'er and the HO compare in a drag race?.... not that it matters. Since the 6 and 7 are the same quad with the exception of 100cc's I just wonder if it's even woth the extra $$$ for the 700. I mostly use it for work anyway. Have seen some decent dollar numbers for used '02 700's but being a first year motor maybe it's better to go with an '03. I've heard of the rich issue and water pump leakage issue but that's it. Both simple fixes.

 

155 main jet is stock on the 600. Same as the 700. The difference in performance is negligable when comparing the 600 to the 500HO. The biggest difference is in the torque and the 600 requires very little throttle compared to the HO when climbing steep hills. It is a real torque monster. The 600 is also about the same as the 700 in performance and torque, except on the top end where the 700 has a 3mph advantage. Stock clutching on the 600 is also much better than the 700. Everyone seems to be installing heelclicker clutch kits @ $189 to make the 700 clutching perform better. IMHO the extra $ for the 700 is a waste of money. Just put 700 decals on the 600 and nobody would be the wiser. Definatly go with 03 or higher as the 02 700 had their fair share of problems and Polaris corrected all of them in the 03 model release. The 600's have been flawless.

 

how can I tell what jet my 700 has? It's an early 2002 build date, I forget when but I can find out.I have never touched it, haven't really had any complaints with it running rich, but it doesn't like to idle when left alone. I think turning up the idle a hair would fix that, but since I rarely let it sit and idle, it isn't really an issue. If I have the wrong jet, would it be worthwhile to change it, I mean performance-wise? Is it hard to do? I have never checked my fuel mileage, I know it's worse than my wifes 500 ho, but I ride all day and never run out, so that's not really an issue either. I didn't spend $9000 on my toy to whine about a couple bucks worth of gas.

 

snowride, you know you really got me thinking. If the 600 has the same carb as the 700, then its either got to be oversized, or the 700s is undersized. I wonder if anybody has tried putting a 40mm HO carb on a twin. I would think that there must be pointy-headed engineers that have thought this all through before it got to us. There must be a way to maximize the power from the 700 as compared to the 600, which is making virtually the same power with the same carb and smaller displacement. I don't see how to get around the fuel economy, after all the twin has two mouths to feed, so to speak.
I wouldn't mind getting a little more snap out of mine, but I don't really want to get too involved with engine work. I'm thinking of doing the heelclicker clutch next, to see if it puts me where I want to be. Out of all the clutch kits out there, the Heelclicker sounds like the best, just based on what I've read.

 

I was just talking with a guy over email that did try a 40mm on a 700 and didn't really find much advantage from it. He said the stock 34mm with 150 jet worked best.

Clutching is a very good place to start to increase performance. You may want to look at trying some different helix's in the secondary before messing with the primary weights. The weights just regulate RPM and belt squeeze. The secondary setup regulates acceleration (upshift). Maybe start by pulling a little more angle on the helix.

 

Since the 600 engine is very similar in output to the 700 and the clutching works very well stock, what about using the weights and spring from a 600 on the 700? Could be a cost effective improvement. I don't know of anyone who has done this, just a thought.

 

My SP700 with a 3/21/02 build date had a 162.5 main jet.

SpruceDeuce