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Discussion Starter · #1 ·
Alright I picked up my 2008 IQ 600rr and just got back. Compression is 122 psi both cylinders, but it runs fine. I have little to no experience with twins but I'm assuming it should be closer to 145-150? I caan rebuild it for little to no cost durig my co-op. I'm bringing it wilth me tomorrow morning and I'll post some pictures of it then. Honestly, I'm kinda glad I'm going to rebuild it, gives me some peace of mind for the winter.

Now, the guy that owns the shop said if I want we can port it and shave the cylinder heads. I kind of want to ride the sled the way it is just for this year but I also will never be able to do that work for so cheap anythime soon, so I'll decide after I read through some of the pros and cons. Ie, How much hp? How much reliablility will I loose with each?

Annd lastly, How does shaviong the heads work? I know about porting but not chaving the heads. Is it exactly as it sounds and gives you a little more hp?

Just realised I didn't test WOT, but it still shouldn't make it change that much should it?
 

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122 isn't bad at all for a 600. If it was an 800 motor, or had its high comp. heads in then I would be worries.

Cons: Every little mod takes away reliability.
 

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Discussion Starter · #3 ·
Okay because the reason I ask is the renegade there had 148 psi and I thought most twins were supposed to be up there...
 

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correct!! the psi seems great for a 600. and when you port and polish your heads you should stick to premium gas if not race gas, thats just what i've heard. feel free to correct me if wrong and i also agree with what dragon700 said, every motor mod you do is just one more thing that isnt how its supposed to be and therfore causes unreliable toys!! if i were you i would just hone the cylinders and put a set of spi pistons in it and youll be golden. JMO
 

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Don't shave the heads, you'd be better off getting an aftermarket head. (smaller combustion chamber, reconfigured squish etc..)
Find someone with a 600HO (fusion or IQ) and ask them what their compression is, it might be in the 130-140 area.


If you want more power + responsibility send your engine off to carls and get a 660/685 kit
 

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How about testing the compression properly first with the throttle open. As for shaving the heads dont bother with them or the cylinders. Why simple put you need to get more air in the motor first then out of it, so a pipe would be need first. Porting and shaving heads are the last things to be done to a motor. Lots of other things that can be done first.Not to mention needing 91 or better gas to prevent detonation. You will get more bang for your dollar setting up the clutch and gearing first then saving for a 660-685 kit and the Pipe to go along with it
 

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Discussion Starter · #8 ·
Alright I'll leave the mods alone. Carl's cylce and SPI have the kit right? I want to check out how much they are... Just gotta figure out compression numbers now. Even if it's supposed to be 130-140 It's going to need new gaskits and rings. I'll re-test the compression tomorrow.
 

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powersledder said:
If you want more power + responsibility send your engine off to carls and get a 660/685 kit
I agree,do a 660 or leave it stock. They run good the way they are.
 

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another option if you want more power, which is what it kinda looks like you want, why not just sell the 600 after this eason and drop in an 8. its been done so many times to the iqr chassis.
 

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for the average trail rider i love the basic port clean ups. its not a huge hp thing, its a low speed mid range thing. helps the engine run just that little bit crisper, more times than not you dont have to change any jetting or pipes. it might add 3-5 peak hp but it makes the throttle response that little bit quicker and more crisp.

for the average trail guy with a 600 i wouldnt spend a lot of money on mods. whats the point, i can do a trail clean up for a twin for about 100-150 bucks for both cylinders, for an aggressive trail port at a pro shop it would cost atleast double that for another 1-2 hp.
to shave the heads or get aftermarket heads will compliment the trail clean up very well, but you make the sled a premium gas sled, if you can always get premium gas its no big deal. but to carry an old oil jug of race gas isnt a bad idea for any sledder that gets gas out of the small back woods stations.
the heads will add up to 8% hp depending on how much compression they raise. but just like a little clean up compression will add low end and mid range power for a trail rider. coming out of a corner will have that little bit more snap.

personally on a 600 i would have your heads reshaped, you can reshape them alot cheaper than buying aftermarket heads. do a minor clean up and be happy with that. to go crazy modding a 600 for about the same money you would be able to upgrade engines. why spend 2 grand on a 660 kit when you could find an old 700 and make a 770 kit and get close to the 160 hp level. 20 more hp for about the same money.

now with all that said. do you think you are going to be able to hold the sled wide open on the trail and think man if only i had more? no, hp is not your limiting factor in 98% of your riding. conditions, common sense or something else will be. I would focus on the other areas before you spend money on hp.
 

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motorheaderr said:
correct!! the psi seems great for a 600. and when you port and polish your heads you should stick to premium gas if not race gas, thats just what i've heard. feel free to correct me if wrong and i also agree with what dragon700 said, every motor mod you do is just one more thing that isnt how its supposed to be and therfore causes unreliable toys!! if i were you i would just hone the cylinders and put a set of spi pistons in it and youll be golden. JMO
I agree 100%. With my expirence playing around with shaving heads and porting i didnt like it. But this was with a 2stroke dirtbike. If you want something reliable and get more power like he said put some new piston and rings in it, maybe some vforce 3s...little add ons here and there but not too much. imo

Im told to if you do play around with the fuction of the motor and do it right. then you can get good results.
 

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I disagree with most regarding the porting. I would not shave the head, but I would take MadHeifer's advice regarding the cleaning of the ports. Cleaning the ports will make a noticeable difference and shouldn't affect the reliability of your set-up. Going any further than this, for instance, race porting, I would not recommend as you'll have to be jetting and changing the reliability of the motor.
 

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that is what we are saying flatlander, you can clean up it all you want but once you start shaving heads and all that jiberish things start to be less reliable and more expensive
 

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I will say that reliability does not have to drop off. I have more then my share of work done to my switchback, just check my sig. I have had no relieability issues with my sled it is a true pull and go setup. I do not play with jets, just have to run premium fuel. I have over 3500 miles on my set up and only rebuilt the topend this year. Due entirely to me lending my sled to some buds and the gas station selling regular as premium. Pulled it apart and the poor fuel had caused some wear to the pistions. That was the only reason for me to pull the motor apart and check. I have even run nitrous on the motor running anywhere from a 30hp shot to 40 with no problems.

I can truely say if done right and kept to trail/mild race setup there is no reason it should be less reliable then anyother motor.
 

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motorheaderr said:
that is what we are saying flatlander, you can clean up it all you want but once you start shaving heads and all that jiberish things start to be less reliable and more expensive
Where did you say that, know it all? I'm pretty sure a few posts up you said that he should hone it and throw spi pistons in it. Do you understand what I'm saying when I say clean up the ports? I'm not saying to take a cleaner and towels to them, I'm talking about cleaning the factory porting job up by clearing any jagged points in the porting that would restrict air flow, usually caused by mass produced castings.

Jonesie is right, all these mods that he's talking about doing don't necessarily negate reliability if they are done within reason. A person can shave a head or change head and base gasket thickness and increase compression and port timing and not change the reliability of the engine it is done correctly and proper octane fuel is run with the higher compression.

Do you know what porting is? If this was your meager attempt at looking like you know something about the internals of an engine you better get your wikipedia out again sonny.
 

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shaved heads dont hurt reliability, bad gas does.

a port clean up is half the cost of v force reeds and you get twice the gains.
 

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im just guessing he doesnt want to spend a ton of cash on getting his motor port and polished and being stuck with having to run race gas forever. for any person that has only one main sled i would not wana be stuck trail riding with a modded sled that you dont wana fill up on pump gas with.
 

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I have a race ported sled and I run 91 octace gas. If I have time before the snow flies more than likely I will be sending the jugs for the xp off to be ported too. Porting doesn't change your compression, whoever told you that or wherever you read that is wrong. Porting allows gasses a less restrictive path in and out of the motor.
 
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