YAMMIEGOD3:16
Active member
I DON,T RUN A THERMOSTAT IN MY 2000 SRX FOR ICE AND GRASS. DON,T RUN ONE IN MY VMAX 800 FOR GRASS OF CORSE FOR COOLDOWN PROCEDURE. I WOULD NOT REMOVE THE ONE IN MY 2002 SRX FOR ALL AROUND USE. LAKES, TRAIL, SNOW DRAGS, WHATEVER. 3:16 (yammie tony)
9801srx
Member
dude, you asked a question don gave you a good answer and you come back with that? do you even know what a cold seizure is? viperkink you should pm don as he suggested and ignore the rest of the b.s that your thread is becoming full of and you will have a great running and completly reliable 780.harness racer said:
harnessracer, actually its very simple to understand, the red head motors are "low out put motors", as are the twins, etc, yamaha simply designs the cooling system to handle the heat output of the engine and then some. With the hp output(produced heat) being low it was determined that the coolers would need to be of smaller size,as a srx has more volume and more fins per inch exchanger both inside and externally in which to cool the coolant,(thermal conductivity area) so along with hose size,and most important "coolant path and speed", it wasnt deemed neccessary to run a thermostat,because the engine doesnt create enough"(hp) heat" to need to regulate the flow or path change. Theres plenty of safety margin built in as if you simply add triple pipes to a sx,sxr,thats 20hp increase right off the bat,and they work fine with the cooling system as delivered when it was stock! Just about everything on a yamaha snowmobile is over built to a certain degree, but thats what makes them the best quality product also.
The srx is a high output triple engine with triple pipes. In order to produce CONSISTANT hp output,the thermostat was required to regulate coolant temp/flow, controlling prime temp to operate the sled, so cylinders,pistons and componets are at a prime operating temp(expanded) for repeatability, meaning when you hit it, thru a variety of differnt snow conditions its 140hp,not at idle...lol.
So you see the yamaha engineers being so stupid as you guys suggest they are actually know the engines prime operating temp and the prime pipe temp for the engine they designed. A simple thermostat aids in improved warmup times but also regulates and automaticlly adjust the engines operating temp based on the feedback of the cooling taking place on the machines heat exchangers.
If this wasnt needed,do you think they would actually spend the money on tooling to produce all this when all they had to do was block a hose with a plug,come on, you cant be that nieave can you?
This is very easy to understand if youd actually do a little bit of research instead of just making arguments with no validity,you might even want to take a peek at the 1998 yamaha update tech book,pg 2-6 and 2-7, with a little research youll find your argument points tend to pretty silly!
The srx is a high output triple engine with triple pipes. In order to produce CONSISTANT hp output,the thermostat was required to regulate coolant temp/flow, controlling prime temp to operate the sled, so cylinders,pistons and componets are at a prime operating temp(expanded) for repeatability, meaning when you hit it, thru a variety of differnt snow conditions its 140hp,not at idle...lol.
So you see the yamaha engineers being so stupid as you guys suggest they are actually know the engines prime operating temp and the prime pipe temp for the engine they designed. A simple thermostat aids in improved warmup times but also regulates and automaticlly adjust the engines operating temp based on the feedback of the cooling taking place on the machines heat exchangers.
If this wasnt needed,do you think they would actually spend the money on tooling to produce all this when all they had to do was block a hose with a plug,come on, you cant be that nieave can you?
This is very easy to understand if youd actually do a little bit of research instead of just making arguments with no validity,you might even want to take a peek at the 1998 yamaha update tech book,pg 2-6 and 2-7, with a little research youll find your argument points tend to pretty silly!
how did you get your srx to an 800?
tait, to get a 800 you need a 74mm bore, and the cylinders get 
THIN I tell you on the skirts in back. Would highly recc. to stay at 73mm, no problems with basic rules and proper set up.
THIN I tell you on the skirts in back. Would highly recc. to stay at 73mm, no problems with basic rules and proper set up.I'm doing research on my srx for a summer project. I'm looking to turn my srx into a decent all around machine good for pounding trails hard or diving off to some powder.
davidgboy
New member
bottom line: yamaha engineers know how to design a sled that is reliable over a wide range of conditions. you can fine tune them. but do not think that u can redesign them by removing parts. u can fine tune a clutch, by substitution of components, not elimination. even sub. can get u into a world of trouble if u are careless. ex. pipes, head mods. air box mods. etc. let us all say a prayer together: please god grace us with those 6 sided, frozen, chunks of heavenly delight. amen
ok so after doing research I think I'm going to stay away from boring it out. I do need more power out of it. I heard slp pipes are good but what else can I do to get more power. I dont want anything crazy and the max octane gas up here in ak is 92. Any suggestions?
And if I do put on slp pipes what other mods should be made to the srx?
tait, there isnt much in pipes offered for a srx, plus,... the stock pipes are about as good as it gets unless your modding the engine alot. When the srx came out in 1998, there were quite a few aftermarket pipe guys trying to out do the factory pipes and pretty much they all came to 1 conclusion after alot of r/d work, the factory are pipes are about perfect. It was very hard to justify a couple hp gain (like 1-2hp gain over stock) for a set of $700-800 investment into pipes. Power inc. made only a couple 2-3hp, and basicly the weight loss was about it. Another thing with factory pipes is the way they are insulated, they give repetitive performance and will still make excellant power on a modded engine with porting,basic engine upgrades. The only pipes for a all out engine were the bender big bore pipes, they will give you a little more power but they are now pretty costly at $1300 a set and still are only needed for a very modded engine(above 165hp). Stock srx700 output is around 140hp, so you have a big margin of gain(20-25hp,which is HUGE on a 2 stroke) till you need them.
Porting the engine would be the way to go along with a good clutch set up will yield the most bang for the buck. You keep all the reliability and up the power output quite a bit.
Use the search feature on porting you will have enough information to keep you reading for quite a while, good luck on your build.
Porting the engine would be the way to go along with a good clutch set up will yield the most bang for the buck. You keep all the reliability and up the power output quite a bit.
Use the search feature on porting you will have enough information to keep you reading for quite a while, good luck on your build.
Thank you that helps a lot. What are some other things that would work well. I was considering maybe getting some heads with slightly higher compression but I don't know if they make them and I don't want to use fuel over 93 octane. My thing is is that I love to have a machine with lots of power but I'm not going to put four grand into an $800 sled. lol
Your best bet is porting and clutching. If you want to up the compression, check the squish and see how much room you have to play with.
mrviper700 is the man to talk to if you want to get some work done.
mrviper700 is the man to talk to if you want to get some work done.
Ya I'm still new to this modification stuff so I don't know what the squish is. All I know how to do is rebuild my '96 KX 250 motor from bottom to top that is all stock.
So in other words I can work on stuff but I don't know all the terminology and on top of that sleds are new to me. I grew up on dirt not snow. Kinda funny considering I grew up in AK.
When its 20 degrees outside, I would think that it would take a much longer time for the coolant to get to operating temperatur with the thermostat removed. I was under the impression that removing the thermostat is only good for the summer grass drags.
if i put on a cold air kit on the sled what kind of jetting should i use when it averages -20F outside? you know so i dont blow my motor
staggs65
Moderator
i'd save the $ on the cold air kit and put it to clutching. jmo
i dont need it for power. i need it so i can ride in snow over ten inches. and i dont want to deal with trying to seal up every nook and crannie of the engine compartment.
PhatboyC
New member
What a bump this old thread.
tait89 use the search function and you'll find answers to everything your asking.
tait89 use the search function and you'll find answers to everything your asking.