Some engine build questions on a 2001 SRX700

TheFarm845

New member
Joined
Sep 13, 2021
Messages
12
Hey guys, I grabbed a 2001 SRX700 from the original owner the other day that had a melted piston. He tore it apart and decided not to fix it so now its up to me to assemble it and get the old girl going again.

First question; the jugs were removed and the sled parked outside for 2 weeks for sale and of course it had to rain, which got water in the case. What is the best solution for this? Pull the case and tip it over then get some 2 stroke in it for awhile? Or maybe bring the bottom end to a shop and they can check crank run out and bearings while its there? Ive never dealt with a bottom end before.

Second; whats the best set of pistons to run for reliability? The jugs look good (the bad one has been replaced already) so I'm thinking i can get by with stock bore. The sled only has 2300 original miles.

Third: I need 1 head replaced. Are the 00-02 heads different from the 98/99?

Fourth; It came with a set of Vforce reeds. Im assuming theyre the first gen since they were bought back in 2001. However one petal is missing. Is it worth tracking down that petal and using them or to go with something different?

Fifth; whats the best gasket set to go with? Yamaha OEM or something aftermarket?

Last: is there anything specific i should look for or check while getting this back together?

Overall its extremely clean, no cracks, no dents, no tears, no fading, etc... Came with all the original paperwork and 2 SRX covers, 2 SRX baseball hats, 2 jackets, 3 snowpants, etc.... (He owned 3 SRX sleds).
 

Maim

Super Moderator
Joined
Mar 13, 2004
Messages
4,116
Age
47
Location
sudbury on. canada
welcome!

would not hurt to get the crank checked as there might still be debris in the bearings that could cause a premature failure as it is apart now. a good flush with wd40 and a coat of 2 stroke oil might be enough for it if you know there is no debris in it.

you can go with an aftermarket gasket kit. i have had no issues with them when i use them.

spi pistons are what i have had the best luck with aftermarket. seen/heard too many motors cold seize from not letting the sled get up to full temp before riding with weiseco pistons. oe are the best though.

cannot help you with the head as never got into an srx rebuild. did a viper with my brother.

unless you are planning a wicked port/big bore engine, the stock yamaha reeds perform just as well as the high end aftermarket ones.

as to checks on the engine, i would make sure the weep hole on the water pump for bad seals while the bottom end is out.
 

Mac

Member
Joined
May 2, 2003
Messages
746
Location
New Jersey
Did you see the melted piston. Sometimes the piston skirt breaks apart ....... equals real bad. Sometimes you just squeak a ring. The answer to this question should help decide whether you check the crank.

Water for a couple days wouldn't worry me. how long did it sit in the rain?

Agreed Yamaha reeds are the very best.

I personally like stock everything.

Make sure you go through the carbs. Ethanol kills many two stroke engines. Just the fact your rebuilding prbly means you know that carbs and tuning keeps these engines running.

---mac---
 

TheFarm845

New member
Joined
Sep 13, 2021
Messages
12
Did you see the melted piston. Sometimes the piston skirt breaks apart ....... equals real bad. Sometimes you just squeak a ring. The answer to this question should help decide whether you check the crank.

Water for a couple days wouldn't worry me. how long did it sit in the rain?

Agreed Yamaha reeds are the very best.

I personally like stock everything.

Make sure you go through the carbs. Ethanol kills many two stroke engines. Just the fact your rebuilding prbly means you know that carbs and tuning keeps these engines running.

---mac---

Ill double check, but im pretty sure the piston just bubbled from getting so hot. the guy said it melted down when he was riding late at night with temps close to -25F.

It sat outside for about 3 weeks, which we had rain only a couple times. So i would guess it has had water in it for no more than 3 weeks

Ill have to even see if i have the factory reeds. he gave me a milk crate full of parts and the vforce reeds were the only ones i saw.

Oh absolutely, Ill go through the carbs and just run all new fuel lines too, to be safe
 

TheFarm845

New member
Joined
Sep 13, 2021
Messages
12
welcome!

would not hurt to get the crank checked as there might still be debris in the bearings that could cause a premature failure as it is apart now. a good flush with wd40 and a coat of 2 stroke oil might be enough for it if you know there is no debris in it.

you can go with an aftermarket gasket kit. i have had no issues with them when i use them.

spi pistons are what i have had the best luck with aftermarket. seen/heard too many motors cold seize from not letting the sled get up to full temp before riding with weiseco pistons. oe are the best though.

cannot help you with the head as never got into an srx rebuild. did a viper with my brother.

unless you are planning a wicked port/big bore engine, the stock yamaha reeds perform just as well as the high end aftermarket ones.

as to checks on the engine, i would make sure the weep hole on the water pump for bad seals while the bottom end is out.

Thanks!

Maybe ill just fork out the money and bring the lower end in to be safe.

Ill check on pricing between spi and oem pistons. ive always used JE and CP Carillo in my 4 stroke machines.

What should i check for with the weep hole? is there a seal in it? or some other issue that is common?
 

Maim

Super Moderator
Joined
Mar 13, 2004
Messages
4,116
Age
47
Location
sudbury on. canada
the weep hole is for the coolant seals in the water pump. when the seal fails coolant weeps out that hole. while the engine is out is a good time to check and make sure that the seal is good.
 

fourbarrel

VIP Lifetime Member
Joined
May 5, 2003
Messages
2,741
Location
St George,New Brunswick,Canada
Hey guys, I grabbed a 2001 SRX700 from the original owner the other day that had a melted piston. He tore it apart and decided not to fix it so now its up to me to assemble it and get the old girl going again.

First question; the jugs were removed and the sled parked outside for 2 weeks for sale and of course it had to rain, which got water in the case. What is the best solution for this? Pull the case and tip it over then get some 2 stroke in it for awhile? Or maybe bring the bottom end to a shop and they can check crank run out and bearings while its there? Ive never dealt with a bottom end before.

Second; whats the best set of pistons to run for reliability? The jugs look good (the bad one has been replaced already) so I'm thinking i can get by with stock bore. The sled only has 2300 original miles.

Third: I need 1 head replaced. Are the 00-02 heads different from the 98/99?

Fourth; It came with a set of Vforce reeds. Im assuming theyre the first gen since they were bought back in 2001. However one petal is missing. Is it worth tracking down that petal and using them or to go with something different?

Fifth; whats the best gasket set to go with? Yamaha OEM or something aftermarket?

Last: is there anything specific i should look for or check while getting this back together?

Overall its extremely clean, no cracks, no dents, no tears, no fading, etc... Came with all the original paperwork and 2 SRX covers, 2 SRX baseball hats, 2 jackets, 3 snowpants, etc.... (He owned 3 SRX sleds).
It would be prudent to have the bottom end checked out while the engine is tore down that far now.As stated above you'd feel pretty sick if there ended up being a problem with a bearing and it showed itself on your first trip after a rebuild.
Most answers to the piston brand will tend to be oem,it depends on your budget,but there are decent alternatives.I've run Wiseco before and you do indeed need to let the engine warm up before getting into the throttle.As for any other brands I can't comment.
Heads are different for the 98/99 engine ( 8DN-00 ) vs the 00-02 ( 8DN-10 ).It isn't like you can't run the older heads on a newer engine,but it will have to be a complete set of 3,don't mix and match them.
I've had the best luck with oem gaskets,especially head/cylinder o rings.You can generally get away with reusing oem ones where some of the aftermarket stuff tends to break down sooner and the rubber willharden up.
Things to look for,well you said the carbs were on your list so that's a definite.Go through them from top to bottom.Check the condition of the oil pump and fuel lines for pliability.If they are the originals,even with an engine with as few miles as yours they will dry out and turn stiff and brittle.Check the coolant hoses for chafing and the water pump seals.You would be best to replace the V force with stock reeds too.
Now would be a good time to go over the engine/chassis wire harness too as a portion of it runs under the engine.If you have the engine out to get the bottom end gone through then you have excellent access to the harness.Pull the harness out and peel it apart to check for wires that may be close to having their coating rubbed through.If your lucky and don't have any then tape the harness up and put a piece of split wire loom over it and route the harness back in place.
That should get you started.
 

destey

Member
Joined
Jan 28, 2010
Messages
311
Age
42
Location
Vermont
These bottom ends are going on 20 years old. I've had my '99 bottom end apart and the bearings were not very good. I replaced my whole crank with a lower miles unit that I got from a member on here. The problem is the bearings that are on the crank are very expensive and discontinued. About all you can do now is replace the outside bearings on the crank (that don't need it to be pulled apart). These are still a challenge and require special techniques to get them off (I do all my own work but I took that to a engine shop). You may be lucky and the bearings on your crank are not really bad. I would say there's no chance they are in great shape, too many miles and years. The question is how bad are they and how long will it last. If you know someone who can rebuild it, I'd love to know about it as I have one that needs it at some point. The Crank Shop here in Vermont has this machine specifically listed as one they cannot rebuild (probably because of the lack of replacement bearings). Blame Yamaha, they went from $25 bearings to $200 bearings (that don't seem to last any longer).

Are the 2000+ crankshafts able to have the middle bearings fixed? I remember something about them welding the pins instead of loctiting them. I see on the parts sites the 2001 microfische doesn't break down the crankshaft into parts, its just a unit. The 2000 and before does. https://www.partzilla.com/catalog/yamaha/snowmobile/2000/sx700r-sx700d/crankshaft-piston

Bearing #24, was bad on mine
BEARING
93390-00028-00
Ships in 2 to 3 days
$328.99
$207.20


So was the 2 number 18
BEARING
93306-28202-00
Ships in 2 to 3 days
$77.99
$56.26

and #17
BEARING
93306-28201-00 Unavailable
15 and 16 also

15BEARING
93306-30715-00
Ships in 2 to 3 days
$71.99
$56.88
16BEARING
93306-30716-00
Ships in 2 to 3 days

$48.99
$37.89

I think the only ones you'll be able to do are 15 and 16. I bought a special puller to get those two out and it didn't work so I had a shop replace those. The other bearings were unavailable, and I also couldn't find anyone to do the work.

Good luck, I hope you get this going!! These are awesome sleds and it'll be sad if they become extinct over a few parts.
 


Top