SRX 700 rebuid

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rcrx5

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Dec 7, 2015
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Hi guys,

Looking for some help rebuilding my 2001 SRX 700. I melted a piston on the #1 cylinder. I ordered a refurbished cylinder from US Chrome and a new set of pistons and rings from SPI. The head was pitted, so I got a used one off ebay.

How do I make sure I get all the particles out of the crank case? I'm trying to get this done with the engine in the sled. Also, being chome lined cylinders, do i have them honed?

THX
 
Use a vacuum cleaner followed by compressed air to clean the crankcase. The cylinder is nickle silicon coated and already finish honed, just be sure to check for proper ring gap.
 
Great, thanks guys! What is the correct gap? Do you just use an outside micrometer with piston at top of cylinder?

Should I at least clean the cylinders with carb cleaner before reassembly?

Also, should I have a machine shop check heads and cylinders for warping?

When I pulled the power valves out 2 of them made a servo noise as the cable was accidentally pulled. I'm assuming I will need to adjust the cables now? I read a thread on here that talked about that, and quite frankly it sounded rather confusing. Is there a simple way to adjust them?
 
1. Clean the hell outta that cylinder. If you think you got it...clean more. Use carb cleaner or a non chlorinated brake cleaner, parts cleaner that leaves no residue. I swear by carb cleaner. Scrub with paper towel until there is zero dirt or black stuff coming off onto the paper towel. I like rifle brushes for cleaning the ports.

2. For powervalves, losen bolts on valve housing, run the sled, turn your idle screw down untill its idling down around 800 rpm...below 900 I beleive is the sweet spot. The servo will Open at this rpm. With it running, put your spacers in the housing as shown in the tech section and adjust the cables until just snug against spacer. Not too tight!! Button it up and turn idle back up and your done. Easy peasy.

3. Use a good straight edge and lay it across the head. Use a feeler gauge to make sure the straight edge is flush to the head. Move it around and check a few different ways. Done like dinner.

3. I can't remeber ring gap. Use a mic to measure piston 10mm up from bottom of skirt. Use a bore gauge to measure the cyl. Check the cyl in a few spots. There is a spec for roundness as well. Compare your measurements and you'll find your clearance.

4. To check the ring gap. Put the ring in the cyl all by itself. Then use your old piston to push the ring down into the cyl as to make it square to the bore. Dont use the new piston you could cratch it and thats a no no. Use feeler gauges to find your gap. If gap is tight you can use a fine file to open it a bit but be careful. Put the file in your bench vice and give the end of the ring a light rub. Make sure no burrs on the edges and your golden.



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If your cleaning the crankcase with solvent immediately get the crank bearings coated with any kind of oil before they flash rust.
 
Very much appreciated gentlemen! Is there a lube that I should be using for new needle bearing and piston pins? Also, is there a proper positioning of the rings? ie position the opening 180 degrees from one another and avoid ports?

I have left the power valves hanging off their own cables, is it advisable to take them apart, or should I press on with them attached?

The exhaust ports on cylinders are pretty rough, can I use a wire brush on a drill to clean those up?

How in the world does the bearings, including crank and rod bearings keep from seizing with no crank case oil in these 2 strokes?

Will post a video of your completed work when and if I get this thing running again.
 
I always use 2 stroke oil as long as its not going to sit a while. It tends to run down into the bottom of the motor if left to sit for a week without running. I don't like using anything in the motor other than 2 stroke oil becuase its meant to burn. Other lubricants are not meant to burn in the motor. Fogging oil is sticky and works good if its going to sit. For a bit.

There are two small locating pins in the piston. You will see them in the ring groove. That's where your gap goes. Piston will have an arrow pointing to the exhaust side and there's a small hole on the intake side so you know which way to install it.

Yes you can clean up the ports all you want. Just don't take too much material out. The wire brush on the drill isn't going to do much though. You need to use a fine Stone or sanding drum. Best to use a dremel or die grinder or something high rpm becuase your drill will chatter like a bastard. Use lube when sanding ports. Mineral spirits works great. I use rapid tap cutting oil.

The case has oil injection holes in the very bottom that shoot oil up into the bearings. Theres oil holes all over the motor. Your fuel pump also gets oil and gas and sends to carbs premixed.



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Lots of good information here.

Here is what I am seeing for parts within the power valve system, according to the manual. I don't see any spacers listed. Where are the spacers located?

Cover
Y.P.V.S. cable (servo motor side)
Valve
Holder
Gasket
Spring
Spring seat
Valve housing 1
Oil seal
Circrip
Washer
Gasket
Valve housing 2
O-ring
Puller
Servo motor assembly

Are the spacers in the servo motor housing or on the power valve assembly?

What happens to the residual oil that is sprayed on the bearings? My crank case looks dry.

Should I clean the power valves attached to cables, or disassemble first?



Thank you!
 
Last edited:
You can clean them however you want. Probably get a more thorough job if you disassembled them. What I mean by "spacer" is the 2.5 mm Allen wrench that the guy used in the tech article. Did you read the powervalve write up in the tech section? The spacer Is not part of the assembly its just what you are going g to use to set your valves. You can use washers too. Losen the valves housing. Stick the Allen wrench between the two peices of the housing and adjust cable until the Allen wrench is snug. Giving you 2.5mm of slack. Then remove the Allen wrench and tighten the housing up. Do yourself a favour and get a manual for it. Check your oil cable slack if your worried about oil. The inside of the motor shouldn't look oily though it should be nice and clean. Remember the oil burns off.

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Click on tech
Go to snowmobile tech
Click ENGINE
There's two different articles there for your valves one is directly from the manual.

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1. Clean the hell outta that cylinder.
Click to expand...

I agree. I've used hot soapy water and dry with compressed air. I coat the cylinder bores and rod bearings with 2 stroke oil.
 
Thanks, I found that thread concerning the allen wrench.

I notice a slight oil film on the rod now that you mention it. Almost undetectable though.

I noticed there is a bunch of warnings concerning the use of oven cleaner for the power valves. I watched a youtube video last week with a professional shop owner advertising the use of oven cleaner. Glad I saw the warnings, I had oven cleaner on my list to get.

Is it Ok to use a razor blade? I have way too much carbon deposit to get it off with carb. cleaner or WD-40. I understand that if you hit aluminum at the wrong angle a razor blade can do damage, but I'm thinking that it could work with enough TLC. Any thoughts on this?

Awesome help here and a Great forum!
 
I use oven cleaner....It works the best. I use a razor too sometimes just be careful not to scratch it.

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Youllbe2nd said:
I use oven cleaner....It works the best. I use a razor too sometimes just be careful not to scratch it.

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Click to expand...

Any sign of the coating coming off using oven cleaner? I really liked that idea until reading some of the warnings here on this forum, now I'm having renewed hope. You seem to have your ducks in a row, how sure are you that it doesn't damage the outer coating?

Since I am installing a refurbished cylinder with a used head, should I have a machine shop check the head for warping? The cylinder is from US Chrome, so not worried about that.
 
Like I said before. Use a good straight edge and lay it across the head. Then take your feeler gauge and make sure you can't sneak the gauge under the straight edge. As far as the oven cleaner. There are many warnings not to use it on aluminum. I never noticed the coating coming off personally but I've never had a problem with the valves. I'm pretty sure it does remove anodizing from parts...I leave it one there for like 5 mins and rinse good. Your welcome to use something else. Make sure you double check your cyl too! Do not skip this step.

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Hi guys, I finally got around to putting it all back together, and thanks to your help it seems to have worked. I am trying to get it to idle at 900 RPM's to adjust the power valves. It is not only not allowing an idle that low, but when you try to restart it wont start. When I check for fuel on the plugs, they are dry, add some starting fluid, it starts up and runs ok. Any ideas?
 
rcrx5 said:
Hi guys, I finally got around to putting it all back together, and thanks to your help it seems to have worked. I am trying to get it to idle at 900 RPM's to adjust the power valves. It is not only not allowing an idle that low, but when you try to restart it wont start. When I check for fuel on the plugs, they are dry, add some starting fluid, it starts up and runs ok. Any ideas?
Click to expand...
Is the pulse hose for the fuel pump connected on both ends?
 
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