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Discussion Starter #1
HI. I'm new to this site and didn't see any posts about this topic. Here it goes. I have a 1979 yamaha srx 440C. I'm trying to restore this sled, It has always run, but never too well. It has 120 psi in each cylinder(checked with 2 gauges at wide open throttle), Carbs cleaned(290 mains, don't know the others), new fuel 32:1, clutches cleaned, and soforth. I was wondering if there were any major problems with this sled, ie: stator, coil, 12v regulator, etc. It just seems to be really doggy(for lack of terms)at the start, and smokes a lot. It has decent spark,(I saw with inline spark testers) but I don't know how to test this to see if it is enough. It engages at around 3500 rpm. Is this good? Oh, one more thing, were can I find the steering boots? Does anyone sells these things aftermarket. I've checked and haven't found anything, even the junkyards. Any help would be appreciated. Thanks.
 

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First Off
Welcome to the Site!
I have a salvage yard just down the street from Me, and the Owner Races and specialises on these old Yammie's.
He can probably find the part's you're looking for.
Just click the link to M&Psalvage in my sig, and that will allow you to E-Mail him directly.
Rick
 

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you can get repro ski boot covers from Tom Todd, Leon Kotch in WI or Lee Frederickson in MN.
if your riding or racing this sled go with the plastic boots from Tom Todd in NY state. they are more durrable than the rubber boots and less weight. if your building a show queen get Leon Kotch's rubber boots. Lee Fredericksons boots are fiberglass.

what are you doing with this sled? racing or trail riding?
your carbs are mikuni powerjet carbs which means you can adjust your mainjet size with a twist of the white dial on the bottom of the carb.
if i was racing that sled, i'd have it engage at atleast 5000 rpm. that will also help your bog issues. have you moved the needle clip position to try and remove some of the bottom end bog?
 

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Discussion Starter #5
Got another problem... I run the sled for a little while and then shut it off, I tried to start again, and it won't start, I don't know what the h e double hockey sticks is going on with this finiky thing. I'll let it sit for a while, then it will start again, it has good spark. I'll try changing the needle adjustment to position 1 and see if that helps. Where can I find parts to make the stock primary clutch engage at 4500 to 5000. Are there any aftermarket parts I can use that are compatable with the stock. Thanks for your help guys. I'm about ready to give up on this old POS. I'll order those belly pan boots one of these days..
 

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Hard starting usually indicates a weak fuel pump. Time for an overhaul/rebuild of the pump.
 

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vintage yami srx's are highly sought after sleds.
you will have no problem selling it.
are the carb floats and needle and seat clean/clear?
a good upgrade would be a comet102c drive clutch.
 

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Discussion Starter #8
Thanks for all the help guys, YOU GUYS ROCK ON THIS FORUM, I think I found the problem, there was a cracked diaphram in each of the fuel pumps, must be a common problem, I never thought to look at that, I guess it's always just the obvious things. I ordered from mfg supply.com and should solve the misterious problem I couldn't figure out. That would explain the all the smoke and not restarting. I think I might spend the 300 bucks for a new clutch. Although that is a lot of money for an old sled like this. Is there anywhere I can get stock clutch parts that will engage the sled at 4500 rpm's or do I have to just buy an uncalibrated clutch? Thanks again for all your help, I'm only 27 and I love rebuilding old stuff like this, I will post pics later.
 

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Discussion Starter #9
Here's the sled and the broke diaphrams in the fuel pump.


[galleryattach=13407]
[galleryattach=13406]
 

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120psi is good. lots of compression there.
stock was probly 130 or so. lots of life left there.
 

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Is it a Yamaha Manufactured clutch or an other one made for it like Comet makes the ones that Cat uses now?

A Comet 102c uncalibrated and a set of weights and a spring can be gotten new for less that $300.
You might find a better price on EBay for a new or even a used one.
 

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Discussion Starter #13
Thanks for your help guys. It has the stock yami clutch. Can you still buy parts for the stock one to engage at 4500? And what setup do I need. It says nothing in the CLYMERS MANUAL about clutching. I really don't feel like spending 300 bucks on a clutch setup, I'm afraid I won't get my money back out of it when I sell it. Any help would be apreciated. Oh, I did look on ebay, and there is one on there, but some guy is asking 220 bucks for it, used. That's outrageous for a used one, might as well buy new. The one I need is 212600A for my year.
 
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