Diablos posessed by the devil himself!

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Diablos posessed by the devil himself!

Post by Go Go Diablo » Fri Feb 12, 2016 11:05 pm

Hi all,

Being as involved with Diablos as I am, I come across Diablos each year that just do not want to cooperate with the general rules of Diablo repair and refurbishment. Some of these are those I work on, some are from people all over asking questions to help figure out their problem. And often when we finally get the best of that little Red Devil, we have to sit back and laugh a little at the path we took to succeed. My friend Greg D from Waupaca, Wisconsin called his Diablo "possessed by the devil" and it gave me an inspiration to share such challenges.

So this post is created to share your stories of troubles, challenges and your eventual victory over satin (regarding your Diablo that is :twisted: ) for all to enjoy and learn from.

Bruce
Too many Diablos and parts to count.
Yamaha 600 SX

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Re: Diablos posessed by the devil himself!

Post by Go Go Diablo » Sat Feb 13, 2016 9:36 am

So I will start. I won't mention a specific name, but if this person cares to reveal himself, it would add more color.

Kevin is from Ontario and is going through a Diablo 502 restoration. As he goes through all the components of a restoration, there is the typical work done to the motor and carb. The motor did not need much as internals were in pretty good condition, so the typical gaskets, seals and all the ignition components to be safe. But this motor and carb had other ideas. When it came time to start this Diablo up, it was a beast to get running. When it did run, it ran like crap. Kevin and I had a dozen emails back and forth and he must have had many many hours of frustration trying to troubleshoot the problem. Eventually, the motor and carb went in a crate and were sent to the Diablo Shop which is not cheap international package to Sobieski, Wisconsin.

Upon arrival in one of the nicest motor crates I have seen, I pressurized the crankcase to check for a good sealed motor and Kevin did a fine job with all of that. I noticed there was an NGK spark plug cap on the spark plug wire. I thought ah ha!, that is it. That might be a problem. Typical snowmobile spark plug caps have a resistor inside of them meant for the high output ignition systems. The ignition system in Hirth motors are low output and a plug cap with any resistor in it would cause weak spark. I found a few other minor things here and there and the motor was ready.

Took the carb apart and did a quick test of the needle pop off setting. It pops off the seat at less than 6 psi and it should be over 12 psi. It does not explain this in any manual that I have found, but I was shown this technique years ago and it has worked well for me. My theory is a low pressure setting will cause the carb to run rich to the point where it floods the motor. A higher pressure tends to atomize the fuel better and thus burns better when it hits the compression stroke. So I set up the carb.

Typically, I would be very confident this motor would run, but I was worried about shipping it back without test running it. So in a Diablo the motor and carb went. When it was time to start it, it started hard the first time, but ran pretty well once I got it started (just revving it up in the shop, not driving it around). I thought I was done, but it was late so I planned to pull the motor out and box it up the next day.

The next day I decided to start it again and that little devil would not start. For the next week, I wracked my brain wondering what the problem could be. I would work on it for an hour or so a day without luck or maybe getting a puff or a backfire. Finally it comes to the point where I just have to start replacing parts. Try a different carb - no luck. Replace the points - no luck. At one point I thought the muffler on the Diablo I was using was plugged because I could not get the fuel up to the plug (it was dry), so I replaced that. I kept wondering what could possibly cause the plug to be dry so I was thinking fuel and not ignition. Then grasping for a ray of hope, I replaced the aftermarket ignition coil and the condenser and it started first pull.

So that was the issue with this Diablo. We don't have means to check the performance of an ignition coil or condenser unless someone had one of those old dyno units. One would think new parts would eliminate the concern of failure. But in this case, replacing the original Bosch parts with aftermarket parts where one of them failed caused a hundred hours of grief and a significant investment to figure out.

That Diablo had demons in the motor - :evil:
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Re: Diablos posessed by the devil himself!

Post by Go Go Diablo » Thu Feb 25, 2016 9:59 pm

There should be two people out there (one in Minnesota and the other in Quebec) that had some happenings with this next Diablo.

My friend (I will refer to him as JP) from Canada was looking for a nice Diablo and another friend decided to let his go for reasons I won't explain. Wanting to help them both, I got in the middle :o

I picked up the Diablo and brought it to the Diablo Shop for a little attention. It needed drive sprockets, a gearbox rebuild and some other odds and ends. A beautiful Diablo, well taken care of but just needed a few things........ :shock:

Remember back in 2008/2009 when we were out of sprockets for the Diablo. We needed a savior to help us. To recreate the molds was very expensive. People were trying plastics and other materials to make a drive sprocket, but none of that worked. I was not clever enough to come up with an answer myself outside of re-creating the molds. Barrie tried to save the Diablo future and trialed rubber drive and idler sprockets. He bought heavy sheets of rubber and cut them with his mill. We were having he steel hubs made down here in Wisconsin and Barrie was sending me sprockets and I was sending him steel hubs. Lots of people are very happy. Although expensive, sprockets were going out the door right and left for about a year. I put a pair of these nice new sprockets on this Diablo from Minnesota.

Then we heard in the wind that sprockets were failing. When we started asking around to those we sold them too, sure enough everyone was having sprocket issues. The problem is, nobody was telling us. I can only presume they did not want to hurt our feelings for trying. At that point, we had no option but to recreate the sprocket molds and start making sprockets with clam molds and high pressure injected rubber. Same design as original but with 50 year newer technology for the rubber.

I remember when I got the first batch, they looked fantastic but you can imagine I was a little worried about their durability. So that week, I pulled my 503 in to the shop and put a new pair of drive sprockets on. That next Saturday was a weekend in April and I took the Diablo up to the cabin where almost all the snow was gone. This was going to be a real test. I purposely went up and down our rocky roads spinning those tracks more than once. If a sprocket cog was going to get ripped off, it would have happened. But they passed the test unscathed.

So with that, Barrie and I warrantied sprockets - each of us had sold dozens and dozens of sprockets all over North America. It cost us both quite an investment to replace them all with new sprockets, but we slept well knowing we did the best we could to solve a bad situation. However, back to this Diablo, it also had those sprockets on. Shipping JP sprockets was not the issue. The issue was he just got this nice Diablo and he would have to take it apart to install the sprockets. I could have lost a friend with all of that, but he is the gentle giant and graciously did what he needed to do.

As if that was not bad enough, that devil was still hiding in that Diablo. JP takes it out and starts getting some miles on it and all of a sudden, the gearbox locks up. :o HOW COULD THAT HAPPEN? The short story is the chain broke and I can say I've never seen a chain break before this one and have not seen one since. But again, the issue was not getting JP the parts he needed, but the poor guy had to take that Diablo apart again and fix it up. You would think by now JP is no longer talking with me. He had that right. But not JP. We built a strong friendship since and his demeanor is like so many I've met from above the border and become close friends with.

Today the Diablo is running strong - Thank You JP and hope to catch up with you soon.
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Re: Diablos posessed by the devil himself!

Post by Jano » Mon Feb 29, 2016 4:17 pm

Well Bruce, thanks for the kind words.
I enjoyed every minute, after initially thinking that maybe I shouldn't have bought this 503, being really a Hus ski guy. Yes I am JP and you all will be happy to hear that the devil was quiet for quite a few years as I got a lot of miles on that great 503. Well things came to an abrupt end this weekend when the devil came out when I was so not expecting him. After some great exhausting deep snow riding with the boys in Val des bois, I noticed some unusual noises coming from under the hood when idling. Ha, nothing to worry about, the engine is running just fine when under power when not idling, lets keep going. But at the camp for a break, I did check around the engine compartment and couldn't find anything. I also checked the tracks for whatever reason and lord and behold, I am missing pieces of rubber on my left front sprockets. I did get stuck a lot towards the left, but this problem can be said to be my fault in a way. Tracks were much too loose and I believe the sprockets may have been cut on the frame. I tightened the tracks and all was well, except for that rattling when idling. Off we went again for some riding with 3 teeth slightly modified on the left front sprocket, right one just fine. However, every time we stopped and I was idling, the noise was getting louder and the tractor shook more and more. Here we go again for a ride from hell where no man had gone since the snow came. I was starting to feel that the the devil was up to something. Things started to come apart and I had the hardest time getting out of the woods to the main road to the camp. Clunk, clunk, clunk, bang. The primary clutch kinda blew up and I coasted down the hill to the road. From there it was downhill all the way to the truck. I was able to convince one of the boys to tow me back with his Hus Ski 444. Yes, the 444 was driven by my good friend Barrie who couldn't keep his teeth inside his mouth. I think I made his day and I will be hearing about it for the rest of my life. The initial report is that the clutch is broken in a way the guys never seen before. I have posted some pictures with the others from our ride in the daily chat forum. Take a look and tell me what you think. I am not a guy that abuses my machine and was very surprised to see that happen. All in all, it was still a great weekend with a great bunch of guys. Wish you could have been there Bruce.
One thing for sure, always be on the look out for the devil in your machines, you never know when he will cause you grief. Needless to say, Bruce, I will be calling for some parts soon.
JP

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Re: Diablos posessed by the devil himself!

Post by BillNH » Wed Mar 02, 2016 3:39 pm

My Diablo has been possessed for the last 2 years. After resurrecting a 503 that had been sitting under a pine tree for 40 years, I, in my infinite spare time (only working 60 hour weeks) completely restored/rebuilt it. I had it running, and proudly posted on here. Then it quit running, I worked on it for several Saturdays, and found a slightly pitted crankshaft. I sanded with emery paper and put on a new seal, it tested good on the bench, or so I thought. This winter I started trying to start it, with no luck, no sputter or pop at all. Then, I tried my carb on the mongrel, and it worked quite well. I checked my timing, and it was good, as best I could tell. Then, after several attempts to get it to start, I decided to recheck everything, and then the devil gave me a break, I remembered the pitted crank, and, with a little help from someone named Bruce (whoever knows him) I got a speedi-sleeve and put it on, only2 attempts, put everything back together and tried it. No start, used my timing light and checked timing, good, but now the plug was wet. Cranked it over without the plug, and clouds of vapor blew out the plug hole. I left it sit in the sun while I had lunch, and a nap, then put in a fresh plug, and what do you know, it started like I had just shut it off.
I guess the moral of the story is, don't relay on the mark 1 memory unit hosed above the shoulders, use a piece of paper and make notes, then, maybe you won't forget that pitted crankshaft when you go back 6 - 8 months later to begin work again. :D
Bill, 503 Diablo Rouge, 444 mongrel. 2009 Arctic Cat 570

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