1988 Exciter 570 Carb Question

Black Bear

Black Bear

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Any thoughts on why one of my VM38 carbs will overflow as soon as I turn the enrichment circuit off? I have checked the pilot jet, main jet, needle valve and seat. If I snap the enrichment lever up to middle position it will stop overflowing and appears to be fine. If the enrichment plunger was not seating correctly wouldn't it still do it with the enrichment lever in the middle position?

Thanks in advance.

Michael
 
I had an 88 EX570. I may be wrong, but I believe at one time there was actually a recall involving those plungers.....or some common issue involving them. Might be worth checking into a little more. If it happened once, it'll probably happen again.
 
The recall was not for the plungers. It was a kit used to re-jet and delete the power jet function of the carb due to burn downs.
 
Throttle Junkie35 said:
The recall was not for the plungers. It was a kit used to re-jet and delete the power jet function of the carb due to burn downs.
Click to expand...

You're probably right, but I thought there was something or other about the plungers too....Maybe it was something to do with decompression? I can't remember, that was a long time ago. :-p
 
Im not sure they ever had a recall on the decompression valve. I could be wrong though. I know aftermarket companies offered block off plugs for them because they could leak.
 
Throttle Junkie35

Thanks for the replies. I am learning a lot but still have much learning I am afraid.

Here is my story so far.

Replaced fuel lines and the oil lines connecting oil injection system to the fuel line. I have checked the pulse line its in good condition. I am able to blow through the vent line on the fuel tank and get fuel all the way to the carbs. Should I be able to blow through the pump? It seems like the pump works but I am curious as to what would keep it from flooding If I was to park the sled on a downhill slope. I have checked/cleaned the main and pilot jets and also looked at my needle and seats they are in good shape. I have not done anything with the jet needles except inspect visually. I have had the air box in and out as I thought I had it licked at one point but as soon as I put the air box back in I struggled with my slide adjustments do to throttle cable routing and could not access anything so I took back out. I am planning to leave it out until I feel a little better about having the problems understood.

# 1 Regarding the Re-Jet. It seems my carbs have the 320 main jet in the correct location but I still have the tube between the carb bowl and the main body with No ball bearing in the line either.

#2 The choke plungers seem to be difficult to adjust when the airbox is in. I think I have them pretty close.
#3 The machine will run and idle around 2500 rpm. Have checked for leaks by spraying around crank seals and carbs does not seem to make any difference. I have tried to balance my throttle cables by placing a drill bit on the air box side of the carb and make sure the slides were adjusted the same.
#4 Air Screw is at 5/8
#5 Put the airbox back in and took it for a spin and when i turned the handlebars to the right the throttle cable stretched and almost rolled me. Only ran the machine straightline for a few minutes before it got hot enough for the red idiot light to come on so I shut it down. Not sure what happened with that, the coolant levels are good and it seems to be circulating? I have a spare thermostat so I changed it. Have not test run since so I cant report on it.
#6 So I took the airbox back out and plan to leave it out until I have some issues sorted out such that i uun.....Is it ok to run without the box while troubleshooting? Next I will try to focus on proper positioning of all carb cables and slides. I am currently mixing my gas until I am sure the oil injection is working correctly so far it seems to be ok no air bubbles in oil injection lines.
 
Hi Michael,

I am working an the same machine, see my post about restoring the '88 and '92. I have a flooding problem as well, but it is when it sits for a while, as well as running. I have done much research on this site and I think my problem is the needle and seat. From what I have read, if they are the original metal tipped type, they will wear and allow fuel to get past, also there are supposedly o-rings around the base of the seat (I have yet to pull mine apart again after learning this). Do your seats screw in or are they a press fit? Did you see o-rings around the base? I see 2 different kinds on parts suppliers sites. Mine is a buggar to start after leaving it sit for a day. The crankcase gets a load of fuel and fouls the plugs. Then after it starts, it runs really rich for a while until it warms up. I can't see fuel coming out of the carb, but you can tell it is running rich at idle. Mine also has the power jet bypass done and I have cleaned the carbs multiple times. For now, I am just shutting off the fuel when I park it. It will start after only 2 or 3 pulls now.

I need to find a good source for the viton tipped needle/seat. I am seeing them for $25-30 each but have read here that they can be had for $7-8. I just can't seem to find where. Anybody care to help us out with this source?

Keep us posted Michael.

Paul
 
Kilohertz,

Thanks for the reply. I have recently purchased three exciters an 88 and two 89's. All in various states of repair so I will keep in close contact with you as we are working through issues. I believe my needle and seats screw in and have the o-ring. I actually had a spare and changed one out in my carb that I thought was an issue but it turned out to be a choke plunger problem. My carbs have the viton tip.

Regards,

Michael
 
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Kilohertz is right on, sounds like you need new needle and seats. Viton tipped needles are worth their weight in gold!! 320 mains sound good. If you dont have a bearing in your power jet hose, put one in it or plug off the bowl and intake bell ports with a screw and some loctite. Make sure your main jet is at the end of the needle jet and not still screwed into the bowl.
For idle adjustment, you can use the drill bit trick, then fine tune each carb evenly to get to 1500 rpm. Then, loosen the slack adjusters on the top of the carbs. Make sure you have some slack, then slowly turn the adjuster out until the rpm's start to increase. mark the adjuster with a sharpie then back off one turn. Do the same to both carbs, then they are sync'd.
You can run without the air box for trouble shooting but I would avoid long wide open throttle runs.
As far as the over heating problems, you could have a bubble in the system. There is a bleeder under the seat you can crack open and get the air out. Run the sled at idle for a few minutes with the coolant cap off. this may bleed off some of the air. Also, make sure you have a snow flap on your sled. Without a snow flap, your not bringing enough snow into the tunnel to cool the heat exchangers and will over heat. On 87-90 Exciters, most aftermarket companies suggest to run without a thermostat to improve circulation. I run mine without as well. Make sure you warm your sled up thoroughly before you gas it hard or cold seizure could occur. I wouldnt recommend running without a thermostat if you are frequently riding in extreme sub zero temps though.
 
Concerning your flooding problem,if your needle and seats are good, and your float height is adjusted correctly, the only thing that would flood a sitting engine is a leaky fuel pump diaphram. The needle and seats are screw-in. No rubber "o" ring. O rings are for press in style used on the TM flat slide carbs.
 
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Throttle Junkie,

Thanks for both your posts...very helpful. I will try to locate the Viton tipped needle/seat combo. Do you have any suggestions for me as to where? I have looked around and am only seeing them for $20 plus each. I can't seem to find the post that said they were available for $7. PS, I'll also check out the fuel pump. Can I just disconnect the discharge side and see if the fuel runs out and if it does, it's leaking. Engine off of course. :p

Cheers

Paul
 
Black Bear, kilohertz, you guys are more than welcome. I know here locally, viton tipped inlet valves are around $20- $25 a piece. I havent searched on line but this is what I've been paying at a local shop.
 
Guys

Worked a little on the sled last night. Followed Throttle Junkies guidance and the 88 machine is running quite well. Also raised the back end slightly and opened the bleed screw and was able to add some additional coolant. I checked the lines on the rear exchanger and they are getting warm. Really don't have enough snow to test ride here in Massachusetts currently so I will wait on that but I think I am good to go. The machine still might be a little soft on the very low end but i have not put the air box back on so it might be just the difference in sound. I am comparing to my 89 which has a PSI pipe and that machine seems a little crisper on the low end. I have the Viton tips and no flooding issues however I think 20-25 bucks is the going rate from what i have seen.

So currently I have two of the three sleds running good...the 88 and one of the 89's. The other 89 is completely ripped apart somebody tried to paint the engine so its a mess. The good news is I think I have all of the parts and than some. I just need to come up with a plan of attack. Really in no hurry as It should be fun. Any ideas on how to attack the painted engine? I will post some pictures soon.

Michael
 
Thats awesome Black Bear!! Keep at it. Now that your sleds are running good, it a good time to inspect and clean the clutches. You can have the best running engine in the world, but if the clutches are worn, you will be left in the dust by a well tuned Bravo! LOL. What is your clutch engagement on the sled with the PSI pipe?? I run a RPC single on mine with a short Y pipe to complement the ported cylinders, which gets me in the 7500 range peak. It seems the piped sleds that I have (and had) like a 4000 rpm engagement and still makes it trail friendly. I'll post the link for the PSI dyno sheet.
So someone went nuts with a spray bomb on your engine?? Well, depending what type of paint was used, you may be able to use some lacquer to remove it or try some water based paint stripper that NAPA has available. I dont remember the name of it but its around 17 or 18bux and works awesome. Basically apply, let sit for a few minutes, then rinse off with water. Of course, block off the intake, exhaust etc..You might have to take a tooth brush to the stubborn spots.
Good luck wrench'n. Im go'n ride'n!! :sled1:
 
Throttle Junkie

Thanks for the encouragement! I have not looked at the clutches yet but will soon. The machine with the PSI pipe is engaging around 3600 rpm's. I have not really tried any of my sleds on the high side yet. Both the 88 and 89 seem like they will go pretty darn fast. I was able to get the soft spot out of the 88 by checking the float height they are both running great. I will stop off this week and pick up some paint thinner and get to work on the painted engine. Most of the weekend was spent replacing the wood on the bottoms of my seats. My seats are all now in pretty good shape.
 
Here is an earlier photo of one of my 89 Project sleds. You can see it was a real mess as some one painted the engine. I also have added an 87 to my exciter fleet so with four EX570's now I am starting to come up the learning curve pretty quickly. I Have all four sleds running now. I have major clean up and system integrity work to complete on two of them but I have all of the parts. All systems seem to work so with time and investigation I should be able to figure out which ones are worn out. Its been really fun working on these sled so far.20140315_200544.jpg
 
I would be very interested in seeing your progress as you get them cleaned up. Good to see you didnt give up.
The biggest problem with Exciters is that they multiply very quickly. I have had over a dozen, probably almost two dozen since 2005. Yeah...its a sickness. LOL The funny thing about it for me is that I never really cared for the Exciter styling. I have no idea why I have grown so fond of these things. LOL :yam:
 
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