Quantcast
Jump to content

  • Join Today, It's Simple and FREE!

    As a member, you can post in our forums, upload your photos and videos, use and contribute to our downloads, create your own member page, add your ATV events, and even start your own ATV club to host your own club forum and gallery.  Registration is fast and you can even login with social network accounts to sync your profiles and content.

moderateatvrider

93 suzuki quadrunner 250 valve issue

Recommended Posts

:aargh:I need a little help figuring out a vavle tightening problem im having with the bike. I adjust the valves with a feeler gauge, start the bike and ride for about 10 minutes then its starts to run really rough, check the valves and their now too tight, so i adjust them again run the bike for about 5 minutes and the bike starts to bearly drives now, check the valves and their too tight again...Now this happens to both intake and exhaust at the same time and approx the same amount of change. Also sometimes i go to start the bike after it starts to run rough (adjusting the valves back out because now thier to tight) after a couple pulls and it doesnt start i go to check the vavles again and they are wayy too loose, causing the bike to not start..Some how the valve timing/gap keeps changing..Could this be a cam or timing chain problem??They both looked good after visual inspection.Cant figure it out and need some help, any help is greatly appreciated, thanks.:confused:

Share this post


Link to post
Share on other sites


Not sure if your model has one, but it sounds like a malfunctioning automatic chain tensioner on the timing chain. I can see a little variance when the chain is worn but what you are describing sounds like ALOT of variance in opposite directions. See if yours has an A.C.T. Thats where Id be looking.

Share this post


Link to post
Share on other sites

Thanks mudflap64, ya it has an auto tensioner, never got to messin with it tho, but tried everything else so hope thats it..Any idea what problems to look for?,How do i know if it is bad?..thanks again for your help, might be able to ride this year after all..:biggrin:

Share this post


Link to post
Share on other sites

Not sure on your bike, but when I had a ACT fail it had a heavy spring inside it wich broke. The spring wound inside itself so the tension on the chain was constantly changing. Eventually the chain skipped & it pointed out the problem. Anothe rthing you should check is to make sure there isnt alot of wear on the tips of the valves or rockers. If theres a big groove worn into either it could caused the adjustment to loosen up & wander all over the place. Just a few of my thoughts.

Share this post


Link to post
Share on other sites

I checked out all the tentionerparts and all is in good shape and working flawless but noticed what I think might bethe problem, the tentioner is at its outmost position and when I place it back in its hole(still all set at its outmost position) its not touching anything inside, there's no tention on it, even if I hold it in place and crank the engine I can feel it push up very sporaticlly but mostly just sits there. So I'm thinking that the chain has streched past what the tentioner can handle but not sure if that's how its supposed to work. If so can a stetched chain cause te valves to tighten and loosen seemingly be themselves?? Thanks for the help.

Share this post


Link to post
Share on other sites


Sounds like a stretched chain to me too. That could cause problems if when you are adjusting the valves the cam is not @ zero open position for the valves. If you are going by the TDC of the crank shaft mark, or even getting to TDC by piston position, the cam(s) may not be properly oriented. How much rotational slop is in the cam(s)? If the chain is that loose it could have jumped a tooth or even be jumping teeth back & forth. Another thing to note is if the valve timing is that far off or the chain has skipped teeth, you could possibly have a bent valve that is hanging up. Id be doing a serious inspection of all the cam timing components. It sounds like it might just be time for a rebuild. Keeep us posted.

Share this post


Link to post
Share on other sites

Ya I'm gonna double check all the parts when I change out the chain, I'll be able to order the chain and rivet tool in the next couple days and I'll keep everyone posted on how it works out. Thanks for all the help. Fingers crossed

Share this post


Link to post
Share on other sites

finally got the cam chain in the mail, just waiting for rivet tool now..While im waiting i wanted to check and make sure the chain is the right one because i wont be able to compare it to the old chain the way im installing it by hooking it up to the old chain and slowly cranking the new one in and old out, so does anyone know the specs on what the chain should be??The new one i recieved is 25H-104L..hope its right..

Share this post


Link to post
Share on other sites

Got the new chain in and its running alot better, also the valve timing is actualy staying where i set it, and didnt know it till now but the engine/valves before replacing the timing chain where making alot of noise/tapping but now i dont hear any noise coming from the engine, what a difference!!..Now Ive run into a new problem that i cant solve, after running the bike for about 15-20 minutes the spark plug is getting covered in black carbon, it also spits out black smoke when i hit the throttle..Is there any other part i should look at besides the air/gas mixture screw?, i set it at 2 1/2 turns out and adjusted it out a little at a time but it seems to have made no difference, now its probaly around 3 turns out but same smoke..Also i cant use most of the throttle, i can only use about a 3rd of the throttle and past that it starts to miss and sputter..ive also noticed that once in a while the bike will start to idle up pretty high out of no where but if i shake the bike it will go back to normal..wierd..but i know i cant be far now, just this last bit holding me up..Thanks in advance for any help, im pretty stuck at the moment..

Share this post


Link to post
Share on other sites


Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Similar Topics

    • By Mike Johnson
      Does anyone know what the 3rd item is behind the battery on this ATV ? I know 1 is the,  solenoid1 is the CDI box, what is the 3rd.
    • By Daniel Gibson
      Working on a bayou 220 that has been ran extremely hard it's whole life. Literally had almost an inch thick dirt/oil covering the motor. Yeah that bad. Surprisingly it runs though. I cleaned the carb and tank multiple times. They're clean enough to eat off of. Readjusted valve lash and set timing. Was about 3 teeth off. It cranks good and runs good only problem is I have to cover the carb intake basically choking the hell out of it for it to start. The com choke works fine. It does this each time I start it regardless of temperature both ambient or motor. Wth? Compression is at 115psi I get 130s if I put a little oil in the piston chamber. Please help. Thanks 
    • By JC4x4
      My Honda Fourtrax won't start. The starter is kicking the engine over, but it won't start. It sat for about a year while I was living away, so I thought it might have been bad gas. I completely drained the fuel, flushed the fuel lines and filled it with fresh gas. However, still nothing. It started and ran fine the last time I used it. Any suggestions on how to diagnose this? It could be fuel or electrical at this point. Is there an easy way to rule one or the other out? Thanks
    • By Steven Alter
      I have a 2018 450 and the digital gause has started flashing on an off while driving. The backlit also goes on and off. It is worse when I hit the gas. The battery died a few weeks ago and I jumped it but its been fine until last night. Called the dealer and showed them a vid and they recommend replacing the gauge and its like 600 bucks. The machine has less than 100 hours on it. I would really hate to have to change it out. also the unit sometimes has trouble starting. Any ideas?
    • By David Miller
      Does anyone know how to access the check engine codes on a 2018 450 sportsman. Just changed battery and spark plug . It runs fine but the light is on and I need this to plow snow and need it reliable. Any ideas . Thanks
  • Similar Tagged Content

    • By BosoxBruce
      Recently I noticed gas leaking from under the gas tank on my 2005 250 2x4. As I looked closer it appears to be leaking from the shut off valve under the tank. It's the valve with the handle that can be turned to open, close or reserve. Can this part be replaced? Thank you.
    • By Derick Joel Smith Trimmings
      Buying a Baja 250 tomorrow for 600 bucks, needs nothing but a wheel bearing, i already know Baja is an off brand crappier. Manufacturer, but does anyone have any tips or knowledge of these bikes? 
    • By fatfarmboy
      Just bought (Tue. evening) an '89 Suzuki 250 4wd that has been sitting out the last 5 yrs. It's complete, including the shift knobs, battery cover, and headlights. It has the optional cooling fan on it (probly stuck - didn't check), and the engine isn't locked up. Plastic looks good and isnt cracked. Racks aren't bent up. Shift lever works, the foot brake moves (needs oil - have to pull it up by hand), and there's black oil and no water in the engine sight glass. Guy was asking $125 and gladly took $100 for it. Anxious to get started on bringing it back to life. Been wanting one of these for years. As soon as I can get to it (working on a junky "Jackel" right now - Chinese Yamaha Timberwolf). I'm going to pull the tank off it and clean it, clean & possibly rebuild carb, put in new plug, and a battery, then see what happens. If nothing, will keep going until it runs. Feel free to respond if you want to, I'm mainly just excited and wanted to tell somebody. 
    • By Flanstone
      I just bought two 1985 TRX250's from my father-in-law. One runs great, the other not so much. The one is having issues with the shifter. The shifter seems to be resting lower than normal. When I press the shifter downward, it just pops back up. Any thougjts as to what the issue might be?
    • By Christopher Williams
      Hello all, 
      i just rebuilt the top end of a 99 Bear Tracker 250 and it can’t get it to hit off of gasoline or starter fluid. Occasionally it will backfire. Right now I’m just trying to get it to fire off without the carburetor like I’ve done a thousand times before with other engines. Usually there is no response, but occasionally I get a backfire through the intake. ISeems like it’s out of time, but I don’t see how that could be possible. 
      Here’s what I know:
      1. compression 120psi
      2. all timing marks are lined up after numerous revolutions. 
      3. Strong spark. 
      4. Valves adjusted correctly. 
      Thanks in advance. 
  • Recently Browsing   0 members

    No registered users viewing this page.


×
×
  • Create New...