# 2005 BF 750 Engine Noise (rattle??)



## cadams (Jul 27, 2010)

I have what I will call a rattle coming from the left side of the engine. I thought it was a loose heat sheild but they are tight. It not a knock as some describe. It happens only during a certain RPM range, and not all the time. After thinking about it it may sound like loose chains in the engine. I pulled the tensioner spring out and reset the setting. I went for a short drive down the street and it seems to have gone away. Anyone had this problem? Do the springs in the tensioners fatigue?


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## Roboquad (Sep 8, 2009)

check the 4small cam bolts for stripping out they keep the cap on over the cam & chain. if the tensioner was out of wack you could have been experiencing the cam jumping up and down on the opposite end of the sprocket. Your cam sits in the aluminum sleeve with no bearings these things wear and if the chain was too tight it will lift that end up causing a rattle or clacking. good luck.


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## cadams (Jul 27, 2010)

I pulled the tensioner and reset it. The noise seemed to go away after a short ride, but it is back. You mentioned pulling the cover? Can you describe where the cover is? Can these tensioners fatigue over time? I ordered one hoping that it is.


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## cadams (Jul 27, 2010)

Sorry, I meant the cam bolts not the cover...


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## rmax (Nov 21, 2009)

how many miles/hrs do you have on this machine? might be time to replace chains, when you took the teninsor bolts out how far did the teninsor move out? you also have 2 chains on the left side that run 1-water pump/oil pump, 2- jack shaft for cam chains both have teninsors. changed mine at 800+mi, 240+hrs, they were so streched i took them off with teninsors still installed


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## swampthing (May 2, 2010)

rmax said:


> how many miles/hrs do you have on this machine? might be time to replace chains, when you took the teninsor bolts out how far did the teninsor move out? you also have 2 chains on the left side that run 1-water pump/oil pump, 2- jack shaft for cam chains both have teninsors. changed mine at 800+mi, 240+hrs, they were so streched i took them off with teninsors still installed


 mine too! they were about a good quarter inch longer than the new ones, I was blown away when i saw the difference. Tensioners were worn and guides as well........Definately has potential to get expensive.


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## cadams (Jul 27, 2010)

I have about 1300 miles and 240 hrs. Mostly easy miles driving around on the deer lease. It's not set up like most of what I see on this forum. When I pulled the tensioner, it still had several clicks left when I extended it. I'm no expert, but it seems like there should be enough left on the tensioner to keep the chains tight.


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## rmax (Nov 21, 2009)

cadams said:


> I have about 1300 miles and 240 hrs. Mostly easy miles driving around on the deer lease. It's not set up like most of what I see on this forum. When I pulled the tensioner, it still had several clicks left when I extended it. I'm no expert, but it seems like there should be enough left on the tensioner to keep the chains tight.


you used the words (when i extended it) did you pullthe last few clicks out,or did the spring push it out? rember you still have 2 chains under the alt cover, 1 drives the jackshaft for the cam chains, if it jumps you will warp all the values, 2 drives oil pump an water pump, if it jumps you could be looking at a total melt down, either condition will cost you big bucks.
with milage mention above, personaly i would replace all the chains, i have seen them go with alot less time on them. good luck an if you need help this forum is always here to help
forgot i have read a post on here about the tensinor kind of sticking and haveing to loosen them off an reset, but if that is the case i would still replace all the chains, an find some small washers to go in the tensionr houseing before the spring to add a little more tension that could have been lost due to age, you can do this for the cam chains buy takeing the caps offdrop a couple of washers in an put caps on, an the chain that runs the oil/water pumps can be done in the same manner, its located on the bottom of alt coverif i rember right its a 17mm try pull it out an drop a washer or 2 in. but the teninsor for the jackshaft you will need to pull alt cover to get to it


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## nathangunn28 (Jul 27, 2010)

*same boat*

hey fellas, sorry to jump on board but i have been hearing this same type of noise from mine for a few weeks now and was just thinking it was a loose heat shield and was gonna get to it when i put the new exhaust on this week and rejet. Any one have pictures of the chains you are speaking of also anyone have the procedure or special tools needed to change these? thanks


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## cadams (Jul 27, 2010)

I removed the spring section of the tensioner, and then removed the spring housing. I pulled the ratcheting part of the housing out to its max length. I then re-installed the housing, and then installed the spring. How difficult is it to replace the chains if I do it myself?


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## rmax (Nov 21, 2009)

1-the only special tool you will need is the puller for altenator rotor, you can use a automotive harmonic balancer pullerbuy removing 2 of the allen head bolts in the rotor, an getting 2 longer bolts to use with puller they need to be around 3in long
2-it is not a real hard job, but depends on mechanical ability, an ability to follow instructions(timming cams can be confuseing)
3-an most important get a good manual if you havent already got one, you can become a subcribing member (around 15.00)an download manual off the forum, if i rember right i paid around 75.00 at the dealer for manual before i found this forum


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## cadams (Jul 27, 2010)

Well, I figured this one out. I found a used tensioner for $20 and figured I would try that before spending the money on a brand new one. I put it on and rode this weekend and the rattle is gone. It seems that the original tensioner had mor eplay in it than I realized once I compared it to the "new" one. Sure am glad there is no need to replace the chains! Thanks all for the suggestions.


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## nathangunn28 (Jul 27, 2010)

does anyone have a diagramn or picture of the area that the tensioner is located and how to access to change would like to try and see if this is what my noise is, also what does a new tensioner cost cadams? thanks


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## cadams (Jul 27, 2010)

It's on the left side of the engine. It mounts almost upside down. There is a larger bolt in the middle you need to remove first, and then two smaller bolts will need to be removed. I have found them new for $70-75, but you may be abe to find one on ebay.


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## BleednGreen68 (Apr 19, 2010)

I've replaced a number of chains on brutes due to lack of oil maintenance. If you dont change yer oil regularly you WILL be replacing chains alot. I change my oil every 20hrs and still runnin on all original chains with no noise and 320hrs of hard use.


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## Roboquad (Sep 8, 2009)

I have extra tensioners. Not looking to sell but will part with for MIMB. Members. Let Me know.... Rob


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## nathangunn28 (Jul 27, 2010)

anybody have the manual diagramn showing the tensioner and how to get at it? or a page in the manual which shows where it is and how to get at it? Still no luck and the noise is still there after checking all possible rattle popints on her. So i am thinking i am definatly having hte same issue as cadams. Thanks


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## rmax (Nov 21, 2009)

the front cylinder chain teninsor located or right lower portion of cylinder, the rear is located on left side just below cylinder base on left case half. do not know how to post pictures or i would, do yourself a favor an drop the 15.00 an become a s/m an down load a manual for your machine. this is a sweet deal as factory manual range from 70-100.00. good luck hope you get it fiqured out


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