Honda TRX ATV Forum banner

1 - 18 of 18 Posts

·
Registered
Joined
·
20 Posts
Discussion Starter #1
Hey all, i’ve been off the forum for a while, but after moving three times and finally finishing my new house, the first thing i did was buy another 400ex! This one is a red 05. Bought it blown up for a cheap price. After opening her up, piston was exploded, rod was slightly tweaked so a new bottom end kit (crank/rod, both bearings, seals etc.) was installed. After the cases were put back together, there was a tight spot in the motor. Knocked the crank w a dead blow to try and center it to no avail. Opened it back up and noticed the counter shaft balncer bearings, one was tight and didnt roll well at all. Ok, replace both bearings for good measure, put back together. Same thing...ok open it up for a third time and replace the balancer bc at this point its the only other moving part when trying to turn it by hand. I also spoke to a tech at a local shop and said he has seen them get tweaked and look like they’re still good but when you do the run out they’re off just enough to rub. Now after replacing the balancer...I still have a tight spot. After turning by hand i dont see rub marks on the crank or balncer itself. Any ideas or anecdotal evidence that might lead me to the promise land??? Not my first rodeo but I am at a lose right now! Any help would be GREATLY appreciated! Thanks in advance
 

·
Super Moderator
Joined
·
3,571 Posts
The crank and counter balance are out of time - I've seen cranks with the marks off by one tooth and the counter balance strikes the big end of the rod just sightly.
 

·
Registered
Joined
·
20 Posts
Discussion Starter #3
Thanks for the reply! I know for 100% certainty that they are lined up according to the manufacturer marks on the backside of crank and balancer but that makes sense if they are off a tooth they would rub. I will pull apart and try +/- 1 tooth and see if it solves my issue. Will report back...
 

·
Super Moderator
Joined
·
3,571 Posts
Rotate the crank in the LH case to observe the clearance before removing the crank and counter balance to re-time - then rotate after re-timing to verify clearance - your counter balance may be damaged and permanently out of time or bent
 

·
Registered
Joined
·
20 Posts
Discussion Starter #5
Before i took the crank and balnacerbout of the left side case I slowly spun it to where it got tight and its when the lobes of the balancer are starting to face forward (front of motor). There doesnt seem to be any clearance issues when turned by hand with the big wnd of the rod. I still went ahead and moved the timing one tooth. Turned in the case, clearance all around seems good. Button the bottom end back up and same thing... I have a brand new oem balncer in there now that has never been run so i dont think thats bent/damaged as im having the same problem whether old or new balncer both with new oem bearings.
 

·
Registered
Joined
·
20 Posts
Discussion Starter #7
No, it still gets to a tight spot even with the case bolts out and it split a little. When I took the crank and balancer out, I put just the crank in and it spun beautiful without the balancer. With both the crank and balncer in the left case, it spins “pretty” freely. What i mean by that is it still has a spot of very slight resistance but spins pretty free like it was just the crank. That points me back to the balancer. Except thats new and so are the bearings. When i swapped the balncer bearings, I inspected the case and didnt see any scoring or anything that would indicate that it was warped.
 

·
Super Moderator
Joined
·
3,571 Posts
Have you tried assembling the cases sans the transmission and crankshaft to spin the balancer in it's bearings? It might be an imperfection in the crank or balancer gear causing a binding at a specific point in it's rotation - just a bit of styrofoam at the bottom of a gear valley can produce a binding as the mating tooth presses against the foam - cardboard and other foreign material could cause the same effect - if the balancer spins free and the crank spins free and the binding only appears when the two parts are enmeshed, look very closely at the gears. If the binding is caused by the gears and it is only slight, the resistance to turning may result in a noise when running, but if it's not severe, it will not hurt, but may take a long time to 'wear' out of it.
 

·
Registered
Joined
·
20 Posts
Discussion Starter #9
Last night in pulled everything back apart. Used q-tips in between each tooth of both balncer and crank. Put the cases back together with tranny and just crank- spins great. Then i took the crank out and put the cases back together with the tranny and just the balancer- spins great. So then I took the crank and balncer and put it in the right side case with the tranny. Spins BEAUTIFUL! Next i started to pull the crank through the left side case. After every 1/2- full turn i would stop, loosen the puller and see how everything turned. What i noticed was that everything spins free until the balancer enters the bearings on the left side case. With cases apart about 1/2”- 9/16” everything spins freely and appears that the tapered end is just sitting in the bearing but not by much. If I pull the crank/balancer in any more, it starts to develop a tight spot when the balancer lobes are faicing fwds which gets tighter the more I pull the crank/balancer in. It does this with both the original and new balancer. Again it points to bent balncer but I don’t think thats the case or as if the bearings on either side aren’t quite lining up exact. When I first opened the bottom end it was pretty aparant that I was the first to do so, so its not like they are cases off two different machines. It just gets too tight fully assembled for me to run it and hope for the best. Just FYI it was the original bearing in the left side case that was basically seized and probably the cause/ part of the cause of the motor exploding.
 

·
Super Moderator
Joined
·
3,571 Posts
OK - well, you are putting it together 'backwards' by my methods - I install the crank, balancer and tranny in the left half and put the right half on last like the manual directs to do.

Maybe you should try it the way the manual instructs to do? I've never done it the way you are doing it. I do cheat and paint the teeth on the RH side of the gears of the crank and balancer for visual alignment instead of relying on the lines of the crank and balancer.

4232

4233
 

·
Registered
Joined
·
20 Posts
Discussion Starter #11
Ive always done it that way (manual way). The only reason i did it backwards this time specifically from what I normally do was to see if anything was rubbing the transmission. I also use a red marker to mark the teeth for timing on crank/balancer so i can see it from the front when installing in left case as I normally do.
 

·
Registered
Joined
·
20 Posts
Discussion Starter #12
To be honest, i was a little reluctant to do it “backwards” because i didntblike the idea of both halves being “pulled” together- basically forced when I normally massage them together so everything lines up smooth. Thats also the reason i never went more than a slight turn on the puller past where it gets tight in rotation as not to bug anything else up pulling them the rest of the way together.
 

·
Super Moderator
Joined
·
3,571 Posts
OK - I follow and approve of your logic, however it does not solve the issue.

You might try my 'unapproved' (not by the book) method of installation - I put the bearing on the crankshaft first, heat the engine case to about 250 degrees F freeze the bearing on the crankshaft with CO2 and just put the crank and balancer in by hand with no effort what so ever. Let it set until cool and it's all tight. I built a frame out of 2x4 lumber that set the case on to install the parts and then let set till cool - after it's cool, I install the transmission.
 

·
Registered
Joined
·
20 Posts
Discussion Starter #14
Just a quick update- I tried your unofficial method...kinda. I mentioned earlier new house- wife was not impressed when i walked into her brand new kitchen with an engine case. Needless to say i used a torch and sweated the bearings in as I normally do but this time they were installed on the crank. With just the crank and balancer in i can get that “tight” spot whenninnthenkedt case. Basically when the balancer lobes are forward and gets to the point where gravity should takes over and pull the heavy side of the crank down, it doesnt. It did not do that in the right case with the crank and balncer in. It spun freely. It also acts normal when the balancer lobes are facing the opposite direction and gravity takes over. I contacted wiseco and they 100% stand by their products and said send it to them and if they find something defective they will replace at no cost. It just means more wait time but I will consider it if it turns out crank/crank gear is the issue. Im going to stop by my local honda shop and have them do the run out on the crank and balncer (new and old for comparison) to see if either are getting a “wobble” (for lack of a better term). My thought is when they are in the right side case, there is enough free play to make up for the “wobble” because they are not secured at the end closest to the two gears. Put in the left hand case, that small amount of free play is no longer present, hence the tight spot when it gets to the “wobble”. Could be completely off base but thats where my head is at. Got it down to only three moving parts (all of which are new) and the case at this point. Gotta be close to a solution! Thanks again for the feedback, I will update when solved!
 

·
Super Moderator
Joined
·
3,571 Posts
I am currently working on 2 400EX's - only new parts are crank and balancer bearings - first one is ready for assembly (crank, balancer, and flywheel installed in left half & new alignment dowels) - I will check rotation to see what I determine and let you know what I determine with it and will do the same with the second engine when I have collected all the parts to assemble it.
 

·
Registered
Joined
·
20 Posts
Discussion Starter #16
So I went to the dealership and spoke with the mechanic there. He said everything checked out w/in spec. He said he saw a small piece of a metal shaving that he thinks was binding it up. I cleaned both sprockets with q-tips but hey as long as it fixed right! I get home put it all back together and wouldn’t ya know it....the tight spot is still there!! A member pm’d me and said he experienced something similiar with a new wiseco crank and he said the oem had a “worn in” mark. He said he ran his and has had no issues. Mine now gets tight to the point you cant turn it by hand with the cases bolted together. He sais he could put his finger in the rod and spin his so I don’t think thats the problem. That and i dont see any wear marks on the old crank. Im in the Hudson Valley of NY if anyone is some what local and wants to have a look. I might bring it back to Honda. The head mechanic looked everything over and “diagnosed” it for free (12-pack) as a favor, so i might just put it in w a ticket for repair...I dont know
 

·
Registered
Joined
·
20 Posts
Discussion Starter #17
Update- the gear on the Wiseco crank is off by 6/1000 causing the tight spot. Called Wiseco and they told me im not the first one to make this phone call. Apparently they had a “bad batch” that went out and I just happen to be one of the unlucky ones who got one. So now they want me to send them back the crank to verify and then send me a new one. Im still out the cost of the shop diagnosing a bar new part. Maybe I’ll contact weisco and see if they’ll cover it since it should have been good to go out of the box. Either way I have finally found a solution. Hopefully this will help anyone else who runs into a similar situation. Thanks again for the help @Here 2 help.
 

·
Super Moderator
Joined
·
3,571 Posts
It goes to show you, that you have to be the recipient of a defective part to get resolution - Wiseco stood their ground when I talked to them insisting the crank (or gear) was not off - since I didn't have one I was a hearsay complainer and even though I run a shop, they insisted the part was not the problem.
 
1 - 18 of 18 Posts
Top