R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric Off-Road

Reply
 
Thread Tools Search this Thread
Old 03-07-2009, 02:58 AM   #1
Tech Fanatic
 
LadiesFirst's Avatar
 
Join Date: Nov 2005
Location: Portland, OR
Posts: 840
Default I Need A Losi Truck Expert

Hi All,
Yes, I am female, but have always been somewhat of a "tomboy". I have built several Losi trucks, as well as a few Associated trucks, so I am no stranger to their design and the way they are put together. I have something that has been stumping me about my MF2 truck. Before I had the MF2, I had the straight XXXT. My husband also had a XXXT. I never had a problem with them. Later after I put together my MF2, I got a deal on a tricked out MF1 that I just couldn't pass up, and actually, started liking the MF1 better, mostly due to the Gen 1 transmission gear ratio and extra touches that were added. At the time there were also a lot of drivers converting the rear-ends of their MF2s back to MF1 with the Gen 1 transmission. Now my problem. I have periodically replaced front bumpers as they would wear out, mostly right where the e-clip and hinge pin would hit if you smacked something. Never had any trouble with the way they fit or snugged up.

However, with this MF2 I have had a lot of trouble with getting it to accept a front bumper. When I try to snug up the bumper (not overtighten, but just snug), the screws go so deep into the bumper that they tweak the bumper and make the holes so big that after a few races, the bumper pops off. I have checked the screw length and type against the directions, I have replaced the bulkhead, I have replaced the Pivot Block, all to no avail. I have never seen a Losi do this before and none of my others have ever done it. I have used brand new bumpers, used bumpers and even tried putting the bumper on with just the two very front screws going through the bumper itself (like Associated - suggested by a hobby shop owner and T4 driver). I have even used shorter screws, and one of the racers who is usually knowledgeable about Losis said just don't snug the screws down. Well, that didn't work for long as I had a lot of side to side play in the front arms because the bulkhead wasn't tight enough. So I have gone back to not running a bumper on it at all. I just can't figure this truck out. No one else I talk to that race Losis has that problem or has even seen it before. The bumpers on all the others all fit flush the way they should. Mine tends to distort and bend as I tighten the screws - again NOT overtightening. I have thought about just buying a new CR, but in May we are losing the only indoor dirt electric track that we have in our area, so it would be a waste of money to buy a new truck. Nothing too promising for outdoor dirt either, except some miles away. It looks like most of the drivers are switching to onroad carpet. But not me.

Oh, and one thing I forgot to mention - the MF1 has the aluminum pivot block and seems to be fine, but the other XXXTs all had the plastic pivot blocks and they didn't bind or distort at all.

Does anyone have any clue as to what could be wrong here? I've used up all my ideas and no one else knows either. I'd sure appeciate some help here. But PLEASE serious answers only, and not just "switch to Associated" or some other brand. Just for the record, the T4s and some of the B44s are constantly breaking out here. Nice vehicles but more fragile than I would like. The CRs used to have a lot of problems also, but it seems like that has been addressed in the newer kits. Thanks for any constructive help!

Diane
__________________
Diane - Losilady
GO ON THE TONE!
LadiesFirst is offline   Reply With Quote
Old 03-07-2009, 03:57 AM   #2
Tech Regular
 
Join Date: Feb 2009
Posts: 398
Trader Rating: 7 (100%+)
Default

I remember having this problem back when I ran years ago, but I am not sure how I fixed it

So you are saying that you NOW have an alluminum block? I notice that you said you have changed the pivot block, did you change a plasitch to aluminum or vica versa. If you have only had the alum ones, I would try a plastic one just to see if it is the block.

Josh
JoshM20 is offline   Reply With Quote
Old 03-07-2009, 05:09 AM   #3
Tech Addict
 
Join Date: Apr 2008
Posts: 545
Trader Rating: 15 (100%+)
Default front bumper

place a thin washer (almost a shim) between the bumper and the block.
uncle everett is offline   Reply With Quote
Old 03-07-2009, 12:29 PM   #4
Tech Master
 
JeromeK99's Avatar
 
Join Date: Jun 2008
Location: Loma Linda, CA - USA
Posts: 1,137
Trader Rating: 3 (100%+)
Default

If you buy the bumper by itself, its an RTR part. Says so on the bumper. It is softer. Buy the front bumper/rear motor guard combo. It is a little stronger.

You can glue a regular gold #4 washer on the backside of the bumper as well so you can snug down the screws if you want or because you are using a aluminum pivot, try a small amount of blue thread lock on the screw so you dont have to tighten it so much (letting it dry before you install it or it will be very hard to get out).

Personally I don't like using an aluminum pivot because of the wear. The plastic ones rearly break for me. I have a ton of them from my bk1/mf1 days because the rears broke more and they came together. Not a problem for the bk2/mf2 with the metal rear brace.

Good luck!

Jerome
JeromeK99 is offline   Reply With Quote
Old 03-07-2009, 12:31 PM   #5
Tech Fanatic
 
LadiesFirst's Avatar
 
Join Date: Nov 2005
Location: Portland, OR
Posts: 840
Default

Josh and Uncle Everett,
Thank you for your responses. Josh, I have the aluminum pivot block on my MF1, which is nice and flat, and I have the plastic pivot block on my MF2, the one that tweaks. I have never had an aluminum block on my MF2 and only had the aluminum one on my MF1 (the MF1 was used and tricked out and came with it). I have replaced that plastic pivot block on my MF2 and it does the same thing. My husband's XXT has the plastic pivot block and it is nice and flat also. Never seen a truck do this before. Wish you could remember what you did to fix it. I may try another new pivot block, but it would probably have the same results. I could buy an aluminum block for the MF2 maybe, but I don't know if they are still available.

Uncle Everett:
Before I wrote the thread here, I did try to put washers between the bumper and the block but couldn't do it by myself. I need another set of hands to do it in order to hold all four washers and bolts on while installing it. But that thought did cross my mind. Maybe I can find some help later today.

Any other suggestions anybody? My MF2 is actually a nice truck with the exception of this problem. But I have to admit, I'd love to have a new CR. But with our track going away, it's pointless. Thank you for your responses on this.

Diane
__________________
Diane - Losilady
GO ON THE TONE!
LadiesFirst is offline   Reply With Quote
Old 03-07-2009, 12:43 PM   #6
Tech Fanatic
 
LadiesFirst's Avatar
 
Join Date: Nov 2005
Location: Portland, OR
Posts: 840
Default

Jerome,
I have purchased both the single bumper, which I have always noticed was RTR, and I have also purchased the one with the rear guard and mounts, both had the same results. My post must have been confusing and I hope I cleared it up with my second post. I don't have any problem with the way the bumper mounts to the aluminum pivot block on my MF1, just the way it mounts to the PLASTIC pivot block on my MF2. Actually, the guy that had my MF1 previously was a serious racer and he did some small things to make it better, one of which is drilling out a small hole in the pivot block where the hinge pins go through and then inserting pinion screws. That eliminates unwanted movement and I actually haven't experienced wear problems with that. I am seriously considering rebuilding my MF1 as I have used it a lot and it has some slop in other areas now. When I bought the truck, it came with a lot of extra parts, so I could probably do this fairly easily, but I do like my MF2 now also (didn't always like it) and would sure like to get this problem worked out. Don't know if calling Losi would do any good or not. I have done that before on some other things and they usually don't have a clue. I do know that Losi is now owned by Horizon and that could be the reason. Not to diss Horizon, they have decent customer service, but I don't feel like they know much about the Losi trucks the way the people did when Losi actually owned it. Anyway, thanks for the reply. I am open to any other suggestions.

Diane
__________________
Diane - Losilady
GO ON THE TONE!
LadiesFirst is offline   Reply With Quote
Old 03-07-2009, 01:01 PM   #7
Tech Regular
 
Join Date: Feb 2009
Posts: 398
Trader Rating: 7 (100%+)
Default

Hmm, comsidering you say the the pivot clock is the main problem with the tweaking and it shows on the bumper I would check a couple things. 1 the hinge pins in the off chance they're bent. You could also check the bulkhead to make sure the block is fitting in it right. Last you check the (*****) I forget the name of it, the part that bolts on the chassis and connects the bulkhead and shocktower. The part where the sero sits. Check that it in cases of some freakish chance it is tweaked, I'm not sure how that could effect the block unless it is somehow slightly tweaking the tower and causing to bulkhead to be a little off. Pretty out there but I would check it just to be safe.

Josh

Oh you could also take the block out and thread the screws and look at them to make sure they are straight. Maybe somehow the holes were threaded wrong (plastic one)
JoshM20 is offline   Reply With Quote
Old 03-07-2009, 03:50 PM   #8
Tech Fanatic
 
LadiesFirst's Avatar
 
Join Date: Nov 2005
Location: Portland, OR
Posts: 840
Default

Thanks, Josh, all good suggestions. After I posted my last note and before seeing your note, I went down to the hobby shop closest to us and went through his Losi parts box. I had been wondering about the very thing you talk about - the bulk head - and incidentally, the bulkhead top plate is what the shock tower bolts to - but I hadn't thought of the holes being drilled crooked or maybe my hinge pins being bent. I did check the hinge pins last night and they rolled straight, but I have noticed a buckling in the pivot block from day one when you tighten it down. I thought that might be normal because on the used MF1 I had purchased, there was a used pivot block in the parts pile that looked the same. Also, my husband's XXT's pivot block looks flattened a little, but his bumper is straight. But my other truck, the MF1, also came with a new plastic pivot block in the parts pile, which is the one I used in this problem MF2 truck. But I noticed that it does buckle when you snug it down. I was thinking then that it might be normal, but maybe that is why the former owner put the aluminum block on my other truck. So I am thinking that the buckle in the pivot block is probably what is affecting the soft bumper. It is trying to conform to the shape of the pivot block. (Again, I never overtighten, and the pivot starts squashing and buckling before it is even all the way tightened. (You might have something there on the holes being drilled slightly off). The hobby store owner said he wondered if there might have been a bad batch of pivot blocks for awhile that might not have been machined correctly - could be. But it is driving me crazy not being able to get this right.

So I went ahead and took a gamble and bought a new GRAPHITE bulkhead and a new pivot block for the front. I will see what happens. I hope this will do it. I don't know if Losi did in fact have a bad run of parts - just a guess, and whose to say this new one might be one of them also if that is the case. These can be older parts from this hobby shop.

But I hate changing the bulkheads - the steering bearings can be a bear to get out of that bottom plate, so I may try to put the pivot on my other truck first to see if it does the same thing. If the pivot works on the other truck, then I will know it could be the bulkhead and then I would go ahead and change the bulkhead on the MF2 - again. I did learn to fill the steering bearing holes with bearing oil before inserting them now so they don't get stuck so tight. The main problem with them being so tight is that I would lend up breaking a bearing while trying to remove it. Those puppies are $20 for a set and at least out here, you can't buy them individually

Anyway, sorry to be so longwinded and I hope I haven't confused you further going back and forth with references to both trucks. I'll let you know what my outcome is. I am also going to do some changing on the wiring on my brushless - switching to bullets as I am going to be changing them around a lot - motor to motor and truck to truck - and I am getting tired of constantly soldering and unsoldering. Thanks for all the great tips guys, I really do appreciate it a lot!

Diane
__________________
Diane - Losilady
GO ON THE TONE!
LadiesFirst is offline   Reply With Quote
Old 03-09-2009, 12:34 PM   #9
Tech Fanatic
 
LadiesFirst's Avatar
 
Join Date: Nov 2005
Location: Portland, OR
Posts: 840
Default End Result

Hi all,
Just thought I'd post a quick note on my break at work. I found an aluminum front pivot block, so decided to go with that. That took care of the problem. Wish I'd done that before buying the new graphite bulkhead. I spent a lot of unnecessary money, but the aluminum pivot block did it. The plastic ones just seem to smash and buckle way before they are completely snugged down. Don't know if the plastic is softer now or what. Never had it happen before. I also started rebuilding my MF1 and have some more to do. I did take it out a little yesterday and it has more steering than my MF2 (always has), but it still needs a lot of work. At least my MF2 is up and ready to run again. Thanks again for all your good suggestions and help. Good racing to you!

Diane
__________________
Diane - Losilady
GO ON THE TONE!
LadiesFirst is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
BANZAI Motors Eddie Garrison Team and Company Discussions 11666 09-09-2015 01:43 PM
The Nitro Pit Dbackmasta Arizona-New Mexico Racing 18732 09-13-2012 09:27 AM
Losi BK2/MF2 thread DerekL Electric Off-Road 2850 07-18-2010 11:59 PM
Change the Hobby for the Better - TODAY - FreqETag Electric On-Road 225 11-10-2009 08:54 PM
19T "Sportsman" 4wd Casper Electric Off-Road 83 06-24-2008 08:41 PM
Your Opinions Please! Re: Pit Stops, 8th Scale Buggy, Truggy, Nitro, Electric mfanke19 Wisconsin & Illinois Racing 139 03-28-2008 08:43 PM
Complete Sellout, No Trades lucky579 R/C Items: For Sale/Trade 6 10-03-2003 09:37 AM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 06:07 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net