Hi all, 

I'm new to the forums and to trials,got a problem with my Montesa 315 r dear wheel alinement, after fitting new bearings and recurring wheel the tyre rubs on a bolt head which holds the chain guard in place, (snail cams are equal) 

Could it be; 

1 wrong bolt fitted, maybe should be a flatter head ??

2 swinging arm twisted!! 

Any ideas?? 

 

Thanks Paul

Watching predictive text.  Rear wheel and refitting !!

Wheel bearings fully home? left & right spacers on the correct sides?

Hi yes and yes !! Thanks

Having the snail cams equal does not always mean that the wheel is in correct alignment. Sight along the chain and see if that looks straight.  It's sometimes necessary to compromise on alignment with a trials bike due to the effects of poor build quality and/or bending of components over the years.

 

 

Ok Thanks I'll give that a go ,cheers

I have had this problem on many different makes of bike and there are 2x ways that I have used to resolve the problem outside of wheel alignment or wheel truing and one is to use a 'Low head cap screw' or to grind or file the top of the head that is already fitted until it is thinner and so giving more clearance....Harold Verderchi.

Edited December 17, 20187 yr by oni nou

use a long straight edge to establish whether the rear wheel is indeed in line with the front, as 2stroke4stroke says above: the snail cams may not need to be in the same positions to achieve this.

Cheers guys not had a chance to do anymore today but will have a look in the more by !

Make sure the snail cam stop bolts that are in the s/arm are in the same position.

Yeah checked that! Thanks

I’m sure there is a diagram in the 4rt manuL that shows wheel off set - 315 is the same - maybe worth a check

The  chain guard bolts I think have a little collar to stop the bolt digging into the plastic - make sure all is flush.

agsin check 4rt manual and parts list to see if the bolt you have looks correct 

The normally issue  is the wheel rubbing the stand spring so strange to be touching the other side 

 

Slacken rear wheel spindle nut, now try to see if you can generate any rock in the spindle where it goes through the swing arm lug. If there is this could causing your problem. The spindle should be a snug fit, if not you may need to check if the lugs are worn or ovalised. A thin shim might be a quick fix but not the permanent one. 

Chain guard mountings not bent, chain guard right side of securing bracket. 

Did you have this issue before replacing bearings, if not then you may need to spring the swing arm outwards very slightly, by 2-3 mm so only a tiny amount. Refit the wheel and leave the spindle slack, don’t tighten the spindle nut. Does the tyre clear the bolt head, if yes then you need to look at the spacers....you are looking for signs of size difference... are each spacer identical. 

Many trials bikes have contact issues with the tyre rubbing against something from exhaust to chain guard and other brackets etc, not always easily cured. Everyone has suggested possible fixes for your problem, you must appreciate it may be something simple that you have overlooked, were the bearings checked against the old ones....this could be an area of fault.

As already mentioned by 2stroke4stroke its more important in aligment terms to have the chain aligned with the gearbox sprocket, and that may be your answer.?

Edited December 18, 20187 yr by section swept

Hi guys just got back to having a look at prob!! Have got left hand snail can on its very first mark and right three steps on and all seems to be straight !! So I'm guessing something bent somewhere ! Thanks for your comments!! Gonna start another thread so any help again would be very appreciated!!