Tag Archives: mechanical

RGV Update

“Good news everyone!”  The RGV’s engine officially works.  The reinstallation of the engine took far longer than planned.  That was due to a combination of intentional stalling to get the budget back on track, unplanned extra work due to faults discovered along the way and limited spare time.

When I went to install the engine back in the frame, I discovered a hairline crack in the engine cradle.  Although the engine has rubber mounts reducing the amount of vibration transferred to the frame, common sense dictated that I should not ignore such an obvious weak point.  A quick trip to a local aluminium welder had that problem sorted out.

During this time, I took the opportunity to superficially tidy up the expansion chambers.  (exhaust pipes)  I say “superficially”, as I made no attempt to reduce the carbon build up that is surely deposited on their insides.  Instead, I sanded back the existing layers of paint, removed as much of the surface rust as possible, treated the remaining rust with a “rust converter” and treated the pipes to a fresh paint job with heatproof paint.  Whilst being a “far from perfect” job, it should give the pipes a bit more protection against the elements.

The reinstallation of the engine, exhausts and cooling system went remarkably smoothly, given that I do not have a workshop manual.  I have yet to buy myself a workshop manual for the bike.  This is largely due to the fact that I used to have one and they are not cheap.  I cannot quite bring myself to buying a new one.  These days, “bootleg” PDF versions are available on the internet.  I have found the PDF version of the RGV manual to be an incomplete series of bad quality scanned in images.  Still, using this and referring back to photos I took of the bike at the beginning of the year meant I did not end up with “bits left over”.

Once it was back in one piece, half a litre of fuel and the battery were “borrowed” from the VFR, and I was able to fire the bike back into life quite easily.  The “build” itself still has a fair way to go.  The high-level short list comprises of:

  • Replacing the brake lines and servicing the brake calipers
  • Front fork rebuild or replace (to be decided based on pricing)
  • Replacing various bits and pieces that are worn out. (chain and sprockets / clutch lever and cable / etc)
  • Fitting the new bodywork.  But that’s a story for another time.
  • Straight as an arrow! (Is there a crosswind?)

    Well, the RGV is as straight as it is likely to get.  As you would imagine, the frame specialist has seen more than his fair share of bent bikes.  He showed me an immaculate looking cruiser that had been restored from a crash and re-sold.  The front wheel was about 40mm (over 1.5 inches) off centre.  Apparently it “rode alright” and it was not until the new owner was cleaning it did he spot the issue!  So, if you go to buy a second-hand bike, make sure you check it is straight.  The frame specialist also told me that it was common to find bikes were up to around 10mm out when they are brand new!  I guess that means some leniency may need to be shown when inspecting a second hand bike.

    My bike had bigger issues:  At some point, it had taken “a big whack” to the front end.  When this happens, the front forks (with their extra leverage) tend to stretch and bow the steering-head assembly.  The cups that hold the steering head bearings had also stretched “out of round”.  The bearings that are meant to fit snugly into their cups fell out in his hands!  It also has the effect of “steepening” the steering head angle, making the bike “quicker steering” and less stable.  If you are considering purchasing an insurance write-off to turn into a track bike, it is probably well worth remembering this point.  Obviously, a bike that has not suffered from a catastrophic reduction in wheelbase length should not be suffering from this issue.  People do crash in other manners!

    Not surprisingly, a couple of minor cracks had formed around the steering head and these have been welded-up. The tortured sub-frame has been coaxed back into being straight.  A common issue with the RGVs was a tendency for a crack to form on the engine mounting brackets.  This had occurred on my frame.  He welded it up “the best he could” but it was difficult to access.  This means the next task is to remove the engine and take the bare frame back for him to finish the job.

    I have been doing my fair share of web-research on restoring the Suzuki RGV.  Most of the write-ups I have found on-line are going to be registered for road use.  In addition, it appears no one bothers to write up “restoration on the cheap” projects.  I guess projects without the bling, do not attract the same fanatical owners. (or at least not the same desire to show off the project)  My goal is to build the bike up to be practical and functional.  That is not to say it will not end up with a few fancy parts on it, eventually, just that the purchase of these parts will not take precedence over what will make it an effective track-bike. 

    My secondary goal is to be “slow and steady”.  I have a monthly budget for the bike and a list of tasks I want to achieve.  There has been more than one web-site where the project starts off with a rush of expensive, light-weight components only to appear to halt with the bike little more than a rolling chassis of finely polished parts.  Strangely enough, you never really see a final post where the owner admits defeat / bankruptcy / declining interest.  Maybe all started and published projects will be “finished” one day… 

    The other point to make is “finished” is a relative term.  My declaration is this:  Once the bike is ready for a track day, the restoration project will be deemed “finished”. 

    Giving it to you straight

    The handling of a motorcycle can be greatly affected by its “straightness”.  Even a minor “topple-over” in a car-park can be enough to warp the chassis and thus affect the handling.  Making sure a bike rides properly is a major concern when buying a second-hand bike. 

    When a bike is not straight, one of the problems is that the rear wheel is not directly in-line with the front wheel.  When this happens, it takes more effort to lean the bike one-way, than the other.  Let’s take an example:

    In our case, the rear wheel remains centred, but the front wheel is to the left of centre.  Leaning to the left is easier than leaning right.  When leaning to the right, the bike has to “climb” past the centre of the rear tyre.  It’s almost as though you are “leaning uphill”.  Leaning left, the bike has already passed the highest point of the tyre and hence falls into the turn.

    Just as brick-layers do, it is possible to get a good idea of straightness with a piece of string.  Preferably, with the bike on a paddock stand (or somehow held vertical) the idea is to run the piece of string down the sides of the rear tyre and towards the front of the bike.

    How long is a piece of string?  

    Starting with the middle of the string, wrap it around the rear tyre two or three times.  Carefully loop the end of the string around itself twice, near the edge of the tyre.

    Looped around the tyreLooped around the tyreThe looping of the string.

     If you pull the string too tightly, where you have looped the string will slip back past the edge of the tyre.  The problem with this happening is that it then makes it difficult to get both stringlines at the same height.  It is not the end of the world, but it does make measuring more difficult.

    Pass the lengths of string through to the front of the bike.  If you would like, you can attach the ends to a rod – ensuring that the gap between the two sides is equal to the width of the rear tyre.  Through a true moment of serendipity, I happened to have an old Ventura gear-sack mounting bar with lugs on it that were exactly the right distance apart.

    It was the

    Ensure the front wheel is pointing straight ahead and stretch the string until it is under a slight tension.  If all has gone according to plan, the only place the string will touch the bike again is at the front of the rear tyre.

    Yes, I haven't washed it yet...

    From the front of the bike, you should be able to ensure the string is travelling straight along the path of the rear wheel.  The distance from the string, to the sides of the front wheel should be equal on both sides.


    One side... ...and the other 


    That's not a pretty picture...


    As evident in the photos the RGV is a long way off being straight.  I already knew that.  It is actually so far out of line, you can see it with the naked eye.  What is worse: SOME SPIDER HAS BUILT ITS NEST IN MY FRONT TYRE!

    Nature reserve

    In theory, it would be possible for the chassis to be bent and for the wheels to still be in-line at some point.  If the headstock of the bike were off to one side, but twisted so that the forks were angled back toward the centre line, it may be possible to not notice the misalignment with a string test.  But, for a quick and fairly accurate approximation of straightness, the string test is a good guide.  In the meantime, the RGV is off to the frame-specialist to get itself straightened out.