Im hoping these 125 forks work out ok. Got some research to do first. Finding decent forks for a decent price is getting harder to do now. If this works how i want then they will be a cheaper option for specials builders.
Engine suggestion ....why not use AC cases but with LC top end. Will make the mounts easy. Top end will go strait on and can use an electric pump to handle the cooling. Or spend a pile of money and get a TZ pump...
I want an easyish build - I don't have the desire for anything too involved anymore ! I popped over to Mouse yesterday with the forks to compare them to some 250 Rgv spares that he has -cheers mate It's easier to compare with loose parts rather than trying to offer them up to my forks that are on the bikes. Initial findings look promising. The forks are slightly shorter than Rgv. The top of the forks and yoke are 50mm - same as Rgv250. The bottom yoke is 50mm, whereas Rgv is 52mm. Importantly, the yoke offset appears to be identical, as the 250 yokes sit exactly over the 125's and line up perfectly. The wheel spindle on the 125 is a smaller diameter than the 250. Yoke stem diameter is the same and the right side wheel spacer is the same length. So I think you could use the 125 yokes and forks, drill out the caliper bolt holes on the left side and possibly fit 125 wheel bearings to a 250 wheel, or drill and tap the fork bottoms to accept a 250 wheel spindle. I will have to cross reference wheel bearings between 125/250 to see what the differences are. There are loads of decent looking 50mm clip on bars on ebay so the stepped top yoke will stay - fitting risers would prove difficult compared to the flat yoke of a 250. I had to cut off all the bolt heads to remove the mudguard, but luckily all the bolts came out and threads are good. Mudguard is in good nic and split/crack free and the bottom yoke is alloy so will polish up nicely along with the top yoke. Hopefully a decent alternative to a far more expensive 250 set up.
Hi Alex There are some on ebay with a 1" rise that lifts them a bit ! And they look good. I think the race tank and seat combo needs clip on bars. The top yoke shape doesn't easily lend itself to risers, and as I'll probably never ride it anyway, clip ons and rearsets are the way to go ! It's a very slow build unless I sell something, so I'm still in day dreaming mode for the time being !
Spent a rare half hour in the shed today so I could offer a few parts up. I had to get the cutting wheel out to remove the bottom race from the yoke stem as the race is far too big to fit in the Rd headstock. I will use Lc/Rd taper bearings eventually as they are the same internal dims as the Rg stem which is handy. Lock stops are way out and will need adapting or I may redo the stop on the frame instead. I bought an Rgv250 wheel off Gaz Sellars on here - thanks mate - and offered that up to the forks. I'm hopeful it will all fit. I need an Rgv speedo drive before I can tell for sure. I fitted an Lc arm and shock just to get an idea of how it will look;
Rgv wheel spindle diameter is a couple of mm bigger than the 125, so I can either source 125 bearings to fit the 250 wheel, and sleeve the speedo drive, or go with 250 parts and machine and re tap the fork bottoms. Option 1 is favourite at the mo, but subject to change !!
Got one coming thanks Alex Gaz has a Bandit item that fits. And I do think it will make a nice special. As I have said, it will be a slow burn but it would be nice to get the front end fitting right. If the 125 forks end up working ok with the 250 wheel I will be really pleased as that is a gamble.
Looking at wheel bearings last night. The standard Rgv250 wheel bearing size is OD 40, ID 17 and width is 12MM Rg125 sizes are OD 35, ID 15 and width 11mm. I rang Simply Bearings this morning and they don't do any bearings that have an OD of 40 but an ID of 15 which is what I would need So I may have to get the fork bottoms machined to accept a 17" spindle from a 250 Rgv. Need to make sure everything lines up first though.
Can't find 12mm wide, but 11 are available.....then just fit a 1mm washer/spacer... :-)
I suspect that custom spacers would be needed anyway if you take the 125 spindle route. In which case you’d just make the spaces 1mm wider. Speedo drive may need lip matching back 1mm or not. In some ways this is possibly the easiest route as you’ll have to bear in mind the spindle your going to use. A 125 spindle will be the correct width.
A 250 spindle may be too wide for the yokes. Measure the width at the bottom of the forks and post it up. I’m sure someone will be able to measure a 250 one for you.
In theory enlarging the forks to 17mm is the best method, as the forks will be braved better. As said you may have to find a suitable spindle though.
Hi Eventually I would like an Rgv 250 wheel in a box section arm. I saw Nigel's swingarm - very nice but funds are low at the mo ! Gaz has posted a speedo drive some when that arrives I will offer it all up for width. The easiest thing may be to alter the forks for 17mm. If it's a goer I will pop them down to my engineering guy and see what he says. As said, it was a bit of a gamble so I expected a bit of hassle but we will see how much !!
Had a better look at the forks today. Overall, the 125 forks are an inch shorter than Rgv250 forks The 125 forks are 50mm at the bottom yoke and 50mm at the top yoke. The 250 forks are 52mm at the bottom yoke and 50m at the top. Yoke offset appears to be identical - I need to confirm but the width between the fork legs at the spindle is identical between the 125 and 250, meaning a 250 wheel can be used. 125 spindle is 15mm, 250 is 17mm. 125 is single disc but has the caliper mount for a second disc set up - just need to drill out 2 blanks The 125 stem is slightly shorter than a 250 - might need a stem swap to make sure of a safe set up. It's certainly not plug and play but I'm hoping that a few mods will still keep it cheaper than 250 items.
Bit of an update. This has been on the back burner recently been building a new deck at home and haven't had time for it although I have been mulling over which direction to take. I still like the idea of an aircooled 400 engine. It would save altering frame mounts and would look good against the tank. Downside is that 400e bikes or engines seem very thin on the ground at the mo, and very expensive when they do turn up. It wouldn't be a massive job to get an Lc or Pv engine in there so that is an option. The forks proved a bit of a challenge too. An inch shorter than 250 Rgv so the front end would sit low, especially with a 17"wheel. If I use an Rgv wheel for the twin discs, I will struggle with bearings - the 125 is a 15mm spindle, 250 = 17mm. Yoke would need a stem swap too, so with all this in mind I decided to go with a complete Rgv front end to save myself some hassle. I have the wheel and discs, and was searching ebay for forks. Only 1 set on there and they were there for ages. Pics didn't help as they weren't looking great, but in the end I got an offer accepted and they turned up today;
I think they are actually Gsxr forks but they will work with Rgv parts. Happy with them as they are better than what I thought. Straight and leak free with no pitting. I think I can use the 125 mudguard with them too. A forum member has some yokes and a front spindle so that should complete all the parts I need for the front. I picked up a couple of VJ 21 rear wheels yesterday but they are an 18" wheel and very slightly narrower rear tyre at 140, so will hold out for a 17" item. I also have a VJ21 front end with RWU forks. I will refurb them - just need a top yoke - and they may be useful for a future project. If anyone knows of a 400e anywhere.....
Ideally I would like a complete 400e. That way I can use engine, electrics, switch gear and then sell the rest or keep to put back together at a later date. An aircooled 350 would be good too. A 250 engine looks the part but I would want the 350 or 400 really. The other option is I have a standard "D" frame that Alex kindly gave me. I could use that and go twin shock at the back. I want to speak to Metmachex and see if they do a box section arm for an aircooled frame that would take an Rgv wheel. That might look good. I did enquire with Nitron yesterday about twin shock piggybacks but they will be a grand for a pair !!