markfoggy

The solution is probably using as RCS 19 , but £300 is a very expensive guess and I'm not sure who would buy one later, if it didn't work. RCS16 seems to work with most bikes and there is a 17, which I guess might help in some applications. Bandit forums to the answer phone please. :lol:

There is something going on with the cylinder sizes of these that is a little strange. Even Bimota sleeved down the slave cylinder to get it to work with a Brembo. I can only guess that the lever point on the original is set for really long travel. Modern Radial master cylinders just don't seem to move enough fluid. @370 Steve has fixed his with a different Slave and Master combo, but not proven yet. I'm keen to find an answer to this.... Help.

Ok, that sounds a little soft. Needs to be about 5-10 with just the bikes weight. What we haven't talked about is where you have the preload collars set on that spring. At this point I would back the collars off as much as possible and then move them to tension the spring about 10-12 mm of travel on the threaded part of the shock or if it works by a step change...similar. Then try again with the the static sag, which is as you described; wheel off the ground and then weight of the bike after a couple of bounces...look for that 5/10 mm again. If you can't get there...too soft. Looking at the last photo, seems that you have the collars all the way at the top, try adding some preload and see if you can get it going where you want. I'm thinking that maybe someone before you has wound all the preload out of it in an attempt to be able to take it apart. Maybe then they have realised that it will still need a spring compressor and given up.

To be honest, 14mm of sag when you are on it is not far off ideal. Static sag with just the weight of the bike in the 5-10mm area could be pointing at a good start point for spring rate.

Yes and I'd be thinking it's quite soft...Maybe/probably is a progressive spring and the rate you are seeing is initial. I could be wrong. What are you trying to do?

WP/N seems to have a stem length similar to just about any Modern ish Suzuki, but if you look at the frame design, it's fairly easy to spot that Anything from SRAD on will probably be a bit short in the fork. I ended up going Trumpet, cause they have and up and over frame design and the 595 955i dropped straight in. Many things were stolen from the Hamamatsu UJB design school, I think. If you want something more USD, ZX10's have a long fork and people have made a mix and match easily enough using Suzuki yokes, i think it's just a matter of knowing the fork stanchion diameters and then messing a little with spacers for wheels and brakes. Haven't actually tried myself, but I have a mate that knows if you want a little more info.

Dropping a spindle size is really useful, but only comes into play if you want to make the wheel spacers captive. All of a sudden though, you are into finding an engineering shop and making lots of bits. The spacers could happily have a sleeve section 28 o/d and 25 I/d, that press into the wheel bearings. Also you could get a pair of accurate stainless tubes that press through Hayabusa Adjusters, but are a press fit. If these were longer by the depth of the slot in the arm, Job Jobbed. Smart money then is to have the brake side one also locate the rear caliper hanger to stop it dropping on the floor when you change the wheel.

pm for more details, i will try to remember.

Oh and swing arm pivot size is an issue. WP had a 25mm spindle and an adjuster on the left and later bikes have a 30 and adjuster from the right. causes all sorts of potential fuck ups. (don't quote me on this, I need to check again). I've got a frame that some fuckwit tried to hack out larger, which is useful for other things, but is only a jig nowadays.

I think the trick is to get something quite narrow at the swing arm mount. Dims on the W series are very similar to pre Boiler so most known things will work. But, I'd steer clear of 6" rim solutions on very modern tackle unless you fancy milling the swing arm pivot width down to size. All doable but would take a big machine to do it. I think whole Priller is probably a good choice and you should get it from a breaker all in one piece to make life relatively easy. I, of course, just wanted to make my life difficult so opted for a combination of Benelli and Triumph wheels, but that is very much about trying to make my wheels QD.

Yes, but you should be careful with your spooling and try searching by describing the model type correctly.

Just remember that the most important bit is the crush tube inside the wheel hub. This is what makes those bearings run true.it needs to be an exact length to support the inner part of the race.

https://www.discovolantemoto.co.uk/Replica-Yamaha-260mm Drops straight in.....ish Stop fucking about. They do a rear as well.

I'm guessing that they centre the crush tube that supports the dimension between the inner bearing race. If they take up the slack inside the wheel hub, the spindle will slide through without you having to wriggle the spindle about to centralise the tube.

FYI, the later frames had all that internal casting plated over, 45 degree box web reinforcement of the top rear cross member. Solid, not bolt in tank bracket, plus additional bracing at the headstock. Plus the very last of them had cast plates from the upper rail that picked up on the engine to make it more of a stressed member and to increase lateral stiffness and longitudinal stability. The later style symmetrical over braced arm was derived from the kit bikes, evidence of them being employed on your frame year is the SERT bikes.

Oh, you probably want some M6 screws, possibly M8 . Is it one of these? https://www.partzilla.com/catalog/suzuki/motorcycle/1975/gt250

I have a horrible recollection that these used to do some racing and that you could disappear down a rabbit hole of stupidly expensive parts making it all work. Which sounds like fun....... Is it finished yet?

Sorry, just reread you first post, Early frame.

Great idea, Not sure how late a frame will fit into the regs, but the one that I've based my project around is later and with all the internal bracing. If you want a frame to untack what they put in and add to an early frame I will have one that can be sacrificial shortly. If it's a braced frame with the swing arm adjuster on the rhs, I have a brand new adjuster and lock nut that I can throw into the cause. 675 wheels are a very light option and I have a round spoke one that I can give away, has had all the factory marks ground off, but it's straight and ready for powder. Hub is a little wide on them and I'm not sure if they can be persuaded to give you a true chain run and still run a 180 rear. I'm running a different swing arm in mine, so cannot help with exact fitment issues. Get a triumph drive hub though, which are cheap and common to a lot of models and is worth experimenting if I can get this rim over to you. It has a new rear disc with it, the disc size changed when they went to the forged look spoke design. Talking of swing arms, good luck finding one. The top braced arm that you want is getting rare, but from memory an 1100 is a little longer and might be the way to go for stability on the Island. They seem to have produced a lot more 1100's the model run was much longer. PM me if I can help.

Love that.........Are you aware about how much filthy knowledge is around for racing those things.

All the water boilers essentially have the same cases, the bigger ones get a little longer in the barrels, but it's only by a mm or 2...Also the cases and sumps are almost identical in size to all the Boilers. I am not saying that a £1000 hand made Japanese exhaust will fit without any issues, but something reasonably priced off the interwebs will heat and a little persuasion may be required. Boiler exhaust spacing is not the same as oil boilers, but again. not a huge difference, needs persuasion. Blandit 650/1250 is probably your best bet, cylinderhead is spaced right, but I'm not sure yet how it works around the sump.

I may be wrong, but I doubt it. 750 and 1100 will be the same casting. No way would they do a different one for both. Cams should drop in. fine, but I'd be counting the cam teeth just to make sure that the tooth count isn't different on the 750. Running a marker pen around the journals and spinning the new cams a few times is a good way to check if they're going to be awkward. Caps really do need to go back in their orininal position and orientation. But is possible to knock out any high spots with a little grinding paste. Really experienced engine builders actually scpape/flake in the journals for a perfect fit, but I've never seen it done. Would certainly make me nervous trying, but I believe that it's possible to get them spinning with negligible resistance and leave a fish scale finish on them that retains oil better.

You like a comfy seat. Jan, that looks very cool.

Good luck with finding any period forks where the Compression adjuster screw at the bottom will turn. Brass into Ally is usually goosed permanently by now. The good news is that the screws of this generation did next to fack all anyway. Spring rate, preload and airgap much more important to get right. Damping rates can be modified a little with blended fork oils, but is not very intuitive. I could go into it, but is hyper boring and really doesn't give you much return.