I think the guys at Walton do a lot of mail order to industry, so are probably working, but unlikely to have the trade counter open I would think ? Worth a phone call maybe ? Are you ready to rebuild the bottom end now ?
Yesterday I decided to clean up the reed cages. Originally I was looking to fit Vforce3 reeds - the Kx ones, but they come individually, and buying 2 makes them expensive, so I thought I would use the cages that I got, plus they are fitted with fibres reeds. The standard items were from an earlier 400 as there is no cross over tube on the rubbers;
The primary gears are holding me up at the mo The C/D model 400's had primary gears that were 14mm deep. The later E had a narrower pair of gears at 12mm, same as Lc/Pv. My 400 primary is 14mm, my clutch gear is 12mm ! You shouldn't mix and match the different widths, so I need to either find an E primary gear numbered 61, 62 or 63 to achieve 131 +/- 1, or find a C/D basket numbered 51, 52 or 53 to match the C/D primary gear ! Cant really progress until I sort this out. Should have stuck to Lc's !!
Not touched the engine recently due to the primary mismatch issue. They say every day is a school day, and that has proved to be the case with these gears !! I was sure I had an E clutch with the 12mm wide gear on the back - same width as an Lc and Pv. I thought the 14mm wide primary gear in my engine was from an earlier C/D model. These earlier bikes also had a 14mm gear on the back of the clutch so it made sense to me. Apart from the difference in gear width, the backlash numbers didn't add up. On the 400e is should be 131+/- 1. Mine added up to 142, so I started a hunt for a narrow E primary. A wanted add on the aircooled forum and here turned up nothing. Ebay hasn't had a primary gear of any number in weeks of looking either. I discovered it is possible to fit the Lc primary and clutch so that was option B. One evening I decided to strip my 430e to see what that was running with. I know for a fact that the primaries in that engine have been in there since at least 1986 when I first owned it, so imagine my surprise when I found an E narrow clutch gear, and a wider 14mm primary ! How unlucky was I !! The numbers didn't add up in there either - 141 backlash. So I put it all back together, no better off. Then Des on the forum offered my a 400e bottom end he had picked up for a project that never happened, so I became the owner of another bottom end ! (thanks again Des - top man ) And guess what ? Slim, 12mm E clutch gear and another 14mm primary ! Time to cross reference the fiche's. I had an E fiche but not a C/D so had to find and download one. The primary gear, it turns out, never changed between the C/D and E, so the same 14mm primary was used on all models of the 400, even after the clutch gear was slimmed down to 12mm on the E. Talk about a red herring ! I've been looking for a 12mm Rd400 primary gear that doesn't exist The backlash numbers were still out though, going by Yamaha's spec, but I thought I could achieve them by going with option B, which was to use Lc/pv parts. I have a primary gear of 91, and Yogi kindly came up with a clutch basket of 63, so I could get within 1 of the Lc's 155 backlash. Great. Only mod needed is to machine the face of the Lc primary gear to recess the Belville washer, as per the 400 item. The threads on the end of the aircooled crank aren't as long as the Lc, so a recess is needed if the nut is to tighten up fully. The 400 primary is on the right, the Lc on the left;
So down to my engineering guy to see about a recess. A quick check with a diamond file proved the primary gear is hardened. No great surprise considering what it does, but the down side is it's not easily machined. It would have to be "normalised", then modded, and then hardened again. That is obviously time consuming and costly, so a non starter. Clive, the engineer, understands backlash, and given it's a 40 year old engine with wear, the backlash figures aren't true now anyway. Even if mis matched gears did bind a bit, they will find a point when they mesh without grinding, which makes sense, and as there are no broken teeth or evidence of heat damage, I guess they have been fine as they are. The fact my 430e has run all these years with virtually the same backlash figures, with no ill affects makes me think I will run with what I've got and see how it goes. I know backlash gets talked about a fair bit here so thought I would share what I've found.
Cheers mate. I'm surprised no one on the aircooled forum mentioned it ? Maybe no one knew ? No problem though, and I guess I was overthinking the backlash issue a bit too much. I think I will try the parts that came with the engine, and have the Lc pairing on standby. The fact the 430e engine runs without issue gives me hope that this will be fine. I just like to try and build as close to spec as possible, but it's up to 42 years old now so the "spec" will have changed somewhat I'm sure !!
Hi Chris Yea, keen to get this moving again. The other hold up I've had is the barrels. They've been away for Cerakoting for over 3 weeks now. Jamie is snowed under, and he needs a few parts to do to make it worthwhile. Not a big problem really, but I'm keen to get the top end on now. Fingers crossed they may be done this week. I know the lockdown has given people a reason to rebuild their bikes. Pjme, Mark Cordwell and Jamie are all people who I've dealt with since February, and they have all said the same - run off their feet with work. Jamie does a lot of Motorcross bikes and parts, so all those guys are using this time for prep and rebuild. Hope you are good mate
Then another head scratcher !! When I stripped the engine I found the 2 thrust washers for the clutch were different sizes ? On Lc's and Pv's the 2 washers are exactly the same. The smaller diameter washer is the same as Lc/Pv, and has to go on first as the bigger diameter washer wouldn't fit inside the bearing retainer;
Now the odd thing is both washers share the same part number, but the bracketed numbers after the part number are the washer dimensions, and my washers match both the 2 differing dimensions ?? I noted that the 2 washers in the engine I stripped last week were both Lc type, and identical, so to get the best of 3 I stripped my running 430e engine, to find 2 identical, Lc sized washers ! Weird that Yamaha list 2 obviously different washers, with their dimensions, under the same part number. Final proof of which washer to use between the hub and clutch was provided by the back of the hub. The Lc sized washer sits perfectly on a raised area of the hub - the bigger washer just doesn't look right;
Haha, don't know about tortured dreams John ! I was trying to imagine if the 1mm difference in thickness would affect the clutch operation, but seeing my 430 proved that 2 washers the same would work fine, and to be honest, that's what I expected to find when I first stripped it. It was more the backlash figures I wanted to correct, but without a lot of time and expense, it's just not worth worrying about. I imagine there is loads of old Rd's of all descriptions running around perfectly well with mismatched gears. Again, the fact my 430 has been running all these years with backlash figures out by 10% has allowed me to "get over it " !! It's just me, trying to build it the best I can, but some things are "best compromise". The "red herring" width of the primary threw me for a time though, and I spent ages looking for a 12mm 400 primary that never existed. When you look at the 2 gears together, it seems odd;
I fitted the keyway, coated with 3 bond to help stop any leaks, and torqued up the nut. I fitted the clutch basket to be able to do that so I could lock the gears with a flattened piece of copper pipe;
Kickstart gear was next. I bag everything individually on strip down, and then go through the bags one by one when rebuilding, cleaning/repairing/renewing parts as they are needed for re fitting. The kickstart gear was cleaned in clean petrol. It's always worth cleaning each part before putting back in the engine;
With the kickstart located in the case, lift the hooked spring up in a clockwise direction, and fit over the top post and it's done. I put a kickstart on at this point and push against the main kickstart shaft as I turn the kickstarter, just to make sure it all operates properly, and the gear returns and clears the idler gear. Job done.
Thanks Dusty but you might be right. Cannot see one in the Haynes plus Fowler’s fiche doesn’t show it either. I was also thinking I would have to pull the clutch cover off the PV as well as I don’t remember there being a shim there either. And relax John
Last Edit: May 23, 2020 12:26:53 GMT 1 by oldbritguy
Just checked my Lc engine build thread John. No shim behind the kickstart shaft mate The hub was now fitted and the new tab washer bent over the clutch nut once torqued up. Clutch plates can now be fitted. I found a couple of the rubber damper rings were a bit frayed, and rather than risk them breaking up, and saving myself some time and money, I have decided not to fit them to this engine. The ac's are noisy anyway and this omission wont make much difference ! The new Ebc friction plates were soaked in fresh light gear oil overnight;
Then a friction, then next steel at 4 o clock, 6, 8 and 10. This balances the clutch under centrifugal force and reduces vibration. There are 7 friction plates and 6 steels, so you start and finish with a friction plate. Once all are fitted, you can pop a new ball in;
The hub has an arrow embossed into its face - it's at the 12 o clock position in my pics. The pressure plate also has arrows embossed into its face. Line one of these arrows up with the inner hub arrow when fitting, and you can then fit the springs. I had 6 new springs included with the EBC clutch pack I got from Mutts. They are 15% stronger than stock, but I tend to fit only 3 as the lever gets hard to operate with all 6 fitted. So, 3 new Ebc springs go in loosely;
Then I had a look at the 6 original springs that came out on strip down. 3 are longer, and 3 are more standard looking. The one on the extreme right is a new Ebc spring, with less coils. I decided to use the 3 standard looking springs;