Yea, that's different to an E primary. Probably someone has matched the backlash numbers, and used an earlier gear to do it. I've got a couple of Lc primary gears that I thought I could use but they are a thinner gear than the 400
I've been going through the parts fiche recently, and ordering parts from Fowlers, Norbo and Mutts nuts. As said, lots of parts still available, thankfully ! I picked up my vapour blasted cases from Jamie today;
Really pleased with them. He loves bikes - if he had his way he would only do bike parts, and his unit is full of bike bits that he is doing for people. I gave him the 400 heads last week - the barrels needing checking over before I give them to Jamie, but the heads were ready for blasting and painting. We went with Cerakote Graphite black, and Jamie polished up the fin edges for me;
Not a great picture, but they look awesome. The barrels will be done the same when the time comes. So with the cases back and ready to start rebuilding the engine, I opened my first bag of parts originally stripped off the engine - 2 spacer tubes that fit between the damper blocks at the front mounting points - the bolts that mount the engine to the frame pass through these spacers. Due to their position at the front of the engine they get a lot of crud thrown their way, so subsequently look worst for wear;
Hi I will list part numbers as I use new parts, and cross reference against Lc part numbers where possible. I think that's helpful for guys who don't have a fiche. I wont bother putting the prices of parts up as they seem to change very regularly, from Yamaha at least, and the Fowlers website has a really useful parts finder with availability and price list, and that's easily accessible. There is a lot of parts that cross over from 250 to 400, and from earlier a/c to later a/c, and then some a/c to Lc and even Pv ! I really enjoy building engines, and love doing all the little bits and bobs like those spacer tubes. And it's nice to do something a little bit different as it's been a long time since I did a 400 engine. This was the last one I did in 2009;
I used standard carbs in the end, and sold the TM28's on. I've ordered new carbs for this engine as I don't have any, and it made sense to buy new Pwk's rather than spend nearly the same money on 40 year old 2r9's ! The only part I think I might struggle with is the correct backlash primary drive, although I have some time before that is needed. And Jamie is great When I picked up my cases and heads from him on Friday, I dropped off a pair of Rgv forks that I asked him to blast - to remove the anodised finish as it was looking tired. Last time I did a pair of forks, I polished it off, and it took forever. Jamie dry blasted, then vapour blasted them Friday afternoon - I saw this pic on his Facebook page;
He also does welding, so when he blasts parts he inspects them for damage, and if he finds cracks or broken welds, he rewelds them before coating He does a lot of Motorcross bikes - he used to race them - so the welder gets used fairly frequently !
I've collected enough parts now to start building the gearbox up,but before I do that I fit 8 new engine damper rubbers. The old ones were tired and a bit loose in their housings. Yamaha have discontinued them, but Norbo does a complete set thankfully;
The 4 0 rings in the pic are for the 2 front spacer tubes, and came from Fowlers. As said, the tubes wont be seen when the engine is fitted, but they will be more corrosion resistant as they are quite exposed to spray from the front wheel/road;
Parts are starting to go back in now. First to fit is the sump bolt, with a new sealing ring gasket. I add oil to the gearbox parts as I refit them, and it would leak straight out the bottom of the engine if you don't fit the bolt first !! The selector drum was stripped down and washed in fresh, clean petrol. As you can see, this drum differs a lot from an Lc/Pv drum at the bearing end;
When it's halfway in you can refit the selector star and fit the new circlip, and then it can push all the way through. Gear fork shafts are next. New circlips on the ends, and they push through from the left side. You fit the forks as the shafts slide through;
Hi Tony The aircooled gearshaft seal is the same part number as an Lc, so internal and external dimensions must be the same. I did consider getting a bush, and then getting the case machined to fit, but the hole doesn't seem too bad to start with. I did think of renewing the gearshaft, but it's NLA from Yamaha. Shambits do a pattern one for £45.00, but I've read they don't fit well, and need modding slightly Where have we heard that before !! The gearshaft is in fairly good nic actually, and although you can see a witness mark where the shaft passes through the seal, it's not really felt with your fingernail. There is always the double lip seal option, or the extended housing option seen on here before. Although the aircooled shaft has a circlip on the sprocket side to hold it in place, I do wonder if it's overkill as the inside of the clutch casing has a post, the same as an Lc/pv that stops the shaft moving sideways.
A bit of tape on the splines of the gearshaft protects the seal as it slides into place, aided with rubber grease. The blanking plugs push into place with some firm pressure, and some rubber grease on the O ring helps seat the neutral switch
The detent plunger can screw into the underside of the casing now. I fitted a new spring - my thinking being it's been compressed to some extent for the best part of 40 years !! When I laid the new one against the old they looked the same, but the new one definitely felt firmer. The gasket is the same part number as the sump bolt gasket;
Once that is tightened up, that's the selector and gear change mechanism completed. As said before, Yamaha greatly simplified these components on the Lc and Pv engines, saving some weight in the process too. Next up is the gear clusters. When I stripped the engine I found some corrosion/surface rust on a couple of the gear wheels. I started searching ebay for replacement gear wheels, intending to strip and rebuild the clusters, but then found someone selling a complete, low miles 250e gearbox that was removed and stored in the early 80's apparently !;
250E and 400e gearboxes are identical, so I bought those, and they do appear really good. Before I found them for sale, I had bought some parts to rebuild the original gears - 4 gearbox bearings and a first gear bearing. I decided to use my new bearings anyway on the new gear set. There is a first gear bearing lurking in this gearbox that the Lc range don't have. It's easily changed by removing the "e" clip and sliding off the gear wheel;
I'm off to Pjme in the morning to drop the crank and barrels into Paul. The crank will be rebuilt, and I will ask Paul to check over the barrels to see if they need a rebore. They will definitely need pistons. Whilst the crank is away I will rebuild the clutch basket and revive a few other parts.
Dropped the crank and barrels off to Paul today, and had a long chat with him. The crank has been apart before, and he commented that the rods were a narrow profile running up to the small end bearings. The barrels are indeed on 1.00 over, but I think either a hone or rebore will get them "right". I'm really interested in the crank building process - I've had loads done over the years but never seen the actual process, So Paul will kindly take some pics as he does the strip and rebuild, and I will post them here, maybe as a separate thread, so we can all see what's involved. He is a busy guy, so I really appreciate him taking the time to do that. In the meantime, I will clean up some other parts from the engine strip, ready for the next stage.
Last Edit: Feb 20, 2020 21:49:57 GMT 1 by dusty350
Back on this now Paul at Pjme did a brilliant job of rebuilding the crank, so that's ready to go in now. I did buy new Yamaha crank seals from Fowlers a few months back when I was ordering a load of parts;
Took some time out this afternoon from the Covid lockdown DIY extravaganza that I have found myself caught up in over the last 5 weeks , to get the cases back together. One job left to do before the cases could be closed up was to fit the tacho drive shaft in the top case. Here are the component parts, along with 2 new circlips;
I was now ready to fit the top case on. I always do a dry run - fit the top case without sealant between the 2 halves, and nip up the nuts underneath and the bolts on top. This is to check for smooth operation of the crank and gear clusters, and to make sure there are no tight spots. Once happy, the top case comes off again, and I apply 3bond to the bottom case mating surface, and leave it a couple of minutes to go tacky. I use this time to check (again) that the crank bearing pips are in their little grooves, and one last check over everything else. I already made sure the 2 dowels were in place - one at the front of the engine was in the bottom case, the rear one was in the top case;
Once the top case is fitted, the 8 stainless nylocs and new washers are fitted underneath, along with 3 M6 bolts that are present on these aircooled engines, and then 8 bolts and washers on the top case. As with the Lc range, the cases are marked with numbers to show the sequence of tightening. Tighten it all up, and the bottom end is in one piece again;
Hi John It's a really small garage - half garage and half office which I converted years ago. Space is tight so I have to keep things tidy. I would love to convert it back to one big garage again, but the office gets used all the time, so I will have to make do !
I fitted the sprocket back on - loosely for now. The spacer behind the sprocket had a groove that I could feel with my fingernail, so I swapped it for an Lc spacer - they are exactly the same part - and this is in better nic. It looks marked but you cant feel it. Lc on the left;
Before I fitted the generator, I lapped the rotor onto the crank. It's easier to do at this point as you can clean the grinding paste off much more easily without the generator in the way. I used fine paste, and it doesn't take long to get a good finish;
I cleaned this up ages ago, including getting the internal magnets back to bright metal, as they had a layer of surface rust on them. I will need to revisit the rotor in due course. Next I spin the engine around, and fit the first clutch washer. This engine differs from the Lc/Pv in that the 2 washers are different sizes, whereas the watercooled bikes have 2 identical washers;
Hi mate I had a load of cap head/allen bolts in stainless in the correct sizes, and I have been gradually using them on engine builds instead of the normal cross head fasteners. They don't need to be stainless as they live in oil. Stainless is a softer metal for fasteners, but I've never had an issue if I've had to remove them. As with any fastener, a good fitting tool is essential to stop chewed up heads. And I always use a low strength Loctite - any thing stronger and you could struggle if/when a strip down is needed again I get all my fasteners, usually in bulk, from that place in Walton I told you about, but I also get stuff to keep in stock from Kempton autojumble - not that the jumble will be happening any time soon