Just wondering is anyone has tried to tighten the big driven gear on the back of the 2KR, 3LN clutch basket ? Mine is fairly noisy so i'd like to try and quieten it I have repaired clutch basket's on pit bike's before, that required me to drill out the rivet's that hold them together and replace the rubber's inside which perish pretty quick with the more powerful engine's. (The rubber's i used to replace the perished one's are from a Honda horizontal engine so pretty easy to find) Then i had to drill and tap the alloy basket to use countersunk high tensile bolt's to reassemble it They aren't meant to be serviceable but i found out you can rebuild them. Anyway my FZR250 clutch basket gear is a bit loose in relation to the basket, there is almost 1mm in and out movement of the gear when you hold the alloy basket I'm guessing it's a pretty common problem ? Anyway i have tightened the gear to basket by using a 13mm impact socket and hammer and tapping the steel retainer plate in toward's the rubber, the basket was sitting on my concrete floor. There is very little play now and i can no longer hear the slight knocking noise it was making The cushion rubber's in between the gear and basket must be slightly offset, as i found out after tapping the first one down I'll try and swap the clutch basket's over tomorrow and report back if it's any quieter If it's not i will drill out the rivet's and see what else i can do I have a question for an FZR400 owner too Is someone able to count the number of teeth on the big gear at the back of their clutch basket for me please and also need to know the od of the gear? And i need the inside diameter where it sit's over the bearing too I'm wondering if they are able to be used as a FZR250 basket substitute ? I know the FZR400 basket's have spring's in the gear instead of rubber's so should be a better option if they'll fit When i was playing around with my clutch last year i found a few other option's for FZR250 clutch plate's too They are the same size as FZR400 Clutch plate's (this gave me the idea that the basket may fit) They are also the same size as a 1981 - 1986 YZ80's I bought a set of 8x organic friction plate's for the FZR400 for $25 and had 2 plate's left over as spare's I also bought a set of Kevlar plate's for the YZ80 for $22 and currently have them in my bike I found a complete kit with Kelvar friction plate's, steel's and spring's for under $100 inc delivery too
I just got some measurement's off my 250 clutch basket the large gear on the back of the basket has 90 teeth, and it's o/d is 180mm The i/d of the centre is 45mm The small gear on the back of the basket has 32 teeth, and an o/d of 60mm The alloy section of the basket at the front is 43mm deep
Your rivets need peening over to ensure the assembly stays up tight... Until physically comparing a 250 basket to a 400 one I would not have thought an interchange was possible. The primary gears are the same no of teeth and same pitch etc - but the 400 is wider. The bearing bore is 50mm for the 400 vs 45mm for the 250. Actual clutch basket is wider too. So yes, it's probably possible. If you've got a big HP 250 with clutch problems it's possible to use a 400 clutch. Extended clutch cover, and pushrod, adapting the center bearing, sorting the oil pump drive gears - all detail work and solvable if you really have to... Lot of work....
Ok thank's, at least i have some measurement's for the FZR400 basket now. The rivet's are pressed in from the steel plate side with a flange on that end, and the other end of them is slightly flared from when they press them together, but i have peened the smaller end as well hoping that it would have tightened it up but it didn't. The little post's on the back of the alloy basket where the rubber's sit over seem to be a touch too tall, this is allowing play between the gear and alloy basket, maybe the rubber's have worn a bit?. I have 3 clutch basket's here and they all have the same play. If this basket i've modified doesn't quieten it down i will pull apart a spare one and see what i can do. I have made up new urethane cushion rubber's for my pit bike and that has solved the rubber's collapsing so might be an option for the FZR basket's too ? If i remember i'll make a before and after video to compare the noise
I swapped the basket's over, i reckon the modified basket is at least 50% quieter now. I had to have the camera closer to show up the little bit of noise it now make's Before video After video
These look interesting https://www.ebay.com.au/itm/Yamaha-...er-Cushion-Drive-Rubber-Set-of-8/282668956677 And I've got a spare clutch basket to disassemble to check. I'd love to be able to hear the engine instead of that bag of spanners rattling transmission
To perhaps assist in your search for alternative clutches - the FZR250 steels part number 131-16324-00 has interesting cross references https://www.partzilla.com/product/yamaha/131-16324-00-00 Used in a YZ80 -> FZR600 and lots of others otherwise FZR250 friction plates 21V-16321-00 comes up with a lot of models used also as well as a new part number 3XP-16321-00, which also replaces 4VO-16321-00 - so there looks to be a legion of potentially compatible outer baskets - FZR400 & FZR600 amongst them Anyway things to ponder
I've gotten around to drilling the rivets on an FZR clutch basket and sure enough the rubbers look identical to the one I posted links to on ebay Drilled out the backs of the rivets as for some reason the drill was wandering even with a centre punch when working on the inside of the clutch basket, it did the same on the back, I think my little drill stand is out of alignment, but anyway I only drilled the heads off and then used a sprung centre punch to drive the rivets out The holes are larger than 4mm and smaller than 4.5mm - checked with a drill bit, my guess is 4.2mm, which I'll verify when I have the imperial bits to hand. EDIT - checked the rivets with verniers and they are 4.15MM - which means 5mm thread tap, I think 0.8mm pitch will be most suitable for re-assembly. The clutch basket I disassembled is one from ebay of unknown km's, so I don't know if it was rattling, the rubbers look healthy enough, not sure if they are overly hard as I have nothing to compare them with. There is movement I might trim the rubbers and use Murdo's hose technique to remove the slack or try a set of rubbers from ebay and see how they work out.
