1971 TM 400 resto

[frostype400]

Ok I will pull them out and get my engineer mate to make them the same as the plastic ones but out of Bronze.

Are all tm ts 400 forks the same only reason is my fork tubes are rusted so either need them re chromed or replaced.

[firko]

Love your work young fella, but can you please learn some punctuation....I got whiplash eyeballs trying to read those posts

Trust me, Michaels improved out of site compared to when he first came on here. He's a product of the no punctuation Gen Y texting generation.....they're all the same . I'm with everyone else on the swingarm bushes....phosphor bronze for sure. The TM400 needs all the improvement tricks you can throw at it. I'd be running that TS outside flywheel ignition though Michael. It genuinely improves the bike, takes the crazy out if it.

Are all tm ts 400 forks the same only reason is my fork tubes are rusted so either need them re chromed or replaced 

TM/TS 250 and TM/TS 400 forks are all pretty much the same. 34mm Yamaha forks are better IMHO so if originality isn't a biggie, swap in some Yamaha forks and conical front wheel.

[Davey Crocket]

Make sure you measure the swingarm size Micheal, the plastic ones can be slightly bigger and being soft the swingarm bolt will still tap in....the phosphor bronze ones wont be as forgiving.....you'll need to size it and make sure the bolt still goes through, but a way better set up.

[tc120]

Talking tm400's, there's a tm400 motor in a rl250 frame as a flat tracker project for sale on gumtree at the moment.No need for laxative's there!

[frostype400]

There are a few young people that aren't like me the scary thing is there are kids coming through the education system that can't read and write at all.

I will put more photos as I go the frame will be done soon then I will get it rolling it is a lot easier bike to do than my gt80 less parts and because I want to ride it I wont be over doing it will be neat but fully usable.

Thanks Davey I will make sure to do that because that is the sort of thing I would mess up I will give all the parts to my engineer mate to work with.

[Simo63]

Talking tm400's, there's a tm400 motor in a rl250 frame as a flat tracker project for sale on gumtree at the moment.No need for laxative's there!

That was posted here as well a few days ago .. the TM400 motor was .. and the seller (hitatreeonce I think??) said he had the RL frame, CR forks and some other stuff as well.

[Maicoman]

Hey Frosty grab the latest VMX mag theres an article on the TM400, might be useful, great read.

[frostype400]

Thanks Maicoman I seen that vmx was featuring the tm400 I will be picking that up sometime this week for sure.

[EML]

sounds like a fantastic project.
Here's a hint Frosty, when typing, if you have a break or breath if you were speaking, that's a good place to put a commer(,).

[JC]

I am going to run the standard ignition no use having a tm if you are just going to run ts electrics.

I have often wondered how much of the TM's legendary handling woes can be attributed to that spindly swingarm

[firko]

Most of the TM400's handling woes had little to do with the frame. The major problem was the engine's erratic power delivery that can be easily fixed by a simple ignition change to the TS ignition or adapting something from another bike. The stock CDI ignition curve is junk and there isn't enough flywheel weight in the pissy internal rotor. Having said that, the frame isn't anything flash either but nothing coming out of Japan in 1971 set any handling standards. The plastic swingarm bushes are crap so going with the phosphor bronze items will be a noticeable difference. Another change that will help the bike turn much better is to bring the trail back a tad by fitting triple clamps with less offset. Bringing the rake in a tad works too, more easily done by fitting shocks about an inch longer than stock than by frame surgery or triple clamp mods. Fit cartridge emulators to the forks and a decent set of shocks and lo and behold-you've got a decent open class pre 75 mount.

I'm NOT a Suzuki guy by any stretch, I have one Yamaha eye and one Maico eye (with a British third eye in there somewhere ) but it's always bothered me that certain bikes got such a bad reputation from the American press that really wasn't warranted. The Yamaha SC500, '82 Maico and Cannondale are just a few of the bikes that have had to live with a reputation they didn't really deserve. The TM400 and the other three are all excellent bikes once the bugs are sorted out. The TM400 has over the years been a great open class bike that can hold its own with almost any bike from the period. If the late, great Andy Caldecott was still with us he'd be on here raving about the TM400's abilities. Granted Andy was a very special rider but his TM400 was nothing special at all, it just had the generic problems that held the bike back sorted and as those of us who were lucky enough to watch Andy ride the bike for the 10 years he raced VMX will know,  he was almost unbeatable on that big TM, Maico mounted Ronnie Dinsdale being the only rider I ever saw beat him fair and square.

[JC]

Yes those issues w the engine are widely known, & everybody seems to concentrate almost solely on that (& no doubt it's a good place to start) but given an engine of that power the swingarm is more than a little wimpy & under-engineered to put it mildly. Flex like soggy spaghetti under a 250s power, never mind a big-bore or one w 'dramatic' advance curve & little flywheel.

[firko]

Yeah John the swingarm is a bit spindly but weren't they all   That's why a lot of people made a lot of money fixing the multitude of wrongs on early 70's Japanese motocrossers. The ultimate in TM400 fix ups is my Boyd and Stellings framed TM400. Besides the obvious improvements such as the ultra light chro-mo frame with adjustable steering head rake and alloy swing arm, YZ250-A forks with gold valves, YZ front wheel and RL trials bike rear wheel, the anonymous original American builder fitted a Skunk Works 2kg steel weight to the original internal rotor on the stock CDI which works pretty well in softening the big hit but it also makes the bike very hard to start as I can't get enough flywheel speed to fire up the starter circuit. It's got TS points ignition in it right now but I got Karl Fuller at Betta Brakes in Adelaide to check this ignition out and he reckons it sparks fine so I'll give it another go. The bike will be for sale later in the year after some needed footpeg mount upgrades are done. In a bid to knock as much weight out of the bike as humanly possible the original owner used aluminium instead of steel to mount the footpegs. The alloy bracket set up is too flimsy and therefore dangerous. I can't sell it like it is...... The bike fell off the stand and broke the left side mount so I'd feel pretty bad if the  new buyer hurt himself because of the bracket breaking.   
                                                     


                                                     
                                                     

[frostype400]

The frame looks spindly but is quite heavy.

I still want it original though that is sort of important to me with most my bikes can any one give me the wheel offsets I have wrote it down some where and lost it.

I am sure it is going to have plenty of go and I fully appreciate that people know how to tame them and fix the flaws I really want to see what it will do though in standard trim.

[firko]

I am sure it is going to have plenty of go and I fully appreciate that people know how to tame them and fix the flaws I really want to see what it will do though in standard trim.

That's a good plan Michael. Ride it bog stock....identify the weaknesses and sort them one by one. That way you'll know what modifications are effective one at a time. If you change everything all at once prior to riding it you won 't have a full picture of which "cure" works and how it impacts on the other modifications.