Honda VTR250 89, lurches forward on clutch release

[forkoil]

Having problem with gf's VTR250. when feeding out the clutch on takeoff, it starts forward fine, then after just get going it sort of lurches forward together with a 'noise' from the driveline/transmission/clutch. Pulled down the clutch, checked plates within manufacturers tolerances, and that they were straight (all good), washed them thoroughly. Carefully filed smooth the corrugations in the clutch basket fingers (thought that was the problem), reassembled coating plates with clean oil, topped up and.......... the problems still there!!
Any ideas please? I was wondering about the cush drive, or something else elastic in the driveline but no idea really.... dunkin,blimin,f*kin Hondas.

[F5 Dave]

Could be matching ridges in the inner basket as well. First guess would have been outer ones though.

Are they a cable clutch?, worth looking at what is going on there, if it is hanging up, if a bent pushrod (not usually on a Honda, usually in case pushing to a bearing). Lever dragging on something?

A heavy hit is often the hub cushdrive rubbers. If you can rotate them by hand then you can pack the sprocket holder with duct tape & force back into the rubber (yes obviously that is bush, but it can't go anywhere). Or in the clutch hub if there is slop it will whack in quickly. That can be packed with nylon shims, but you have to machine & replace the rivets.

But either of these things, while amplifying the symptom will not be the cause. Obviously it is hanging up on something & the plates to basket is the obvious issue.

[hayd3n]

i think they are a hydrolyc clutch

[bogan]

i think they are a hydrolyc clutch

think they went cable in 88 iirc

[forkoil]

Could be matching ridges in the inner basket as well. First guess would have been outer ones though.

Are they a cable clutch?, worth looking at what is going on there, if it is hanging up, if a bent pushrod (not usually on a Honda, usually in case pushing to a bearing). Lever dragging on something?

A heavy hit is often the hub cushdrive rubbers. If you can rotate them by hand then you can pack the sprocket holder with duct tape & force back into the rubber (yes obviously that is bush, but it can't go anywhere). Or in the clutch hub if there is slop it will whack in quickly. That can be packed with nylon shims, but you have to machine & replace the rivets.

But either of these things, while amplifying the symptom will not be the cause. Obviously it is hanging up on something & the plates to basket is the obvious issue.

Thanks for the considered reply. Its a cable clutch, but its not the cable I dont think cos it pulls in smoothly enough, but I will lube just in case. I did check the inner basket, and the slots were very smooth. Is it possible that the fibre plates although within thickness spec, may be binding in a non progressive way due to some previous "bad" oil being in the bike?

[bogan]

had a better read of your post, if you filed down the corrugations in the 'fingers' you will now have play in the clutch mechanism. Depending on the condition of the torque dampning springs (forgot the correct name) on the back of the clutch it could set up significant oscilations. if you take the clutch cover off, there should be no movement in the basket at all.

[forkoil]

had a better read of your post, if you filed down the corrugations in the 'fingers' you will now have play in the clutch mechanism. Depending on the condition of the torque dampning springs (forgot the correct name) on the back of the clutch it could set up significant oscilations. if you take the clutch cover off, there should be no movement in the basket at all.

Could you explain this further? How do I test this?

[bogan]

Could you explain this further? How do I test this?

take the clutch cover off bike so you can get at the clutch, then grab the fingers and rotate (while in neutral), there should be no movement at all. That how i did it on my 88 honda bros, so i assume it'll be the same on the vt, i had bout 3mm play on the circumference, rebuilt the basket and it's way better now.

[forkoil]

So if there is play, due the the extra play created by filing the basket fingers, then removing the clutch basket entirely, you can compensate for the play by doing something to the dampening springs behind the clutch basket? Have I got that right?

[bogan]

So if there is play, due the the extra play created by filing the basket fingers, then removing the clutch basket entirely, you can compensate for the play by doing something to the dampening springs behind the clutch basket? Have I got that right?

no, if theres a significant amount of play from when you filed the basket fingers, you're fucked, if theres play from the anti-chatter (i remembered the name!) springs on the back then you can rebuild it with new springs. Also I have an 84 VT250 engine sitting in the shed at home, its the same as an 86, if it's got the same clutch as yours I could sell it to you cheap as!

[SS90]

From memory, the VT 250 (88 and later) had no cush drive on the rear wheel, they simply relied on the cush drive in the clutch hub.

As has been said, best thing is to check.

Hold the out hub in one hand, and lock the primary gear so the engine is solid. You should only feel a slight spring loaded play, if their is a noticeable "clunk" and it feels like excessive play (1mm is normal), then there is every likely hood this is your problem...... there are plenty of bikes (high milers) that end up breaking the cush drive springs giving the same symptoms.

[forkoil]

no, if theres a significant amount of play from when you filed the basket fingers, you're fucked, if theres play from the anti-chatter (i remembered the name!) springs on the back then you can rebuild it with new springs. Also I have an 84 VT250 engine sitting in the shed at home, its the same as an 86, if it's got the same clutch as yours I could sell it to you cheap as!

Bogan. Thanks for your help, sincerely. I've just got off the phone to Warren, out west Auckland who is the Honda mechanic legend (40 years) (ph (09) 8361547), one helluva nice guy, and ran thru the problem with him. He says its the fibre plates, become hardened over time and dont progressively bind anymore, but slip and then grip (beyond a certain load point), causing the lurge/launch forward, he had a name for it I dont recall. Anyway new fibre plates and a touch up with emery paper for the metal plates was what he recommended. He also said not to use synthetic oil under any circumstances, it f*cks clutches, and said the best oil to use was generic "modern engine" oil from places like the Warehouse or supercheap autos! And that the story that mineral car oil f*cks bike wet clutches isnt true (he prepares many race bikes so has hard edge knowledge on this). Also asked him about my 03 Fazer thou which has just turned 40, and he said just leave it alone, modern valves are hard, dont wear and alot of expense for no effect.
So he just lost himself probably $500 in work from me, for which I thanked him, and he replied, just keep the bikes running well, regular oil and filter changes every 5K, and hes happy!! Not many around like that these days.
Cheers,
Ken

[bogan]

Bogan. Thanks for your help, sincerely. I've just got off the phone to Warren, out west Auckland who is the Honda mechanic legend (40 years) (ph (09) 8361547), one helluva nice guy, and ran thru the problem with him. He says its the fibre plates, become hardened over time and dont progressively bind anymore, but slip and then grip (beyond a certain load point), causing the lurge/launch forward, he had a name for it I dont recall. Anyway new fibre plates and a touch up with emery paper for the metal plates was what he recommended. He also said not to use synthetic oil under any circumstances, it f*cks clutches, and said the best oil to use was generic "modern engine" oil from places like the Warehouse or supercheap autos! And that the story that mineral car oil f*cks bike wet clutches isnt true (he prepares many race bikes so has hard edge knowledge on this). Also asked him about my 03 Fazer thou which has just turned 40, and he said just leave it alone, modern valves are hard, dont wear and alot of expense for no effect.
So he just lost himself probably $500 in work from me, for which I thanked him, and he replied, just keep the bikes running well, regular oil and filter changes every 5K, and hes happy!! Not many around like that these days.
Cheers,
Ken

does sound like a good bloke! makes sense about the fibre plates too, i just did the bros's fibres cos they were slipping, measured in spec though so same must have happend to mine. I would still check the play when you get it apart next, as any play will accelerate wear on the clutch assembly, and make for some rough transitions to engine braking from acceleration. From my recent experience, 3mm play in the clutch was like a very slack chain to ride with.

[F5 Dave]

I've found the best way to clean up metal plates is on some real smooth concrete & wipe them figure 8, gives them a honed appearance, cleans off glaze & you can see if they are fairly even or coned. Obviously clean them.

[forkoil]

I've found the best way to clean up metal plates is on some real smooth concrete & wipe them figure 8, gives them a honed appearance, cleans off glaze & you can see if they are fairly even or coned. Obviously clean them.

Not a bad idea thanks Dave, will try that. Have just ordered an aftermarket clutch kit, $90, so not tooo bad. In the old days I probably would have just scuffed the fibre plates with emery, but the bike was originally used in a training school down in Wellington, so I think the clutch has had a fairly tough life.