Hi Everyone,

After going through some more :Bultaco: parts, I found another head with 3 holes. Here are some comparison photos:
IMG_20220913_115749.jpg
IMG_20220913_115718.jpg
Both heads appear the same except for the number 105 stamped in the underside of the second beadblasted head, maybe ...

Is it Michael's bike, Graham?
I have an M180 LH sidecover in the shed. I might try and post a pic of it

David the open class Bultaco MX bikes all had twin plug heads. Even the El Bandito. They were all 60mm stroke until the MK 9 which had a 64mm stroke to make it a 370. They got 360cc by using an 85mm bore with a 60mm stroke. I know of a MK 10 370 that I am working on at the moment which has what ...

I took an eBay punt with this recently. Hasn't arrived from the US yet. Seller described it as a TY250 head which it obviously is not.

My guess is an early DT250 head with a decompressor fitted into a second plug hole. The decompressor may be the answer when my legs say no.

We do have an XL250 ...

If I recall correctly, the DT250 cranks have smaller OD than the TY ones. Not an insurmountable problem but you'd lose some crankcase compression and flywheel inertia with a straight swap.

Good job Dave,
Clever man

Yes, I'd love to try it but won't be up there till next winter probably

How much did you reduce axle offset

I had the pleasure of sampling David's much modified KT while in CQ recently.

Like Chippy, I like the KT's handling. Or at least, most of it. Mine has different footpegs which effectively lowers them and rear-sets them by 10-15mm each way from standard.

Others say the KT steers slowly but the rake ...

Been a bit slow returning here

Looks promising Greg

Would you have a spare TY250 rear wheel (with brake, axle, adjusters and sprocket if possible) to include in the swap as I need one for my project TY250?
cheers, J

See below Greg

But first, I completed my previous post above in answer to Dave's question about the KT actuator profile, so it makes more sense now.


I found a fair bit of surplus trials stuff for your consideration Greg. Here's a few pics.

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Italjet ...

Dave, I'd have answered like Greg did, as you probably thought too.
As to why other manufacturers don't do it I'd have simply said, too slack.

Or perhaps more to the point, when the front brake is setup the right right way it doesn't matter much.

Here's an interesting point. Bearing in mind that a ...