Specifications for 158

[Justdrew]

Does anybody have an owner's manual for a 158 Sherpa that gives the basic specs, HP weight etc. Mine is going on display at a bike show and I need some data to put on a sign for the display.

[David Lahey]

length 1960mm
wheelbase 1290mm
ground clearance 330mm
empty weight 92kg
capacity 237.55cm3
bore 71mm
stroke 60mm
compression ratio 9:1
max power at rear wheel 14.1 HP at 5500 RPM
max torque 2.04 at 4000 RPM
number of gears 5
info from the book Historia de la Sherpa T

[Bully fanatic]

Hello all. What David has posted is correct but some of the Aussie 158`s were 244 cc and these had a 72mm bore. The factory quoted 18 HP or 18.5 hp at the crank as well. Graham.

[brownie]

There is some interesting reading in Bultaco Sherpa T Buyers Guide by Maurizio Gaudenzi about the 158 (for Bully nuts anyway) how they started out making a 238cc version for the French market,from how I read it even earlier than the 158, but due to the Japanese trials invasion around 1975, Bultaco made too many 158 238's so they had to sell them in Spain at a lower price than the 244cc version, so I suppose we in Australia got a bit of a mixture, did all the 238 158's have the 238 sticker instead of 250 sticker, it doesn't actually say in the book, but from 182 on all 250's were 238's (237.55cc).

Back to specs the only differences are
238 / 250
14.1 @5500rpm / 14.4 @5500rpm Max HP at the wheel
2.04 mkg @4000rpm / 2.47mkg @4000rpm Max torque
3rd position / 2nd position Needle
2.5-2.8btdc / 3.1-3.3btdc Timing

[Justdrew]

Thanks for the information. I'm still having difficulty with refitting the rear wheel with the speedo drive in place. Peter at Bultaco Parts Aus. sent me the pages from the parts book which show an exploded view but it doesn't show enough detail and the speedo drive is different. When I put all the parts in the axle nut runs out of thread before it gets tight. I tried adding washers etc but this doesn't seem right. If I take the speedo drive out and replace it with a spacer its fine but I need the speedo for registration in Qld. Has anybody got a 158 with the speedo drive installed? A picture would be worth a thousand words.

[Bully fanatic]

Hello Justdrew. This is reasonably common on Bultaco`s. Why I am not sure. The best way to overcome it is to put a thick washer on the axle head side under the axle head so the washer sits on the snail cam. I have had to do this to quite a few Bultaco`s. It is very stange. Graham.

[Justdrew]

Thanks graham I'll give that a go. I'm off to a bike show tomorrow and I'm putting the Sherpa on display with my Metralla. I've taken the speedo drive out at the moment and with the spacer in there is no problem at all it all goes together very easily without drama. I'll give your idea a go, you mean I take it a washer between the axle head and the snail cam on the drive side. Extra washers on the nut side did not work.
What is the best timing setting for the 158 mine has always been a bugger to start.

[Bully fanatic]

The timing on a Sherpa is always a hotly debated subject Justdrew. I owned a 158 in the really early eighties and I always found that 2.6 mm BTDC was what I liked. At that they were really smooth and still revved quickly. Get them too close to 3 mm BTDC and they will run backwards. One thing to watch out for on the Sherpa`s is the plug gap. Set it the same as the points at .40 mm and you will be fine. I hope this helps. Graham.

[Justdrew]

Thanks graham I'll give that a go. I'm off to a bike show tomorrow and I'm putting the Sherpa on display with my Metralla. I've taken the speedo drive out at the moment and with the spacer in there is no problem at all it all goes together very easily without drama. I'll give your idea a go, you mean I take it a washer between the axle head and the snail cam on the drive side. Extra washers on the nut side did not work.
What is the best timing setting for the 158 mine has always been a bugger to start.

Problem solved. A friend made me a new spacer which protrudes a poofteenth from the drive and I then put a spacer between the drive and the swingarm (a washer the diameter of the axle). Everything seems to work properly now.
Is there anyway of knowing if the 158 I have is a 238 or 244 by the engine number, I don't really want to lift the head to measure as the bike has never been apart and I don't want to disturb it. Also I don't have anything to measure it with accurately.

[pop]

KTMs have small digital speedo.