jonjeans

Many thanks for advice. I have seen the steel ones for sale at InMotion. Will do that with swinging arm bushes upgrade. jj

Hi all. Please excuse my ignorance. Ref Cu head gaskets. My 325 Sherpa Model 191, did not and does not have one. Should it? My Vincent's, no gone, sealed with alloy head onto cast iron line same as my 325. Looking forward to your observations. jj

Thank you for the advice. On the to do list. There is a rear section on sale locally, so may procure if affordable, and keep on the look out for front section for my 191. Frame is in for straightening and aligning: top tube bent in 2 planes, swinging arm out of alignment, and forks may also be out. Hope to get it back by end of the week. And seized bonded type swinging arm bushes mean they need changing. The rear engine mounting is "floppy" as not been clamped by bushes, and is worn on engine mounting ears. Needs welding and machining to sort properly. jj

More very helpful advice thankyou: reading up before tackling my 191 exhaust system. jj

Excellent information, thank you all. I have yet to clean up my Model 191 exhaust. And am a tad nervous about the process, so it is most useful to see what is inside. jj

Very done, and an interesting read. Thank you for your pictures and input.

Fascinating read and education thank you all. My 191 has perhaps a Mahle piston, assistance in identity will be welcomed, at 84.75mm size. Some scuffing and broken lower ring. 20mm diameter gudgeon pin retained by circlips, and 2 alloy spacers. InMotion stock 84.70 ring sets, and I have asked them if they will fit. Hope so, as do not wish to buy complete new piston at this stage in the rebuild. So, what piston do I have, it looks like "guys" in earlier post this thread, and if new required, what do you suggest with 84.75mm bore? And should bottom of barrelled be chamfered to aid piston with rings insertion? Many thanks, jj

Thank you, they do needful looking at as the alloy rear engine mount is "floppy" and not clamped up firmly between the swinging bushes. Loose, but not rattling. And these bushes are seized on the spindle. I suspect it's should be clamped firmly and centered in the frame. Is that correct? Many thanks, jj

Thank you for the input. The "taphatless" spacer on my set up within the brake does space the brake assembly apparently satisfactorily. Just appears odd that brake plate abuts the fork leg. And in the picture of a shiny new spindle and spacer set up, there is a thick washer next to the spring washer. I do not have that washer and there is insufficient length on the spindle to accommodate it. My spring washer is clamped between nut and alloy fork leg. Should I have that washer? Many thanks, jj

Thank you for your observation and answer. Appears that my fittings are good to refit. I need to ensure that front wheel is correctly centered before taking the bike to a frame straightening jig next week. Thanks again for this forums assistance.

Hi, brief question regarding a Model 191 1977 Sherpa front wheel spindle. Does the Brake plate abut the RH fork leg, or is there a spacer between the leg and brake plate? The parts list I have does not make that clear. And the only picture I have is of the complete spindle, spacers and nut and washers. Not where they fit. The brake arm return spring hooks around the brake plate and is prevented from sliding off by the fork leg. It does not appear correct. Additionally, the spindle head LHS buries itself into the Left leg when the spindle nut is tightened. New spindles are 200 mm long, and so mine is. The less than shiny picture is of my spindle, spacers washer sand nut. The larger sleeve remains in LHS fork. I do not have the top hat style spacer. Nor do I have a washer under the spring washer to prevent the alloy fork leg from damage. Order of fit from nut on my bike is: Nut, spring washer, bake plate(not shown), spacer, then on LHS Spacer, sleeve (not shown, and the head of the spindle. I am confused, as the alignment may be incorrect if a spacer is not fitted between RH fork leg and brake plate. Many thanks

Thank you input gentlemen. I intended to remove swinging arm to jig the frame. But, would have needed to destroy the spindle and bushes. The is a job for the future. That job needs doing as the rear engine mount in alloy has some play on the spindles and also slides about 2mm from center either side until it abuts the swinging arm bushes. I ended up jigging the 3 engine mounting bolts with box section mild steel tube, and centered it in the mounts on all 3 with the rear engine mount lying horizontal. Manufactured a half moon section dolly, and used heavy club hammer to beat lower tube back into line:n and refitted engine to ensure that frame tubes clear engine: it does, and appears approx equal on both sides; the clearance. Top frame tube is bent out of line so have booked in an appointment with motorcycle frame alignment workshop. I suspect that frame front downtime is also bent a tad. Ongoing, but may take awhile. Would like to have it MoT and road legal by April: it is road registered and I have V5c. But if I wait until end of May it will be MoT exempt as well as road Tax free. Hurrah!

Hi all. And another issue. Removing swinging arm looks so simple, however. ..... The bushes appear to be rubber bonded type, no doubt similar to Series Landrover suspension bushes with steel collar and sleeve. So, sleeve rusted to swinging arm spindle, and spindle rotates to frame stop, and then bonded bushes flex to give more travel. Presumably solution is to burn bushes out, and re-fit new bronze with steel sleeves, or nylon? Any input will be appreciated.

Thanks for input, will give it a go.

Hi, reference "unbending" frames. My Model 191 has had a heavy impact lower left frame tube: that now fouls the Mag cover on the engine. Fairly common I believe. Chrome moly tube frame: will heat require annealing to bring back the metal strength? I can live with the deformed tube, and have removed engine and will fit dummy bars in the frame to "lock the geometry" like a jig, to ensure engine fits back in. I would like to finish up with the frame to be true with wheels in line. Any advice most welcome. Thanks Guys