JimR

hmm rd400's in 1979 where white and red with red mag wheels the modals with 4L0 prefix are watercooled (4L1 for the 250) and there is a differnce between tuning and geting the bike to run right

is this a 1980 model ? if so there was a load of mods done to get over this problem ... from memory one of the progression holes in the carbs had to be enlarged main jet was upped 1 over standard ....you may have a bike that never had the mods done

this is posted elsewhere .... it is difficult to track all replies I guess

did you bleed the air out of the oil galleries ?? one bleed placed on top of the oil filter housing and the other on the head on the right hand side of the engine

The ma50 would need more than a big bore, you would also need to look at the crown wheel and pinion as this effects the overall gearing, you can tune the top end of the motor but it will do you no good if the gearing is to low

Get a copy of tuning for speed by Phil Iriving well worth a read

a picture would be good

hmmm I had this back in the 70's with a brand new DT175mx, the speedo showed a "row of duck eggs" (zero miles). It turned out to be the carb body (a progression hole blocked) .... back in the day we had to replace the whole carb but perhaps a sonic clean of the body may help

no in the loom there are some soldered joints over time they decay and need re soldering ... from memory I think the light brown/white trace has a soldered joint .... check the wiring diagram if you have one

that really sounds like the flasher can .... however if the battery is below par the can will make a noise and the indicators will fail to work... As the bike is now a bit old the following may help replace the flasher can with a rating less than the original spec .... I.E if the can is rated at 10w replace with an 8w can & bulbs also check the brown wire (with a white trace) to check that there are no dry joints in the loom ....

are you sure the rectum fryer makes a noise .... I would guess this to be impossible with an RX100 ..... would guess your flasher relay is knackered

is this a one piece or two piece head ?

This is odd .... back in the day to remove an armature (DT125E/RD200) we used the Yamaha special tool (slide hammer) however other models used a hardened bolt, which after it was screwed into the rotor (armature) until resistance was felt then it wss shocked with a hammer and then tightened until the rotor/armature was released from the crankshaft taper & woodruff key

dont forget this is a DC system and requires power from a battery to work ...

I have being playing with designing a forum designed at old Yamaha tech problems ... look at http://www.yamahabikersclub.com ... I know it's no good but did help with what I do for a living

why not drill and tap the filler (if it is strong enough) ?? else if things don't look to bad down there and there is plenty of ally left why not helicoil the drain plug ? if you go for a helicoil it may be a good idea to use a skilled machinist .... to save an engine strip

so owners manual not service manual ? buying a service manual will help you out loads. a word of caution obtaining copyright content from a party (other than from the copyright holder) may break some laws

I would guess the bike to be OHC and not OHV .. on saying that the smaller engines do require cam chain & valve adjustment in a shorter time span .. buy a service manual

what happens if you have a 6 volt system ? and to be fair I would never diagnose a non charging problem in this method. but each to their own

Nope !! XS500's are a bit different

You should be more worried about the grease in the shaft drive housing (rear wheel) you need to look at that every 1500 miles the engine oil could live to to 3000 miles and on change don't forget to replace (or clean) the gauze filter and use a good quality 10w40 oil also insure the cam chain is correctly tensioned if you want more T80 info PM me Regards Jim

Have you done a compression test yet ?

Thanks Guys you have given me a good learning curve ... I'll just have to work out a few more programing bits so any 'random' post will be welcome ... I'm not taking anything from here I just really need the learning curve Regards Jim

Hi All, A question can you help out ? I have a job to do for work which includes on line access from the public, so after deliberation I felt that using pre written software may help me learn how the underlying tables are written Tech over I have added a forum site (within my interest Yamaha) to see how things are done so if you could head over there and just add something so I can see how things are added to the tables it would be a bonus so the url is The Link I must say that this site is just there for development of my work. Give it a go Regards Jim

Hi Mike if 93102-08205-00 is the correct part number for the part you have the -00 indicates no modifications Yamaha parts followed the following definition Model specific parts :- id code-part no-modification eg Part no for a head gasket is 11181 (whichever model) model code for a '78 RD50 (uk spec) is 2L8 assuming the head gasket was first designed for that model the original part number would be 2L8-11181-00 any mods would be 2L8-11181-01 (-02, -03) dependant on the modification level general parts followed :- type of part-dimension-modification so 93102 = oil seal 08205 = dimensions 00 = modification (this explaination of early Yamaha part numbers is simplified I have not added modifiers for coloured parts and/or finish eg 2L8-11181-01-E7 could be a modified pink head gasket (it does not exist !!! tho) so I would guess the part you require is 93102-08205-01 or greater (-02 -03 etc) but if you fit the -00 version you must ensure the push rod has no ridges on it as it's failure was the inner lip of the seal getting damaged via very small ridges on the push rod and it is fitted square, I can also see that the modified seal supplies ran out years ago and your supplier is supplying you the only part they can Regards Jim