Dave C

Sounds like it could be restricted to 33bhp.

Just wondering if it could be the oil, if its to thick like 20w50 it could be taking all the juice in the battery just to turn it over leaving nothing for the spark, after you have warmed the engine it could be turning over a lot easier and starting.

Just a thought, does it have any safety lockout devices fitted like sidestand switch or clutch switch as these can give unexpected problems.

Most parts are still available from dealers and i`ve never had to wait more than 3 days for them to get parts in. I use the site below to see if i can get it, take the part number to the dealer and he will order it. http://www.cmsnl.com/yamaha-xj650_model16829/ for carb parts try these http://www.nrp-carbs.co.uk/contact_us.htm

When i got my XJ650 it used to run great for about a mile then cut dead, would not start until it cooled down a bit then you could go another mile or so and it would happen again. Problem was the TCI unit, once replaced no more problem, if it was starting to break down it could give the symptoms you are getting and a replacement is quite cheap of ebay. The only way i know of checking this is to replace the unit, cant think of anything else that would affect both coils at the same time. This guy had a similar problem http://members.tripod.com/dave_jack/id41.htm You could also check the fuse box, if its original it will have the old glass type fuses and as they get old they give all kinds of problems, most people replace them with newer type blade fuse box.

For a small cheap screen you cant beat these http://www.getgeared.co.uk/PUIG_Universal_...torcycle_Screen I used one one my XJ650 and comfortable cruising speed went from 50 to 70, it just deflects enough air to make it comfortable without making it a liability in a cross wind.

What you are describing sounds like typical running rich which could also account for the rough idle. Also balancing the carbs on these bikes can make a world of difference to the idle and general smooth running and quietness of the motor.

Might be better to post the pics, then people can see the problem. Also when trying to retap the hole i think you might struggle with a standard tap due to the depth of the hole, you might fare better with a blind tap.

I've just got some mat black PJ1 from the local YAM dealer.

Not familiar with the bike, does it have an Exup valve on the exhaust, if it does that is probably the problem.

Just checked the parts diagram http://www.cmsnl.com/yamaha-xj750rh-seca-1...slist/B-06.html and that says they should fit. If you click on the part number it will give you all the bikes that part will fit.

I think the 5G8 was made for the japanese market and i also think it was the SECA.

Finally got to the bottom of it, it was the pickup coils dieing once warm, Fitted another set and all is well> Thanks for the suggestions Dave C

Tried on prime and it made no difference, but i will give fuel cap a go and see what happens, just strange as it pulls like a train then just dies.

Got a problem, bike will start from cold no problem, runs off choke as it warms, revs no problem, then it cuts dead. It will not restart until its cooled down, my first thought was cdi but checked when it cut out and i still have a spark. I have checked the carbs and they seem nice and clean, checked valves for adjustment, coils check out ok. Just wondering about the spark as to me it looks weak, i generally look for a big fat blue spark but all i am getting is a very thin lined purple one, any gurus out there with an opinion please shout up with any thought on problem. Oh yeah its a 1985 GPZ600R (sneaked that one in) i know its not a yam but you gotta go where the knowledge is