I am from the UK. I've spent 10 years trying to get a 250R, I finaly got one last year then had to get loads of parts sent from canada for it (thanks Quadpro). I finaly got it rebuilt and it ran well for 30 minutes, I then stopped it and it wouldn't start. We tried towing it but it just smoked and wouldn't clear. I replaced the crank seals and rebuilt the motor. I also found the main jet and air screw were different to stock so replaced them with stock. It revved fine when fired up and rode OK until I slowed to turn round where it immaediately flooded up. It has a K&N cone paper filter and carbon reeds with no stops. Unfortunately parts over here are hard to source and very expensive any advice on my persistent flooding? I'm trying to find some stops but they come with the block and cost $240. Could this be the problem? Any comments or advice would be gratefully recieved as most people over here don't even realise three-wheelers were ever made.

 

First of all...your reeds. Are they fibreglass (Boyessen makes them)? Are they whitish in color and do they have 2 "stages"...meaning, do they have 2 layers?. If so, then you simply have after market reeds which don't require stops on them. They're actually better than stock.

As for your smoking and loading up problem. If you're running stock jets, then my guess is that your mixing your oil and gas too rich. What type of oil do you run? Is it synthetic (Klotz, MC1, Golden Spectro, etc)? If so, then don't run the recommended 20:1 listed on the bike. That was intended for 1980's oil's. Most were petroleum based and were mixed richer. Today, they have much better oil which will "load up" your bike if you put too much in the gas. You should be running at about 40:1. (you can vary from 32:1 to 50:1). I, personally mix mine at 40:1 for gas and 32:1 for alcohol.

If this isn't your problem, then maybe your cases are leaking tranny fluid into your crank (maybe a seal is out of place). It usually doesn't happen, but it'll be a problem in rare instances.

Finally, check your air filter. Is it REALLY dirty? I doubt that this is your problem, but it may be a contributor. Also, are you running an NGK B9ES, B8ES or any equivalent plug?

Definitely check your oil mixture...that's my best guess. If you provide more details about your motor, then I can help you more.

86ATC250R
85ATC250R
97CBR900RR

 

Some reeds cause a more rich condition. Try a more lean carb setting in whatever circuit that is affecting the range you are having problems with.
ERIC

 

I have checked the reeds and their is indeed two layers of reed so I presume they must be aftermarket. I am running a BR9ES plug and a 30:1 mixture using basic two stroke oil and unleaded petrol. The filter is perfectly clean. When removing the reed case I noticed there is a small crack in the rubber where it mounts on the carb so I shall rectify this and try a better quality two stroke oil at a lower ratio. Would anyone recomend a different plug? I am running standard jets but am unsure about the needle and airscrew so I am going to replace them. What's the easiest way to clear a flooded engine?

86 ATC250R
85 ATC250ESF
87 Fantic 300
74 Bultaco Pursang 360

 

hi as the other guy said if your useing any of the finer oils don t mix them so rich i do 50:1 useing bell ray mc1 and 95 octan fule is that 3 wheeler ported is the jug overbored?/ ported? are you running with your airbox on or off do u ride high above sea level?

 

o yea thats on my 86 4trx250R which is bored 20 mm. over ported baysson reeds&cage fmf fatty pipe gold runing airbox lid off i also have a nearly stock 86atc 250R ride red or ride home

 

Try a squirt of starter fluid in the spark plug hole to see if it will ignite.

 

The airbox lid is made of mesh, as to wether it's ported or not I don't know. The previous owner didn't have it long any mods were done by the original owner. You guys don't know how lucky you are I read all these forum bits and pieces and it makes me seriously consider coming over the pond to join you. Thanks for all your advice I shall put it into use in a week or so when I'm not so busy at work and I've someone to tow me!

 

Sounds like you got the rich problem at low speed like you said when you were turning around. I would go with s smaller pilot jet, leaning out the low speed circuit in the carb. My friends 85 250r had the same trouble when we put the boyseen reeds in it. Went with a smaller pilot jet and that was it.

84 ATC 300R, 86 ATC 200X