Just finished my project TL270 and I must say I am more than thrilled with the result.... I ended up using a 270 cc piston kit, a heavier xl250 flywheel, and a cut steering head (1.5 degrees). The shakedown ride went quite well - I've never enjoyed a trials bike more in my 35 years of riding. The bike was pure joy.... and then, and you knew this was coming, she signed off with a misfire.

Back at the ranch I started the investigation. The bike kicked over with good compression, but had no spark on what I would call a plug that had a good tan color to the ceramic part, yet had black carbon ash on the edge of the threads. Plug was new before hand. The points looked a bit burnt as well, so I ordered a new set and a used coil / condensor to try in case it was needed. The old points got so hot that the fibre plastic type washer on the points body was melted. Indeed the bike ran hot...

OK, so with the new points / new coil and even the old coil - no spark........ I used the old plug after giving it a good cleaning. Am i missing something else that may have failed due to excessive heat?

Other info: When assembling the motor I powder coated the cylinder and head. The ignition plate was adjusted about a quarter inch counter clockwise. As the motor spins that direction, I assume this is retarding the ignition. If I can get spark I'll readjust this closer to normal.

I figured the bike would run a little hotter during break in, but it appears I've gone more than a little hot. I've considered running a colder plug in additon to the ignition adjustment. My air seal on the intake is good, so no worries there.

Any advice?

^{source coil?}

I don't know these engines, only the tl125 series but if it's points ignition with a battery and not CDI, check with a meter that the points are definitely making and breaking and that you've got voltage at the coil . If you touch the points wire to earth and then break the connection with battery power on the coil you should get a spark at the plug, making sure of course that the plug body is well earthed. That way you should be able to isolate it to the points or coil. Could be that. the isolating washers are incorrectly assembled at the points wire connection.

Edited May 9, 201214 yr by craig10

Gday, if the points have melted you have the wrong type of coil on the bike. You need one for a standard magneto, you have probably fitted one designed for CDI which has a lower primary resistance. Also, fit a new condenser as they can sometimes cause burning on the contact faces. Check the source coil resistance as Christopher mentioned above and there is nothing else to do. Leave the plug, it sounds perfect, as does your carb settings. You always take notice of the ceramic, the rest has no bearing on the plug reading.

Hope this helps,

Cheers,

Stork

Any updates? Solutions?

"Just finished my project TL270 and I must say I am more than thrilled with the result."

Photos please.

"Just finished my project TL270 and I must say I am more than thrilled with the result."

Photos please.

yup.....pictures please

these engine run hot at best of times,so powder coating head and barrel it will get even hotter,you will also need oil cooler,and best oil you can find changing oil every time you use it.

Totally agree with Maxbikes , never powdercoat any parts that need air to cool them, the powder coating

traps the heat and you will cook the item .... you now have the un-enviable problem of getting the coating

off the fins.

Guessing this is Old But Here Goes anyway. I Have a Honda TL 250 and would like to know if i can fit a XL 350 Crankshaft  and barrel/Piston to my Crank case 

 

Hello am new Here but looks great 

 

Buzz  in the UK 

I had a fraser with 380cc, Xl350 cranc and big bore piston, made by a dutch mechanic....

 

 

http://www.trialscentral.com/forums/topic/52663-some-fraser-tl-questions/#entry396041

Edited August 29, 201510 yr by hendrik

Thanks its a Good Start, Just a Standard XL 350 would be ok for me.

Parts  Required (I am Guessing)

XL 350 Crankshaft.

XL350 Barrel(Jug) & Piston,

XL Cylinder Head ? 

 

My TL250 Crankcase 

 

Any Answers would Love to Know.

 

Dave.

might be a daft question....but why not just put complete 350 motor in there?

Would do That,but Correct me if i am wrong but the Gearing in the Gearbox are different on the TL 250 

The TL250 gearbox is different, but fits in a 350 engine...