Hey guys, its been a while, Bike has been sat for a couple of years now i've finally cleared some time top get her back on the road with a little help from all of you i hope!

the bike currently has an 'external combustion engine'

I'm a diy mechanic, i can change gearboxes, stip and rebuild an engine etc, however there are just some things that experience is just essential and sadly i get get through this one!!

i had a no start issue after replacing the original carbs with another set of identical ones. ive had the carbs apart and cleamed them thoroughly and all looks mint. when i first re-assembled the bike ran for a couple of minutes with no help then died, i noticed that there was a large leak originating from the t pipe between the fuel feed and carbs 1 and 2. i separated the carbs, cleaned and replaced the o-rings. back together now. however now it turns over lovely but a massive flame/backfire from the exhaust and bike no starty. #sigh

Things ive already done:
1. Cleaned and checked jets in carb, checked all aspects of carbs they are mint, i do not believe an issue to be here unless it is with the air mixture screws.. (although i have put these back exactly how they were before stripping them down)

2. I have checked fuel, im running shell V-power (never use anything else personally) and it has a little redex mixed in just for good mainenance, i use about 1/4 bottle per 25l jerry can just as a maintenence thing.

3. air filter is brand new and is a hi-flow since i find them better than the k&n ones for my bike.

4. plugs are as new as the air filter, i 'could and should' take them out again and re-check to see if any colours etc, i may just replace them anyway as a matter of course. i hate doing this as they are a real pain in the butticous to get to there must be a specific tool for this? got a link?

5. brand new battery

6. kill switch, taken apart, cleaned and lubricated using electrical lube, multimeter show this working fine

7. new ignition barrel, key, fuel cap and helmet lock fitted.

not checked:
1. coil packs, i wouldnt even know where to start testing these so any tips would be gratefully recieved.
2. timing, can imagine this would be an issue since it was working just fine until the carb died. (turned out to be 3 blocked slow jets in the end )
3. regulator, ive put a brand new one on so unless that is faulty i dont know how to check it, there was nothing wrong with the old one and the multimeter readings are identical with both so probs didnt need changing.
4. someone also suggested the 'igniter' but i dont know what or where this is, i assume its the coil packs? but happy to be corrected.

Many Many thanks in advanced for any assistance. (i 'could' take this to a garage but i dont want to i would like to fix myself with some guidence (previous owner did all the work on it and id like to retain that aspect))

also if ive not provided enough information please do ask, im sure ive not explained everything needed.
if anyone can offer any advice, on places to check and how/what things 'should' look like i would be eternally grateful. this bike has so much sentimental value its crazy (i know you'll get this) and i need it to live!!

 

Back to basics then. Fuel / Air / Spark.
Does it spark?
Are all of your breather pipes connected properly?
Do you have fuel in the bowls? If not is the pump working when engine is spinning to fill bowls up?
Last resort have you tried easy start if you are getting a spark?
Trouble shoot guide from manual:

 

oooo thanks for this! back to basics is definately a better approach than i was taking!! i was getting to the point of illogical panic diagnosing

will run through this and revert. thanks

 

Sounds like the ignition coils wires and cap are in the incorrect location? Have you tired that? Right side should be 1 and 4. Left side 2 and 3. Also, I put in the original specification copper plugs the NGK CR9EH-9 and had a quandary. Replaced with Iridium CR9EHIX9, pre-gapped and never have a problem with spark starting correctly now. Should be able to remove the side cover. Pull the plug caps, stick a spark plug tool in the spark plug port, then extension and remove the plugs counterclockwise. Reverse order for installation.

I just replaced the motor last week and had a backfire issue. The ignition plug caps were assigned to the wrong cylinders. =D

 

thanks guys i think this is the issue!!

i have no spark on any of the 4 ht leads
all 4 plugs are good, and have confirmed using my trusty motorcar

ive pulleded the coils out and tested resistance on the HT leads, looking good, and there is voltage going in but nothing coming out. used a spark plug tester before pulling the coils.

i found somewhere that the ohms between the feeds should be between 2.7 - 3.1 when set to 200ohms, mine is 2.7 on both. and it should also read between 11k - 15k when set to 20k ohms but i have nothing here. so i assume both coils are duff? i know they are still the originals, i wonder if the backfire is a result of the combustion of pressure alone? but im not sure that this sounds right? i know you can ignite on compression alone but im not sure that this engine will have enough wack to do it??

im going to order a new set of coils and pray this is the fix. any more thoughts of other things to test?

i have checked all the hoses and pipes, no leaks, no disconnects, new fuel filter and air filter etc. all good seals and the retaining clips are either all in working order or have been replaced with jubilees.

 

How about the order of the spark plug wires. The left side should be 2 and 3. Right side 1 and 4. Otherwise this will cause a backfire.

 

yer these were definately in the correct holes :P top left 3, bottom left 2, top right 1 bottom right 4.

 

Also is it worth upgrading to iridium? do i need to do any modifactions or adjustments to do this or are they just plug and play?

 

have you checked your cdi also?

 

If you are changing plugs, yes to going with iridium. The only adjustments is to check the gap