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Discussion Starter · #1 ·
So finally after waiting for parts and good enough weather (I live in Seattle and don't have a garage), I was able to put my bike back together after cleaning the carbs, changing the oil, new starter and new battery. Also putting in a new mechanical seal (thanks Shep) and realizing I was missing the thrust washer thanks to the help on this forum. New radiator plug after the old one broke off in my hand and new coolant.



Anyways...



When I was almost done, screwing the left intake boot back onto the cylinder, the last few turns it started to spin on me. I was a little baffled, I hadn't had to force it at all, but now the threads on my left cylinder head are stripped and I can't get a good seal because of it. So frustrating, it was a rare sunny day too and I was looking forward to riding after a month of not being able to. Argh.



So, I read through the manual, and am glad I don't have to drop the engine to get the cylinder body off. I'm going to remove it and take it to a machinist I think, I don;t really have the tools to fix it myself.



I pretty much was just looking for advice so I don't screw anything up while I'm in there, I know the manual can be kind of fuzzy sometimes. Also, I looked on bike bandit and the new gasket is $50 (yikes), any suggestions on where to get one cheaper?



Thanks,

Sara
 

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So finally after waiting for parts and good enough weather (I live in Seattle and don't have a garage), I was able to put my bike back together after cleaning the carbs, changing the oil, new starter and new battery. Also putting in a new mechanical seal (thanks Shep) and realizing I was missing the thrust washer thanks to the help on this forum. New radiator plug after the old one broke off in my hand and new coolant.



Anyways...



When I was almost done, screwing the left intake boot back onto the cylinder, the last few turns it started to spin on me. I was a little baffled, I hadn't had to force it at all, but now the threads on my left cylinder head are stripped and I can't get a good seal because of it. So frustrating, it was a rare sunny day too and I was looking forward to riding after a month of not being able to. Argh.



So, I read through the manual, and am glad I don't have to drop the engine to get the cylinder body off. I'm going to remove it and take it to a machinist I think, I don;t really have the tools to fix it myself.



I pretty much was just looking for advice so I don't screw anything up while I'm in there, I know the manual can be kind of fuzzy sometimes. Also, I looked on bike bandit and the new gasket is $50 (yikes), any suggestions on where to get one cheaper?



Thanks,

Sara
Sara,with the conditions you have worked in,you have done very well.have you the tools to fit a helicoil.?..that bolt is a non stress item,id try that first
 

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Sara,



I'm having a tough time understanding what exactly stripped ? You mentioned as you were putting on the L/H intake boot back on the cylinder ? What stripped ? Was it the hole where you put the gauge to sync the carbs ?? I ask because the only thing you could strip while putting the intake boot on would be the clamp that holds it ??
 

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Sara,



I'm having a tough time understanding what exactly stripped ? You mentioned as you were putting on the L/H intake boot back on the cylinder ? What stripped ? Was it the hole where you put the gauge to sync the carbs ?? I ask because the only thing you could strip while putting the intake boot on would be the clamp that holds it ??
Rick,i read it as though its the small 6mm[i think] bolt that holds the boot to the block
 

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Discussion Starter · #6 ·
Yes, the 8mm bolt, #21 in the diagram. Though it wasn't the bolt that stripped, but inside the cylinder. I looked at some videos online on how to install helicoils, can I do that without a tapset? And I would still have to remove the cylinder, right?
 

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Yes, the 8mm bolt, #21 in the diagram. Though it wasn't the bolt that stripped, but inside the cylinder. I looked at some videos online on how to install helicoils, can I do that without a tapset? And I would still have to remove the cylinder, right?
Sara,im at home,no manual.im 100% sure its a 6mm bolt,with an 8mm head.and i think its possible to do a helicoil,without removing the cylinder


just bear in mind,im working from memory
 

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Sara,with the conditions you have worked in,you have done very well.have you the tools to fit a helicoil.?..that bolt is a non stress item,id try that first




A Helicoil can be done there with the head on the bike and is absolutely the best and proper choice for a repair, no argument there, but there may be another way if you are in a pinch for time or on a budget.



Take the metric screw into a good hardware store and ask for a tap for the SAE screw size that is just a hair larger than the original metric screw was (maybe a 1/4-20 would work for a stripped out 6mm?). Then also buy a cap screw of the new SAE size that is the same length as your original screw.



You probably would not have to drill out the stripped hole, just run the SAE tap into the hole to cut the new threads, then assemble the intake using the SAE screw in that location. A little bit of light duty blue Loctite on the threads wouldn't hurt either.



Backyard engineering it is, but it can work.
 

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A Helicoil can be done there with the head on the bike and is absolutely the best and proper choice for a repair, no argument there, but there may be another way if you are in a pinch for time or on a budget.



Take the metric screw into a good hardware store and ask for a tap for the SAE screw size that is just a hare larger than the original metric screw was (maybe a 1/4-20 would work for a stripped out 6mm?). Then also buy a cap screw of the new SAE size that is the same length as your original screw.



You probably would not have to drill out the stripped hole, just run the SAE tap into the hole to cut the new threads, then assemble the intake using the SAE screw in that location. A little bit of light duty blue Loctite on the threads wouldn't hurt either.



Backyard engineering it is, but it can work.
totally agree,IS.love the back yard fix.like i said...a no stress item
 

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You do not have to remove the cylinder if you wish to heli-coil.You need an M6 heli-coil kit,





http://cgi.ebay.com/NEW-M6-X-1-00-O...319?pt=LH_DefaultDomain_0&hash=item45f988df7f



Remove the boot and undo the carbs and swing them out of the way and tape them to the top of the frame.



If you can get an electric drill in there with a 6.3mm(1/4" will do) drill bit drill into the hole but only to the natural bottom stop,end of the threads.You can get this dimension by putting a thin pencil or rod or smaller drill bit in there and putting a bit of tape on it where it stops and the use that against the drill and put a similar bit of tape on the drill bit.Then you know how far to drill in or some electric drills have a drill stop bar that can be set so as not to go too far.



Basically you ream out the hole with the drill bit.If you cannot get a drill in there you can use a set of vise grips and slowly do it by hand.Bit of a chore but still works.Just try to keep straight.The alloy will be pretty easy to chew out with the drill.





Then you turn the Tap that comes with the Heli-coil kit into the hole.



Use some grease when tapping and when drilling as it will not only help the cut but also soak up some of the metal debris/swarf.Then blast out with Carb/Brake cleaner before inserting the heli-coil.



Then once that's done you screw in a heli-coil and then punch it's tang off.



http://www.helicoil.com.sg/HeliCoil-Installation-Instructions.htm



It sounds a lot harder than it is.Helicoils are usually stronger when done than the original threads cut into the Alloy engine block.
 

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If you do use a tap,,when turning it into the hole,once it starts to turn hard, turn it a half turn or so , then turn it back about a quarter turn, then ahead a half turn and back a quarter turn. Repeat this until you have it the whole way in.



Also a bit of oil on the tap or squirted in the hole every now and then is recommended.
 

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Discussion Starter · #15 ·
I guess I was assuming I needed to remove the cylinder just because I was afraid of getting metal flakes in there if I tried it still attatched. I will call around to hardware stores and try the helicoil tomorrow, thanks.
 

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I guess I was assuming I needed to remove the cylinder just because I was afraid of getting metal flakes in there if I tried it still attatched. I will call around to hardware stores and try the helicoil tomorrow, thanks.


You can just stuff a rag in the inlet port.The holes for the carb boots don't go all the way through and if you use grease as a lubricant instead of oil as it will catch a lot of the swarf as you work and wipe continually.As Allen said turn tap in a little until it bites,then out and clean and repeat until done.



As these are metric you may have to send away for the Helicoil.
 

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Damn, more waiting


Yellow pages and ring round.There may well be somewhere local




If you get friendly with a small motorcycle shop and they are decent they may hire/lend one out if they have one.Don't let them charge any silly money though because as you can see they aren't that expensive.
 
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