Sign in to follow this  
Followers 0
800screws

ok so far but now...

19 posts in this topic

i did the decomp mod with the hot cam and adjusted the valves. everything was still in time before i buttoned it up. now it will not start. it has the beginnings of starting...like a duh duh duh, but it won't go. any ideas.

Share this post


Link to post
Share on other sites

What happens if you give it a couple extra squirts?

If you used a Hot Cams camshaft that was made for a 426, you should have timed it using thetiming marks on the sprocket, and not by counting pins. Did you?

Share this post


Link to post
Share on other sites

yeah, it's timed with the marks. i tried the couple of squirts of gas, but then i smelt gas, so i think i flooded it. (although i do use that technique before i did this and it started right up). i'm gonna leave it and see if it starts tomorrow, since the carb was empty when i put it back together. should i try to pop start it and see if it starts after that? i'd really hate to take it apart again...

Share this post


Link to post
Share on other sites

You could bump it off, but you should be able to clear it. Raise the idle speed, crack the throttle, or crank it few times with the throttle open. Sounds like you might have gotten it a little wet. Once it gets lit, trimming up the fuel screw should make it behave better.

Share this post


Link to post
Share on other sites

well, i took off the head, just to check the clearances again and i got these readings looking at the head from the shifter side of the bike.

exhuast ------------ == intake

.10 out ------------- .002 out

.029 out ------------- good

-------------- .002 out

would these clearances make it hard to start? i probably will shim it again, but just wondering if this is the reason.

Share this post


Link to post
Share on other sites

I'm afraid I don't follow what you're telling us about your valve clearances, but it doesn't look good.

Tight valves, particularly tight intake valves, will certainly make it hard, if not impossible to start.

If you want me to look at the clearances, please present them as actual measurements for the left and right exhausts, and the left, center, and right intake.

Share this post


Link to post
Share on other sites

ok, with the left side being the shifter side, it goes like this

exhaust left valve is .10mm out of clearance

right valve is .029mm out of clearance

intake left valve is .02mm out of clearance

middle valve is in clearance

right valve is .02mm out of clearance

clearance being .2-.25mm for the exhaust and .1-.15mm for the intake

i'll be going to alaska this week, but i will check this post when i come back. thanks

Share this post


Link to post
Share on other sites

I'm sure we went over this already, but once again, please present your valve clearances as actual measurements for the left and right exhausts, and the left, center, and right intake.

You're telling us they are out of spec, but which way? Can't tell.

Share this post


Link to post
Share on other sites

Put it on TDC start putting feeler gauge's in there till it snug now what's the number on the feeler gauge :D

Share this post


Link to post
Share on other sites

ok, with the left side being the shifter side, it goes like this

exhaust left valve is .229mm

right valve is .305mm

intake left valve is .152mm

middle valve is .127mm

right valve is .152mm

clearance being .2-.25mm for the exhaust and .1-.15mm for the intake

these are the measurements marked on the feeler guage.

sorry about that repeating the same info.

i left the intakes alone and reshimmed the exhaust. i also put in a decomp cam (hotcam brand). i lined up the timeing marks and followed exactly how to do it with TT instructions. the compression feels really low? is this how it should feel with the new cam? and i can not get it to start. it backfired and that's it.

Share this post


Link to post
Share on other sites

i took the head off again, all the clearances are ok, but the kickstarter is pretty light in the stroke. is this normal with the decomp mod? and alas all it does it backfire.

Share this post


Link to post
Share on other sites

OK, let me repeat my self. Was the Hot Cams cam you bought made for a 426, or for a 450? If you used a Hot Cams camshaft that was made for a 426, you should have timed it using the timing marks on the sprocket, and not by counting pins. The TT instructions for using a 450 cam in a 426 should not be used in timing an aftermarket decomp cam made to be used in a 426 to begin with. That may be your problem. Use only the instructions that came with the cam if that is the case.

Share this post


Link to post
Share on other sites

it was made for the 426. the timing marks are aligned with the top of the engine and the lopes are facing away from each other and the lines are matching at the stator...? anything else i should check?

should the kicker be that easy to kick?

Share this post


Link to post
Share on other sites

I don't know how easy "that easy" is, but it will be much easier than without autodecompression, yes. The engine should still generate about 100 psi of compression with AD. Before, it was more like 200.

It sounds like you did the timing right. Check the plug and be sure you have decent spark.

Share this post


Link to post
Share on other sites

ok, it was my fault, i took the top off yet again and the right side exhaust shim was too big. i went with a 155. it started on the first kick. now it seems to have more engine noise..? kinda sounds like u can hear the chain turning. it's been over two weeks since i ran it and it has been awhile since i started it up in an enclosed space, so i'm not sure if i'm overreacting...i can't remember how the engine sounded before. i'd rather not ride it or give it gas if some engine noise is not normal. if it's not normal what should i check now?

Share this post


Link to post
Share on other sites

Did you put a healthy amount of oil on the cam bearing caps when you installed the cam? Make sure you have re-engaged the cam tentioner (unscrewed the adjuster and let it move out on its own) These engines are quite noisy and from what i have read on TT a lot of people do some work on their bikes and only then do they actually listen for how noisy the motor is. As we cant actually hear the engine its difficult to tell.

Now that you have put the new cam in i personally would put some new oil and a new filter in, and change the oil after the first ride. New cam and motor need to bed in and inevitably there will be a small amount of wear while they seat.

Just my 2cents...

Share this post


Link to post
Share on other sites

yup, i used assembly lube and changed the oil before i started it. that could be what i am hearing.

any more suggestions?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0